96 chevy blazer overheating

[jrroyal]

the entire cooling system has been overhauled; including heater core replaced 3 times, new radiator, new theromostat 2 times, new water pump, new radiator hose. truck continues to overheat into the red quickly with or without a/c on.
1996 chevy s10 blazer 4x4 4.3 liter (1 owner)

does anyone have suggestions on why or how to fix?
thanks

[drdd]

do a pressure test ... Autozone will rent you a pressure tester for cheap.

is it holding pressure? if not, there's a leak somewhere ...

on a '96, my first instinct after radiator and thermostat would be a leak in the intake manifold.

In the morning, after your engine has completely cooled, open the rad cap. Is it completely full to the brim? It should be.

Also, check your overflow level and that the hoses are not blocked ...

another check would be the temp sensor ...

try to eliminate one thing at a time ...

Originally Posted by jrroyal

the entire cooling system has been overhauled; including heater core replaced 3 times, new radiator, new theromostat 2 times, new water pump, new radiator hose. truck continues to overheat into the red quickly with or without a/c on.
1996 chevy s10 blazer 4x4 4.3 liter (1 owner)

does anyone have suggestions on why or how to fix?
thanks

[BlazerLT]

Replace the rad cap.

Check to see if the rad is full when dead cold in the morning.

[rlord]

My Blazer is doing the exact same - checked out or replaced all the same parts...any new developments?

[BlazerLT]

Originally Posted by rlord

My Blazer is doing the exact same - checked out or replaced all the same parts...any new developments?

Including the rad cap?

[rlord]

including the rad cap - although mine only overheats with A/C - and will cool fairly well by turning on the heater! Alternator just went out last evening (got the voltage meter to agree a bit ago) and was actually searching the site about alternators...thanks for the quick reply.

[BlazerLT]

When you say overheating, how hot does it get on the gauge?

[rlord]

If I let it- up into the red...it runs a bit over the 210 for the first 30 miles or so, then jumps quickly up to 230-35 before I turn off air and turn on heat - just had mechanic check water pump, fuel pump, head gasket, etc. etc. - the only thing he found was that the radiator was 20 degrees difference between top and bottom - we're planning on taking it out (again) to have it flushed (again), at a radiator shop tonight - maybe that will work...?

[BlazerLT]

Originally Posted by rlord

If I let it- up into the red...it runs a bit over the 210 for the first 30 miles or so, then jumps quickly up to 230-35 before I turn off air and turn on heat - just had mechanic check water pump, fuel pump, head gasket, etc. etc. - the only thing he found was that the radiator was 20 degrees difference between top and bottom - we're planning on taking it out (again) to have it flushed (again), at a radiator shop tonight - maybe that will work...?

You best be flushing the whole system instead of just the rad.

Reverse flush it and make sure EVERYTHING is clean, not just the rad.

[matt rock]

Mine just started overheating today. There's definitely pressure.
And it doesn't seem to be leaking. After 5 minutes after starting,
it rides slowly but surely near 260 degrees. I release some pressure,
to get my car to a safer area of town. This keeps it around 235-240
degrees. There's no leaks. I'm hoping its the temp sensor.

[matt rock]

When I say slowly but surely, I mean the gauge,
not the car. I'm reading in another thread about
fluid anaylsis and replacing the radiator. But
it's going to have to be rectified soon, because
the weekend has very little mechanics open,
you know? And I can't feel like I can get away
with releasing pressure just to get where I
need to be. That's what my Blazer's for, and
it's a problem child. Even with the right amount of TLC.

[magnum3456]

Originally Posted by jrroyal

the entire cooling system has been overhauled; including heater core replaced 3 times, new radiator, new theromostat 2 times, new water pump, new radiator hose. truck continues to overheat into the red quickly with or without a/c on.
1996 chevy s10 blazer 4x4 4.3 liter (1 owner)

does anyone have suggestions on why or how to fix?
thanks

Mine would appear to have overheated too a while back...I ended up replacing the intake manifold gaskets because the shit dexcool coolant they tell you to use corroded away the gasket and it put loads of coolant into my oil...does your oil look milky? I swear the only reason they tell you to use DexCool is so that the Chevy company can ensure repairs down the road. anyone else think the same?

[matt rock]

actually. it's not milky at all. I'm goin to get some codes
in a minute. now I know I'm ignorant about this stuff.
but I've been reading this forum through and through today.
and I don't have anyway to drive it sparingly until
monday afternoon.

[muddog321]

If you did all that and its also not the intake or head gasket and you did the pressure test then- radiators are aluminum now and Dex cool can clog the passages but you can't see in there - you only see in the plastic end tanks with the trans cooler below the cap. A new radiator is $160-200 DIY.

[Teal95Jimmy]

Also check to make sure your fan clutch locks up when the engine is getting into the higher temps. My 95 was doing the same thing but when i spun the fan it would just free spin when the engine temp was pinned at 260. Replaced it and its running a tick or 2 below the 210