What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Cooling System Overhaul - Stumped and Frustrated

Not real familiar with the diesel stuff. I know the big block mounts are different, and if I'm not mistaken, if you look where the 34" radiator mounts on the drivers side(?) the bolt holes are on the angled portion. That must use a different bracket then.

On top of that, different fan shroud, not sure how easy it would be to find a 34" radiator fan shroud for a small block. Would need to make sure that nothing is mounted on the core support that the larger radiator would interfere with.

Whole other can of worms, but if cooling capacity isn't enough, towing will always be a problem.
 
dyeager535 said:
Not real familiar with the diesel stuff. I know the big block mounts are different, and if I'm not mistaken, if you look where the 34" radiator mounts on the drivers side(?) the bolt holes are on the angled portion. That must use a different bracket then.

On top of that, different fan shroud, not sure how easy it would be to find a 34" radiator fan shroud for a small block. Would need to make sure that nothing is mounted on the core support that the larger radiator would interfere with.

Whole other can of worms, but if cooling capacity isn't enough, towing will always be a problem.
Click to expand...


Thats why i didn't get the larger one when i did this cooling system overhaul.

f*ck me.
 
If the links I had are even close in specs, your '91's radiator capacity is about half of what the '94 was.

My initial thought was that airflow was the key, but that may not be true. I would want to hear from some folks that push their '73-87's hard with fairly stock cooling systems.

Pretty sure my Dads 454 K20 towing a 3000lb trailer over the mountain passes never gets "hot", but it's also not doing it in the summer...ambient temps are probably 50* at best.
 
You are saying capacity is half based on Length x width x height volume?

Really, at this point, throwing money at the problem will be acceptable, assuming i get the right solution.

During this thread, lots of people have recommended some reasonable "performance aluminum" radiators. My concern is how they will mount, how "universal" they are, and if they have the trans cooler built in that i need.
 
I probably mentioned it already, 4 row radiator, heavy duty fan clutch.

I've never had a problem with heating up, even while towing and still using the factory fan blade. It was a huge improvement since when i bought the truck, it had a stock, I believe 3 row and a stock thermal fan clutch.

When I left Phoenix a few years ago, pulling a decently heavy loaded trailer, it never ran anywhere over the 210 mark on the mountains leaving Phoenix heat.

Once in the cooler climate, I couldn't get the engine to maintain enough heat, it would never read the t-stat range, usually 10-15* cooler, even with the grille completely covered with vinyl and part of the radiator covered with cardboard. That 4 row with hd clutch was basically overkill for a cooler climate, but worked good in Phoenixs high summer heat

I saw where you replaced the fan clutch with new, I don't remember though without searching the whole thread again, was it a standard clutch or heavy duty.
 
4xcrazy said:
I probably mentioned it already, 4 row radiator, heavy duty fan clutch.

I've never had a problem with heating up, even while towing and still using the factory fan blade. It was a huge improvement since when i bought the truck, it had a stock, I believe 3 row and a stock thermal fan clutch.

When I left Phoenix a few years ago, pulling a decently heavy loaded trailer, it never ran anywhere over the 210 mark on the mountains leaving Phoenix heat.

Once in the cooler climate, I couldn't get the engine to maintain enough heat, it would never read the t-stat range, usually 10-15* cooler, even with the grille completely covered with vinyl and part of the radiator covered with cardboard. That 4 row with hd clutch was basically overkill for a cooler climate, but worked good in Phoenixs high summer heat

I saw where you replaced the fan clutch with new, I don't remember though without searching the whole thread again, was it a standard clutch or heavy duty.
Click to expand...

Do you happen to have part numbers for what you ran?

I'm running ACDELCO1540131 (15-40131)Radiator Fan Clutch
 
No, I bought from AutoZone back when I still bought their stuff. It's just labeled as either sever duty of heavy duty.
 
Seems like the HD Delco is: 154553

That definitely seems like somewhere that I have made a mistake.

Not having the right fan clutch. That was always a concern of mine, too.

Little details like that make a big difference, only took 228 posts in this thread for me to identify it :doah:

Going to leave my AUX gauge hooked up for a while, remove the Tstat this weekend, and get the HD fan clutch in there.

Thanks for the continued help guys!
 
4xcrazy said:
I probably mentioned it already, 4 row radiator, heavy duty fan clutch.

I've never had a problem with heating up, even while towing and still using the factory fan blade. It was a huge improvement since when i bought the truck, it had a stock, I believe 3 row and a stock thermal fan clutch.
Click to expand...

What were your truck specs? I don't mind someone else spending money, but I don't like suggesting things that don't work. Obviously though, that 34" radiator was used for a reason. Would be helpful to know what all your truck was setup with regarding motor, trans, gears, tires, to get an idea how close the two are.

Was that the 34" radiator, or the 28" one?

And yes, just based on the H x W x L is how I derived the half capacity. Even that seems odd to me though, realistically you are only able to move "cold" air over a spot of the radiator the size of the condensor, everything else is just additional capacity with marginal ability to cool due to underhood air.
 
New rebuilt 355 with roller can& lifter setup added, all stock except the cam/lifters and headers. New rebuilt th700r4, both new when installed the same time, np241,14bff rear with 4.11 gears 35" tires.

This cooling system setup was installed with the previous factory engine that had well over 260k miles on it. Only time it ever heated up was when I JUST installed the bigger radiator and clutch, drove it to So.Cal one summer without the fan shroud in place. It's amazing how much that one simple piece helps.

Leaving L.A. area back to Phoenix, climbing the hill from Indio/Coachella area, It's a pretty good climb, I was pulling a trailer with truck parts and the engine ran up near the 250 mark and the heater running full high. That was the last ling road trip that engine made. It never blew up but developed a small leak in the head gasket. I just opted to rebuild with the mileage that was on it.
It still ran for several more months, but occasionally it would heat up real quick, then cool down real quick in a few cycles, I'd check the coolant and it was low.

After the shroud was modified slightly to work with the larger radiator, it never overheated, unless it was real low on water, obviously.
 
Honestly I never measured, whatever the factory size is for the 89 half ton suburban, it was just a sever duty cooling design, 4 core instead of factory 3.

It fit directly in place of the factory unit, only mod was "stretching" the upper brackets to reach all the way around the tanks and some trimming of the fan shroud to accommodate the thicker radiator.

It's the Burb in my signature picture, below.
 
I was just towing 17,000 with my 1988 V10 Suburban (far from stock) and I have a 180 degree thermostat with two 1/8" holes drilled through it. The temp gauge never left the mark between 100 and 210.

Martin
 
Martin might be on to something with the bleed hole. I have known of some vehicles that needed it, tho i dont remember why.
 
It bypasses the stat to let some water by to keep the engine cool as its warming up. BB's use a hose from the waterpump to under the stat and bypass it that way. And, if absolutely no water is circulating, the stat would take an awful long time to open up.
 
I am betting a hole in the stat will help also, But it shouldn't help the overheating concern while towing.

The small block does have a coolant bypass built in, any chance it is blocked somehow? It is the small hole under the right water pump coolant port.
 
black dawg said:
I am betting a hole in the stat will help also, But it shouldn't help the overheating concern while towing.

The small block does have a coolant bypass built in, any chance it is blocked somehow? It is the small hole under the right water pump coolant port.
Click to expand...

It is a brand new engine, it shouldn't be.

Mafrtin
 
y5mgisi said:
Martin might be on to something with the bleed hole. I have known of some vehicles that needed it, tho i dont remember why.
Click to expand...

No thermostat should help that. LOL.

Plumbed with a heater, the small blocks are all "bled" since the intake feeds into the radiator (or water pump) via the heater hoses.

AFAIK none of our trucks used a valve on the heater hose to shut that off, so it's constantly circulating coolant whether the thermostat is opened or not, and is why on at least some cars GM actually used valves to keep coolant from entering the heater core and thus cabin with the heater off.
 
You must log in or register to reply here.

Latest Posts

Top Bottom