Ok... I have an 03 blazer. there is no overheating problems while driving but if i let it run without moving it starts getting hot... like between 210 and 260. is that normal. once i start moving again it starts cooling off.

Anything???

 

I had that issue before purging my Radiator(got it done in an expert shop),I also added prestone in the overflow after the purge(I guess the tech forgot to fill it up),I made sure to have the GREEN liquid and not the orange one! After that ,the Temp.was normal compare to having my heat sensor up and down all the time liek before.I also replaced the Termostat myself before taking it to the shop.

...Whats odd is after I replaced the Plugs (2 weeks after the purge) with platiniums, the temp got even more coller and very stable,humm...

GL!

Mart

 

It's possible that the fan clutch has failed and isn't pulling the required amount of air through the radiator when warm.

 

The fan works good. Roars nice and loud.... changed the thermostat. flushed the cooling system. whats weird is that it only seems to do it on hot days like 98+.

Could it be a pluged radiator?


on days ≤98 it runs normal (Around 195-200)

 

BUMP...

Anyone?

 

Have you done the obvious? Cleaned the condenser and radiator of any bugs/debris? When you look inside the radiator, is there any buildup of junk on the inside? This may indicate that rows of the radiator are plugged, hindering it's capacity.

Does it do this more so when the A/C is on? If so, how hot does it get when you turn the A/C off?

And green/red/purple/orange, whatever, does not matter. Just can't mix them unless the product you are putting in specifically states that you can.

 

It does it more when theA/C is ON. did do the cleaning of the condensor with air compressor. There was junk in the radiator So I flushed it. Seems to cool down when the A/C is OFF.

 

if you replaced the tstat and flushed it and it still does it, i would try flushing the heater core out itself although that would be more of a inside no heat issue. Those hoses are notorious for breaking down from the inside out and clogging the heater core. Its gotta be a fan and or clutch issue. Thats the only thing that truly makes sense, when your driving it runs at normal temp(while wind is being forced across the radiator0). When your stopped it gets hot(no air being forced/ not enough air being forced across the radiator). I would check those out.

 

How would I check the clutch fan?

 

Hes a simple but easy question. When you flushed the system did you use any sort of cleaner to clean out your radiator (for example like prestone super cleaner)? If not you might want to give that a try to get some of the garbage out of your radiator. Ive been having the same issue with my blazer even after just draining, rinsing, and refilling. Ran the super cleaner through it and refilled and i havent had an issue since. Reason why that works better is it flows through all the hoses and pipes and scrubs off the junk and frees any blockages. On mine after running it for a full day everything drained out dark rust water brown (when you fill it the solution is clear and you mix it with water). If you already did this then just tune me out but if not give it a shot, its cheap and easy to do.