High Temp Light 02' silhouette

I have the 02' silh. premeire. I started it up the other morning and let it warmup for 10 min. I drove it down the block and the gauge went to high and the high coolant temp light came on, heat stopped coming from the vents, and the engine started to lose power, like it was chugging to get 20 mph. Mechanic says he checked everything pressure tested the seals and gaskets, can't find the problem. He drives it for about 15 miles to try and duplicate the light and problems, can't get it to reoccur, says the thing runs great. I take it back, and the same thing happens the next morning, warm up drive it for 3 min. and lose heat, gauge goes to high,etc. Mechanic says it could be head gasket, but usually a head gasket will not "come and go". Anybody else have this problem? also checked the thermosat, it was fine. any replies greatly appreciated!!

Is it possible you are losing a ground on the engine block? Does the guage shoot to high, or move very slowly? I'm thinking it could be electrical, not a temperature issue. Can you see what the temp. is by using an IR thermometer to verify it is overheating?

t-stat sticking..... what happens when you cut it off ? do you have to let it cool ? or does it cool down pretty quick .an electrical problem would not make it loose heat .a sticking t-stat will make the temp go way up then start back down after the t-stat finally opens.

t-stat sticking..... what happens when you cut it off ? do you have to let it cool ? or does it cool down pretty quick .an electrical problem would not make it loose heat .a sticking t-stat will make the temp go way up then start back down after the t-stat finally opens.

If it cools down quickly after turning off what does that tell you as mine does. However since I have bubbles coming up in the overflow tank I think I have head gasket problems as system has been bled several times.

Thanks for the replies. I ended up letting it sit overnight at the mechanics place and let him start it up in the morning. It finally duplicated the problem. It is either a head gasket or cracked head. Said he won't know until he gets into the engine. Is it just me or are these vans really made crappy. Ihad a 99 venture also which I BABIED!!, and at 135,000 miles the cam shaft was junk. I'D like to know who's going to bail me out of a 1600.00 bill to get this fixed?

g.m. will get the help you won't.

Your on your own with the cost. I just had to do the Head gaskets on my 02 with 125k Kilometers and GM basically said tough luck even though I complained about losing coolant well before the warranty expired and even had the dealership on my side and they still declined to help with the cost. With service like this I wonder why their business is going down the tubes. $1600 is a fair price for the repair if it includes milling the heads Just make sure they use the latest revision gaskets.