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.

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

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

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

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

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.

"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

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

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)

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