I recently changed the clutch in my Evo 6 GSR and while I was at it changed the coolant and did a flush as well. I believe that I may not have properly burped the system and now my radiator is leaking from an unkown source. First off, I flushed the old coolant out, put the new stuff in, ran the engine for a while but I don't think it was long enough to get the air out from the system. I then went on a 2000km road trip to visit family (I know stupid idea, I was in a rush and everything came together at the last minute, I can't see them often). When I got back, I re-burped the system, this time running it longer. This time, a lot of extra coolant seeped out as soon as I started burping the system but eventually it stopped, air bubbles rose up, and I closed the rad cap, and filled the reservoir. I drove it, but still the rad leaks, and the reservoir is almost empty again. Could I possibly have over pressurized the system initially by not burping it properly and now busted the rad somehow?

Should I pull the rad out and test it somehow?

Here is where the coolant is collecting, but there is no obvious point where it is leaking from.


Closer up


It's also leaked onto the a/c pump and hoses somehow:

 

did you recently replace your radiator cap?

 

Your radiator end tanks could be the culprit. Over time the plastic will separate from the aluminum core and start to leak. I would try pressure testing the radiator and see how it holds up.

 

Common leak spot replace the rad. OEM replacements are fairly cheap and will last you another many many years


Good Luck

 

Haven't replaced the radiator cap.


Problem with that is I'd have to order an OEM rad from the UK for the 6, or buy an 8 rad from the States and modify my fan to fit it, along with a new top rad hose. Mishimoto sells a Evo 4/5/6 rad that I might buy, would be a direct fit and they sell it in the US.

I'll definitely try this first, before I order a new rad.

 

Depending on your budget you could source a nice aftermarket radiator from CBRD for example. Most CT9A guys prefer the VI radiator since the upper pipe is a straight shot so they should be readily available.

 

I had the exact same problem as you, the culprit I encountered was the plastic endcaps started to separate and leak.

 

I got the rad tested, leaking and unrepairable. Going with an Evo 4/5/6 Mishimoto rad. Thanks for all the help!

 

Is this unit confirmed direct bolt on with no modification required?

 

Pretty much, you just have to twist it sideways to slide it in and I had to cut about an inch off my upper rad hose.