Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Replacing radiator - cap off transmission cooling openings?

The radiator in my 93 Toyota 4Runner developed multiple cracks…when I was quoted $1000 to replace it I decided to do it myself. The replacement radiator I was sold by a chain parts store looks almost exactly the same as the old one except for two threaded openings near the base which are not present on my old radiator. I think, after much web browsing, these are for oil or transmission cooling lines? But, since my truck doesn’t have these, can I buy a threaded plug for these openings? Or do I have the wrong replacement radiator? I already went back to the parts store, and they assured me that I had the correct replacement but had no suggestion for blocking these openings. Help!

If your truck had a slugomatic you would hook up the cooler lines there & trans fluid would flow thru the cooler.

Just disregard the threaded openings & install the radiator as is.

Hmm…but if I leave these open holes in the bottom of the radiator, won’t the fluid just run out? Or are they separate from the rest of the radiator altogether?

Obviously I have never gotten this far into my engine before :slight_smile:

What fluid would you expect to run out of these open holes? (what fluid is going into these holes)? nothing, nothing going in nothing comming out.

The transmission cooler works by circulating transmission fluid into the radiator (where it circulates in sealed lines, not mixing freely with the coolant) as opposed to coolant flowing from the radiator to the transmission. Therefore, if you leave the cooler fittings open, nothing’s going to leak out because nothing’s going in to that part of the radiator

I remember seeing somewhere on the internet where someone with a truck with a manual transmission ran some water lines through the non-used transmission cooler portion of the radiator so he could have hot water for his wilderness shower.

It is a radiator inside of a radiator. The one doesn’t leak into the other. No need to cap them or anything.

who da man;… YOU da man. a hot shower at camp!!! i am going to be the hit of the camp this hunting season. I NEVER thought of those unused lines b4. what a great idea!!! i just have to blow out the line with compressed air to get the water out it doesn’t freeze.

thanks for sharing. sometimes a not so obvious idea is sooooooooooo simple.

amy: the aftermarket replacement radiators are made to accomodate ALL types of your engine models. some have extra heavy duty transmission coolers, some dont, some have extra layers of cooing fins. some dont. some radiators have an extra small spout on the top next to the radiator cap for an alternate way for antifreeze to get out of the radiator sometimes you have to buy little rubber caps to hose clamp onto the spouts too.

you just hook up what you have, just like original and leave the extra holes there. you could go to the hardware store and buy small plugs to screw in (in case for some reason there develops an internal leak) but if that happens it would be time for a new radiator anyway. note when you fill up the radiator to check for obvious leaks, and make sure those small holes aren’t leaking. then its all good.

Thank you all so much for your insight! I just finished installing the new radiator and am waiting for the engine to cool back off.

In the mean time, I’m going to figure out how to set myself up with a totally awesome car-powered shower. All my surf trips will be incredibly better now! Thanks again!

Congratulations, just one thing, after I replaced the radiator on my 2000 Blazer the level dropped for a couple of days afterward as the air worked its way out of the cooling system. Just keep an eye on the radiator and overflow tank for the first week or so.

Ed B.