So this morning I go out to start my blazer before I go to work, because it was -2. So after letting it run for about 10 minutes I leave and it is just starting to warm up. I get about 2 miles up the road and realized that I have no heat. I looked down at the temperature gauge and see that it is around 210 degrees and steadily climbing. Its normal operating range is around 160 degrees. So I turned around and got about another mile and I was at about 230 degrees so I pulled over and turned the engine off. Popped the hood and the overflow was almost full and the radiator cap was steaming and it was wet all around it. I drove home with the hood popped and it stayed around 230 until I got home. I changed my engine this summer and it had brown muck in it. We changed the intake gaskets and thermostat with the engine. Also I ran distilled water in it for about a week, then put fresh coolant in it, which almost immediately started to turn brown. I think I will do a coolant change and get a new thermostat and see what that does. Sorry for the novel but I like to leave enough information.

 

Sound like a classic freezeup due to insufficient concentration of antifreeze. Normal operating temp should be around 190°. 160° thermostat is too cool.

 

Your city is at 1° and sunny right now (9:30 am), so I suspect was as low as -7° at your l;ocation last night. (We were -10 last night and right now it is -2°).

 

I would also check the radiator and all the cooling system hoses. Sometimes all that "brown muck" is tartar and rust due to water minerals that start to acumulate and block coolant to circulate freely (like blocked arteries). You should also check that all the gaskets were installed correctly, so that you're not loosing pressure from the cylinders, generating extra pressure in your cooling system. Finally, I would also check the thermostat, I've seen some installed upside down....
Good luck!

 

I know the thermostat is installed correctly. I drove it on the day when it got to -15 and it was fine. What I might do is just drain it and refill it and replace the thermostat tonight and see what happens.

 

Is there a chance ethylene glycol, (green coolant) was added to the cooling system by mistake? When it mixes with Dexcool, it turns into a brown sludge. If that's the case, a simple drain & fill will not cure the problem. The engine, radiator, hoses, & heater core will need to be flushed separately, (possibly requiring chemicals) to clean it out.

 

Sounds like the logical thing to do. I would go back in with the normal temp thermostat and add only straight antifreeze, not the mixed stuff. But I'm sure you already know that so don't take offense.

What Captain said if the antifreeze types have been mixed.

 

When I got the engine I was pretty sure that it had Dexcool in it, so I flushed it with water, and then ran water in it for about a week. When I drained it earlier today only about half a gallon came out. However, I was on a slight incline. also I noticed that there was coolant all around the radiator cap and it also looks like it had come out of the overflow bottle. I'll work on flushing it this weekend.

 

So it has been almost a month since I had the overheat issue. I ran 6 gallons of distilled water and Prestone cooland flush through the system with the bleeder open and the engine running and no thermostat.

This is what I had after the first 3 gallons. It didn't look that blurry when I took it, but you can still make out the color.


After the next 3 gallons it started to come out clear. So I put a new thermostat in and filled it with 1 gallon of straight cooland and 1.5 gallons of 50/50. It is now green, but it has a little bit of brownish tint to it. I was planning of doing another flush in a week or so when it warms up. My only issue now is the temperature. I put a new 195 degree thermostat in but it won't get over about 165 - 170. Even with my e fans uplugged. If I let it sit and Idle for a long time it it will get warmer but during normal driving it won't get to 195.

 

Yeah sounded like a freeze up to me, plus the thermostat did not open or could not open.