Coolant Problem?

[MA87K5]

The problem is that when I start my 99 Tahoe old style in the morning or after sitting for a few hours it will run rough. It will eventually smooth out after 5 or 10 min or so or after I rev the pi$$ out of it. I do smell coolant after start up and back up. Could a bad head gasket do this. Thanks

[Zembonez]

The problem is that when I start my 99 Tahoe old style in the morning or after sitting for a few hours it will run rough. It will eventually smooth out after 5 or 10 min or so or after I rev the pi$$ out of it. I do smell coolant after start up and back up. Could a bad head gasket do this. Thanks

Quite possible although this is nowhere near enough information to make a good diagnosis. I'd get it looked at before it becomes a more serious problem.

 

Good luck!

[MA87K5]

I'm thinking the the gasket is letting the preasurized coolant leak into a cylinder while the engine is off. I did have a code after I tried to "clear" the coolant from the cylinder while at a light instead of after being started.

[MA87K5]

I read in another post to check for bubbles in the radiator. I open the rad cap and started the engine and seen no bubbles. Reved it and the level went down. Pump is working. On a warmer day I'll pull the plug that popped the code. I just don't know where the coolant is going. The engine as never overheated and had very minor pinging due to cheap gas and heavy foot. But only checked to see if I could get away with cheaper gas. (hyperchip powerprogrammer III was installed needs 93 octane) Didn't ping under calm driving. But that was 2 tankfulls ago. I checked the oil dipstick and only seen oil no coolant or runny oil.

[MA87K5]

Any ideas?

[mr_bots]

Intake manifold gasket is my guess.

[MA87K5]

I would be very happy if that what it is. Just need to find time to work on it.

[mattjulien]

can you hear a definite dead spot/miss in the exhaust???

[MA87K5]

After I rev it a couple of times, no. When I first start after sitting, yes.

[mattjulien]

sounds like a leaky head gasket unfortunately. i just had this same problem with my old dodge minvan. the coolant is not flowing completely through the engine causing "hot spots" that result i a miss/dead spot.

[MA87K5]

Did you have white smoke out the exhaust? I don't have smoke.

[mattjulien]

Did you have white smoke out the exhaust? I don't have smoke.

 

at first, no. then after like a week it started...but it was more like LOTS of water vapor than a smoke...idk i guess you could call it smoke lol.

how often do you drive this truck??

[MA87K5]

ok then I don't have lots of water vapor. But for everyone else including ase cert mechanics and repair manuals it is called white smoke LOL Anyways I drive it everyday.

[MikeInCtown]

Are you losing coolant, or needing at add a quart every so often?

 

I've been told that the full size trucks also suffer from the leaky inatke gasket problems. I thought I ditched that when I ditched my old S-10. (sigh)

 

Easy way to tell is to pull your plugs. if coolant is getting into one cylinder, one or two plugs will be far and away cleaner than the others, and probably almost spotless due to the coolant being burned off in the cylinder. if you were getting leaking like that you would probably also start getting engine codes for lean operation in one bank. You also wouldn't smell coolant at the front of the truck, but more likely at the back as the coolant would be expelled after the combustion process.

 

Also check your oil for signs that it is looking brown or muddy rather than clear or black like normal.

[MA87K5]

No coolant in the oil but get missfire code if I drive away without reving to clear coolant from cyl. I also talked to a mech and he said the same thing about the intake problem with chevy. Working on it today I will let ya know.