Hey guys and gals. I just recently bought an 02 ls blazer 4x4 and the oil pressure says its low. We've checked the oil and all that and its fine. Last night I replaced my oil sending unit, as fun as that was, it did not fix the problem. Any ideas? I started to think its a faulty gauge but I dont know how to be sure and im out of ideas right now.

 

Did this develop suddenly or gradually? Any performance or noise issues?

The best thing to do is verify the actual oil pressure with a known good sender and gauge.


George
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I've only had the car for less than a week. So I'm unsure how long its done this. But ill have someone with a mechanics gauge check it out. Thank you.

 

What is telling you the oil pressure is low? Is it just the oil pressure gauge or is there an OIL light on?

A mechanical oil pressure gauge does not cost much....and it is not going to be fun to connect it....goes same place as the electrical oil pressure sender that you just replaced. Be best if you could put in a "T" to have both connected so you could compare readings.

Fun times ahead!!

 

Worn out rod bearing cause's low oil pressure...It happen to me once

 

As does worn-out main bearings. But the 4.3L engine is usually good to over 200k miles....dependent upon how maintenance has been done.

 

There are multiple causes for a low oil pressure indication. If the low reading is verified through proper testing then of course the cause must be determined: bearings, oil viscosity, oil pump, oil pump pick up, oil filter/bypass, etc. I encourage the OP to confirm the pressure reading first because most of the causes if verified are serious to address and chasing those ghosts would be a shame if there is say a wiring harness corrosion problem from the sending unit .

George

 

I put synthetic in a few months ago and the pressure needle stays past the mid-mark, like 1 O'Clock. I'm pretty sure the old oil was 11 O'clock.
Edit: though I saw today the needle dropped to 11:00 when I was idling.