Oil Pressure need help!

[tipp98-sean]

hey everyone i just bought a 1995 jimmy the guy told me when he sold it to me his mechanic said it needed a new oil pump.
the problem with the truck is the oil gauge read 40 after a 2 mile drive it goes down to zero if i sit a red light and i have to accelarte to boost it up but it still doesnt go that high up, maby 20. if i let the truck sit for about 5 minutes and start it again it starts at 40 and does the same thing. i heard from a freind of mine that i might that somthing might be clogged and if i flushed some kerosine through it it might fix the problem i have already changed the oil and oil filter and that has not changed anything.
so before i tear this truck apart to replace the oil pump i was hoping i could get some advice .
thanks,
sean

[MT-2500]

Originally Posted by tipp98-sean

hey everyone i just bought a 1995 jimmy the guy told me when he sold it to me his mechanic said it needed a new oil pump.
the problem with the truck is the oil gauge read 40 after a 2 mile drive it goes down to zero if i sit a red light and i have to accelarte to boost it up but it still doesnt go that high up, maby 20. if i let the truck sit for about 5 minutes and start it again it starts at 40 and does the same thing. i heard from a freind of mine that i might that somthing might be clogged and if i flushed some kerosine through it it might fix the problem i have already changed the oil and oil filter and that has not changed anything.
so before i tear this truck apart to replace the oil pump i was hoping i could get some advice .
thanks,
sean

Flushing a high mileage engine is a No No.
May make things more bad.

First thing is to get a manual oil pressure test gauge on it and see what the real oil pressure is.
Post back reading with a manual gauge.
MT

[MT-2500]

A note of caution here.
If you can head the valve lifters or rod and main bearing making noise do not drive or run the engine.
If no noise get that manual oil gauge on it.
It may only be a bad oil sending unit.
Never trust a electrical oil pressure gauge.
MT

[tipp98-sean]

nope the gauge is right on thats the first thing we tired with the maual guage im postive the sending unit is ok. i havent driven it since the problem because after a few rides we were sitting at a red light and when the gauge dropped down to just about 0 it started knockin im sure the guy before me was driving with the low oil pressure for a while so the engine cant be all that pretty it has 211 thousand miles on it to begin with but im just lookin for somthin to get be to school n back

[534BC]

A new pump may fix it, a hv pump will fix it better, but if the pump is bad and has the same miles then the low oilpressure may be from a well,worn out engine also.

In otherwords, I think the mechanic may be right, but I'd question whether or not to put a pump on a engine that is nearly worn out.

[Chris Stewart]

Since the weather is warming up, you might try going to 10W-40 oil...good stuff like Valvoline and use the stock AC-Delco PF-52 oil filter.

[ericn1300]

Originally Posted by 534BC

A new pump may fix it, a hv pump will fix it better, but if the pump is bad and has the same miles then the low oilpressure may be from a well,worn out engine also.

In otherwords, I think the mechanic may be right, but I'd question whether or not to put a pump on a engine that is nearly worn out.

worn out? if it's a 4.3 it's good for over 300k usualy, I bought mine with over 180k expecting to keep it for seven to ten years. oil pumps are cheap and easy to do on the 4x4 models. on the 4x2 you have to remove the engine though. and i wouldn't go with a high volume pump in an engine that old, it got along fine this far with the stock one.

[blazes9395]

If you are getting knocking while idling, its not a good idea to keep driving it this way. This could be a stuck pressure relief valve, loose/damaged/clogged oil pick-up tube. Sounds like when the oil warms up it thins, and because of this, you get you low oil pressure.

For this I would change the oil pump out ASAP, clean it up inside(oil pan, etc, etc), and you might be alright. Either way don't drive it with low oil pressure, you just destroying it.

[tipp98-sean]

Originally Posted by blazes9395

If you are getting knocking while idling, its not a good idea to keep driving it this way. This could be a stuck pressure relief valve, loose/damaged/clogged oil pick-up tube. Sounds like when the oil warms up it thins, and because of this, you get you low oil pressure.

For this I would change the oil pump out ASAP, clean it up inside(oil pan, etc, etc), and you might be alright. Either way don't drive it with low oil pressure, you just destroying it.

thats the advice i got from all the mechanics i asked i think were gonna just tear it all apart clean everything out n put a new pump