Recurring Coolant Leak at Bypass Hose

ReedTX · Post by **ReedTX** » 31 Aug 2018, 17:19

I have a 2008 3.2 FWD XC90. I have recently replaced the coolant bypass hose (30713530) and the o ring (30670569).

It seems to hold for 40 or 50 miles, then start leaking again. I replaced the o ring again in case I had pinched it. The end of the fitting is popped off each time it leaks and I take it off and reinstall. It pressed back on, but I think it is coming loose while running and allowing the o ring to lose its seal.

Has anyone run into an issue like this, or have any tips to keep it from leaking the 4th time around? I am about to the point of using some high heat epoxy to secure the tip onto the fitting to see if that solves the issue.

Right now I'm stuck in a real seedy part of Fort Worth waiting on a tow truck...

Post by **jimmy57** » 01 Sep 2018, 00:51

What if the oil cooler is plugged and the pressure is high and blowing that out? The end of the fitting is a taper that pushes on the o ring. If the force there gets too high then it deflects at that "ear" and then the o ring moves. See if a garden hose can push water through the oil cooler.
Those style oil coolers are plugging up on many engines that use them. The small passages are ripe places for coolant to coagulate.

ReedTX · Post by **ReedTX** » 01 Sep 2018, 10:49

Well, I survived the 2 hour wait for the tow truck.

If the cooler is plugged, is there a recommended method to unclog it? Or do you end up replacing it?

Post by **jimmy57** » 01 Sep 2018, 12:54

You could try cooling system flush. To test pull off the hose that's leaking and the one on bottom. You can first try flushing from top to bottom and then bottom to top.

ReedTX · Post by **ReedTX** » 01 Sep 2018, 13:33

It flows freely through the cooler. Small victories!

I'm waiting for the epoxy to set before reinstalling.

Will keep my test runs close to the house- I had my fill of "interesting" people yesterday.

Post by **jimmy57** » 01 Sep 2018, 14:54

Test coolant tank cap for pressure relief. It is a 21 psi release cap. Those fittings have not been leaking like yours. Some have cracked and are replaced and it's done.