Ok Guys, thank you all for the help with the heater core it was installed. Now I have bigger problems than I did before! The heater core was replaced and now the truck overheats before I can get 1/2 a mile from the house. I turn it on and 2 min later its in the red! Also, we STILL have NO heat. Im so sick with this Im about ready to cry and of course the mechanic (kinda) has NO CLUE what the problem is. With hubby gone I feel so helpless Im ready to cry! I am stuck here in Germany with 4 kids and noone knows whats wrong with my trcuk. If ANYONE can help please please let me know! Thanks so much~Heather

 

Sounds like when the heater core work was done, a line was plugged, and still is plugged. No flow = overheating.

 

could be the thermostat???

 

Try to check your thermostat and relays if you don't have the HEAT and still going to red zone. And also try to check the water pump to know the water circulates well.

 

If you are overheating in 2 minutes your cooling system might have some large pockets of air trapped in the pump causing the cooling system to stop flowing. ALso, if this is the case, the block and heads might have some steam pockets in the cooling jackets too. This would be VERY bad. This is how heads and blocks get cracked.

Anyway, try to purge the air from the cooling system if you have not done so already.

D