oil pressure at idle speed

[zaza]

Hello,

The engine of the 2.2 I just bought runs well without any bad noise or any fumes. BTW, my oil pressure is really low at idle speed (850 rpm), the pointer is between 0-20 psi. This is when engine is hot, 180 °F ...

At 2600 rpm, the oil pressure is then at 60-70 psi.

I would like to know if these values are acceptable for a never rebuild 35 years old engine or they mean that engine NEEDS rebuilding

Thank you

[gruen911]

Hi Zaza,
An oil pressure reading below 20 at idle when warm is normal and not uncommon. An oil pressure reading of 60-70 at 2,500 rev's seems a little on the high side. I have read in numerous manuals that 60psi at around 4k rev's is good rule of thumb, although my engine shows around 75psi at 4k. Readings on the higher side are not necessarily a bad thing, but really high oil pressure is. What is your oil pressure at 5k rev's? If it is not thru the roof, your gauge is probably a little off and should not be anything to worry about. Notwithstanding the above, an oil pressure gauge reading should not be used as the primary basis for determining whether or not your engine needs a rebuild. They can be pretty sensitive, and are easily disturbed. I have spent alot of money over the years on rebuilding calibrating my gauges. Nonetheless, because the technology back then was pretty basic, there is going to be some margin for error. However, they are certainly good enough indicators for getting an idea of whether you have a potential problem with your engines temperature or oil pressure.
Most direct way to find out the condition of your engine is to take it to a mechanic and have both compression and leakdown tests done. The mechanic you take it to should be someone who you know well and trust.
A decent engine will have compression numbers by cylinder all within a range of around 15% or less of each other. Leakdown should be at or under in the range of around 7%.
If you do not know or trust the mechanic doing the testing, and he tells you that your numbers are bad and you need a rebuild, by all means take it to another mechanic and have the same tests done. Do not tell the second mechanic about the previous test. When you get the results, compare for yourself.
It is self serving for a mechanic to tell you that you have a bad engine since he is virtually guaranteeing himself a paycheck to himself of over $5k if he does engine work for you. Since it's close to Christmas, a bad mechanic will be even more tempted to create new business in order to buy his family presents.
Good luck

[Mr9146]

If your 2.2 is making that kind of pressure at 2,500 RPMs you may have a 3.0-liter oil pump. Mine does because I do.

Also, your idling pressure when warm is 100% normal.