HELP !! - Coolant leaking from behind brass radiator fittin

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HELP !! - Coolant leaking from behind brass radiator fittin

Unread post by ScottyB » Tue Oct 20, 2015 8:36 am


1997 Chrysler GS Voyager 3.3L (EGA):

Decided to renew the coolant (previously had just water) in the engine/radiator. Prior to this, the radiator showed no signs of leaks, but after renewing the coolant, there is coolant seeping from behind the brass trans cooler fitting (screwed into the plastic tank). This internal fitting protrudes out from the plastic tank and is secured only by a thin metal washer and thin nut (refer to attached image of an identical fitting).

So, just to be clear: the coolant is leaking from the body of the plastic radiator (behind the fitting).

The nut wasn't very tight, so I tried tightening to stop the leakage, but didn't seem to make much difference as coolant was still seeping out from behind the washer. I didn't want to tighten it excessively, in case I damaged the plastic tank.

To inspect the fitting, I drained some coolant and removed both nut & washer. There was no o-ring or seal behind the washer. The fitting can be partly pushed into the tank, allowing coolant to escape.

It appears this fitting mates against the internal wall of the radiator when tightened with the nut on the outer wall, but I see no way of sealing the fitting.

So, even though I've tightened the nut, there is still a "gap" in the plastic tank behind the washer, allowing coolant to escape.

Should there be an o-ring, rubber seal (or similar) behind the washer?
Is this repair a simple matter of using a suitable sealant compound?

Can anyone please suggest how to remedy this small leak?

Thank you in advance...

Radiator_Trans Cooler Fitting.jpg
Example of brass fitting (trans cooler)
Radiator_Trans Cooler Fitting.jpg (201.54 KiB) Viewed 3298 times

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Re: HELP !! - Coolant leaking from behind brass radiator fi

Unread post by carriedi » Wed Oct 21, 2015 10:30 am

the cooler that runs inside the tank is installed before the tank is attached to the radiator core. Pretty sure the seal is on the inside of the tank. If there is a gap behind the washer when the nut feels like it's tightened up you should probably take the line off and remove the nut and add a washer that will take up the space so the nut will tighten up and secure the cooler to the radiator tank.

I think what I would do to try and save you from having to replace the radiator would be to drain the radiator. at least below where the cooler comes through the tank. Take the line off the fitting and remove the nut and washer. Clean the area with something like brake cleaner and let it dry. push the cooler in a little bit and use silicone sealer around the cooler fitting. Not a lot but enough to make a seal around the cooler fitting. Put the washer back on and what ever spacer so the the nut will tighten up the cooler to the radiator and let it dry the silicone for half an hour. put the line back on the cooler fitting and pour the coolant back into the radiator and keep an eye on the coolant for a while to make sure the cooling systems stays full and it doesn't leak.
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