Hi, I own a 1989 chevrolet s10 tahoe blazer 4wd. My oil pressure gage reports a low lever oil pressure after the engine is warm. What could cause this ?

 

How low? say 1/8th inch above the red line? If so thats normal. these engines only need 6-8 psi at ever 1k rpm.

 

Hi chris015, it goes down to 0 (zero)

 

oh. ouch.Do you have the 4.3 or 2.8?

First thing to do is,check oil (duh,but u would be surprised on who doesnt)
Get a mechanical gauge. Replace the oil sending sensor with it and see what the real pressure is. Sometimes the gauge or sensor can go bad resulting in this. If pressure is still 0,its time to replace the engine. You could try the oil pump,but chances are the engines just tired.

 

I have the 2.8, from April 1995, nice truck !! I noted that sometimes, when the spark plugs or the spark plugs wires are bad, the oil pressure goes down after engine warm, given to a poor electricity condition inside the engine. But now I checked with a multimeter the spark plugs and wires and are ok.

 

I don't think the ignition system would have anything to do with your oil pressure. If the oil pump is good, then the low pressure is a result of excessive clearances, i.e. worn out bearings. A new oil pump, or even thicker oil might help the problem. Assuming the sending unit or gauge is working properly.

 

he is correct. the electrical (spark) has nothing to do with the sending unit as long as your alternator and battery is good.

sounds like you need a new engine. Test pressure using a mechanical gauge first.

 

Ok, I will check it with a mechanical gauge.
Thanks