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Transmission fluid in coolant?

S

stephenspann27

NAXJA Forum User
Location
College Station, Tx
This past weekend I swapped on a radiator of my '89 parts jeep. I had it pressure tested and flushed. I looked in my pressure bottle today and it has red fluid in it..

Now I've have had some rust color in my coolant before.. so it didn't alarm me at first.. but this looks more red than brown.. and is frothy.

I checked the trans fluid on the dipstick and it looks fine..

I'm draining the coolant right now.. and will refill with water... and see what happens..

I do have a trans-cooler.. maybe I can bypass the radiator for a while and see if the color changes..

Anyone seen this before on a XJ?
 
I did the swap myself... I had just carried the radiator in to have it flushed checked..

There is no doubt now.. I just drained it.. added water.. drove around the block.. came back and its red again.. and bright red.. not orange.. not brown... FML...
 
If you just do the pan (not recommended) about 4 quarts.

If you do the "poor man's flush" a complete change is about 12 quarts--3 gallons.
 
you probably have the inlet line for the transcooler in the radiator leaking and it is getting tranny fluid in the tanks on the side of the radiator. flushing the transmission will not fix this or really help in anyway
 
88xj 4.0 31" said:
you probably have the inlet line for the transcooler in the radiator leaking and it is getting tranny fluid in the tanks on the side of the radiator. flushing the transmission will not fix this or really help in anyway
Click to expand...
Ummm.. Yea I realize that. I'm putting my old radiator back in.. the one that's having this issue came from my parts jeep.

I'm planning to just pull the drain plug on the transmission.. I"m changing the trans fluid in case coolant got into it.
 
Replace the radiator.
Then flush coolant system (and heater) GOOD.(Get the ATF OUT!) Cooling system cleaner. Flush good. Final flush or two with distilled water. Then New coolant.
Then Transmission poorboy flush.

Good Luck,
Orange
 
ehall said:
I wouldn't freak out about residual tranny fluid in the coolant. I would freak out about coolant in the tranny though, that stuff will destroy bearings
Click to expand...

Absolutely, just had a Chrysler 300 smoke its trans a few weeks ago due to radiator's internal trans cooler failure.
 
I'm now more seriously considering bypassing the radiator and running straight into the cooler.. I live in Texas.. and park in a garage.. it never gets that cold..

My old radiator that I was going to swap back in has a pin hole in it that seeps coolant..
 
One thing I might look at.. before giving up on this radiator. Where the transmission line goes into the top of the radiator, that fitting was kind of loose. I noticed this right before I installed the radiator. I tightened the brass fitting that is actually threaded into the radiator, and it was already fairly tight but I thought that maybe it was supposed to be tightened until it bottomed out. So I tightened it quite a bit more.. and the feel was strange.

I know now.. after doing some reading, that that brass fitting carries tranny fluid into the radiator, and all around it is coolant, so I must have broken the seal in some way by tightening that fitting.

Am I correct about the top fitting being the IN, and the bottom fitting being the OUT ?
 
If you do that, make sure you cap off the ends of the tranny cooler section, or you'll lose coolant out of it since there is obviously a leak between the two.
 
I drained the tranny fluid on my lunch break it looked brand new.. smelled new.. . I think I'll just bypass the radiator, refill the tranny and be done.
When I plum directly to the tranny cooler, does it matter which fitting is the IN and which is the OUT? I wouldn't think it would matter since it just changes the direction the fluid flows across the cooler..
 
ehall said:
the leak is internal but its going to get in the tranny passage and then leak out from there

maybe you can plug up the tranny lines and prevent external loss, maybe you can get the end cap replaced at a radiator shop
Click to expand...

yea I could have that left tank replaced.. its the more expensive one.. and I've already spent $65 on this thing having it flushed and pressure tested..

I really don't want to spend even more on a freggin used radiator..
 
I'd just buy a new radiator personally. Radiators are one of those things I really hate to trust used - same goes for filters/bearings/brake consumables.
 
kastein said:
I'd just buy a new radiator personally. Radiators are one of those things I really hate to trust used - same goes for filters/bearings/brake consumables.
Click to expand...

x2, time for a new one.
 
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