losing antifreeze

[dr.peter]

hi guys. just replaced pmd with fsd, new marine injecters and new glow plugs in 95 2500 6.5 turbo diesel suburban. 171000 miles .runs awesome. a year ago flushed cooling system and since have had low coolant warning sometimes and have lost about a gallon in 5000 miles. i cannot find leak hav e replaced senser in coolant tank did not have heat upon warm up until engine revved up. no hydrocarbons in fluid runs great. any ideas? no leakage from heater. had all pipes to back air conditioner replaced last summer. thanks. dr. peter

[6point5]

Dr. Pete:

Probably the notorious GM cracked head. Sorry for the bad news.

[Garth J]

Check the water resevor for oil film and check for bubbles when its running. If there is a head crack or gasket problem you will usulally see bubbles in the coolant ...Garth

[6.5 on da bayou]

Dr. Peter
2 years ago I had the same issue. Didnt pay much mind to it. When the head gasket blew and the engine was locked up (water on top the cylinders), I took my heads off and low and behold, those two heads had so many cracks it looked like a road map. Once i replaced the heads with new gaskets, the coolant dissappearing act ended.

Sorry for the bad news,
Floyd