Overheating AGAIN.

Well i've had a problem my blazer overheating. When i drive 90 percent of the time the temp is at 190 the 10 percent its at about 210 - 220. I've replaced the rad cap with a pressure release 16 psi aftermarktet and did a rad flush. around 3 months ago Chevy replaced the tstat.

After all of that i notice when i shut off my car to go into the house really quick and come out it reads 240 then i drive i notice it goes down to 190 or 210 - 220. I know when i shut off the car it reads 190.

I'm Confused ?

It will increase as it sits as no water circulation or air to cool but that does seem alittle high. Is the Dex cool at 50/50 or higher or lower can effect temp. Do a pressure test and see if it holds - low pressure due to a system leak will let it raise. Does the coolant level drop over time in the overflow - if yes possible intake leak. Keep the overflow at Hot full level when vehicle Cold to keep all air out of the system and make sure the tank and tube are not sludged up so the system can work.

Bought my truck at 50,000 miles.... First thing I did was Take the orange stuff out did a flush and put the green stuff in.... At 130,000 miles not one problem with my cooling system... One of the workers at the dealer warned me about the orange stuff...

http://www.automotiveforums.com/vbulletin/showthread.php?t=456944

Read this thread, it is in the FAQ.

Maybe it is not overheating at all? Did it ever boil?

Well it made it to Southern Cali to Arizona 700 Miles in 115 + with no problems. I do notice when it idles the temp goes up but when i drive its fine. Chevys Replaced the tstat at least 2 or 3 times.

At 130k that water pump and fan clutch are about used up.

Well it made it to Southern Cali to Arizona 700 Miles in 115 + with no problems. I do notice when it idles the temp goes up but when i drive its fine. Chevys Replaced the tstat at least 2 or 3 times.

When you flushed out the orange antifreeze, did you use a radiator cleaner like Prestone radiator flush or did you just use water and rinse the system out?

The reason I ask is because your problem sounds similar to one we just solved on this forum. In that thread, the Rad was ultimately replaced to solve the problem.

But before you start throwing parts at this problem, you might consider a good reverse power flush or at least a Do-it-Yourself flush WITH a good quality cleaner.

Hold on guys, there is nothing wrong with his cooling system.

What he is seeing is called heat soak and it is when the coolant temp near the sending unit peaks when you shut the engine off and there is no coolant flowing but the stangnant coolant is still absorbing heat.

COMPLETELY NORMAL.

BlazerLT , when it idles like at a drivethrew it will heat up. Engine Is On

BlazerLT , when it idles like at a drivethrew it will heat up. Engine Is On

Did you use any commercial radiator flush like Prestone when you changed coolant?

BlazerLT , when it idles like at a drivethrew it will heat up. Engine Is On

What will it heat up to?

What TheBrettster is describing is EXACTLY what my truck was doing up until about a month ago. Because my truck has 125K+ miles on it I decided to do a little R&R of some components. Water Pump, Radiator, T-stat, Rad Cap, flushed and refilled with the orange stuff. But like a bone head I did not replace any of the hoses:banghead: .

I immediately noticed the type issue that TheBrettster is describing. I was slowly losing coolant, but never saw a leak. I replaced the gasket on the top of the enigne (air intake manifold) just in case thinking maybe leaking coolant there. Still I was getting the same tempature results he described. Oh and did I mention the "gurggling" sound coming from under the dash.

After driving with it for about a month (temps never got serious enough for me to panic) and getting tired of refilling coolant, I did a scan of the hoses.

Low and behold I had a pin hole leak on the heater core hose that would not be apparent with the engine running. I had to wiggle it to physically see it leak. I replaced ALL the hoses with Goodyears, refilled coolant, problem has gone away.

I'm not saying mine is the ultimate fix for TheBrettster, but I would definately think about pressure testing the system.

My two cents.

around 3/4 around 240. Taking my car BACK to chevy. Ever since i they replaced the tstat without me saying anything the cars been overheating.

around 3/4 around 240. Taking my car BACK to chevy. Ever since i they replaced the tstat without me saying anything the cars been overheating.

Just for the record, ask them to price a complete Reverse Power Flush for you.

around 3/4 around 240. Taking my car BACK to chevy. Ever since i they replaced the tstat without me saying anything the cars been overheating.

Maybe you had a 192 and they put a 198 in it. I'm not real sure of the ratings, but there are tolerances and also is possible you had one on the low side of the tolerance, now you may have one on the high side. There's also a range for cracking and full open and is possible you have a bit larger range now than the one before.

All i have to say is i never had a problem before and after they replaced it i'm having problems.

All i have to say is i never had a problem before and after they replaced it i'm having problems.

This sounds all too familiar to that record breaking thread I refered to earlier. It took over 100 posts to figure out that the guy's rad was plugged up. He never had a problem either until he did Intake Manifold gaskets. He ultimately replaced EVERY PART IN THE COOLING SYSTEM before figuring out his rad was plugged.

http://www.automotiveforums.com/vbulletin/showthread.php?t=600298

All i have to say is i never had a problem before and after they replaced it i'm having problems.

If that is all they did then that is exactly where to look. You can test the cracking temp, and full open temp in a pan of water on stove with a candy thermometer, you have to watch very closely and carefully and even plot a graph on paper.