low oil pressure problem

Sounds like the pump may be slowly loosing pressure. Could also be crankshaft bearings worn but it sounds like the pump.

Brian

is the 75 when cold. I was told that the normal expectation is 10lb per 1000 RPM. How many RPM do you pull at idle? Geoff

"mike" wrote in news:Rik9d.15531$ snipped-for-privacy@fe2.columbus.rr.com:

Sounds like perfectly normal behavior for an engine with more than 30k on it. All the Ford manuals I have seen recommend 10psi/1000RPM.

Those figures all sound quite normal to me. My old '76 runs about 75 cold,

35 hot on the highway and barely off the peg at idle hot. s

I had a 66 F-150 with the 352 engine in it. It ran pressures like this all the time, except I don't remember it being as high as 75. But I do remember it dropping to close to 10 psi. I ran it for like 2 years at this pressure with no problem. I did a rebuild and put a new pump in. Then when I was at idle, it would drop to like 25. But if this happened sudden like, it sounds like the pump, unless you ran it low on oil, then the rod bearings might be suspect.

Right. I think his question should be about the 75 lbs and why it never fluctuated before. Maybe the gauge is bad. Don't worry about it when it's normal. Worry about it when you have low oil pressure.

I would be wondering how come the gauge just started working....

No fluctuation means a broken gauge.

Your pressures sound right for a 'good' engine although the 75 psi cold sounds high.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

mike wrote:

So what's that problem? Sounds like a normal engine. Drive it and forget it. You might want to take the gauge out and put in an idiot light.

R> heres the lowdown. 79 ford van with a 460ci.

I agree, 75 lbs seems high. Normally the relief valve in the pump give up pressure around 50 or so to keep too much oil from being sprayed onto the cylinder walls. There are several questions that need to be answered. First, what viscosity oil are you using? How often do you change your oil and did the oil pressure remain the same with new oil and filter as with well-used oil? At what time of year did the change in pressure take place--summer, winter? The 15-20 psi is normal at idle with warm engine. If you previously had high pressure the likely cause is the oil pump. There are several bearing surfaces which could cause a drop in pressure but the most likely suspect is the cam, with mains a close second. I wouldn't worry too much unless the drop in pressure continues.

Everything is fine and normal for your Ford. No problems with oil pressure. My truck held a constant 80 psi for a long time, then started fluctuating after about 50K miles .. tolerances within the engine where back pressure is created finally loosen up with age and the pressure begins to move around with rpm .. no worries.