A buddy of mine has an 89 Chevy 1ton 4x4, reg cab, long bed, with the 454 engine and auto tranny. He has a slide in camper on it at the beach, and is having problems with it overheating while driving down the beach. He has removed all of the debri from inside the radiator, there is nothing blocking the radiator, and he has replaced the t-stat. Is there any common advice to get this thing running cooler????? He is thinking about replacing the clutch fan with an aux electric fan, and replacing the radiator to a larger unit. That is $$$$$$ that he really dosent want to spend on the beach rig, but if that is the only way that it will run cooler he will.

Thanks, JB

 

1st thing I would do is replace the radiator. I worked on a 2000 model Tahoe that was overheating, changed t-stat,w/p and hoses.

Still ran hot... took a hose to the rad while it was running and the lower half of the tubes in the rad were blocked. I know this because the water from the hose evaporated from only half of the radiators height. Top half was hot bottom half was cool, loosened drain valve while it was running warm and got cool water for a few seconds. Changed the rad and it runs like it should.

 

I'd have to agree replacement of the Radiator is probably your best bet!

Don't even bother to try and repair it! You'll spend money on nothing if you do!!

If the truck runs good and all within specs then check the fan clutch for leaks and replace the Radiator.

Rick

 

Before I agree with everybody here, is it overheating while driving it on the beach, like actually in the sand? With a camper on the back of the back of it, that's a pretty hefty load plus fighting through sand. I might try hitting the pavement again and see if that "cures" it before I started parts shopping.

 

Did it just start doing this or has it don’t this all along?

I would not replace the fan clutch with an electric fan.

When the clutch is working properly, it is a good design.
Just because the fan is spinning it does not mean it is working.

An electric fan with enough CFM to replace the clutch unit will draw enough amps to load down the alternator and at an idle might even be discharging the battery.
I know GM has 2 different types of fan clutches, thermal and non-thermal
The thermal ones have a bimetal coil on the front side and the non-thermal do not.
I had a suburban and it had a non-thermal I think the PO installed and I had an overheating problem.

I replaced it with a thermal clutch and it ran fine after that.
At the time the non-thermal clutches were around $20.00 and the thermal clutches were $80.00 so I can see how a lot of them got installed.

This can also cause a catch-22 situation if you are using your air conditioner,
Your AC is on and it is hot outside, your fan clutch is slipping so your engine is overheating also now there is not enough air being drawn through your AC condenser so the compressor head pressure raises 300- 350- 375 PSI with the pressure, now up goes the condenser temperature superheating the incoming air to the radiator.
At this point sometimes the compressor clutch is screeching or your AC belt is slipping or smoking.
See how it can get out of hand?

I have replaced AC compressors that have gotten so hot it had cooked the paint off them.

Besides the clutch,
Is there excessive pressure in the radiator check the coolant for combustion gasses.
With the engine cold, remove the cap and start the engine. There might be bubbles popping out the neck or the coolant level will rise.

I have worked on quite a few big block Chevy’s that have had exhaust gas in the radiator and most of them were in trucks or motorhome chassis.
This can be tested with a block check. I got mine from NAPA, it draws up a bit of coolant from the radiator and the test liquid reacts with carbon monoxide and turns yellow if there is a leak.
If you do have a leak, you can find which cylinder by grounding each separately.

Also check:
Leaking water pump seal allowing air to aerate the coolant.
Slipping water pump belts.
Lower hose kinked or internal spring missing. Hose will collapse under RPM’s
Fan shroud missing.
Ignition timing way off.
Auto trans slipping overheating fluid cooled by radiator.

Have the radiator re-cored with 4 row or better.

 

I really appreciate all of the information from you guys!!!! I will let him know all of this!!!

 

from past experience with several 454's I would vote for replacing the radiator. They can be flowing but have enough interal buildup that lets the engine overheat.

 

Well not wanting to step on any toes here or disagree with anyone, it very well could be your radiator.

But a number of years ago we had a similar truck (3500 GMC crew cab dually auto matic 454) and fought over heating problems for some time. Replaced the rad, several thermostats etc...... finally after several different shops took it to a friends 4x4 specialty shop 70 miles away and he found the water pump to be faulty. at high speed it would circulate enough water to keep it cool. at low speed (as on a beach) or idle it would overheat.


Just my $0.02

 

Sorry I can't help myself - tell him to install a Cummins under the radiator cap and all will be well.

 

His other truck has a Cummins in it!!!! This is his play toy/Beach Buggy!!!