Hello all, I have a '97 V6 3.8lt 160,000 miles. I did not know a lot about cars and bought it with a blown head gasket, eventually my oil was just nasty and foamy, white smoke and all the other sympthoms... after getting ripped off at a HG repair (was done incorrectly since he did not replace thermostate, clean heater core and plastic reservoir hose was obstructed, eventually did all that myself) water was going into my oil again, so i changed oil and used a coolant treatment until i have time to do HG myself (Have Helm's Manual and have read a lot about it in this forum and other sites) and it has been runnig fine, but i noticed that after the "repair" my Oil Pressure was 0 when engine is not running and key is in ignition position, going to 60 in first start and dropping until light in dash turned on after about 20 min of driving, i changed Oil Pressure switch and now light is never on again but gets at around 10 and bordering the red area when engine is hot. I dont have any noise or shake (gauge does fluctuates) but i want to know if i should be concerned about 0 pressure when engine is not running and key is in ignition position. Thank you very much for any help you can give me.

 

No oil pressure with the engine stopped is normal. Your problem is low oil pressure when the engine is running. What weight oil are you using? I suspect the bearings have seen better days.

 

Thx for reply. i changed oil like a week ago to Penzzoil 10/40 High Mileage. I also noted my rpms never go above 4,000 rpm, i dont think i have an issue speedwise, but probably i do in acceleration...? If is the bearings, What do i have to do? take block to machine shop? Thanks a lot.

 

Bad news time.
Anytime antifreeze mixes with engine oil and is allowed to sit for any amount of time there is a very good chance of bearing damage. The antifreeze has a chemical reaction to the babbitt on the surface of the bearings. It will strip the babbitt just like a paint stripper. The babbitt then gets into all kinds of places it should not. As a general rule the motor fails within a short period of time. Back in the 80’s we used to have to repair motors under warranty at the GM dealership. There was only 2 ways GM would allow a new a crate motor. #1 was a non-repairable block, #2 coolant in the oil. GM would not even pay the time to disassemble the motor if it had coolant in the oil. Just replace it. I cannot even guess how many engine I have replaced with NEW head gaskets installed by non-trained mechanics.
You could try changing the oil a few times to get out all the babit material and hope there is enough babbit to keep the car going awhile but from my history 9 out of 10 of these motors fail in a downward spiral that is worse almost daily if driven. You should be looking for a low miles replacement motor.

 

Thanks a lot, it was a very informative and relevant message. I have made about 3 oil changes within 2k miles after that, last time i added 8oz seafoam to oil (and 8oz to brake booster vacuum line doing the slow 2/3 first and 1/3 last thingy) and i have been checking oil to see if is dark, 100 miles after sea foam, oil looks clear and i start wondering if i should change oil/oil filter as instructed in sea foam process instructions... on the other hand... could sea foam have made my pressure drop?

I apologize in advance my ignorance and if i ask something which answer is obvious, but... is it possible to replace/repair bearings? and... considering engine swap... what year, size of engine would fit my car's body? Thanks a lot for all your help.

 

Replacing bearings requires removing the engine. But as Gorn said, due to the antifreeze getting into the oil, the engine and all the oil passages will need professional cleaning to get all the metal particles out. Most likely the crank journals will need to be reground, etc..
As for Sea Foam, I have my own opinion, it is good for getting rid of biting bugs. lol
If you keep driving with bad oil pressure, sooner or later something is going to break and cause a lot of damage.
If you want to change the engine out, the only one that will drop right in would be another 3.8 that came from a 4th gen F body or perhaps from a pick up truck of the same vintage. Any other engine will require a lot more work and expertise, which you professed not to have. However, you may want to verify the oil pressure using a mechanical test gage, just in case the one in the car is bad.

 

There is a sticky in the V6 section listing the cars that have the same long block. 3.8 in a truck?
Pete brings up a good point if you have no other syptoms, Rod knock or lifter noise, you should get a good manual reading to see where the oil pressure is.

 

What should the oil pressure be on an LT1? I was going to post a thread, but figured I'd hitch a ride on this one for a sec. The needle is at the mark below the 80. (if it were a gas gauge, it would be 3/4 full.)

 

Thanks again for your messages, i appretiate the fact that both of you guys state reasons for why do something or why not to, my brains assimilates that so much better than just DO's and DONT's, and thanks for bearing with me. So... for a Manual reading... can i switch from Oil Pressure Switch to Mechanical Gage while engine is running... or at least after it warmed up? i kinda want to drive the car and take manual reading when engine is warm and my gauge is showing in the lowest possition, but i dont know if by doing so it will splash hot oil all over the place.

Stainless, i dont know the answer for that, i do know there can be many things affecting it, for which you need to provide some specs for your ride, oil you're using and when you took the reading: year, size of engine, mileage, type/weight of oil, etc...

 

96 Z. 350 Mobil 1 10/30 165,000 miles. Taken today, just driving steady at 45 to 55.