Ok I am having issues with my heat. It's luke warm to cold at times. I replaced the thermostat today and purged the coolant system of any air pockets to no avail.

My temp gauge at it's highest reading will only go to about 160 degrees when I am on the gas and as soon as I let off will drop down between the 100 and the quarter mark which is about 155 degrees.

However now if I hit the gas you can hear a gurgling sound coming from the heater core. There are no leaks, no smell, and no fogging of the windshield.

My next step I thought would be to flush the coolant system and get that dexcool crap out of there. I have never been a big fan of it anyway and was in their when I bought the car.

Any other ideas?

 

DexCool is not the problem. Sounds like you have a plugged heater core. Flush it out both directions.

 

lol I know it's not the problem I'm just a little old school and don't appreciate the change

I was wondering if a flush would help? The coolant color is a funky orangish brown color, almost like a muddy river color. Only issue is I left all my hoses in the shed and they are froze solid.

However my cousin works at a local GM dealer so I may take it in there and have it done for cheap.

So is the opinion flushing the entire system sound like the way to go?

 

Flush it. Refill it with whatever you prefer. I still run the dexcool but I can't give a logical reason why.. <G> The secret to it is never let it get low and get air in the system so it's never given me a problem. The thing I wonder about are those cool temps, it sounds like the stat is stuck open? (new or not) Also did you remove the cap and check the antifreeze level in the radiator? (Check it cold) Don't just go by the bucket level, if you have a bad cap it may not refill the system properly. That "gurgling" after replacing the stat sounds like the system isn't full.

 

I've checked it cold and it is full, the cap on the radiator is new, and the reservoir tank is full too. I am wondering if the heater core is just plugged up?

 

I have experianced the same problem,
I have to purchace a Prestone flush and fill kit, cut the heater line and install the flush adapter, and just like the other posts mentioned
flush, and also a cleaner to remove all the build up in the line,
It all works fine now, just a little time consuming

 

ok I took some readings after letting my car warm up...Line running into thermostat housing was around 200 degrees, upper radiator hose was at 155 degrees, lower radiator hose 100 degrees, passenger side heater core line (larger diameter hose) 155 degrees and driver side heater core hose (smaller diameter hose) was only 120 degrees. btw these obvisouly are all fahrenheit and my blazer is a 1997 4dr 4x4 auto tranny. maybe this can help?

 

In for response. I have the same issue with my 97 blazer. It will get hot to open the stat, then run at 155 only blowing warm air not hot. I recently did the intake gaskets cause they were leaking, and replaced the stat then. I had this problem before doing the gaskets also.

 

I see this a lot after doing an intake manifold gasket. Usually it is a plugged heater core due to tiny bits of the disintegrated gasket making their way through the cooling system and getting stuck in the small lines of the core. (note that this can also be an indicator of pending gasket failure)

Flushing out the system, including back flushing the core usually fixes the problem. The more through the flush the better as it does not take much to plug up these heater cores.