Oil Pressure Reading

[VisionIsle]

I am running a AQ240A/280 Volvo. My Oil pressure varies between 70 at startup to 40 at idel in gear. It recently dropped to just below 20 after running her for 25 min at 3800 RPM. I have searched these posts and my manual for the correct range of oil pressure to no avail. Does anyone know what is concidered too Low or too High pressure? What number should I be concerned with?

Thanks,

 

[bruceb58]

Re: Oil Pressure Reading

I am running a AQ240A/280 Volvo. My Oil pressure varies between 70 at startup to 40 at idel in gear. It recently dropped to just below 20 after running her for 25 min at 3800 RPM. I have searched these posts and my manual for the correct range of oil pressure to no avail. Does anyone know what is concidered too Low or too High pressure? What number should I be concerned with?

Thanks,

Sounds pretty normal. What type of oil are you using?

I have found that when running synthetic oil, the oil pressure drop off at idle on a warm engine is a lot less than with non-synthetic oil.

 

[VisionIsle]

Re: Oil Pressure Reading

Im running SAE 30 but just recently switched back to 10W30 (what Ive been runnning all last year) The readings I mentioned are from SAE30.

 

[Gary H NC]

Re: Oil Pressure Reading

20 to 25 at idle with the engine warmed up sounds pretty normal...

 

[bruceb58]

Re: Oil Pressure Reading

I wouldn't use 10W30. Try using 15w50 Mobil 1 synthetic.

When I used to use straight 30W, I would get the numbers you are getting. After switching to synthetic, my idle oil pressure does not drop below 40.

 

[f_inscreenname]

Re: Oil Pressure Reading

From what I hear a motor only needs 7 to 10 lbs of oil pressure at idle. Not that I would be happy with that but yours seem fine where you are at.

 

[Coors]

Re: Oil Pressure Reading

yep, 10 lbs per each thousand rpm. I put delo400 15/40 in my new jasper- get 50 lbs at idle, 70 at 3400 rpm.

 

[Don S]

Re: Oil Pressure Reading

Here are the specs for your engine right out of the manual. The specs on the right are for the AQ240 (351 Ford), the left is the 190 (302 Ford), center is both.
The one thing I would do is temporairly install a mechanical gauge to verify the sender or gauge isn't acting up.

 

[VisionIsle]

Re: Oil Pressure Reading

Thank you for your input, Ill be sure to put the information in my notes.

Carden

 

[AZ_Ron]

Re: Oil Pressure Reading

Speaking of oils...
What are the opinions of you guys on changing an older engine over to synthetic? The boat we just bought is a 1972, but the engine has been gone through in the past few years.
Engine is a Ford/Volvo 302ci.

Thanks!!!

 

[Coors]

Re: Oil Pressure Reading

My understanding is that the syn will leak threw a questionable seal before straight oil will. But if you change back, then no problems. If it was in my truck, with a newer engine, I would try it. But not in a boat, involvlng pulling the engine ? Dunno. Never used it except in my tractor-no leaks, and 4 years old, when I first used syn.

 

[Silvertip]

Re: Oil Pressure Reading

A rule of thumb for GM engines is 10 psi/1000 RPM. 5000 RPM = 50 PSI. I agree though that most engines with proper oil viscosity should not be below 20 PSI at idle. My 4.3 in my pickup, even after towing at freeway speeds for hundreds of miles does not drop below 35 psi at idle using Mobil 1 synthetic. But granted, its not running at 3800+ either.