I just bought a 1999 Camaro Convertible with a 3.8 and 147k on the clock. I'll give some back story so readers can have a full understanding of my wtf.

When I bought it there was water in the oil and it wouldn't start. The guy I bought it from said the oil pressure sending unit was also bad and that's supposedly why it wouldn't start. It has a new battery. He only owned it for a month or less and only drove it a few times while trying to sort out its issues. He had limited mechanical knowledge and didn't know how to deal with its problems so he got rid of it. Before that it sat for a while because the previous owner died (I didn't know him).

When I got it home I drained the oil and put some used oil in it, figuring that the engine would water down the oil anyways while I tried to figure out the source of the issue. It had at least a gallon of water in the oil because I drained out almost two gallons of milkshake. I didn't change the filter. After charging the battery the car started, but it was tapping and the oil pressure gauge was on zero. I removed and cleaned the oil pressure sending unit. After that the oil pressure gauge started moving, but still mostly read zero. I started the car several times and drove it around the block once while tapping. It sounded very much like a lifter tap. The next day I started it again and the oil pressure read 1/4 up on the gauge and there was no tapping. There has been no tapping since that first day.

Now the oddities. There is no smoke, no missfire, and it's quick to spin a tire with very moderate throttle when going around the block. So I'm certain it's not a blown head gasket. I'm leaning towards a blown lower intake manifold gasket. However, the oil pressure never goes above the 1/4 mark, even when revved. If anything, it goes down a hair. When the engine warms up, the oil pressure drops to around zero. The check gauges light usually comes on, but not the low oil light, and it stalled/shut off once while running like that. When the oil pressure gauge drops, it doesn't tap or knock, but there's a whining sound similar to the sound that a power steering pump makes when it's low on fluid. The power steering fluid is full. When the engine is shut off and restarted while hot, the oil pressure gauge will read maybe 1/8 on the gauge at first, and then fall to zero within 15 seconds or less. There is no more water in the oil so far. Wtf.

My thoughts: Perhaps the milkshake froth has clogged some passages somewhere and it's not knocking because some of the engine is getting oil while other parts, like the oil pressure sending unit, are not. But why does the oil pressure only bottom out when it's hot? Could the oil pump make that whirring sound? Could the extra gallon of fluid in the oil have damaged the oil pump? And why isn't there any more water in the oil?

I have upper and lower intake manifold gaskets on order and after I replace them I'll replace the oil and filter with more used oil and a used oil filter from a 1997 Firebird that's in the family. I won't put new oil in it until I solve the water in the oil issue and run some Seafoam through it to clean the froth out.

I'd like to hear thoughts from you guys on this strangeness. I tried searching, but I can't find any posts with all of my issues together.

 

once coolant gets in the oil and the engine is run with it, your bearings are toast. you will be better off finding a good used low miles series 3 3.8 and put it in, gain 20hp to boot.

 

First off power does not equal "no blown head gasket. In fact if you have old gas in the car a drop or two of water could even increase combustion pressure and if cooled the charge enough it could allow for the PCM to add some timing. Back when gas was really bad in the late 70's water injection was a thing. As a general rule by the time you could "feel" a blown head gasket it is a really bad blown head gasket.

Failed lower intake are common and they are the the most common cause for engine replacement in a 3800. In fact there was a class action law suit against GM, you could have applied for money from GM as late as 2007 if you had a failed lower intake.

Ethylene glycol (AKA antifreeze) has a reaction to the intense pressure inside the oil pump. It breaks down and a by product of that is acid. The acid melts the babbitt in the bearings. This causes excessive clearance in the bearings and can even cause the plugging in the oil passages. Clearance is why you have low oil pressure. The 3800 is a tough motor which is why it is still running but it will spin a bearing a lock up at some point soon.

 

Wow, thanks for the quick replies. I'm not sure if there was any antifreeze in the cooling system when the gasket failed. There was only water in it when I got it. It has a leaky radiator cap too so I'd be willing to bet that it's been getting just water for a while. Running straight water here in South Florida is common in older cars. I read a post about a guy with a 350 TPI in a 3rd gen who had low oil pressure when hot, but without the water+oil issue, and the diagnosis for him was the same.

Is there any specific bearing that has increased clearance, or is it all of them? I'm guessing all of them, in which case the engine would have to come out. Would changing the bearings without resurfacing anything fix the problem? Replacing the engine isn't an option. The least expensive one I found is $900 and that's impossible for me.

If I can't find a financially feasible solution, I'm going to have to part out the car. It also needs a new convertible top and new tires. Those were at the limit of my budget as it is. If I put heavier weight oil in it, with maybe some type of additive, would I maybe be able to drive it for the summer at least? Or is it likely to lock up within a few hundred miles regardless of what I do?

Btw, you guys don't know how much your input helps. I was about to replace the intake manifold gaskets and run some Seafoam through it thinking clogged oil passages were likely the problem. That would have been a lot of work for nothing. It's too bad I already ordered the gaskets.

 

The motor would not be worth fixing. The babbit material will be in all the oil galleries so everything needs dipped in a hot tank at the machine shop including the block. Every bearing should be replaced.

GM made that 3800 for a lot of years and they are built proof so the junk yards are overflowing with them. There is a sticky thread in the V6 section with details but prety much any 3800 up till 2008 will work and I have seen people find them with 30-40,000 miles on them for 4-$500. It is a lot of work but you could have a car ready to last 5 years 100,000 miles on the cheap. Once you fix the dam intake these 3800 run forever and get decent mileage doing it. I was hitting 30 MPG in my 96 5 speed. Click on "96 Camaro build Thread" in my sig.

 

Even $500 would be out of my reach. I could get by without doing the top because I patched it for now, but it still needs tires. Plus there's only two junk yards here in town, and both of them suck. I may call them to see what they have, but I don't think I can swing it. I'd hate to part it out though because it's a good looking car and everything else works fine.

 

I wish I knew where those people found engines for $400 to $500. However, even that would be out of my budget. I could skip replacing the top, but I can't ignore the need for tires. I understand that the 3.8 is a diehard engine, there's been a 3.8 Firebird in the family for 13 years with 200k+ on it. It looks like it's just not going to happen for me though.

 

Just an FYI when I say your motor is toast I am not saying because I heard it friend or a read it some where. I have torn a part several motor with coolant contamination. I know that the inside of the motor looks like. You have two things going on, One you have very thin bearings and two you have little silver ***** rolling around in your oil passages just waiting to form up a blockage. I have seen people try to repair a coolant contaminated engine before and there is a very low success rate. The engine may last a week or it may last 5 min, heck it could have spun a bearing the last time you turned it off.

I would not go over 2500 RPM or let of the throttle fast. If you feel the car driving the engine faster slip it in neutral.

Back in the 80's I was a GM warranty tech, They made us fix everything. If an V6 needed a crank and 5 connecting rods then that what it got. The only exception was when we had coolant in the oil and any noise GM policy was do not waste a minute on trying to fix it, order a new engine.

Car-Part.com--Used Auto Parts Market

 

I really appreciate your description. It gives me a good understanding of what's going on. It's not a happy prognosis, but at least I won't be wasting time working on this engine. Since the engine is toast, I think I'll try flushing the engine out with some more used oil since I have plenty, and then I'll put in some new heavy weight oil, like 20w50 or straight 40, along with some Lucas and see what happens. I'd try straight 50 weight oil but my local store doesn't have any. We'll call it an experiment. When it locks up, I'll just tow it home and start parting it out.

 

I hope it holds together for you for awhile. Too bad your so far away I have a great running 3800 in my driveway that is in a worn out car.