Head gasket? Or what? Lots of white smoke

Ok, so I just got my first tahoe. It’s a 2002 z71 lifted hoe. I’m in love with it. But I am having some major issues.

I got it last night, and I drove it home almost an hour. It drove… Ok…

The exhaust is kinda rigged up. It is completely cut right behind the cats. And you can smell it.

Here’s my issue… When I went to start it this morning it was pouring out smoke. Then after it sits it stops, but every single time you press the gas it shoots out white smoke. So I was thinking head gasket? So I went and bought some blue devil sealant, and flushed my radiator and did everything correct and I believe I wasted my $$. It’s still smoking bad.
It’s not overheating

Also I took off my air intake. My throttle body had a puddle of oil in it. Wtf :eek:

Here’s some side notes. The guy told me it has a brand new transmission. But didn’t have paperwork…

When I put the vehicle in park, on the dash it tells me it’s in reverse. Another WTF.

I’m scared to drive it. I don’t want it to blow up.

Also it idles funny. It goes really high and then really low, and I can really hear the AC kicking on and off.

A little less white space please…

How many miles on this? Where is the smoke coming from? the exhaust? Does the idle shift continue if you turn off the AC?

How can you be in love with a truck you are afraid to drive?

If it’s not too late, tell the seller you want your money back. I think he saw you coming…

Take it to a good mechanic.


There are some tests that should be done to verify engine condition. Compression test, oil pressure test, cooling system pressure test, and hydrocarbon test.
The white smoke and oil in the throttle body does not sound good. These tests can let you know where you stand.

A “brand new” transmission should be very apparent by a quick look as it should be super clean. Some people also consider a 150k miles used transmission or engine to be “brand new”. Not.

Offhand, I’d say you screwed up after buying this thing at night with a cut exhaust and you’re screwed

I agree, you are probably screwed. Learn the lesson, always have the car checked by YOUR mechanic before committing to a used car purchase. If the seller won’t allow that, walk away. Quickly.

Why did you buy this thing? Surely all of this didn’t start happening only after you got it home.

Don’t buy hackjob cars. This one is probably toast. It would probably cost you more to fix it than it would cost you to get another one.

Also, don’t use those head gasket sealer products in a vehicle that you want to keep long term. They rarely work, and even when they work they often plug up other things that shouldn’t be plugged up. These products should only be used in an old beater that you want to try and get 6 more months out of.

You want a quickie test? Start it up, put a white paper towel up to the exhaust pipe with the white smoke coming out. Collect a bit. Is it wet? Smells a little sweet? You probably have a blown head gasket… a really blown head gasket that NO amount of stop-leak is going to fix.

OR is the paper towel wet with a raw gas smell? You may have a seriously blown injector or 2 or 3 stuck open a blasting gas down into the engine. Cheaper but still it needs fixing right now.

OR is it oily and smells oil and burnt? You have a massive internal oil leak like rings or valve seals or both. The color is usually black when that happens but if you might smell a combination of any 2 or all 3. In that case the engine is likely a doorstop and will need rebuilding or replacement.

Didn’t you drive this before you bought it??

Was this an as-is purchase or do you have any chance of canceling the sale? You definitely want to get out of this deal if possible. I hope you paid far under book value here.

If you end up keeping the car and fixing the engine and exhaust system, please also have the suspension checked by a mechanic. Lifting a car can stress parts in ways that they weren’t designed for. You want to be sure nothing is going to fail while you’re driving.

As others have said, next time, don’t buy a used car without a pre-purchase inspection.

This sounds like a Craigslist ripoff .

I agree with Volvo V70.

Whoa…none of this sounds copacetic. The white smoke issue could have been sussed out during the thinking about buying it stage. The reverse indicator issue is evidence the transmission was either rebuilt or otherwise worked on and the linkage is maladjusted. Not that big a deal. The smoke however IS… You jumped to a bad head gasket AWFUL FAST… these engines are VERY WELL KNOWN for blowing the intake manifold gasket…the intake is cooled by coolant so when the gasket goes…and it WILL GO eventually. It mimics a head gasket in exhaust pipe symptoms ONLY…it wont have the other textbook symptoms AT ALL…thats when you know its the intake gasket set. I would have figured out which it was with certainty before using the Devil. Blue Devil actually works well for head gasket failures…it wont do a damn thing for that intake blowout.


This truck has a plastic intake manifold, which does not have coolant running through it

That said, I agree that OP made the mistake of his life buying this truck

Either he didn’t check it out at all,didn’t drive it, or he actually believed all the BS the seller was telling him

I think OP should contact the seller and politely ask to reverse the sale, because the truck has many major and expensive problems. I’m not sure if the seller mentioned any of the problems, or the buyer didn’t ask any questions

Can’t hurt to ask

The worst thing that could happen is if the seller laughs and tells the buyer they’re up the creek without a paddle

The only easy thing to repair might be the gear indicator. The shift cable or neutral safety switch may need to be adjusted and/or replaced

Everything else sounds very expensive to repair

Good luck to OP. He’s going to need it


Congratulations. You’ve just had your first class in used car purchasing. Your tuition bill will come from your mechanic(s).

One other quick headgasket test is what I call a “lab kit”. It tests the coolant for the presence of hydrocarbons, which if the test is positive means “sell me - fast!”. I attached a link to some.

Also, if you decide to try to keep this vehicle, I urge you to please follow lion’s advice and have the chassis looked at. This vehicle sounds like it’s been butchered by a kid with a catalog and little actual knowledge. Lifting a vehicle can cause some very dangerous problems, inclidng but not limited to overstretched flex lines on the brakes, severely overloaded ball joints and bearings, dampers that cannot operate in their design range, steering component problems, even a driveshaft without sufficient capacity to change length with the suspension movement (ever see a driveshaft slip off of the tranny tailshaft?).

You already have exhaust dumping out under the passenger cab, an extremely dangerous condition. It would not surprise me to find out that the things I mentioned (and more) existed.

I’m in the car 1800$. I bought a bmw 328i for 800$ with a blown head gasket and fixed it with some bars head sealant. I then traded the 328i with 202,000 miles and 1000 cash for this tahoe the other night. Tahoe like this go for 10k easy. It’s lifted up 6inches with new 35 inch tires. I absolutely love it…


I removed my intake manifold, and OMFG. Is this why I’ve been smoking. I’ve almost got it all cleaned up.

Also there was about a 1/2 cup of oil that came out of my intake manifold when I layed it down…

Btw that’s stuff on my manifold was an inch deep. I’ve been scraping it out with a spoon for 2 hours.

I’d be headed to the liquor store and double up on the MD 20/20… :smiley:

No disrespect meant, but that “bars” was not a permanent fix.
I stand by my (lion’s) recommendation. Pleas, I urge you, get this chassis evaluated by someone knowledgeable before taking it on the road. I don’t like the sound of what you’ve written at all.

I bought a bmw 328i for 800$ with a blown head gasket and fixed it with some bars head sealant. I then traded the 328i with 202,000 miles and 1000 cash for this tahoe the other night.

Well I guess fair is fair you both got had ! And that is the nicest thing I can say about this whole thing.

I guarantee a Tahoe “like that” will only go for 10 grand to a supreme sucker.

$10,000 for a 13 year old Tahoe with a smoking engine and hacked up exhaust?

BTW the picture you posted shows a pile of mud on top of the engine and under the manifold. I can’t see how dirt on an outside of an engine will affect the way it runs or make it smoke out the exhaust.

Well, I honestly think a 13 year old Tahoe would have a hard time capturing $10K even if it were only driven to church on Sunday by a little old lady.

There’s a perception that jacking a vehicle up, putting big tires on, and hacking the exhaust system will increase the value. It works exactly the opposite. Potential buyers take one look and say “I’m not touching that thing”. Any that decide to take the risk will want a very, very steep discount.

Before you start to shovel money into this vehicle, and you definitely will, you need to be realistic about your expectations. My guess is that your money-shoveling will start with a replacement engine. Or a total rebuild. That’ll only be the beginning.