2001 blazer LT 4Door 4wd

I have had some heating issues in the past with this car, but as of late I can not seem to figure it out. I have just changed the thermostat (admittingly I bought the cheapest one) and that worked for a bit but then after 2 days the car over heated again! I'm gonna try changing the thermostat again since it is under warranty, but this would be the third thermostat in a couple month period (first in may, then I over heated and ran out of coolant. Second 2 days ago and another probably tomorrow).

Also on more of a side note I decided to look for a potential leaking head gasket. Well the dip stick came up clean but in the coolant res there were what looked like brown flakes in the mix. I do not think it is oil though, and the reason why is because the first time my car over heated I lost all of my coolant and there was a brown coating all over the res but it was like dirt, not oil, kinda looked like rust almost (redish brown). I rubbed my finger on it and it was like a dusty substance. I think the flakes in the coolant are left over from what ever that was. (had the system flushed). And on the last over heating there was coolant coming out of the overflow and there was no moister on the exhaust.

Either way, I came here trying to figure out two things, what can cause the blazer to keep over heating, and confirmation of no leaky head gasket.

 

Could be that you have a bad fan clutch.

I just replaced mine from being engaged nearly 100% of the time, but they can fail where they engage 0% of the time as well. Even though the fan is spinning, doesn't mean it's doing any cooling.

 

I don't know if this will make a difference or not, but when the thermostat was replaced the car worked fine for about 2 days... 20 miles of 60 mph and 10-20 miles of city driving total.

When I noticed this last time I was on a trip to town. It overheated and I had to pull over, let it cool off and drive a few 100 feet before it heated back up, inching my way home. Bout 1/2 way there the car stopped over heating... I still replaced the thermostat and it worked for a short bit. Not sure on exact symptoms of failing fan clutch so not sure if this is a symptom as well?

How difficult is replacing the fan clutch, do I need any special tools, and what should I look for when doing the replacement?
Also what brands/part number is best, but I am on a very tight budget, collage has a way of finding your wallet and draining it if you know what I mean.

 

Fan clutch can be found for about $25 online used. The typical tools to replace the fan clutch would be a large adjustable wrench (I'm takling about 1.5") and a strap wrench. They make a special fan clutch removal tool as well. If you have a compressor and an air chisel, that'll do nicely as well.

Are you sure the radiator is in good shape? How about the radiator hoses? Bulging or collapsed? You mentioned a flush, was it refilled with green or orange coolant? Does the heat work in the car?

 

You may have an air bubble in your system and you need to burp it. Put the front wheels on car ramps. Remove the radiator cap and run the engine through a couple rotations of the thermostat opening. Top off the coolant as needed.

 

The new coolant is green. The heat works when it is not overheating

 

No ramps, but I do live in the northern UP with very steep hills. Would a hill do the trick?

 

Yes. You are just wanting to tilt the truck so that an air bubble would be forced to float to the top of the radiator.

 

Changed the thermostat out with a new one and looked inside the radiator to see what the fluid level was... well lets just say it took nearly a gallon.
Strange part is that it is not leaking any of the new fluid, and passed a pressure test.

2 days with new thermostat and no overheating car

There was a bunch of brown gunk still in the radiator though. Pretty sure it is dex-cool remains.

 

So were you just low on coolant or was there an air lock that was causing a false full?