mattXCoupe

heya people,

just wondering what causes low oil pressure and how much damage it can do to my engine... its a 351C with some basic performance engine work... can give details if helps.... basically, going by the standard XC fairmont oil pressure guage in the dash... when at high revs it only reaches half way (3.5) im unsure of what unit its measured in (psi maybe?), the max on the guage is 7... am i making sence? and when at idle will occasionally drop down to about 2..... this is much lower to what it use to be at....

the oil level is good and has had a service about 3 months ago... should i not be driving it? and what could possibly cause it...

im sure this is fairly basic knowlege, but my car skills have dropped over the last few years...

thanks guys!

matt

ch7472

Matt i run a 387 clevo and at idle i am lucky to have about 10 psi and that is on an liquid auto meter gaue the motor has done about 30 1/4 mile passes and have had no problems to date. And i remember Ray Ward at warlord race engine had thi same thing in his darg car, so i would not realy worry about it.

STROKEXD

Those pressures are typical of a standard oil pump and a clevo in good condition so I wouldn't be too concerned.

Having said that, if you modify your clevo a good idea is 10psi for every 1000rpm, esp when holding at those revs. That's why a high pressure/volume pump should give you 60-80psi.

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ESP

Do what I did,

Screw in a mechanical oil gauge so you can really see your PSI at idle.
If you can get one with a longer than normal extension, it'd be an idea to do a lap of your street to see the pressure under load.

This is how I diagnosed my cactus oil pump

Never trust your Factory Oil Pressure gauge. There are different VDO sender units for the Ford which also show different readings.

Low oil pressure is not good for prolonged periods and there are various problems that can and will arise..............but you need to verify the actual reading first.

@40 psi on HOT idle is OK and @60 - 65 psi when under load HOT

When Cold, it may get @65 - 70 Psi on idle

You will also find that your actual idle will vary the reading you are getting.
Mine idles at @780 RPM and my Hot idle is @40 PSI. If I Hold the idle to 800 - 850 RPM the oil pressure jumps to @50 PSI.

And you need to take your clearances into consideration and your Oil pump. Is a standard volume pump or Hi Volume ????? as this can affect your PSI slightly.

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XE ESP The last of the CLEVO's
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cedric

my xc fairmont coupe does exactly the same but at idle it goes all the way into the red but it only seems to do it when hot. might as well keep driving it as fixing it would take new pump, new cam bearings ,etc and that would be part of total rebuild . when and if theres a problem totally rebuild it

blueprinted

Oil pressures vary due to different bearing clearances as well. Stuffed oil pump or pressure gauge sender. Asstated in an earlier post, fit a manual pressure gauge which is quite simple and see the real pressure. You may not even have a problem.