Radiator

[Matt S]

JHerman1,

I'd have to agree with Gary that it may not be your cooling system. Do you have a pyrometer? What kind of temps are you seeing?

 

[JHerman1]

overheating

No I have not checked pump timing I was not aware there could be a change in the pump. the pyro runs 700 to 950, not what I consider high, the boost is 12 to 14lb when the overheating occurs the ambient temp is 100 to 105, the road speed is 74mph, the rpm is 2k to 21k. If I slow to 60mph or less I can continue to move, if I get in stop and go traffic my temp is 180 to 195, this appears to be boost or fuel related or a combination of the two, I hope my ignorance and self taught info is not showing through . I will inquire as to pump issues with the local shop to see if I can get a free education, any education you may offer would be appreciated. Thanks for the lead. John

 

[Gary - K7GLD]

Only other suggestion I might offer, is that the downflow radiators in the earlier Dodges (like MINE!) were too capable of "short-cycling" - allowing the hot water in the upper tank to quickly drop directly thru the radiator core using only a small percentage of the core, and right out the outlet directly below and back into the engine (VERY poor design!). A fix that worked decently for me, was to have a radiator shop install a baffle in the top tank to fully distribute the heated coolent ENTIRELY across the radiator core so the radiator efficiency was maximized. It helped a lot in my case, but the 2 row core just wasn't adequate for my needs, and I recently installed a later 3-row crossflow as used in the later '93 trucks - now my overheating problems are a thing of the past...

 

[Rockcrusher]

Originally posted by Gary - KJ6Q

Only other suggestion I might offer, is that the downflow radiators in the earlier Dodges (like MINE!) were too capable of "short-cycling" - allowing the hot water in the upper tank to quickly drop directly thru the radiator core using only a small percentage of the core, and right out the outlet directly below and back into the engine (VERY poor design!). A fix that worked decently for me, was to have a radiator shop install a baffle in the top tank to fully distribute the heated coolent ENTIRELY across the radiator core so the radiator efficiency was maximized. It helped a lot in my case, but the 2 row core just wasn't adequate for my needs, and I recently installed a later 3-row crossflow as used in the later '93 trucks - now my overheating problems are a thing of the past...

Sounds like the 93 radiator fit OK? Hopefully a 93 will fit a 90???

 

[RDavidson]

Running hot

Have you talked to your local radiator shops about adding another row (or two) of tubes. I have done this on older mopars to help with cooling problems. If the top tanks are big enough it's a simple thing. Check with more than one shop though, some of them are more helpful (and talented) than others.

 

[Rockcrusher]

Originally posted by Gary - KJ6Q

I converted my early '91 to a '93 radiator - the radiator was about $220, new fan shroud was $20, and a new radiator hose to match the new radiator inlet... "course I did all the work myself, and DID have to cut the new shroud to match the old fan, and then fabricate a new rear aluminum plate for the shroud to match to the older style fan - and had to cut the old cast iron thermostat housing, rotate it a bit and re-weld it... . Piece of cake - and it works great, too!

Gary, you said you changed the shroud also, does this mean the old shroud wont fit the newer 93 radiator?

Did the 93 rad fit the existing "brackets" or did you have to do some mods to make it fit?

Richard

 

[Gary - K7GLD]

NO, the old shroud won't fit the new '93 radiator - a new one costs $20. The '93 radiator drops right in to the space where the old one was, but requires minor trimming of the top mounting "ears" of the '93 radiator - very clear when you see one. Look at the top mounts on a stock '93, and you will see how easy it is to fabricate top mounts for the earlier truck - I used 3/4 pipe caps bolted to the bottom frame crossmember to sit the rubber cushions into on the new radiator. Actually, physically installing the new radiator itself was the easiest part - adapting the fan to the later shroud and modifying the thermostat housing was more difficult...

 

[Rockcrusher]

Originally posted by Gary - KJ6Q

NO, the old shroud won't fit the new '93 radiator - a new one costs $20. The '93 radiator drops right in to the space where the old one was, but requires minor trimming of the top mounting "ears" of the '93 radiator - very clear when you see one. Look at the top mounts on a stock '93, and you will see how easy it is to fabricate top mounts for the earlier truck - I used 3/4 pipe caps bolted to the bottom frame crossmember to sit the rubber cushions into on the new radiator. Actually, physically installing the new radiator itself was the easiest part - adapting the fan to the later shroud and modifying the thermostat housing was more difficult...

Thanks, I shall proceed.