'97 Blazer Overheating...need help

[rajiv1]

hey, i have a '97 Blazer and last week the temp peaked on me but nothing blew (thankfully) the next day i replaced the thermostat and once i did that everything seemed to be fine, i will drive it normally and it will maintain the average temp, but yesterday i was in a hurry and was doing about 85+ on the highway and sure enough the temp. started to climb on me again....this weekend im going to flush the system, pressure check and check the fan clutch....is there anything else i should look out for?

Oh and sometimes when i drive it i hear something that sounds like pressure bubbles coming from behing the dashboard.....what is that?...its the first GM i've owned so im kinda new to all of this.....any help would be greatly appreciated

[N8SBlaze]

Any idea if the water pump has ever been changed on the Blazer? Just a thought.
The gurgling sound behind the dash is probably air trapped in the heater core. I have the same sound on mine from time to time. I have seen a procedure posted on this forum to get the air out by parking on an incline, or put the front wheels on ramps to raise the front end. When the engine is cold remove the rad cap, start the vehicle, let the coolant circulate, as the air works its way out of the system it will burp at the rad cap opening, add more coolant as needed and replace the rad cap. This works because on level ground the heater core is positioned higher than the radiator, and air can get trapped in the high spots. When the front end is inclined the radiator is then higher than the heater core.

[rajiv1]

thanks alot for the advise, i will definately do that to try to get the noise to stop....as for the water pump...i have no idea if it has ever been replaced, but i also plan on checking that tomorrow as well

[J-Ri]

If the EGR system is not flowing for any reason it will run hotter than it was designed to and can overheat. Also if it has dex-cool in it, I would flush that crap out and have it refilled with new universal green coolant. It will break down, form sludge, and start blocking parts of the cooling system. If it gets too bad, it will start disolving aluminum parts.

[old_master]

If you use green ethylene glycol in a system that was designed for Dexcool, you're asking for trouble, and you'll get it, guaranteed! It creates expensive ongoing problems that will continue to cause problems until you completely flush ALL of the green coolant out and replace it with Dexcool. Always use the coolant the engine was designed to use. Here is a great article that explains why NOT to change over from Dexcool to the Green ethylene glycol coolant.

http://free-auto-repair-advice.blogs...pens-when.html

Dexcool will sludge up if the cooling system is not maintained correctly. The system should be completely flushed and then filled with a 50/50 mixture new Dexcool, every 5 years or 100,000 miles. Dexcool will turn to a brown mud if even a small amount of green ethylene glycol is added by mistake. The radiator cap can also clog up and not regulate the pressure correctly. Cheap insurance just to replace it.

[N8SBlaze]

Originally Posted by old_master

If you use green ethylene glycol in a system that was designed for Dexcool, you're asking for trouble, and you'll get it, guaranteed! It creates expensive ongoing problems that will continue to cause problems until you completely flush ALL of the green coolant out and replace it with Dexcool. Always use the coolant the engine was designed to use. Here is a great article that explains why NOT to change over from Dexcool to the Green ethylene glycol coolant.

http://free-auto-repair-advice.blogs...pens-when.html

Dexcool will sludge up if the cooling system is not maintained correctly. The system should be completely flushed and then filled with a 50/50 mixture new Dexcool, every 5 years or 100,000 miles. Dexcool will turn to a brown mud if even a small amount of green ethylene glycol is added by mistake. The radiator cap can also clog up and not regulate the pressure correctly. Cheap insurance just to replace it.

Old Master,
Thanks for posting that article. It was good to read and understand the differences in the coolants.

[rustymac]

Make sure you get all the air bubbles out after you flush the system. That is probably what is causing your issue. At high speed the trapped air is not allowing your coolant to flow properly to cool your engine.