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KAMD-42 Low oil pressure

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colsum

New member
My son has just replaced his original volvo with a used KAMD-42 that has around 2900 hours. The engine has been checked over, oil, filters etc all been changed. The engine starts and runs well had initially has an oil pressure of about 65 psi when under power. However after 10-15 minutes the oil pressure gradually drops to around 35 psi and then if you go back to idle the pressure drops back to virtually nothing and sometimes the oil pressure warning comes on. If you stay in idle for several minutes and then throttle up the pressure comes up to near normal and then slowly decreases. We are told the correct 15w-40 oil has been fitted. The engine runs at normal temperature around 85 deg with no overheating. Any suggestions, thoughts would be appreciated.
 
colsum said:
My son has just replaced his original volvo with a used KAMD-42 that has around 2900 hours. The engine has been checked over, oil, filters etc all been changed. The engine starts and runs well had initially has an oil pressure of about 65 psi when under power. However after 10-15 minutes the oil pressure gradually drops to around 35 psi and then if you go back to idle the pressure drops back to virtually nothing and sometimes the oil pressure warning comes on. If you stay in idle for several minutes and then throttle up the pressure comes up to near normal and then slowly decreases. We are told the correct 15w-40 oil has been fitted. The engine runs at normal temperature around 85 deg with no overheating. Any suggestions, thoughts would be appreciated.
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Run a manual gauge in parallel with the stock sending unit and compare readings. hopefully it is the sending unit or possibly an electrical issue such as a bad ground or charging issue. See many of those engines with more hours and no oil psi problems. Most of the time we see oil psi under way at about 80 psi.
 
As above, check the pressure with a manual gauge before doing anything else. The oil pressure warning light coming on is a worry though. You need to check, but a lot of that vintage Volvos have a separate pressure switch for the alarm and don't use the reading from the oil pressure sender that powers the gauge.
Just saw that you are in Whangarei. There is a guy in Auckland that is a great source for parts (new or used) and advice. John at North Harbour Imports. He more or less spe******es in that vintage of Volvos.

When you drop back to idle the oil is initially hot and gives low pressure, then it cools and the pressure comes back up. When you go back up to higher rpms the oil heats up more and the pressure will drop again. That can be the oil pressure relief valve getting tired or sometimes a little stuck, or it can be wear in the bearings etc. I am thinking that engine will probably have an oil pressure alarm switch separate to the sender, and if so you may actually have an oil pressure issue. Not sure how those engines cool their oil, but if it is sea water cooled rather than internal with coolant I would strip the cooler and check it.
 
guppy said:
Run a manual gauge in parallel with the stock sending unit and compare readings. hopefully it is the sending unit or possibly an electrical issue such as a bad ground or charging issue. See many of those engines with more hours and no oil psi problems. Most of the time we see oil psi under way at about 80 psi.
Click to expand...

Thanks for your reply. We considered that maybe it was an electrical issue however looking at the circuit, the sender unit and oil pressure gauge system are totally independent of the low oil pressure alarm circuit. The fact that the low oil pressure alarm activates when the oil pressure gauge indicates next to no pressure when at idle indicates to us that the oil pressure is probably low. Oil pressure starts of at around 65- 70 psi but just gradually drops off as the engine heats through. Engine has plenty of power with no abnormal noise. Thought perhaps we should change the oil and see if that helps.
 
aliboy said:
As above, check the pressure with a manual gauge before doing anything else. The oil pressure warning light coming on is a worry though. You need to check, but a lot of that vintage Volvos have a separate pressure switch for the alarm and don't use the reading from the oil pressure sender that powers the gauge.
Just saw that you are in Whangarei. There is a guy in Auckland that is a great source for parts (new or used) and advice. John at North Harbour Imports. He more or less spe******es in that vintage of Volvos.

When you drop back to idle the oil is initially hot and gives low pressure, then it cools and the pressure comes back up. When you go back up to higher rpms the oil heats up more and the pressure will drop again. That can be the oil pressure relief valve getting tired or sometimes a little stuck, or it can be wear in the bearings etc. I am thinking that engine will probably have an oil pressure alarm switch separate to the sender, and if so you may actually have an oil pressure issue. Not sure how those engines cool their oil, but if it is sea water cooled rather than internal with coolant I would strip the cooler and check it.
Click to expand...

Thanks for your input. I agree with your comments about John. As in my previous post the two oil pressure circuits are seperate. The oil cooler is on the raw water circuit so my thinking was that if the engine is not showing any signs of overheating then one would think the oil cooler would be ok but maybe I am overlooking something here.
 
colsum said:
Thanks for your reply. We considered that maybe it was an electrical issue however looking at the circuit, the sender unit and oil pressure gauge system are totally independent of the low oil pressure alarm circuit. The fact that the low oil pressure alarm activates when the oil pressure gauge indicates next to no pressure when at idle indicates to us that the oil pressure is probably low. Oil pressure starts of at around 65- 70 psi but just gradually drops off as the engine heats through. Engine has plenty of power with no abnormal noise. Thought perhaps we should change the oil and see if that helps.
Click to expand...
hi!
Did you manage to solve the problem? I have the same situation and cant find the problem. Even changed the complet oil filter house.
 
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