2002 Chevy Tahoe Z71
After the car has been running a while, when I accelerate from a complete stop, there is a sound coming from under the truck, also notice a sizzling / popping. Cracking sound when I turn the tuck off after it has been running a while. Sound like a hot pan cooling down.
Replaced the water pump, but I am still losing coolant, although it is NOT running hot, the coolant level keeps dropping in the reservoir.
Did not replace thermostat
Since you are not overheating, thermostat is likely not the problem. Chances are you have some seepage at either an intake or head gasket that is dripping onto a hot pipe when you stop. Leak may be so small at this point that coolant loss is barely noticable. but if you look carefully at all head/block parting lines and check all obvious connections that could leak, you will find the problem. Any white smoke from exhaust?
OK I left out all that stuff because I wanted you to go at the problem, not the symptoms. If there is some coolant loss, it may be dripping on the exhaust, making the same kind of noise as when you drip water on a hot frying pan. Also, the exhaust may be a bit hotter than normal if some coolant has been lost. Then, it can make "contraction" noises on cooldown.
What seems like evaporation is generally coolant being lost somewhere you can't see. It likely is not coming from the recovery bottle, but is being lost elsewhere. Sound you hear on acceleration may or may not be related...at this point you need to focus on the item that can ruin your engine...coolant loss will do that. So, at this point, the noise is something to keep in mind, but don't permit it to distract you from finding the source of the coolant loss.
Just one other item I thunk of...if you have an internal coolant loss (crack in cyl head or head gasket), coolant may be gradually destroying the catalytic converter, which could be making the noise you are hearing. That would explain "invisible" coolant loss etc. A radiator pressure test would definitely be useful. (not compression or cyl leakdown test)
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What about an issue with the exhaust system?
Also, what about the sound it makes when I accelerate, and the Sizzling hot sounds I hear only after the car has been running awhile?
On Another Note, the coolant in the reservoir is NOT dripping out, it seems to be evaporating.
Thanks, I'll try the radiator pressure test
Thanks, I'll try the radiator pressure test
Thanks, I'll try the radiator pressure test
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