Engine Cooling problem
2000 Chevy Silverado V8 Two Wheel Drive Automatic 226000 miles
I have been loosing engine coolant every2-3 months for over a year.I have had a pressure test done and no problems found. There are no signs of any leaks at all, no oil contamination from water, nocracks in hoses, no overheating problems, ac/& heat work fine. No thermostat problems. But after I am through driving and I park the truck and shut it down, I can smell the coolant on the front drivers side of the truck.I have checked my repair manual and there is a mention of a " Vacuum Atmospheric Valve", but it does not show where it is.I'm just guessing that since I can smell but not see a leak, the word" Atmospheric" would be a place to check.
A common problem with that truck is the intake manifold leaks coolant. Look way under the A/C compressor where the head and intake manifold come together. Use a flashlight. It appears to be a small leak since you can go 2 to 3 months without having to add coolant. What happens is the gaskets become brittle and come apart. They're plastic with rubber inserts and they just come apart. They can leak into the crankcase as well as to the outside. A very small amount of HOT antifreeze can cause a big odor so that may be where your smell is coming from. It may also be such a small amount that it's not showing up on your oil dipstick. It will eventually get worse. Now that you know where to look, maybe you can go ahead and condemn the gaskets and fix it. Hope that's it. Sounds like it.