96 chevy blazer overheating

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

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 ...




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

Replace the rad cap.

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

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

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

Including the rad cap?

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.

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

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...?

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.

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.

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.

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?

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.

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.

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

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

Any engine miss at start up or white smoke out tail pipe?
If all else fails.
Run a chemical block check test for head gasket leakage or crack head or block.
Most garages can do it for you or you can by the tester 50-100 $ US.
http://tools.batauto.com/index.php?crn=223&rn=1086&action=show_detail
MT

I just took my car to get looked at, and had the thremo replaced.
Ran smooth for an hour. Now it's getting closer to 260 degrees
every 4-5 minutes, then goes down to 220-235 range, then
back up 4-5 minutes later. And it's leaking coolant now.
I'm not sure how to broach the subject to my mechanic.
I have a lot of respect for him and his hard work. But man,
the problem just got worse. I'm taking it back in to show my
man the new development. I just took it in because I thought
they'd catch something in there while working on it.

I just took my car to get looked at, and had the thremo replaced.
Ran smooth for an hour. Now it's getting closer to 260 degrees
every 4-5 minutes, then goes down to 220-235 range, then
back up 4-5 minutes later. And it's leaking coolant now.
I'm not sure how to broach the subject to my mechanic.
I have a lot of respect for him and his hard work. But man,
the problem just got worse. I'm taking it back in to show my
man the new development. I just took it in because I thought
they'd catch something in there while working on it.

Well ask him to run a head gasket chemical block test on it.
If he has not done it or refuses to do it find someone else that will.
MT

I've just started to encounter the overheating issue and it seems to be getting worse as the days go on. I had my rad flushed, changed the cap and the water pump was replaced about a year ago. I also just replaced my heater core (What a nightmare job) It seems to run OK with everyday driving but I have two trailers that I pull, one with a boat and one for work. The boat trailer is relatively ligt so it doesn't ssem to affect things so much but the work trailer weighs in at about 1500# and it doesn't take long for the engine to get good and hot and it won't cool back down. My next step is the clutch fan but I don't even know if it's functioning correctly or not. When I first start the truck up you can hear the fan blowing pretty good for about a minute after I put it in gear and drive which is pretty normal to me after driving it for four years but I guess I'll see. Anybody else found this to work?

The only thing I can suggest is hooking up a scan tool and checking the temp as live data. I believe these vehicles use two separate sensors one as the ECT and the other for the instrument panel gauge. So its possible that the gauge sensor is bad. Hope this helps

my 92 s10 blazer just started overheating the same, its overheating im going to change the thermostat but have been reading that it could just be the radiator cap, now i have a leak and a puddle of antifreeze that i have to try and locate, any suggestions?

I have a 97 s10 that's over heating I done checked the fan clutch and the water pump I just flushed it and I have the thermostat out but it's still running hot any suggestions :confused:

I have a 97 s10 that's over heating I done checked the fan clutch and the water pump I just flushed it and I have the thermostat out but it's still running hot any suggestions :confused:

How many miles on it?
Does it heat up right away or just on a pull?
OUT and replaced or just out?
After ever thing else check rad air flow and run a head gasket test.

Go to Advanced Auto or Auto Zone and get a loaner pressure tester.
Put this on the radiator pump up to around 10 or 12 psi. Look for leaks if any are found repair. Then with the pressure on the system start and run the vehicle if the pressure gauge pulsates it indicates a blown head gasket. Depending on the water you have you may also need a new radiator.