Help with flushing transmission cooler in radiator

I am replacing my radiator in my 2001 Volvo V70 XC and I got a used one from a salvage yard. Pretty stupid in hindsight, because now I am paranoid that the transmission fluid cooler line in the radiator has gunk that will turn a fix into me losing the car for good. It’s not in the car, so I was thinking that I could use some solvents like Kooler Klean to really clean it out. I could also just order a new Behr radiator from IPD with the exact proper o rings and green clips, and just eat the cost in the face. What would you recommend? Thanks for the help in advance.

You just answered your own question.


Flush the cooler out with brake parts cleaner.


Well all I can say is that when my transmission went in my olds, the shop simply added a separate new cooler on the front of the radiator. They didn’t bother trying to clean it out. Maybe cleaning will be fine but you have no history of what’s in there so do a thorough job.

Flush it with this…Most auto parts store carry it,

Agree with @davesmopar but that wouldn’t be my biggest worry. If the radiator was not properly maintained during its previous life, the cooler could be leaking and that will really destroy your transmission. You could pressurize it and check to see if it holds pressure for a period of time, or lay it down with the cap on, hose and transmission connections up, fill the radiator with water and then pressurize the cooler and see if any bubbles come out of either hose connection.

But honestly, I know I would sleep better with a new radiator and I really need my sleep.


I own two considerably older vehicles than your Volvo, and I wouldn’t be installing any used radiators in any of them. New radiators, esp after-market versions, are relatively inexpensive. I installed a new aftermarket radiator in my Corolla 5 years ago, easy job, still going strong & keeping coolant at correct temperature. The aftermarket radiator fin density is not quite as dense as the original radiator, but Corolla is manual trans & has no A/C, doesn’t need oem fin density.