So I am victim once again to the infamous oil cooler o ring leak that has plagued many MINI owners. I say again because this is the third time and I am at a total loss on what to do. Let me give some background. The vehicle had this leak once before and while replacing the axle we tore into it and replaced the o rings which seemed to stop the leak for about a month or so. The second time I replaced these o rings the leak never went away and it seemed to just slow down a bit. The leak is definitely the cooler o rings and comes from the lowest point of the heat exchanger. It is a constant oil drip.

Now I am going on my third and need help. What can I do to ensure a good seal? any tips or tricks from someone who has done this? Besides making a mess of my car I have tech inspection coming up for SCCA season and need these little puddles of joy to stop.

 

Are you using OEM o-rings?
If not are you sure the o-rings are the exact same size as the OEM o-rings, such as are you using metric size o-rings.
I had a problem once with fuel injector o-rings that I purchased from an auto parts store that were suppose to be direct OEM replacements (Fel-Pro brand) but continued to leak. I purchased o-rings from the dealer and the o-rings sealed great.

 

Try high temp RTV or similar with the O-rings.

Jeremy

 

ummm? i never had any issue with these o-rings even with the aftermarket oil cooler adapter plate i had for 6 months. agree with jhiggs, use hi temp rtv with the o-rings.

 

Yes I am using the factory OEM o rings from MINI directly but suspect they arent matching up to the 110,000 mile old oil cooler ring spots so RTV may help fill those gaps. Any specific way or method to use RTV with these seals? I was always told that a seal should be fine by itself so dont really have much experience with RTV products. Do I run a bead ? wait time? both sides?

 

After you get the heat exchanger back off make sure it's flat with straight edge. Place bead in O-ring cavity then put in O-rings and add a bit of RTV on top of O-rings then mount heat exchanger to oil filter housing. Make sure you follow time limits on RTV tube instructions for final torque up.

Jeremy

 

I agree that RTV might help. I used a little on my crankshaft position sensor o-ring seal when I replaced the o-ring.

The only issue with using RTV is that it can be a pain to get all the old RTV off of parts if you need to remove the plate/o-rings in the future.

 

Thanks!! Will try this afternoon. I don't visit the dealer too much but found it funny that the parts department basically told me "if its not leaking oil, its out of oil".

 

Well I tried the rtv method and was extremely careful regarding cure time and torque settings but the leak refuses to go away. I did notice some little scratches on the heat exchanger that probably were developed in the now three times its been removed and now one of the torx screw heads is stripped from being installed and removed so many times so that will be fun to get out. I guess the next step is to replace the heat exchanger in hopes that oil is escaping from one of the tiny scratces. Anyone know where to find an oil cooler cheaper than the dealers $135?? or know how to remove a hard to reach stripped torx screw??

 

Anyone have a step by step on how to remove and install heat exchanger

 

i had stripped one of my bolt heads out on my oil cooler also used a easy out that fit right in the stripped head lucky it came right out don't remember what size it was hope this works for you i have an oil cooler what would you give for it i have an extra one i had to buy a oil filter housing and it cane with it

 

Best way to remove oil filter housing without a lift. Need help!

 

You may be finding out why MINI insists on replacing the whole housing: heat exchanger and all when fixing the leak. I'm still up in the air about this. We've had success replacing gaskets, but since the replacement is a PITA and a little messy, we sometimes replace the whole shebang.

 

I ended up just replacing the whole heat exchanger but had to take off the whole filter housing assembly in order to easily and safely remove the stripped heat exchanger torx bolts.New bolts, gaskets, and heat exchanger and a quick reassemble of the housing and I am finally leak free .

As far as removing the fliter housing I did not use a lift. I used myself and a friend. Removed the passenger tire to easily see the housing assembly, removed oil filter housing top and filter, went in with a wrench through the top while my freind guided the wrench using the open passenger wheel well. Remove the heat exchanger hoses and pressure sending unit and the whole housing comes off...putting it back on with new gaskets was a whole nother game but doable in an afternoon. Good luck and make sure to clean in detail before reassembling. I learned the smallest peice of grime or dirt will make these things leak.

If I could go back I would just replace the whole unit as one piece.

 

Thanks a lot helix and redhotchillypepper. Going to get my hands dirty now lol

 

I hate to revive an old thread but after chasing a small oil leak on my recently bought 03 R53 I finally rented time on a overhead lift and behold the leaking oil exchanger.

 

That's where our R53 was leaking as well. Time will tell if the new gaskets do the trick.

The old ones were hard like plastic so no surprise they were not sealing very well. I had originally thought it was the housing leaking, but that connection was dry so I left it alone.

Was a relatively easy and quick repair that had me thinking that there was more to it, but in the end, the 220K mile R53 is now leak free.

 

It's a very common leak. I replaced mine about 3 years ago and they're weeping, again...

We've got them on hand: Oil Cooler Gaskets

 

Did you pull the 1/2 shaft to get more room when you changed out the o-rings on the heat exchanger?

 

Nope, didn't need to pull the joint. Only removed the wheel and used an 8 inch, maybe 1 foot wobble extension, torx bit and a socket wrench.

Make sure your torx bits are sharp and new, don't want to damage the heads of the bolts. 30 mins tops and you're done.

 

I did my O-rings today on the oil exchanger but I did pull the 1/2 shaft to change the right side inner and outer ball joints as well as the control arm bushing. The 1/2 shaft will get new boots while it is out----the old ones are looking old and they are cheap to replace---better than loosing the whole side due to fatigued boots. Pulling the fender liner would have been enough to change the O-rings only.

 

Out of curiosity, once the oil cooler has been unbolted from the oil housing, how do the o-rings interface at the union when reconnecting? I've only seen photos of the cooler only, which has a couple holes. Are there corresponding nipples on the housing that the o-rings wrap around?

 

The O-rings fit into recessed trough in the oil filter housing and seal against the smooth side of the oil exchanger. Over time the O-rings become hard and stop sealing.