Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

hookipa wrote:
I recently moved my boat from New Zealand (cold water) to Tonga (very
warm water) and I am now experiencing very low oil pressure at
operating temperature at idle. The engine is a Volvo Penta AD31B and
I am not sure of the hours on the engine. As the engine has seperate
circuits for the oil warning light and the gauge, I believe that the
problem is not the gauge/sender. At operating speed i get about 50
psi, but at idle it sometimes turns on the warning light. Any
thoughts or checks before I pull the boat and remove the engine to
check the main bearings and oil pump?

By circuits, do you mean separate senders as well?

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

I recently moved my boat from New Zealand (cold water) to Tonga (very
warm water) and I am now experiencing very low oil pressure at
operating temperature at idle. The engine is a Volvo Penta AD31B and
I am not sure of the hours on the engine. As the engine has seperate
circuits for the oil warning light and the gauge, I believe that the
problem is not the gauge/sender. At operating speed i get about 50
psi, but at idle it sometimes turns on the warning light. Any
thoughts or checks before I pull the boat and remove the engine to
check the main bearings and oil pump?

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Oct 24, 9:48 am, hookipa wrote:
I recently moved my boat from New Zealand (cold water) to Tonga (very
warm water) and I am now experiencing very low oil pressure at
operating temperature at idle. ...

I doubt that the problem is the water temperature. As you know lots
of folks make that trip and don't have this problem. I'd change the
oil out for a heavier weight and see if that helps.

-- Tom.

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

hookipa,

A sticking oil pressure relief valve would cause these symptoms.

Dave M.

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Wed, 24 Oct 2007 12:59:25 -0700, "
wrote:

I'd change the
oil out for a heavier weight and see if that helps.

Yes, that was going to be my advice also. HD 40WT would be typical
for an older diesel engine in the tropics. You could also bump up
your idle speed a little

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

Hi

Check the oil pressure relief valve and clean it.

Try a heavier grade of oil, not one of the modern wide range synthetic or
semi synthetics multigrades.

30 or 40grade or possibly a 20/50 I would stick with a mineral oil for an
engine of this age.

Castrol make an oil for older higher mileage vehicles but I expect it is not
available where you are.

Alec


"David L. Martel" wrote in message
...
hookipa,

A sticking oil pressure relief valve would cause these symptoms.

Dave M.

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

You did not say what the pressure is at idle.

Does the guage read when idling? Some manufacturers allow a very low
pressure when hot idling. I will check my engine manual next time I go to
the boat.

50 psi when running seems quite OK.

Alec


"hookipa" wrote in message
ups.com...
I recently moved my boat from New Zealand (cold water) to Tonga (very
warm water) and I am now experiencing very low oil pressure at
operating temperature at idle. The engine is a Volvo Penta AD31B and
I am not sure of the hours on the engine. As the engine has seperate
circuits for the oil warning light and the gauge, I believe that the
problem is not the gauge/sender. At operating speed i get about 50
psi, but at idle it sometimes turns on the warning light. Any
thoughts or checks before I pull the boat and remove the engine to
check the main bearings and oil pump?

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Thu, 25 Oct 2007 11:05:13 +0100, "Alec"
wrote:

....
Try a heavier grade of oil, not one of the modern wide range synthetic or
semi synthetics multigrades.

Alec

I'm not arguing with this general advice. But the sentence I
quoted shows a mindset that may not tie to reality.

A synthetic almost as thin as water when cold, can STILL be thicker
than a thick mineral oil when really hot. Its viscosity vs
temperature slope is that much flatter. That's why they are rated
multi-grade. The synthetic doesn't burn off and has better high
pressure film strength.

Brian W

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

I do not know if you have the manual with you but the manual online at
volvo, states engine hot idle pressure 21 psi and full power hot 60 psi. It
does not say max or min so I assume this is typical.

Oil grade CD 15/40.

Alec


"hookipa" wrote in message
ups.com...
I recently moved my boat from New Zealand (cold water) to Tonga (very
warm water) and I am now experiencing very low oil pressure at
operating temperature at idle. The engine is a Volvo Penta AD31B and
I am not sure of the hours on the engine. As the engine has seperate
circuits for the oil warning light and the gauge, I believe that the
problem is not the gauge/sender. At operating speed i get about 50
psi, but at idle it sometimes turns on the warning light. Any
thoughts or checks before I pull the boat and remove the engine to
check the main bearings and oil pump?

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Oct 25, 8:04 am, Brian Whatcott wrote:
On Thu, 25 Oct 2007 11:05:13 +0100, "Alec"
wrote:

...

Try a heavier grade of oil, not one of the modern wide range synthetic or
semi synthetics multigrades.
Alec

I'm not arguing with this general advice. But the sentence I
quoted shows a mindset that may not tie to reality.

A synthetic almost as thin as water when cold, can STILL be thicker
than a thick mineral oil when really hot. Its viscosity vs
temperature slope is that much flatter. That's why they are rated
multi-grade. The synthetic doesn't burn off and has better high
pressure film strength.

Brian W

Stay away from switching to synthetic on an older engine, they tend to
develop oil leaks.

John

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Thu, 25 Oct 2007 08:55:27 -0700, Capt John
wrote:


Stay away from switching to synthetic on an older engine, they tend to
develop oil leaks.

John

Yep!

Brian W

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Thu, 25 Oct 2007 12:04:53 GMT, Brian Whatcott
wrote:

On Thu, 25 Oct 2007 11:05:13 +0100, "Alec"
wrote:

...
Try a heavier grade of oil, not one of the modern wide range synthetic or
semi synthetics multigrades.

Alec

I'm not arguing with this general advice. But the sentence I
quoted shows a mindset that may not tie to reality.

A synthetic almost as thin as water when cold, can STILL be thicker
than a thick mineral oil when really hot. Its viscosity vs
temperature slope is that much flatter. That's why they are rated
multi-grade. The synthetic doesn't burn off and has better high
pressure film strength.

Brian W


One thing to try before anything else is pull the oil cooler and see
whether it is stopped up. If you have ever broken a water pump
impeller the bits are still probably in the inlet of the oil cooler.

I nearly went crazy trying to solve a similar problem after a fellow
ran aground on a mud bank. Finally discovered the heat exchanger tubes
full of mud after someone told me the boat had been aground and I
noticed there was no inlet strainer.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

Bruce in Bangkok wrote:
I nearly went crazy trying to solve a similar problem after a fellow
ran aground on a mud bank. Finally discovered the heat exchanger tubes
full of mud after someone told me the boat had been aground and I
noticed there was no inlet strainer.

Also the heat exchanger tubes can get slowly clogged with marine buildup
so the engine eventually starts to run hot. The problem seems to just
appear suddenly so its easy to misdiagnose, and can appear in older
engines as a drop in oil pressure due to the higher engine temp. I am
working on an engine now that this has happened to. There are some
commercial products to clean this growth out. I have this heat exchanger
pickling in Rydlyme Marine solution which seems to be working, but I
suspect most of the products are the same.
Red

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Oct 25, 8:45 pm, Brian Whatcott wrote:
On Thu, 25 Oct 2007 08:55:27 -0700, Capt John
wrote:

Stay away from switching to synthetic on an older engine, they tend to
develop oil leaks.

John

Yep!

Brian W

I heard that if you switch and do not switch back you will not have
leaks.

Anyone switch to synthetics and stay switched?

Joe

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Fri, 26 Oct 2007 05:05:53 -0700, Joe
wrote:

I heard that if you switch and do not switch back you will not have
leaks.

Anyone switch to synthetics and stay switched?

I did it with an older sailboat diesel once. It was a disaster. The
engine developed a major oil leak around the main bearing seal in no
time at all. I've never used synthetics since then.

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

"Joe" wrote in message
ups.com...
On Oct 25, 8:45 pm, Brian Whatcott wrote:
On Thu, 25 Oct 2007 08:55:27 -0700, Capt John
wrote:

Stay away from switching to synthetic on an older engine, they tend to
develop oil leaks.

John

Yep!

Brian W

I heard that if you switch and do not switch back you will not have
leaks.

Anyone switch to synthetics and stay switched?

Joe

I've only switched in the cars... no problems at all. According to the local
mechanic, you can mix oil and synth without problems.

--
"j" ganz @@
www.sailnow.com

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Fri, 26 Oct 2007 09:47:29 -0700, "Capt. JG"
wrote:


Anyone switch to synthetics and stay switched?

Joe

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.

I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sat, 27 Oct 2007 00:16:42 GMT, Brian Whatcott
wrote:

On Fri, 26 Oct 2007 09:47:29 -0700, "Capt. JG"
wrote:


Anyone switch to synthetics and stay switched?

Joe

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.

I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK


Not to be picky, but why a mix of synthetic and multigrade?


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sat, 27 Oct 2007 13:08:19 +0700, Bruce in Bangkok
wrote:

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.
-
I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK
-
-
Not to be picky, but why a mix of synthetic and multigrade?

Bruce-in-Bangkok

I once witnessed an extreme pressure oil bench-test.
Basically, a ball bearing is pressed hard onto a rotating shaft
and left to run. With mineral oil, there was soon a good flat.
With synthetic, the ball held in there, much longer.

But then, they cut the synth lubricant with mineral, and
the wear life held up at fair dilutions.

So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.

Finally, the makers started marketing a synth mix, but I do
it myself still - its no trouble to do. (The only precaution I take
is to use both types from the same maker - I chose Castrol)

I have read often enough, that synthetic can be searching in old
engines and unclog them or loosen seals and also that they
may not carry crap as well, and staying runny, the oil can
drain from cylinder walls
so it could be hard on startup, but the improved flow at
startup makes that point moot, I'm guessing.

Brian Whatcott Altus OK

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sat, 27 Oct 2007 13:11:25 GMT, Brian Whatcott
wrote:

On Sat, 27 Oct 2007 13:08:19 +0700, Bruce in Bangkok
wrote:

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.
-
I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK
-
-
Not to be picky, but why a mix of synthetic and multigrade?

Bruce-in-Bangkok

I once witnessed an extreme pressure oil bench-test.
Basically, a ball bearing is pressed hard onto a rotating shaft
and left to run. With mineral oil, there was soon a good flat.
With synthetic, the ball held in there, much longer.

But then, they cut the synth lubricant with mineral, and
the wear life held up at fair dilutions.

So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.

Finally, the makers started marketing a synth mix, but I do
it myself still - its no trouble to do. (The only precaution I take
is to use both types from the same maker - I chose Castrol)

I have read often enough, that synthetic can be searching in old
engines and unclog them or loosen seals and also that they
may not carry crap as well, and staying runny, the oil can
drain from cylinder walls
so it could be hard on startup, but the improved flow at
startup makes that point moot, I'm guessing.

Brian Whatcott Altus OK


Interesting. I had always assumed that synthetic oils were more
durable as they stood up to high temperature better but your test
seems to say that they have a higher lubricity factor.... Or perhaps
it is the resistance to heat. But, for whatever reason it seems that
they provide better lubrication.

So - why not 100% synthetic? Cost?


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Oct 28, 8:07 am, Bruce in Bangkok wrote:
On Sat, 27 Oct 2007 13:11:25 GMT, Brian Whatcott





wrote:
On Sat, 27 Oct 2007 13:08:19 +0700, Bruce in Bangkok
wrote:

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.
-
I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK
-
-
Not to be picky, but why a mix of synthetic and multigrade?

Bruce-in-Bangkok

I once witnessed an extreme pressure oil bench-test.
Basically, a ball bearing is pressed hard onto a rotating shaft
and left to run. With mineral oil, there was soon a good flat.
With synthetic, the ball held in there, much longer.

But then, they cut the synth lubricant with mineral, and
the wear life held up at fair dilutions.

So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.

Finally, the makers started marketing a synth mix, but I do
it myself still - its no trouble to do. (The only precaution I take
is to use both types from the same maker - I chose Castrol)

I have read often enough, that synthetic can be searching in old
engines and unclog them or loosen seals and also that they
may not carry crap as well, and staying runny, the oil can
drain from cylinder walls
so it could be hard on startup, but the improved flow at
startup makes that point moot, I'm guessing.

Brian Whatcott Altus OK

Interesting. I had always assumed that synthetic oils were more
durable as they stood up to high temperature better but your test
seems to say that they have a higher lubricity factor.... Or perhaps
it is the resistance to heat. But, for whatever reason it seems that
they provide better lubrication.

So - why not 100% synthetic? Cost?

Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)- Hide quoted text -

- Show quoted text -

Someone explained to me that the synthetic mocules are all the same
size, like billions of BB's, where as regular oil would be like
billions and billions of BB's all very different sizes. So the load on
Synthetic could be carried easier and more even than regular oil. This
friend has a Cumming's Dodge truck and said he gained almost 10%
better mileage. He said once you switch do not go back or you will get
leak problems, but if you stick with it you will not have any
problems.

Joe

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sun, 28 Oct 2007 20:07:55 +0700, Bruce in Bangkok
wrote:


...why a mix of synthetic and multigrade?

Bruce-in-Bangkok

...
So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.
-
-
So - why not 100% synthetic? Cost?


Bruce-in-Bangkok

Yep, I'm basically cheap. And the crap suspension issue
with mineral oil gives me some comfort.

Brian W

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

"Joe" wrote in message
oups.com...
On Oct 28, 8:07 am, Bruce in Bangkok wrote:
On Sat, 27 Oct 2007 13:11:25 GMT, Brian Whatcott





wrote:
On Sat, 27 Oct 2007 13:08:19 +0700, Bruce in Bangkok
wrote:

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.
-
I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK
-
-
Not to be picky, but why a mix of synthetic and multigrade?

Bruce-in-Bangkok

I once witnessed an extreme pressure oil bench-test.
Basically, a ball bearing is pressed hard onto a rotating shaft
and left to run. With mineral oil, there was soon a good flat.
With synthetic, the ball held in there, much longer.

But then, they cut the synth lubricant with mineral, and
the wear life held up at fair dilutions.

So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.

Finally, the makers started marketing a synth mix, but I do
it myself still - its no trouble to do. (The only precaution I take
is to use both types from the same maker - I chose Castrol)

I have read often enough, that synthetic can be searching in old
engines and unclog them or loosen seals and also that they
may not carry crap as well, and staying runny, the oil can
drain from cylinder walls
so it could be hard on startup, but the improved flow at
startup makes that point moot, I'm guessing.

Brian Whatcott Altus OK

Interesting. I had always assumed that synthetic oils were more
durable as they stood up to high temperature better but your test
seems to say that they have a higher lubricity factor.... Or perhaps
it is the resistance to heat. But, for whatever reason it seems that
they provide better lubrication.

So - why not 100% synthetic? Cost?

Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)- Hide quoted text -

- Show quoted text -

Someone explained to me that the synthetic mocules are all the same
size, like billions of BB's, where as regular oil would be like
billions and billions of BB's all very different sizes. So the load on
Synthetic could be carried easier and more even than regular oil. This
friend has a Cumming's Dodge truck and said he gained almost 10%
better mileage. He said once you switch do not go back or you will get
leak problems, but if you stick with it you will not have any
problems.

Joe



Well, now we've heard all the ways... leaks if you switch to synch, leaks if
you switch back to regular oil, not effective if you combine them. I've done
all three with older car engines with no problems.


--
"j" ganz @@
www.sailnow.com

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

Thanks to all for the suggestions. I pulled the oil cooler and the
oil pressure valves this weekend and all looks good. The Oil cooler
tubes are almost scary clean. I did change the oil, but the only oil
I can get here is a 15w-40 for diesels from BP. Believe it or not,
that or a 20w-50 is all that I can get here. I am getting about 10-15
psi at idle and about 50 psi at max speed. My manual says that I have
seperate senders for the warning light and the gauge. The time the
pressure really dropped off and the light came on was right after
pushing the engine hard for a while (on plane). After I change the
oil and checked the cooler and such, I cruised around for an hour or
so and the pressure never went below 15 psi.

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sun, 28 Oct 2007 13:10:50 -0700, hookipa
wrote:

Thanks to all for the suggestions. I pulled the oil cooler and the
oil pressure valves this weekend and all looks good. The Oil cooler
tubes are almost scary clean. I did change the oil, but the only oil
I can get here is a 15w-40 for diesels from BP. Believe it or not,
that or a 20w-50 is all that I can get here. I am getting about 10-15
psi at idle and about 50 psi at max speed. My manual says that I have
seperate senders for the warning light and the gauge. The time the
pressure really dropped off and the light came on was right after
pushing the engine hard for a while (on plane). After I change the
oil and checked the cooler and such, I cruised around for an hour or
so and the pressure never went below 15 psi.

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sun, 28 Oct 2007 06:43:35 -0700, Joe
wrote:

On Oct 28, 8:07 am, Bruce in Bangkok wrote:
On Sat, 27 Oct 2007 13:11:25 GMT, Brian Whatcott





wrote:
On Sat, 27 Oct 2007 13:08:19 +0700, Bruce in Bangkok
wrote:

I've only switched in the cars... no problems at all.
According to the local
mechanic, you can mix oil and synth without problems.
-
I've used one quart of Castrol synthetic to 3 quarts of Castrol
mutigrade changed each 4000 mile interval since new,
for over 300 k miles on two festivas, where the engines
work for a living.

Brian Whatcott Altus OK
-
-
Not to be picky, but why a mix of synthetic and multigrade?

Bruce-in-Bangkok

I once witnessed an extreme pressure oil bench-test.
Basically, a ball bearing is pressed hard onto a rotating shaft
and left to run. With mineral oil, there was soon a good flat.
With synthetic, the ball held in there, much longer.

But then, they cut the synth lubricant with mineral, and
the wear life held up at fair dilutions.

So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.

Finally, the makers started marketing a synth mix, but I do
it myself still - its no trouble to do. (The only precaution I take
is to use both types from the same maker - I chose Castrol)

I have read often enough, that synthetic can be searching in old
engines and unclog them or loosen seals and also that they
may not carry crap as well, and staying runny, the oil can
drain from cylinder walls
so it could be hard on startup, but the improved flow at
startup makes that point moot, I'm guessing.

Brian Whatcott Altus OK

Interesting. I had always assumed that synthetic oils were more
durable as they stood up to high temperature better but your test
seems to say that they have a higher lubricity factor.... Or perhaps
it is the resistance to heat. But, for whatever reason it seems that
they provide better lubrication.

So - why not 100% synthetic? Cost?

Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)- Hide quoted text -

- Show quoted text -

Someone explained to me that the synthetic mocules are all the same
size, like billions of BB's, where as regular oil would be like
billions and billions of BB's all very different sizes. So the load on
Synthetic could be carried easier and more even than regular oil. This
friend has a Cumming's Dodge truck and said he gained almost 10%
better mileage. He said once you switch do not go back or you will get
leak problems, but if you stick with it you will not have any
problems.

Joe


That sounds logical as regular oil is actually a mixture and the
viscosity is measured by how fast it flows. You could have a mix of
100 wt. and gasoline that would be rated at 10 wt., for example.

The Synthetic, being man made would undoubtedly be a more constant
molecular size.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Sun, 28 Oct 2007 12:22:02 -0600, Brian Whatcott
wrote:

On Sun, 28 Oct 2007 20:07:55 +0700, Bruce in Bangkok
wrote:


...why a mix of synthetic and multigrade?

Bruce-in-Bangkok

...
So, in view of the cost difference, and knowing they are
designed to be completely miscible, I used the 1:4 cut.
-
-
So - why not 100% synthetic? Cost?


Bruce-in-Bangkok

Yep, I'm basically cheap. And the crap suspension issue
with mineral oil gives me some comfort.

Brian W


Do you mean that synthetic does not hold the gunk in suspension as
well as mineral oil? Probably not the oil for my old diesel pickup
then.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Mon, 29 Oct 2007 09:17:38 +0700, Bruce in Bangkok
wrote:


Do you mean that synthetic does not hold the gunk in suspension as
well as mineral oil? Probably not the oil for my old diesel pickup
then.


Bruce-in-Bangkok

That's what I meant - but it's little more than hearsay. I don't have
solid evidence for the difference.

Brian Whatcott Altus OK

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.

I am with you on the gauge and warning lights being correct. There is
actually seperate senders for both. I was looking to get a mechanical
gauge sent out here, but I am in no rush to do that right now.

I must admit that I never looked at the oil side of the cooler (stupid
move). I was focused on the water side as a friend had 50% of his
tubes clogged. I guess I hoped my cooler looked like his, so I
blanked out on looking at the oil side when I sas it was so clean.
Now if the oil side was gummed up wouldn't my pressure be higher? Or,
would the cooler just get bypassed and overheat the oil?

There are two pressure relief circuits for this engine according to
the manual, one is for piston cooling oil and the other for engine
cooling oil.

If the washer raises the oil pressure, should I leave it there until I
can get parts? Or, do I need the parts right away if the pressure is
acceptable?

Kurt

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

On Mon, 29 Oct 2007 01:35:46 -0700, hookipa
wrote:

The viscosity numbers mean that when the oil is cold it will flow as
well as 15 weight and when hot won't be any thinner then 50 weight. I
would doubt that is your problem.

You mention that "the pressure dropped off and the light came on"
which implies that both the gage and warning light circuits are
working correctly.

When you say that the oil cooler tubes are "almost scary clean" what
does that mean? The oil side should be full of nasty old engine oil,
it is, isn't it?

You say that you checked the oil pressure valves - plural? If you can
get at the oil pressure relief valve try sticking a washer behind the
spring and see whether that raises either the idle or full throttle
pressure. If it does then either the pump is worn or the spring in the
pressure relief valve is getting weak.

I am with you on the gauge and warning lights being correct. There is
actually seperate senders for both. I was looking to get a mechanical
gauge sent out here, but I am in no rush to do that right now.

I must admit that I never looked at the oil side of the cooler (stupid
move). I was focused on the water side as a friend had 50% of his
tubes clogged. I guess I hoped my cooler looked like his, so I
blanked out on looking at the oil side when I sas it was so clean.
Now if the oil side was gummed up wouldn't my pressure be higher? Or,
would the cooler just get bypassed and overheat the oil?

There are two pressure relief circuits for this engine according to
the manual, one is for piston cooling oil and the other for engine
cooling oil.

If the washer raises the oil pressure, should I leave it there until I
can get parts? Or, do I need the parts right away if the pressure is
acceptable?

Kurt
Probably if the oil side was gunked up the pressure would be higher as
the oil cooler is usually between the pump and the engine.

Frankly, the engine will probably not blow up just because the oil
pressure is a bit low. I think someone said that idle oil pressure was
about 20 psi and you have nearly that.

I have no experience with your engine but usually there is a single
pressure relief valve located at the pump outlet, but if you have two,
and they are accessible I'd put a washer behind the spring on both and
see what happens. If the pressure is in the ballpark and oil
consumption does not go up then I'd leave it alone - at least for now.


Bruce-in-Bangkok
(Note:displayed e-mail
address is a spam trap)

Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

Bruce in Bangkok wrote:


I have no experience with your engine but usually there is a single
pressure relief valve located at the pump outlet, but if you have two,
and they are accessible I'd put a washer behind the spring on both and
see what happens.

He says his motor develops something like 50PSI at higher rpms, so it
doesn't sound like the pressure relief valve(s). Maybe the pump is
worn, perhaps the main bearings are going, perhaps the ambient
temperatures are higher than he's used to and that's thinning the oil
some,,, maybe a bit of all of the above?



If the pressure is in the ballpark and oil
consumption does not go up then I'd leave it alone - at least for now.


Fair enough.

Cheers
Marty
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Low Oil Pressure at Idle, Volvo AD31B in the Tropics
 

Thanks for all the replies. I am believing that it all comes down to
an old worn engine. The manual I found states 31-42 psi at idle, so
at 15 psi I am pretty low. 59-71 psi at speed. Not quite as low
there. I am hoping to be able to get at the oil pump with out pulling
the motor. Now, if the rain would just stop I could get to work.
cheers all,
Kurt