is the "Frostbite FB167 Aluminum Radiator, 4 Row, 1973-1991 Chevy/GMC Pickup" garbage? bbc c30 getting hot with ac on

[winfred]

hello, i'm winfred and i have a truck problem, 91 v2500 square burb, 78 c30, 96 dodge 12v dually, deuce and half, 84 c20 that might get upgraded from parts truck to nasty blown LS stepside if i can get a title.... i am an ase master tech for diesels at a chevy dealer in baton rouge loserana, and a dozen years before that i did bmws and volvos

trying to get my 78 454 c30 3+3 dually on the road and it gets warm, some back story, got the truck off ebay as 100% rust free socal truck, so far that's the only correct thing from the listing, but that's a story for another time, maybe a build/introduction thread, looked to have sat 20-22 years (by the registration and possible original inner rear tires, the completely hashed th400 due to the retarded way they lowered the back suspension is certainly what parked it) the guy i got it from got it running, wiped some clear on it and flipped it as a drivable runner (junk trans and all).

i dig in and start pouring parts/money all over it, original brass rad was covered in fuzzy green splotches where it was getting thin and seeping, a couple of which started leaking on the first real drive other than put putting around the block on 1.5 working gears, so i hit it with a 4 core aluminum after a good flushing (coolant was nice and green that came out, but very old) hosed out the block good then fished around in the jacket with the coolant machine suction pipe looking for crud, new water pump, 180 t-stat, new hoses, distilled water/peak and all was well with that system while driving or idling, till i got the ac working, added a new severe duty fan clutch to the system and that helped a little, but it slowly warms up on the interstate, and creeps up at idle, i kill the ac at 215 on interstate and 225 at idle then fast idle it back down below boiling point before shutting it off, it has not blown the cap at any point

i installed a holley terminator x max 4150, it's temp reading from the crossover by the t-stat on seems to agree with the cylinder head gauge reading, 200-205 seems to be around straight up and 216 is approaching 3/4 mark, its not building any extra pressure that remains after cool down, nor is it losing coolant, without ac on it runs 180-190 on interstate with the t-stat's rating (4.10 gears put 65 at about 2750 70 @ 3k but a 4l80e is almost ready to go in and might help by slowing the engine down) the gearing is not helping the temps with the rat all wound up tight, but that doesn't effect the idle temp, i even pulled the trans cooler duty out of the radiator and stuck in a big hayden cooler, as the trans seemed to be getting excessively hot and grumpy (i think too much metal went though the valve body scarring it up, seems a little less grumpy on the external cooler)

7 blade fan on new clutch, on new water pump, through new hoses (don't think its sucking the lower closed, if it was it would do it with ac off) big radiator (read about 4 core having airflow issues, but i would expect that to be more of an issue at idle) fan shroud in perfect shape

lotsa rambling, hope it is not too horrible to read

 

[Finkaire]

After ordering two aluminum radiators “didn’t fit” I had my original copper and brass radiator from 1984 recored. So I can’t say I had an overheating problem with the aftermarket radiators. Wasn’t inexpensive but it’s original. My question is and maybe I missed it, did it overheat before swapping out the radiator. The fan and the shroud do play a major part.

 

[winfred]

ac was not functional or a priority while the original rad was still in the truck, and it didn't get hot with ac off, it can idle or go down interstate at 70 just fine, the heat from the condenser pushes it over the edge

7 blade fan and shroud are original to the truck, i fitted the shroud to the radiator with rubber to close any gaps, it did take a little creativity to secure the radiator in the mounts, but its secure and in position

 

[Sad Sack]

Fan clutch used?

 

[winfred]

new severe duty hayden, it locks up and gets after it, it stays locked up while i'm cooling it down at a fast idle and ac off till sensor readings are in the 190s

 

[Ricko1966]

Have you sprayed out the condenser from the front and rear? Sound like the condenser is getting hot and heating up the radiator. Where is your timing at? I think I'd clean the condenser fins put a pusher fan or 2 in front check my A/C presdures and make sure I had enough timing. Low timing causes heat also,but sounds like major issue is heat off the condenser.

 

[winfred]

cleaned the condenser multiple times, had so much sand in it and the original radiator, i thought i was going to need to file taxes in california

can eat off of it now. timing 13-33, no room for front fan with 73-74 grill, tried to put a big spal puller on the back side, but the listed measurements and actual measurements aren't close to the same thing, so my supercharged bmw will get it.....

ac just has 2 pounds of r134 so far, but it cools pretty good, like it's close but i haven't had a chance to find the goldilocks charge amount yet (i'd guess low 50s high 40s at the vents by hand feel, no thermometer verification yet), truck so far lives at the dealer i work at near my 11' long snap on box of goodies, so weekend tinkering is mostly out

 

[Ricko1966]

Wrong AC pressures will heat up the condenser. IDK just something I'd check. Heck check the condenser temp see how hot it's getting. Maybe we need to figure why it's getting to hot and how to cool it off.

 

[winfred]

light performance tested the ac and cooling system friday, condenser failed miserably with r134, at 13-1400 rpm fast idle with fan clutch locked up and my big shop fan feeding air the engine stays cool, and the clutch will disengage in the 190s with ac on

problem is, now the kinda high at 250 head pressure goes thermonuclear without the fan clutch, i give it a bump of freon and it goes up more than it should've while fan was in, so i drop 1/2 pound to 1.5 and run again, down to a better (for a r134 conversion) 225 but system is low enough the accumulator/return line has stopped sweating, bump it 1/4 pound and it starts sweating some and pressure goes up to the 2# reading, bump it another 1/4 and it's back to making serious water and approaching mid 40s vent temp (with snap on thermal camera, my normal digital required repair when battery connection broke)

conclusion that the condenser can't keep up without serious fan that i don't have room for, i focus on the engine, let it drop to idle and it climbs to 227 before i kill ac and fast idle it to 210

interesting, my 91 small block burb dual system was happy with a 5 blade and 12" pusher on stock condenser on the r4, (and not much difference in the condenser core between those two, just the pipes swap sides) and is happy with a not as big as it could be parallel condenser and sanden after i got tired of replacing r4s, the c30 has one of those new a6 replacements, which is pretty much a sanden with some prosthetics to make it fit in an a6 bracket, and a 7 blade plus a 3200cfm with a 2000cfm squirrel cage portacool stacked on top of it ain't enough, 3200 into the grill, 2k at the engine with hood open

i'm gonna say the rad and condenser are unacceptable for gulf coast heat, if i try to pull a trailer with this thing it's gonna fry with the ac off, it obviously has a capacity issue, and the ac will fry itself as i can only hope to save it with an electric fan, that won't fit behind a 73/74 grill, and i'm not sure much more room exists behind a 76/78 grill, which i like even less than the roomy pawpaw pipe grill that came on the truck (that looks much less crap with a factory bow tie i harvested from the PDI bay off a debadged new truck)

 

[winfred]

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[AZ_old_man]

I happen to have an '87 454 mounted in a P30 chassis motorhome. Looking at the same radiator brand that you are currently using. But I'm going to replace the stock clutch fan assembly with twin electric fans. I also have an oil cooler, trans cooler, and the a/c condenser coils in front of my radiator, and the factory original is only a single core. It wasn't doing anything bad for the original owners, but it was kept up in cooler country for practically it's entire life before I got it. Now I have to prepare it for the desert heat, which is why Im looking at a 4-core with twin electric fans. It's got a 12 inch pusher on the oil cooler, a pair of 8 inch pushers on the trans cooler, and what looks like (can't really get to it to get an accurate measurement) a 14 or 16 inch pusher on the a/c condenser. You might have to dump the stock clutch fan and go strictly electric. I'll admit that I have a lot more heat blowing onto the radiator than you do, but you have a lot smaller airflow area than I do. I would also recommend that you change out the thermostat for a failsafe version, especially until you get the heat issue figured out.

 

[winfred]

thinking about a cheapo plastic tank stock replacement as a test unit

 

[Ricko1966]

I happen to have an '87 454 mounted in a P30 chassis motorhome. Looking at the same radiator brand that you are currently using. But I'm going to replace the stock clutch fan assembly with twin electric fans. I also have an oil cooler, trans cooler, and the a/c condenser coils in front of my radiator, and the factory original is only a single core. It wasn't doing anything bad for the original owners, but it was kept up in cooler country for practically it's entire life before I got it. Now I have to prepare it for the desert heat, which is why Im looking at a 4-core with twin electric fans. It's got a 12 inch pusher on the oil cooler, a pair of 8 inch pushers on the trans cooler, and what looks like (can't really get to it to get an accurate measurement) a 14 or 16 inch pusher on the a/c condenser. You might have to dump the stock clutch fan and go strictly electric. I'll admit that I have a lot more heat blowing onto the radiator than you do, but you have a lot smaller airflow area than I do. I would also recommend that you change out the thermostat for a failsafe version, especially until you get the heat issue figured out.

Electric fans do not typically move as much air as a mechanical fan the difference is HUGE in many cases. A 4 core radiator has more resistance to letting air through, so e fans are also not recommended on 4 cores. If I were to switch I'd try to find something factory from a similar engine on something newer. That way GM did the testing on fan cfm and compatibility with the radiator. Instead of aftermarket fans if I wasn't going to grab a late model radiator with fans from the junkyard. I would use Ford Taurus, Windstar,Lincoln fans. They are 2 speed factory and bad ass, they use a lot of juice you'll need relays a good alternator and battery.E Fans do typically have an advantage in low speed traffic. Above ~20 mph the blades and motors just become obstacles blocking air flow.

 

[legopnuematic]

What is your fan to shroud clearance like?

 

[Ricko1966]

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