5.3 Coolant loss

[Olav]

I loose coolant on my 2002 Tahoe. Is there any known problems with these engines. Oil is not milky or white smoke. Not pressure in the tank. Fill about 1 litre in 600 km.

Olav

[garys 68]

Search for a TSB for Castech cylinder head cracks.

[hifi875]

Or a cracked block

[TT302Z28]

I just had the same problem on my 2003 Tahoe. Take a good look at your water pump vent. Mine looked ok until I got the pump off. This is a very common issue.

Replaced and no issues since.

[novaderrik]

my brother's '01 had a slight leak for the last 4 years that we could never track down.. they'd lose about a gallon every 1000 miles or so and leave a little puddle on the ground below the engine everyday, but we could never quite pinpoint the leak. it wasn't too bad, so they just lived with it. about a month ago, i was under the truck with a mirror and a flashlight and traced it to one of the water pump gaskets. so his wife got new gaskets ($9 total) for it and we took the pump off, only to find that the oem gasket had a slight deformity in the rubber that's bonded to the steel backing around the water ports that lead to a leak. the gaskets had a GM part number stamped on them and they got the truck with 40,000 miles on it, so it was probably the original gasket from when the truck was built in the fall of '01. it took us a grand total of about 1/2 hour to take it apart and put it back together with only a 10mm socket (fan shroud and water pump bolts), a screwdriver (plastic push clips in the fan shroud), 15mm wrench (belt tensioner)and a channel locks (hose clamps) and it doesn't leak any more..

[Olav]

Thanks! I will take a look on waterpump before I go to the cyl heads. Anyway I found a leak on the hoses for LPG the evaporator.