1999 GMC C1500 Losing Coolant

Greetings from Alabama.

I have a 2000 GMC 5.3L 4x4; same issue. I did find a tiny seep @ water pump about 4 months ago. Fixed that but didnt fix problem. Here's where I am now: there is a gasket on the throttle body. At least one....I am told....looking for another. I too do not have any water in my oil or coolant on my floor. If you resolve anything, please let me know. I can best be reached @ [email protected]

--Bryant

Sound like the intake gasket. This is a very common problem with these gm's. I have had to replace alot of them. They do not leak outward they leak inward and the engine burns the antifreeze you get a little extra steam out the exhaust.

Thank you, Racefan. I did look into that; was told my not a few GM techs that the intake manifold of the 5.3L is "dry"; no coolant paths up there.

Was told by Jack in here that it could be a head gasket that is not leaking coolant into the oil but into the combustion chamber. Now wondering if I am hurting my engine...?? I hate the use of coolant like that, but I dunno if a head job is worth it.

--Bryant

Now I am not refering to the upper intake or plenum I am refuring to the lower intake. If you do have a head leak then you should go to a radiator shop there is a leak detect they can do. They put this fluid in this tube and put in place of the radiator cap and the fluid changes color if it is a head leak. If the head is leaking however then you should have alot of pressure on the radiator too. See if it can pull coolant into the cylinder the compression can get into the radiator. But this leak detect can see that. Hope this Helps.

...so go to a radiator shop. will do.

But, in the mean time, am I hurting my engine? I thank you for your explanation about the pressure in the radiator; just wondering if I am hurting my engine.

--Bryant