LOw Oil Pressure when Ideling

[don04]

I have 145000 (just broke in )and the oil pressure drops to 0 after the truck has warmed up and is ideling... I can speed the idle slightly and it ju\mps to about 10lb running down teh road after it is warmed up it runs around 20lb...

Question 1: Has anyone put in a new oil pump without pulling the moter that the manual recommends .. if so any tricks I need to know ??


Question 2: I replace the sending unit. Should I try a gauge first before the oil Pump? I have not heard if there has been a problem noted with the Oil gauges on these trucks..

Comments appreciated.,..

Don

[GMCTech]

Definitely try a manual guage before you change anything.

I'm guessing that you truly have low oil pressure though.

Does it have the same readings right after an oil change? If so, it is a low pressure situation' if not, you may need to jump up one viscosity level to maintain good pressure.

If you do need to replace the oil pump, you will need to drop the pan down about 12 inches, which will be the same as removal for all intents and purposes.

Hope this helps.

[JoNeZ3]

I have the same problem, 135k and exactly that, it almost touches the red, just lijke you when it "recommended" the egnine pull, I put it behind me.. so i'm glad you're asking

however I just honed my shit and the lip wasn't that bad or anything, when I did put heavier oil after pullin the head, it just got worse

and I have heard it's because people put in heaver oil when it wasn't needed

[Nomlas]

I've had a lot of vehicles over the years. Chevy's all seem to have the "low oil pressure" syndrome. I have a 1988 Chev. S10 Blazer that I bought brand new so, I can tell you what works there.....Several years ago, In summer and, after the engine warms up, if I stop at a stop sign, etc....the oil pressure drops below 10 and check guages light comes on. If I give it just a little gas, oil pressure goes back up to about 12. I started removing the thermostat every summer (I switched from 195 degree to 185 degree) which allows the engine to run cooler (put it back in for winter). I have only used Castrol GTX 10w30 since it was new in '88 (even though 5w30 is what they recommended for the vehicle.) I set the idle speed screw up so with the vehicle in gear, it idles at about 15 on the tach (I set it back down in winter). I change the oil every 6,000 miles and add a slick 50 type oil additive (brand doesn't matter). This solved the problem and the 2.8L engine now has 206,000+ miles on it with no major word.....oh yea...I replaced the radiator some time back. The new one had an extra run of core in it. I found the problem only occured after the engine reached 195 degrees or higher, probably thinning the oil viscosity. Without the thermostat and letting the engine cool down after a hard interstate run, I found the pressure returns to an acceptable level.

[BlazerLT]

I would swap in a new oil sender unit before yanking the engine.

Sending units are known to go on these.

[jzimms]

Where is the sending units on these? I have a 2.8 and it will run at 60-65 going down the road, and drop to 30-40 sitting at a stoplight.

My chilton's manuel does not list the oil sending unit. Thank you.

[BlazerLT]

Originally Posted by jzimms

Where is the sending units on these? I have a 2.8 and it will run at 60-65 going down the road, and drop to 30-40 sitting at a stoplight.

My chilton's manuel does not list the oil sending unit. Thank you.

That is normal, leave it alone.

[jzimms]

Thank you BlazerT. It just concerned me a little because I had never seen this before.

[BlazerLT]

No worries, the oil pump is connected to the distributor so oil pressure is directly related to engine rpms.

Just make sure you use a good 5w30 oil and a non-fram oil filter and you will be fine.

[mthunter]

My hanes manuel said that if you get to low of oil pressure it can cut the fuel to the eng.

At what pressure does it cut the fuel?

[BlazerLT]

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