i have a 99 blazer, 4X4 with 110000miles, my temp gage when running the first say 5 or so mins will go up to a couple notches past210 then settle down to just below 210, then with in a few mins. it will start to go just above 210 and then go back to just below as long as i drive it(it goes back and forth) one of the times it lost heat for about a second or two when it rose just above the 210 mark. what do you think this is? i love this site i've found 2 of my fixes (the "vehicle speed sensor, and fuel injector problems)!! please help!!

 

3 thoughts:
Air in the coolant system, bad thermostat, or faulty engine coolant temperature (ECT) sensor. Have you had the system flushed recently or have you noticed a drop in the coolant level?

 

it has not been flushed, i have added water 2 times in the past 3 months to the over flow tank(its hard to remove the rad. cap) but there was no fluid in the overflow. my husband said he will check the fluid today(he's better with his older60s chevys) but i wanted to get an idea so i can tell him, as i did with the vss. thanks i will get back to you on this!!!

 

I would do a complete drain, flush, and refill making sure to purge the air out of the system and put on a new Stant lever vent radiator cap. If the problem persists we can go from there.