New Radiator

[herkyhawki]

Got a new universal-fit replacement Radiator that has transmision-coller connections AND oil-cooler connections. My truck does not have an oil cooler.
I plan to plug the oil ports. Should I put oil inside the unused cavity? or antifreeze, or just leave air? I'm thinking air will build up pressure when heated.

Another crazy idea I had was to loop the transmission oil through both the trans cooler side and the oil cooler side. The previous owner added an additional trans cooler on front of AC radiator, so hoses would be remade to reach the other side of radiator. Then I'd delete the up-front trans coooler. I only tow a small (2500 lbs) boat.

5.7L auto trans 1998 K1500 with 110,000 miles

[jdmccright]

You're better off keeping the external tranny cooler. With trannies, the cooler the fluid is kept, the longer they last...period. In-tank coolers don't actually cool the fluid much, only down to the coolant temp of 180° or so. They are also there to heat the fluid up quicker when it is cold. External coolers have a better chance of dropping the fluid temp down further since it is in direct contact with ambient air. Besides, all that custom hose fab sounds like a big PITA for little gain.

You could do this. First, plug the oil holes and leave it either empty (my choice) or fill it with coolant to prevent any possible fluid mixing. Then, if you want to, you can go buy the oil cooler adapter that bolts onto to the existing oil filter flange plus hoses from a junkyard/used parts shop, drain & flush out the oil reservoir (if needed), and hook it up. If you do this and go used, be sure to also get a new oil cooler o-ring seal set to avoid any leaks. Hope this helps!

[J-Ri]

I agree with jdmccright, leave it empty. Anything in the unused cooler will expand when heated, having only air just means no mess when it leaks out. My Cavalier has the factory radiator which has transmission cooler fittings in is, but guess what? It's got a manual transmission. Leaving it empty doesn't hurt anything, and is much easier than trying to fill it. Also by filling it with a liquid and them plugging it, you will blow something out from the pressure, the liquid won't compress as air will. If you do decide to plug the fittings, don't put anything in there.

[herkyhawki]

UPdate, I Left the unused ports open.
The new radiator started leaking after 6 months.
Got warranty replacement. Second one is leaking after 2 weeks.
Both Leak is where the plastic tank is crimped to the tubes/fins. There must be some kind of o-ring or rubber gasket in there. It leaks the worst on cold 0 degrees F mornings and seems to seal up when it gets hot. Am I just dealing with junk-brand radiator here or what? The side that leaks is the side where I do not have an oil cooler hooked up.

[herkyhawki]

The third "new" radiator seems to have no leaks. The auto parts sales guy suggested I add stop-leak when I put this one in because it is a "common problem". I did not add the stop leak (yet), just hoping it holds as it should.

BTW, the brand of this radiator is Proliance Ready-Rad #431333. Avoid this if possible unless you like wasting time and spending $13 / gallon on Dexcool.

[j cAT]

Originally Posted by herkyhawki

The third "new" radiator seems to have no leaks. The auto parts sales guy suggested I add stop-leak when I put this one in because it is a "common problem". I did not add the stop leak (yet), just hoping it holds as it should.

you need a 15 psi coolant cap. if the cap is more than 15 psi find one that is 15 or lower psi..seen this before !

stop leak is good for metal / gasket leaks...with the radiator plastic and seal this is moving to much to be effective...the pressures being too high for the radiator to handle it then the O ring gets blown out...

In the past I have replaced these cracked plastic tanks..they all crack at the point where the hot coolant enters the top of the radiator.

[jdmccright]

Wonder if the trapped air is causing excessive expansion on that side? Maybe leaving it open to the air will reduce the warpage. The other radical thought (which would void the warranty) would be to take a drill and drill two holes through the inside tubing so that the oil reservoir can be filled with coolant then cap the inlet/outlets. Or you can go online and buy one specifically w/o a oil cooler (eBay)...or you can go all aluminum and get rid of that seal altogether. Using stop-leak in a new rad is just a dumb idea from the parts guy.

[herkyhawki]

There is no trapped air, the oil cooler ports are not plugged.

Originally Posted by jdmccright

..... take a drill and drill two holes through the inside tubing so that the oil reservoir can be filled with coolant then cap the inlet/outlets. ......

I like this idea, I'll take a closer look at it, and would need to find the right plugs before drilling.

[j cAT]

Originally Posted by herkyhawki

There is no trapped air, the oil cooler ports are not plugged.


I like this idea, I'll take a closer look at it, and would need to find the right plugs before drilling.

if you do,,, then what about the warrantee...mods are usually not allowed !

you got a pressure problem dude...

[jdmccright]

As I said, it was a radical thought. First have the pressure checked and make sure the rad is bolted in tight to prevent any vibration-related fatigue. If you did try to drill it, you will have to make sure none of the chips fall into the rad and block the passages....flush everything out VERY well.

[herkyhawki]

3 year update. found this old post by accident! The radiator is still working fine with the oil cooler ports left open.