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I am hoping I can get some help here with a terrible coolant leak I am experiencing. I have replaced the thermostat, thermostat gasket, thermostat housing, and coolant expansion tank. I am still getting a terrible coolant leak. It isnt the type of leak that pours a lot of coolant all over the ground, it seems to be a high pressure leak. See the picture below of the coolant over spray.
My best guess is the "T" hook up for the hose coming out of the thermostat housing. I drew some arrows to show what I think the spray pattern is showing.
Does anybody have any other ideas? I am stumped and very frustrated at this point.
I am hoping I can get some help here with a terrible coolant leak I am experiencing. I have replaced the thermostat, thermostat gasket, thermostat housing, and coolant expansion tank. I am still getting a terrible coolant leak. It isn't the type of leak that pours a lot of coolant all over the ground, it seems to be a high pressure leak. See the picture below of the coolant over spray. My best guess is the "T" hook up for the hose coming out of the thermostat housing. I drew some arrows to show what I think the spray pattern is showing.
I would think that if you have a high pressure leak making that much of a mess, you would be able to see or hear where it is coming from.
Also noticed another nipple protruding from the top of your coolant tank.
Normally, MINI tanks only have the one hose on top; not two.
Where does that connect to?
If it's left open, the tank can't hold pressure and you'll overheat.
Could the coolant be shooting out from there?
Last edited by AoxoMoxoA; Sep 12, 2018 at 06:12 AM.
Better inspect that aluminium cap of your new expansion tank. Many of these tanks shipped with just a machined cap that is not thermostatically vented. If you don't know what I mean, go get the cap from the OE tank that you swapped out and look at it. You might be able to reuse that old on the new tank.
Are you sure you have burped all the air out of the system, by loosening the bleed screw on the upper radiator hose?
There is also the possibility there is a small head gasket leak from the combustion chamber to the water jacket.
Have you inspected that plastic Tee you circled? I read those plastic pipes can fail due to age, heat, time, or any combo of the three.
The spray pattern definitely looks to be pressure induced. It doesn’t look like it’s coming from the cap since the pattern seems to be coming down lower.
We put in a similar aluminum tank, just in a cool shiny polished flavor. There are indeed two hose connections at the top. One is for the factory hose, the other is optional and is used to redirect cap over pressure released coolant if you happen to more than 16 psi of pressure or you decided to open the cap. (And burn your hand) while the coolant was still hot. Poof!
That's not so much a leak as a pressure release from that overflow pipe. Fit a tube to it and drop it towards the floor above the heat shield or away from the exhaust.
If you overfill the tank it will shove out what it doesn't want. Especially at high rpm. It is possible the system is pressurising due to an issue somewhere, and it can be a cap as suggested above, some of the ebay stuff is not so good.
I used a Canton tank personally, with a Stant cap which at least is a recognised type. Make sure the system is bled, you need to see a constant trickle of coolant going into the top of the tank plus out of the hose bleed valve with a hot heater, and radiator if you can feel it.
