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#1
posted to rec.boats.cruising
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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? |
#2
posted to rec.boats.cruising
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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. |
#3
posted to rec.boats.cruising
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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 |
#4
posted to rec.boats.cruising
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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? |
#5
posted to rec.boats.cruising
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Low Oil Pressure at Idle, Volvo AD31B in the Tropics
hookipa,
A sticking oil pressure relief valve would cause these symptoms. Dave M. |
#6
posted to rec.boats.cruising
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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. |
#7
posted to rec.boats.cruising
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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 |
#8
posted to rec.boats.cruising
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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 |
#9
posted to rec.boats.cruising
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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 |
#10
posted to rec.boats.cruising
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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) |
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