WHY is this engine overheating?(truck, not tractor)

[Olmike]

I think John Bud hit it on the head.A 91 caprice has A serpentine belt that turns the water pump opposite of the pickup.

 

[gemini5362]

If the water pump is turning the wrong way, would it not overheat even with the thermostat out ?

 

[oliver28472]

That is unlikely. He did not say that the water pump had been removed from the V-8. As far as we know so far all the accessories on the front of the V-8 came with the V-8.

 

[Hooked_on_HP]

Check your ignition timing. If it is to far advanced it will cause overheating. Is the v8 carburated or throttle body. If it has TB it may not have enough fuel pressure, causing a lean condition.

 

[normde2001]

Does this engine have a t-stat bypass hose, and if so is it clear?

 

[Jstpssng]

Thanks for your replies, you've given me plenty of food for thought.
Of course, the diagnosis is only as good as the information I provided.

Most likely I have several issues to address, which are causing my problems.

The water pump appears to be working; the thermostat is installed properly.


However not only is the radiator for a V-6, the previous owner just informed me that they didn't switch out the computer either. That could result in improper timing as Hooked on HP suggested.


Thanks for the help. I'm trying to get better at fixing things, instead of just keeping them running; I may have bitten off more than I can chew this time.

 

[RobJ]

I wouldn't think a v6 computer would even run a v8.

 

[Jstpssng]

I wouldn't think a v6 computer would even run a v8.

that's what I thought, also; so assumed they had swapped it out.

I guess that's what I get for ASSUMING!

At this point i'm realising i have more problems than I care to deal with; anybody want an even swap for an old single speed bicycle?

 

[mrcaptainbob]

Had a similar problem in my truck. Inherited it from my son a couple years ago. He had a weather screen across the grill to help warm it up. After several t'stats, I inadvertently left the rad cap loose. It bubbled the coolant to the point of overheating...not maxed out, but close. Filled the coolant back up to level and have had NO problems since! Turns out there was an air bubble in it! Also found that this is a common method for 'burping' the system!! Maybe your problem??

 

[TrippleT]

I think all the ideas are pretty good, but I would bet George is right. The radiator and shroud make a lot of difference. I had an old GMC that came with a 6 cyl engine and it was switched to a V8 and always gave trouble in the summer because the fan was to far from the radiator and there was no shroud. And if the rust was severe it may well have ate the fins on the pump too. Can you take the cap off and see the water moving? DON'T do that while it is hot! If it is moving pretty good the pump is probably still good.