'98 Regal.... no oil pressure after changed oil

[Mr_D]

What would cause a 1998 Buick Regal 3.8L with 70K (3.8L V6 series II) to have no oil pressure after changing the oil? It was running smooth and quiet before, and is in excellent condition.

There is more history here and I should say it may have more to do with having the intake gaskets changed but the problem didn't show up until the oi was changed.

The motor had a small leak from the intake gasket visible on the outside of the engine (as many of these do) so I decided to get it fixed by a local mechanic who said he's done 40 GM intake gaskets while working at our local GM garage. Then he got laid off like many others.

He changed both the upper and lower intake gaskets today to fix the leak. Then he changed the oil and put in new antifreeze. He says it ran fine after the work and he drove it for several miles with no issue. He purged the air out of the cooling system using the vent, etc.

I found out later that he drives vehicles really hard, in case that could break something related to oil pressure.
He also told me that he had to flush the oil 3 times because it kept coming out cloudy, which was something he hasn't seen before.

So rather than use new oil he put in the used oil that he took out earlier plus some used oil that he had in his shop.
I think that is a bad idea because the oil pan he used didn't look very clean. I mentioned that and he said it's fine cause he filtered it through a funnel with a metal screen in it. I would never do that and I think a metal screen would miss all the small particles, like sand. He still says he's sure it was clean but I'm not convinced
and I think that's a bad idea to put used oil that sat in an oil pan back into a good engine. Especially if some came from some other vehicle.

The drain pan he used has a built-in cover so I couldn't see what's in the bottom of it, the top doesn't come so it can't be cleaned inside.

So he put the used oil back in to save a litte money without asking me, and he ran that oil for a while trying to use up the remainder of antifreeze that got into the engine during his intake gasket work

I wasn't here for any of these things up to this point. I came out to get the car because he said it was done and that's when I found out the details.

He wanted me to take the car home and run it with the used oil but I wouldn't do that. So when I went to pick up my car he was changing the oil and filter again. With the new oil/filter in place he started the engine and it immediately starting knocking, fairly loudly
I saw the oil pressure warning light was on so I shut off the engine. what's going on?

He topped off the oil, and tried it again with the same results, revving the rpm's slightly had no effect other than knocking louder.
The oil light stayed on so we shut it off.

I presume the main knocking is lifter and bearing noise noise due to no oil pressure but maybe it's new internal damage somewhere.
It's also running rough and missing, also maybe due to the low oil pressure so the valves aren't opening all the way.
The oil and antifreeze level both look correct.

I had him put the previous oil filter back on because he says it was running fine 10 minutes ago with that filter on it.
That didn't work so I had to leave the car there. He's going to call around for help on Friday because he has no idea how to fix it.

I hope he's telling the truth about the sequence of events and that he didn't wreck my engine. It was in perfect condition when I brought it there.

Suggestions?

[Airjer_]

Unfortunately sometimes you get burned when you try to save a buck.

The first thing I would do is pull the pan and see what the screen looks like on the pick up tube. The guy you had do the previous work would not be my first choice to have this done. Using used oil to save a couple bucks, well.... probably didn't save you any. If the oil was changed before the engine was started after replacing the lower intake there shouldn't be any issues with "cloudy" oil (another red flag) since the coolant would be the first thing to drain out when you pulled the plug!

It doesn't seem possible but there is a chance that the main bearings where trashed running the car with coolant in the oil. GM's do not like coolant in the oil!

[Mr_D]

Thanks Airjer.

The oil was definitely cloudy. so much that is surprised the repair guy.
He had to change the oil 3 times to get it to come out clear after working on it and he said he never saw that before. When he pulled the drain plug the antifreeze came out first (at least 1 cup full I think), and then cloudy oil came out.
I know there was no antifreeze in the oil prior to him working on it and I think that was caused by the sequence or method he used to do the work, not by a leak.

Later I found out he drives cars very hard cause I was stranded at his place after my car wasn't ready, so he gave me a ride back and I was surprised how far he he wound up the rpm's in his truck (with cut off exhaust) and took off with a loud roar.
I suspect he drove my car the same way,,, with the dirty, diluted oil in it, and he said it seemed to get hot during his test run before I arrived,,, and he didn't know why.


Bad Main bearings..... oh..........
If it's really bad, do you think he's liable to fix it right?
He advertises in our local paper and also works full time.
http://eauclaire.craigslist.org/aos/1647599032.html
LOWER INTAKE GASKETS LEAKING 3100,3400,3800 (EAU CLAIRE )
re your lower intake gaskets leaking on your 3100, 3400 or 3800. I can fix them. coolant mixing with the oil?? get it fixed before you motor is junk. dealer cost for this repair is over $500 bucks
i will fix it for half that. $250 bucks and i will do a better job guaranteed
i also do many other jobs.
give matt a call at (916) 893-xxxx
former Markquart chevorlet employee


He used a small hand grinder to clean up the old intake gasket and metal surfaces.
So maybe there is leftover gasket material that fell down inside or a thick layer of oil/antifreeze goo blocking the oil pickup tube or blocking an oil passage.
Maybe contaminated oil could mess up the oil pump and sheer off a pin or clog it up.
Oil Pressure relief valve stuck open?
Maybe he used the wrong type of oil filter with oil channels in the wrong place blocking the flow.

I sure didn't want anyone putting in used oil but I didn't know about that until later and he did that without my knowledge. He seemed surprised by the engine noise, like it suddenly started doing it after shutting it off and changing the oil.
It was fully warmed up with warm tires when I got there to pick it up. He'd been driving it a while to finish flushing the cloudy oil issue that he created.
I didn't hear it run after the initial work earlier that day so I wonder if he messed it up hours ago or if the problem suddenly appeared after changing the oil.
The guy was working at a local GM dealership until they closed the place.
So he should have the training, but maybe it's too late now.

[Airjer_]

There are always two sides to every story and without hearing his side I wouldn't make any judgements other than the fact that using "used" oil is not a "better job Guaranteed"!

I don't understand why the oil was that cloudy unless the lower intake was neglected long enough on your part that it started leaking coolant internally. If that's the case than unfortunately its not his fault.

We can't hear the noise your are describing so I have no idea what exactly is wrong but it definitely sounds like there is a lack of fuel pressure. At this point I think you would be best served getting your vehicle somewhere else for an evaluation.

[Mr_D]

The mechanics story is the same as mine.
He doesn't know what's wrong now and he said so.

Most of the details came from him directly other than what I observed later myself when I went to pick up the car and found it undriveable and knocking.

I would never put used oil (despite filtering a bit as he claims) from some other motor into another persons car. That has me worried, as does the engine knock that was never there before.
This is a quiet, well maintained car.

The oil has always been clear and it doesn't burn any between oil changes.
I checked it the day before he worked on it and it was fine.
The vehicle doesn't use any oil or antifreeze.

I was being proactive to fix a small leak visible only as a wet area near the intake manifold.

Update: Friday 1pm he pulled the oil pan and found some type of soft debris,,, maybe old gasket material (he's not sure what it is) clogging up 60% of the oil filter inlet screen. He cleaned that off and reported that the bottom of the oil pan was quite clean, with the exception of chunks of gasket material or something.

I think would be a good idea to also check the condition and cleanliness of the oil pump while the pan is off.
We'll see.

[HotZ28]

With the pan off, it would be wise to pull the front main cap and a few rod caps to inspect the bearings.

[Mr_D]

Saturday update:

After the oil inlet screen was cleaned the motor sounds ok and the oil pressure came back . The oil is remaining clear so far.

I wasn't able to check the bearings because the oil pan was back in place before I could check it.

I wonder if it cost any engine life during a couple 20 second runs mostly at idle with minimal oil pressure.