Hi. I own a 02 blazer 4x4. Last friday my car was running higher than normal. I noticed my heater was blowing cold air, but then after a few minutes the heater kicked on and my temperature dropped back down to where it normally sits. I checked my fluid level and all was good. Yesterday it was running way high with no heat again. but again the heater kicked on and then all was ok. This morning I was on my way to work and it over heated. I checked my fluid today and the resevoir was empty. my first guess was that it was going to be the thermostat, but i changed that and that didnt do it. still overheats but now the resevoir wasnt emptied. I need to get this fixed before tomorrow if possible because i need to get to work. thanks in advance for any and all help. oh and one last note... im not the smartest by any means about what under my hood. i can pretty much tell you how to change oil and after that not much more. so please explains very well what you say. Thanks again

 

Simple things you can check, is there any depris in the fins of the radiator? Did you install the thermostat in the right way?(seems stuipid but it happens) How much coolent was in your radiator when the truck was cold(not the resevoir and don't check when hot hot coolent burns) Grap a hold of your fan in the engine (ENGINE OFF) and see if you can wiggle it, don't wrench it just see if it wiggles.

 

Any fluid underneath when you park?

 

sounds like the cooling system has air in it. the problem is why does it have air in it?

 

Adding to that, what kind of coolant have you been using and have you ever had the intake gaskets replaced?

 

if you still havn't fixed it, check to see if the top end of the motor is wet at all (intake gasket leaking) check under the vehicle after parked for a while. When the motor is cool and sitting fairly level check to see if you can see fluid in the radiator itself (top off if not) if your coolant level is ok and there are no leaks then i'd hope that you installed the thermostat wrong. from there the problems get more complicated. I had an uncle whose transcooler line inside the radiator busted mixing his coolant and trans fluid. cost about grand for a new radiator, coolant system flush, and transmission flush...he first noticed the problem when it started overheating but would cool off with the heater. check to see if you see a gel like substance in your coolant reservoir, radiator, or the trans dip stick.

 

Here is an update. Thank you for all of your help on this. I have a leak somewhere because I'm having to add water to my radiator about a half gallon every 3 days. My oil is clean. Haven't checked my trans but will do that tomorrow and I don't notice anything under where I park or anything leaking while my car is on. I just want it to run normal again anyway. Ill check my trans fluid tomorrow and let everyone know. Thanks again

 

any up date on this issue?