My mother's van just had a head gasket blow and so she is going to be driving my blazer since I am going to be gone for a month but the thing is is that every now and then it will start to overheat.

A couple months ago I noticed it overheating and the radiator was empty but it was full the previous day. So the next day I check it and it was empty. We looked for several hours trying to find a leak till eventually we gave up and poured in Bar's stop leak.

Well now around 2 weeks ago if you drive it for more than an hour it will overheat. The reservoir and the radiator are full, compression tests were good, the water is circulating, and the thermostat is currently missing to see if that was the problem.

A/C seems to accelerate the time it takes for it to overheat. The coolant is now a murky brown in color but it doesn't have a sludge consistency, I figured that could have happened from the Bar's. The oil levels haven't changed and the color of it is still the color of oil also.

Any help would be really appreciated and the faster the better. Thank You.

 

first off what is your blazer?
year?
2x or 4x?

i would check the fan clutch...i had a similar overheat issue last summer...ac would make her heat up...turned out the fan clutch was bad.

i hope you have that disappearing coolant issue fixed....ever have the intake manifold gasket done? if compression check was good i would look there. i also had that problem...not as bad as you but very slow and steady coolant leak on to the top of the engine.

search around...i think those maybe your two issues.

 

Thought I was forgetting something. It is a 2003 2wd. I will look into those two things. It hasn't leaked since I put the stop leak in it. My mechanic couldn't find it either so he was the one that recommended the Bars.

 

bars makes a mess of things, gums everything up just a band aid fix. x2 on the intake manifold just because you said the coolant is murky, it could be internaly leaking and burning the coolant out the exhaust. best thing to do is put a coolant pressure tester on and pump her up and let it sit for awhile. should hold its pressure if not she got a leak and you gotta find it.

 

Pull your dipstick and oil filler cap. If it smells like coolant you have a leaking intake gasket.

 

coolant disappearing is never good at all. It could be 2 things that I can think of. First guess is Lower intake. I have heard of coolant leaking through the exhaust ports and exiting via the exhaust which doesn't show up for a while until the cat gets clogged up over time. Another less likely one I have heard is the tranny cooler baffle breaking inside the radiator and mixing atf with coolant. Coolant ends up draining into the tranny. Check the tranny dipstick aswell. LIMs usually leak on these motors underneath the a/c compressor so I would check there as well for coolant. It is a hard to see spot on these motors. Good Luck hope its an easy fix.

 

my 96 blazer lt, had a slow leak in the overflow bucket, and every time I took it to the mechanic, it would appear fine, he used plug tabs and ran it hard for 20mins, replaced rad cap, and some other things and it just finally blew the reservoir, we replaced that and haven't ha a problem since

 

Alright here is break down of responses to the thread.

I have checked the oil dipstick and the oil reservoir, all looks fine and smells fine.
I will never no if it is the exhaust leaking by the Cat clogging because I don't have a Cat.
Pressure was looking good last I checked.
I will check the transmission.


Is the fan clutch the brown round disc that is infront of the compressor like on the other side of the belt? Because every now and then when the car is running it will stop spinning and then a bit later start back up.

 

That would be your a/c compressor, the fan clutch is attached to the engine fan which is bolted to the water pump pulley.

 

And put the thermostat back in. The purpose is to trap coolant in the radiator so it has a chance to cool. If the system is open, constantly circulating, the water cant cool off. Put -stat back in.