Oil pressure gauge

[roknjock2]

hey so i have a 1982 chevy el camino with a rebuilt 350 and no computer...so my oil pressure gauge is stuck on full well past full but it doesnt move ...car on or car off...the wiring is pluged into the pressure sender thing ha and a friend said that if that thing goes out it should stay on 0 psi so idk what it to do...

[534BC]

generally an open is 0 and a short is full. Look for the wire,sending unit,gage to be shorted. I'd look at the sending unit first and check it with an ohmmeter.

[roknjock2]

i just bought a new mechanical gauge and routed the tube to where the oil pressure switch was it works good just when its hot and ive been drivin for a bit and i stop the pressure is really low but the temp doesnt go up....is that normal or is it the gauge

[534BC]

Your new gauge sounds good, it is normal for oil press to be lower when hot and idling.

[roknjock2]

thanks man

[roknjock2]

well it was really low like at 7 psi

[534BC]

That's very low, but not uncommon with rebuilt engines. All is well if increasing rpm a slight amount brings the pressure right up quickly.

[roknjock2]

k ..ya if i touch the gas it goes up quick...so im goin to increase the idle speed ...thanks

[oldblu65]

What weight engine oil are you using ? You could go with a thicker weight oil ( for example - from a 10w30 to 20w50 ) blend .That would help bring the oil pressure up.

[roknjock2]

I've been driving it around and there seems to be no problem but it just bothers me...should I do anything and well the engine be fine
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[RahX]

Are you using nylon or copper for the line? If it is nylon you should look into getting copper for the gauge. The copper can put up with more crap. I've had several experiences with the nylon where it gets kinked and starts leaking. You should also bleed as much air out of the line up to the gauge as possible since the gauge reads oil pressure and not air pressure which could be why you are getting an inaccurate reading. when you bleed it make sure you take extra precautions to not make a giant mess in your car as it shouldn't take much

[MagicRat]

Good posts so far. The rule of thumb is 10 psi for every 1000 rpm. So 7 psi at idle is okay, but minimal. I think going with heavier oil is a good idea. I like 10W40 for engines with low pressure.

Also, in my experience, bleeding the air out of the nylon tube won't work. Most oil in the tube will drain out when the engine is switched off. Also, the air in the tube will not affect accuracy, but make the gauge react slightly slower... but likely not enough to be noticable.