I have an 01 dmax in the morning you can start up the truck warms up heater blows hot then temp gauge drops to cold heater wont blow hot it blows ice cold then about 5 mins later the temp gauge will jump to normal temp the heater starts blowing hot and then the low coolant light will come on and when you check it you have to put water in truck (about 1/2-3/4 galllon) no signs of leak on ground No white smoke,No Water in Oil, No white foam around dipstick, The truck runs great except for this problem. GM tech said he has never seen this before Service Mgr. said they think they know what it is and can fix it for around $1600.00 (Sleeves):eek:

Can Any body Help?????????? Thanks

Head Gasket

Sounds like headgasket, sounds a little extreme to be just injector sleeves. But there is always hope