Blazer overheats, bypassed heater core, still no luck
 

Hey all. I have an 84 s10 blazer 4 wheel drive, v6. I have had this Blazer for about 6 months. From the very beginning this vehicle has run hot. But in the last two months it has gotten worse and worse. Another good peice of info is that this blazer sat dormant for at least 10 years before given to me.

I have flushed the radiator. It was full of rust. Replaced radiator hoses.

Today I bypassed the heater core as I know it needs replaced.

None of this has helped the overheating. The last time I drove it, it overheated so bad that it was boiling.

What is next? Tomorrow I am going to put in a new thermostat. Hopefully that will fix the problem?

Any advice would help. What would be your next step in trying to fix the overheating problem?

Thanks for your help.

I'd also suggest picking up a new radiator cap...

good idea
 

I noticed that the radiator cap doesn't fit very well like it should, but would that be the source of the problem or just add to the problem

Both.

If the radiator cap isn't sealing and holding 16 lbs of pressure, the boiling point of the water held within is lowered.

I would say get a new radiator, or at least a good used one.

Did you flush the block itself? If the radiator was full of rust, so is the block. If it has been sitting for 10 years some of the cooling passage may be blocked solid.

And bypassing the heater core will not help with the overheating but rather make it worse. It is just another heat exchanger in the cooling system.

crap!
 

Ohhh boy. I took off one bolt of the thermostat housing just fine, but the other took some major strength, about half way getting the bolt out, the head snapped off. Now what do I do. ALso I noticed that there was no thermostat in there to begin with. What to do now? Also, how do I flush the block, as another poster indicated I do above?

To flush the block, it is best to pull the drain plugs that are on either side of the block just above the oil pan rail. They are difficult to get to for sure, but only then can you really get the block flushed properly. If there is crud down in around the cylinders, then you need to pull these plugs. You may have to fish up in through these holes to clear out any junk and then flush flush flush! Just use a garden hose through the thermostat housing opening.

About that housing bolt. If there is still a stub sticking up above the intake manifold, then you can get on it with a bolt-out socket or a vice grip and work it back and forth, using some WD40 or other penetrating type oil to help loosen it up. Do not try to just turn it out or you will snap it off again.

Good advice about the drain plugs, then a flushing tee to push the water thru. Did that with mine and got the temp down.