1989 Chevrolet Other engine overheating

Hello,

Have you check the Fan Clutch?

With vehicle cold and not running spin fan - should spin easily - now start vehicle run till normal operating temp, shut engine off, Carefully spin fan again should be tight or harder to spin. If spins easily like vehicle when Cold replace fan clutch.

When vehicle is cold the fan will not go but a quarter of a turn, should it turn freely without my hand on it.

No it should just turn easily by hand

it is very stiff so does that mean it is the fan clutch needs to be replaced.

Is that with vehicle hot or cold...

If hot then no - When cold should be able to turn by hand easily, as it heats up it begins to tighten up to create more air flow so will be harder to turn by hand.

Ok, you said you checked the Radiator how did you check it?

If you can run your finger along the fins if they disintegrate or break up then would replace radiator.

flushed it out and it has a good flow to it.

that was with the vehicle cold on the fan we checking on it when it is hot.

What is the normal operating temperature for a Chevrolet 350 V8 5.7 L ?

ok with the vehicle is hot the fan turn easily for a few turns then it tightens back up like when it is cold. Also when you first start the truck the fan runs really fast then starts to slow down some.

I believe it around 180 - 195

Even if you have good flow in radiator it the Cooling Fins aren't doing there job it will over heat.

ok how will I know if the fins are doing there job.

With vehicle cold run your finger down different areas of the fins on the radiator. If they brake up easily or disintegrate then they are not doing there job.

Also, you said you changed the Water Pump did the overheating start after the replacement?

it started before I changed the water pump. I took the fan clutch off and it has a broken spoke on it. So do you think that could be it. I checked the radiator again and there are not any brake up or disintegrating.

Since it is broken I would replace it. It could be the cause but not sure.

Another thought is that there is an air pocket in the engine causing a hot spot which will cause it to overheat.

The way I usually attempt to get it out is to jack up the front of the vehicle so that the bubble will start to work its way out. Then run it with the cap on loose till gets heats up if has a gauge run till not quite in red, then let cool down refill with water if needed. You will know once bubble is gone, temp will go back to normal. This could take a few hours. It once took me 3 hours to get it out.

We are going to change the fan clutch out and then I will let you know what I find out. If that fixes it or not.

OK

changing out the fan did not work. when you are sitting idle it does not run hot. when you go down the road as long as you stay below 55 miles per hour it does not run hot. when you get up to 70 it starts to run hot.

OK, did you change the Fan Clutch or the Fan, pics below are the Fan Clutch may not look exactly like the one on there.

sorry I said fan but it was the fan clutch.

OK, do you know what temp thermostat you put in also did you replace the Radiator Cap.

I put in a 195 temp thermostat by Murray and replaced the radiator cap with thermo king by Mr. Gasket.

OK, well I am looking more toward the Radiator since pretty much everything else has been changed.

Now a few other things, less likely but have seen a few times in my 25+ years as a mechanic...

Have you noticed if any of the hoses are or have collapse, if not run vehicle and check all hoses. The lower radiator hose is the one I have seen collapse, and it's usually do to age.

Check the top hose does it get hot after vehicle has been running or is just warm. If just warm then thermostat isn't opening completely so may have a bad one. I would also suggest using a 180 instead of the 195.

Forgot to ask what is the exact vehicle you have?

it is a 1989 Chevrolet 350 5.7L . I checked the hoses they get hot not warm and I checked the one on the bottom and it is ok.

OK, So all you are giving me is that it is a Chevy with a 350 or 5.7L engine. Getting the exact Make, Model and engine I can look it up to see it there maybe something I may be missing.

So I know it's a Chevy now what kind of chevy .....

Need Model - I take it that it is 2 wheel drive since you have it as RWD and not 4WD

If Car what model Malibu, Monte Carlo, etc

If Truck what Model - C1500, C2500 C3500

If Van what Model - Astro, G10, G20 G30

And I know it has a 5.7L/350 Cubic Inch Engine