Oil pressure problem.
 

Well i just bought this 2000 Blazer 4x4 2 days ago and im noticing the oil pressure is lower than my s10 and sonoma were. on cold start-up its stays at about 42psi. once its warm idle stays around 15psi and when i give it gas around 24psi.

My problem is today after going up some hills and then down some hills, when i would stop and idle it would idle at like 2psi and the check gauges light would come on, immediatly i would give it gas and it would jump back up to 24psi. when it was idling with the 2psi i did not hear any knock what so ever. truck has 169k on it and its from utah. the guy I bought it from had just rebuild the whole front end suspention, and only thing he did to the motor was a valve job, mech said engine sounds to healthy to have a oil pressure that low. I asked the owner what oil he was using and he said hes been using conventional 5-30w the whole life of the truck.

My question is, what could cause this. Is it the oil pressure sending sensor? Bearings? Oil Pump? I do have a slight oil leak but oil is full. Im Broke and dont have much money to put into this truck.


IDLE!!

https://blazerforum.com/forum/attach...ine=1360873168


RUNNING!!


https://blazerforum.com/forum/attach...ine=1360873168
http://i193.photobucket.com/albums/z...ps402a2190.jpg

Start with the sensor.

Cruising on the highway taking pics? LOL

Anyway, it's usually a sign the engine is getting tired, bearings wearing out letting more oil past than the pump can supply. Might be worth putting a test gauge on it to confirm oil pressure.

Yea. pick up a 15.00 mechanical oil sender and test it. if its still low id just drive it until she lets go. Nothing you can do really to help it. You and me are both in the same pickle,except mine is the trans. i just bought it a week or so ago.

where do i hook the test gauge up to on this truck.?

I don't know... :icon_errrr: near the oil lines at the rear of the engine near the pan on drivers side, or around the distributor. Where i would look to pull a sensor to install a test gauge.
I'm sure someone will chime in the best place though.

well,your oil sending unit as far as i know,is on the driverside of the engine,beside the distributor. its kinda tough to get too but its doable.

heres a video of the engine running

yea. i think shes just tired. I wouldnt worry to much about it though. these 4.3s only need about 6 psi for every 1k rpm. just dont get in on it unless u have too.

The needle seems to come up quick to a point and then not change with RPM after that. It could be the pressure sensor...

well i guess im going to get a new sensor. good thing my friends a mechanic, i put my hand behind the destributor and couldnt feel the pressure sensor at all.
im going off this diagram

http://i11.photobucket.com/albums/a1..._Locations.gif

It may be worth testing to see if its the problem before simply swapping parts that could be the problem. Maybe the sender is correct and it's the oil pump that's gone bad... Or it may be as simple as running a heavier oil(say10w30 of 15w40) in it to get the pressure up a little to prolong its life for a while. I'd hate to see you blindly throw money and parts at a problem.

Im going to get the sensor anyways being its only $20, and if its the oil pump those are cheap and i have a friend who owes me and hes a mechanic so labor free, he can do the bearings while the bottom end is open, i just hope it doesnt come to that, i didnt buy this truck for her to be tired, i bought her to work, i got 245k out of my stock double cab sonoma, and 182k from my zr2 s10.

From reading up all it can be is the sensor, oil pump, or bearing, so i can only throw so much money at it, im renting the mechanical oil pressure guage at autozone tomorrow so my friend can put it on.

Cool! Sounds like you have it under control. Good that you've got the right friends that owe you a favor.

My oil pressure drops to the first 1/4 mark on the gauge when idling warm and in gear hit the gas its like just below the 3/4 mark on the gauge should i worrry?

I want your oil pressure lol, thats what all my other trucks were at, thats fine

Thing just rolled over 65k lol

if its more serious swap out a liter of oil for a bottle of Lucas oil stabilizer
You will need to add to every oil change from then on to maintain results

I have 187k miles on my 93, and my oil pressure rarely drops below 40.

How many miles to a full tank do you guys get

not enough.

Agreed

You might want to switch to a 10w30 oil at your next oil change or add a quart of lucas oil stabilizer to help with the oil pressure. It won't fix it but it should help extend the life of your engine.

I turned up my speakers to try and replicate actual volume, and I do hear a slight knock when you rev to about 2K. Sounds almost like a cold diesel. It's a constant knock and the pitch changes slightly. I have heard that sound before and driven like that for months with no problems and I had almost exactly the same oil pressure and mileage.