jhjohnson
New member
- Joined
- Oct 12, 2021
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- Buick Ownership
- 2003 Buick Lesabre
Ok here is some backstory if it can be relevant: I bought this 2003 LeSabre from an auction about 7 weeks ago, its my first LeSabre so everything's new to me. The motor was coated in oil with small pools in the space between the plenum and front valve cover. There was chocolate milkshake on the radiator cap and in the coolant reservoir, figured they were from the intake gaskets, not head gasket.
I replaced practically every gasket on the top of the motor - lower & upper intake, valve covers, water pump elbows. I changed the oil and drained the coolant, refilling with water. But the thing still billows out white smoke from the tailpipe. It starts from cold start but fades away as it reaches operating temp and settles at just a little bit, if its not just steam (only distilled water in it for right now so cant smell coolant).
I feared it was the head gasket or head itself since I replaced both intakes. I pulled off radiator cap too see if water would bubble over, and it did, but I didn't see any actual bubbles, the water just rose and started pouring out. I wanted to be absolutely sure it was the head/ gasket so I rented a combustion leak detector. I waited for the car to reach operating temp with radiator cap off and water kept rising as it was warming up so I had to suck a bunch out with a turkey baster so the detector wouldn't suck it up. I poured liquid in the detector, and pumped it for a little bit, no change it color. I tried it again with new fluid but same result. I did it again the next day, this time from the coolant reservoir so I didn't have to deal with the water, but same result. I even used it at the tailpipe to see if my fluid was defective or something, but it changed color after a few seconds. I took off the plenum to check if it was the leak caused by the egr tube that leaks water into the intake, but it didn't look like any plastic was melted.
I'm under the assumption that the combustion leak detector test is definitive that it isn't the head gasket. Because if the white cloud is water being evaporated in the cylinder, and its getting in through the head gasket, then combustion gases would definitely be in the cooling system, right? It looks like my oil and water have mixed, so this leak walks like a head gasket, talks like a head gasket, but isn't the head gasket? Only other thing I could think of is the lower intake gasket, but I just replaced those and if I did it right they should be good. Or the lower intake itself is cracked/ warped, but I gave it an extensive cleaning when it was out and didn't notice anything to be unlevel or cracked. I know that aluminum expands when hot so i have an idea that the head is cracked, making a lot of white smoke on cold start, but the crack closes as the motor heats up, really not sure about this one, though.
Other problems I thought I'd mention if their is some connection I'm not seeing: Idle is inconsistent, wavers about 30-90 RPM, it comes down like its supposed to after cold start. I've checked/ cleaned everything I could think of for this besides spark plugs themselves, though I did check the coils and ignition control module. I graphed the voltages of the o2 sensors while diagnosing this. The first/ pre-cat sensor seemed fine but the second/ post-cat sensor was way to ranged and followed the voltage change that the front did, which to my understanding means the cat is bad or the sensor is bad, but more likely the cat.
Ok that's it, sorry for the long post, just really in need of ideas and didn't want to leave any detail out. My next step is to tear into the lower intake to see if its the gaskets or I messed up the installation, but I really don't want to do that for two reasons; First is that, well, its a lot of work and I'm not certain at all that's it. Second is that I've ran the motor quite a few times in testing for all of this so the gaskets have to have at least several hours of runtime on them, and I don't know if I take them out and put them back in that they'll work right, assuming I don't see an obvious mistake/ defect with them.
TL;DR: White smoke billows from tail pipe from cold start, minimal/ none when warms up. Replaced upper/ lower intake gasket, valve cover gaskets, water pump elbows. Oil appears mixed with water, has all symptoms of head gasket/ head but no combustion gases in cooling system, tested it 3 times.
I replaced practically every gasket on the top of the motor - lower & upper intake, valve covers, water pump elbows. I changed the oil and drained the coolant, refilling with water. But the thing still billows out white smoke from the tailpipe. It starts from cold start but fades away as it reaches operating temp and settles at just a little bit, if its not just steam (only distilled water in it for right now so cant smell coolant).
I feared it was the head gasket or head itself since I replaced both intakes. I pulled off radiator cap too see if water would bubble over, and it did, but I didn't see any actual bubbles, the water just rose and started pouring out. I wanted to be absolutely sure it was the head/ gasket so I rented a combustion leak detector. I waited for the car to reach operating temp with radiator cap off and water kept rising as it was warming up so I had to suck a bunch out with a turkey baster so the detector wouldn't suck it up. I poured liquid in the detector, and pumped it for a little bit, no change it color. I tried it again with new fluid but same result. I did it again the next day, this time from the coolant reservoir so I didn't have to deal with the water, but same result. I even used it at the tailpipe to see if my fluid was defective or something, but it changed color after a few seconds. I took off the plenum to check if it was the leak caused by the egr tube that leaks water into the intake, but it didn't look like any plastic was melted.
I'm under the assumption that the combustion leak detector test is definitive that it isn't the head gasket. Because if the white cloud is water being evaporated in the cylinder, and its getting in through the head gasket, then combustion gases would definitely be in the cooling system, right? It looks like my oil and water have mixed, so this leak walks like a head gasket, talks like a head gasket, but isn't the head gasket? Only other thing I could think of is the lower intake gasket, but I just replaced those and if I did it right they should be good. Or the lower intake itself is cracked/ warped, but I gave it an extensive cleaning when it was out and didn't notice anything to be unlevel or cracked. I know that aluminum expands when hot so i have an idea that the head is cracked, making a lot of white smoke on cold start, but the crack closes as the motor heats up, really not sure about this one, though.
Other problems I thought I'd mention if their is some connection I'm not seeing: Idle is inconsistent, wavers about 30-90 RPM, it comes down like its supposed to after cold start. I've checked/ cleaned everything I could think of for this besides spark plugs themselves, though I did check the coils and ignition control module. I graphed the voltages of the o2 sensors while diagnosing this. The first/ pre-cat sensor seemed fine but the second/ post-cat sensor was way to ranged and followed the voltage change that the front did, which to my understanding means the cat is bad or the sensor is bad, but more likely the cat.
Ok that's it, sorry for the long post, just really in need of ideas and didn't want to leave any detail out. My next step is to tear into the lower intake to see if its the gaskets or I messed up the installation, but I really don't want to do that for two reasons; First is that, well, its a lot of work and I'm not certain at all that's it. Second is that I've ran the motor quite a few times in testing for all of this so the gaskets have to have at least several hours of runtime on them, and I don't know if I take them out and put them back in that they'll work right, assuming I don't see an obvious mistake/ defect with them.
TL;DR: White smoke billows from tail pipe from cold start, minimal/ none when warms up. Replaced upper/ lower intake gasket, valve cover gaskets, water pump elbows. Oil appears mixed with water, has all symptoms of head gasket/ head but no combustion gases in cooling system, tested it 3 times.
