Low oil pressure question.

[jp0863]

my m1009 has about 80,000 on the ticker. since shortly after i bought it,i installed an oil pressure gauge instead of relying on the idiot light. when the engine is cool the oil pressure is around 40psi. after it warms up, or after i turn it off and restart it after driving a bit, the oil press drops to 5-15 psi depending on how much i have driven. i use chevron delo 400 15/30... anyone have any ideas on why this is? or what i can do about it? or if i should just leave it alone? thanks.

 

[devilman96]

STOP DRIVING IT... 5-15 psi is to low for an engine to be properly lubercated.

Assuming your oil and filter are within their life span... Get a second gauge to verify the PSI, mechanical gauges do fail... If the PSI is that low it is critical you change the oil pump before you smoke the engine.... Its a few $ and some time but a gauge and a pump will cost ya far less than an engine.

 

[jp0863]

i should have mentioned i have a new pump in it. thinking that was the problem i changed it. the opinions i have so far from local shops is: one says main bearings... one says down to 5 psi is within range for the 6.2 (this came from a military mechanic that works on m1009/m1008's all the time, but did say it was the lowest he has seen). without yanking the motor is there anyway to know where the problem lies?

 

[clinto]

without yanking the motor is there anyway to know where the problem lies?

Well, not really. You could pull a main cap and see where it is via plastigauge. I know some folks who have gotten lucky and just put main and rod bearings in tired engines that had excessive clearances and gotten some more life out of them. But it's a gamble, albeit a cheap one.

I have to say, in my humble opinion, 5 psi is too low. I have read that the minimum pressure required to keep the hydrodynamic wedge between the crank and the bearing(s) can be as low as 3 psi, but I still say that 5 is too low. if it were me, I'd try and throw a set of bearings in it and if it doesn't come up to maybe 15 psi at idle, start looking for a replacement or planning to rebuild it.