Not in the blazer, but in an S-10 pick-up. The 91 S-10 Imm driving now has 206,000. miles on it. The oil pressure gauge is showing low oil pressure, 10-20 psi when cold. When hot 5-10 psi. With this milage should I replace the oil pump? Also, should the timing gears and chain be replaced at this time. This engine is tight, no oil leaks, dosent burn any oil between changes.

 

If it's not dripping, or burning oil, an still running good, I don't know if I'd be alarmed about the gauge.

I'm not sure they need lots of pressure anyway, but the pump sounds like the right move.

I've got a 92 S-10 4.3 with 186k, Cold it's pegged, Hot it's 20 @ idle, then gas it and it pegs it again.

When I had it tuned last, the service guy told me it only had 4 degree slop in the timing chain, said not to worry about just yet.

It don't burn any either, but I sure hope it makes it to 206k, lol.

Good Luck.

 

If it were my truck, I would replace teh oil pressure switch first. After 209,000 miles there is bound to be some sludge built up on the sensor. Besides the replacing the oil pump is not quick and if you have a 4x4 requires either lifting the engine or removing teh front driveshaft.

 

It should have 8-10 psi for every 1000 rpms

 

I would consider your pressure to be at the bottom of the acceptable idle range. Have a mechanic (or yourself) hook a mechanical gauge to the pressure sending port and see if the readings you have are due to the factorysending unitor the pump itself.

 

I would add a quart of Lucas at every oil change & run it. Run like 20-50 wt oils or a 50 weight racing oil. 4.3 is a 350 with 2 cylinders dropped, I have seen small block chevy run with little pressure, when the lifters start to make noise on a regular basis then it is time to replace. I doubt an oil pump will do much with that mileage. I have a Lumina with a 3.1 V6 with 236,000 miles on it. All it has are idiot lights thank God. But it runs great.

 

Dang, fuel pump went out this morning.[sm=smiley19.gif]