The Stovebolt Site Forums The Shop Area Engine Shop Fan shroud?

Did our 47-53 trucks come stock with a fan shroud? Mine is a '53 GMC 1-ton with a Chevy 235 engine and does not have one, but if I sit in traffic in 90℉ heat it gets up to 215-ish℉ and doesnt seem happy.

I don't think that they did. Later models like my '59 didn't have shrouds with a 235 engine. V8 engines had them but the fan was farther away from the radiator with a V8. I don't have any experience with your truck model though. Old radiators are often partially clogged up. When I was younger, I had several old vehicles that ran hot in hot weather until I got the radiator rodded out.

Retarded ignition timing can have an effect on engine temp.
What year 235?
Water pump location and fan clearance could also be a problem.

A fan shroud was installed on big trucks, this will retrofit to small trucks and is easy to install as it splits. Here are some pictures of the shroud it install on the same bolts as the radiator. I am unsure of the ordering or installation scheme, I have found four on 32 AD trucks, all identical and all on 2-tons.
https://www.flickr.com/photos/advance-design_parts_co/10039269655/in/album-72157631868452754/

As the locus of fan blade position sweeps closer to the top and bottom tanks (covering the entire core) the need for a shroud diminishes.
If the fan sweep is not centered, or is significantly small than the core, hot air already behind the radiator will simply be recycled (rather than fresh air being pulled through the core).

According to the casting number the engine is a 1954 GM replacement engine. Brand new water pump and a stock fan. Stock radiator. The engine is mounted back tight against the firewall so there is some space between fan and radiator.

A 1954 engine should use the high mount water pump. There will be a little more space between the fan and radiator with a Chevrolet engine in a GMC,but I have seen this swap work without heating problems.
I would look closely at the timing, and radiator condition.

Ok thank you

When looking at Brad's picture of the big truck shroud, do not scoff at the diminutive design of it. It makes a huge difference in the airflow and cooling ability while sitting still.
I put one on my '49 with a 350 in it and the fan now will suck the sheets through the key hole from the other side of the house (as they say).
Carl

my 52 with the 235 had no shroud and it never got hot and I drove
it daily, well I take that back, it almost got hot once when the
harmonic pulley came off at 65 and I was trying to get off the hi-way... I was lucky, it dropped and hung up,only lost the belt and nothing hit the radiator.. had to have it towed home but I was ok with that..

Air management has 2 separate functions, divided by vehicle speed.
Below 35-50 mph (roughly, depending on the shape of the nose and grill) the fan delivers most of the air, and works much better with a shroud.
Above that speed the fan does nothing, all incoming air that reaches the grill opening passes through the radiator core regardless.

Well I put in a brand new radiator and advanced the timing and it still creeps up to 220℉ on a hot muggy day outside. Its probably 90℉ and sunny. Any other ideas or just don't worry about it?

Is the coolant boiling? Does the temp go down when the vehicle gets up to speed? If you can answer "No" and "Yes", respectively, don't sweat it. A 15 pound pressure cap will let the coolant go to 257 degrees before it boils. Just be sure to run a recovery tank so any coolant that pukes out will get drawn back into the radiator as the engine cools down.
Jerry

Thanks Jerry - it does not boil, but it only cools down when it sits at idle, and it goes down to about 210. It seems to run hottest at about 50 mph in overdrive.

Check to see which way the fan is moving the air. If you happen to have a fan for a serpentine belt system and conventional belts it will be pushing against the air stream out on the road. If the fan is cancelling out the ram air, things will get hot in a hurry.
Jerry

I had a similar issue on a Ford 302 V8 one time. It turned out the cylinder head had a small lump on the mating surface that allowed exhaust gases to flow into the coolant. That was a huge pain to diagnose. After replacing every single cooling system component with upgraded parts I figured out what the problem really was.

Place a funnel in the radiator filler neck. Fill with coolant until it is in the funnel itself. Run the motor until the thermostat opens and look for any air bubbles coming up through the coolant. The test seemed a little weird, but sure enough I had big bubbles coming out of the radiator. Had the heads machined and the overheating problem disappeared.

Chad

Thanks for the additional ideas. The fan seems to be pulling rather than pushing so I think thats ok.

Interesting idea on the head gasket. It does leak some oil out of the back of the head - who knows, maybe there is a leak.