2009 Mcs 6MT with 190K miles on the clock

Out for a drive and noticed coolant temp spike to 130DegF. I monitor coolant temperature with a scangauge-ii like a hawk and normal operating for my car is 220-225DegF. As luck would have it, i was less that 1 mile for my home, so I go directly home, pop the hood and Bam, large pool of coolant on top of transmission.

Ugg, Pos Mini cooling system with it's plastic thermostat-housing and plastic water-pipe is a total PITA. If I didn't enjoy driving this thing as much as i do, it would have been scrapped long ago.

Anywhoo, ordered new Mini OE thermostat-housing and water-pipe. When I removed existing leaking Mini OE thermostat-housing, that I installed myself 32K miles ago, I noticed that the thermostat-housing gasket was flat, barely protruding out of it's groove on the the thermostat-housing. I assume this was the cause of the leak.

On a whim, I decided to obtain a fel-pro thermostat-gasket (Part #: FPG 35922) so I could compare it with the OE Mini gasket on my new thermostat-housing. Over all dimension was the same however, the fel-pro gasket was noticeably more dense, much harder to compress/squeeze than the Mini OE gasket. So, I elected to install the Mini OE thermostat-housing with the fel-pro gasket. Existing water-pipe looked fine. Probably could have re-used it but, why take the risk. I always replace both even if only one is leaking.

Also fwiw- I use silicone grease on water-pipe o-ring (that goes into block behind water-pump), on the thermostat-housing o-ring (that goes into water-pipe), and a little on the thermostat-housing gasket. Makes for a smooth 'snick into place', installation. I also use a laptop w/ a usb video scope camera to view inserting water-pipe into rear of block behind water-pump so I don't have to remove the intake.

Hopefully, this thermostat-housing installation will make it past 32K miles.

Cheers

 

I've had so many issues with the coolant system on the R56. It just doesn't last very long and I've learned (painfully so) there is a definite quality difference between thermostat and water pump manufacturers. I'll be going with the metal water pipe from ECS anytime I do them again. I've seen so many pipes fail within a short period of time by cracking around the O-ring on the water pump side. It's just very frustrating, but you're right, if they weren't so damn fun, I would have drove it off a cliff.

 

Your "failures" in your signature made me laugh so hard

 

Just keeping it real :-)

I'll have to update my failures list to include wheel bearings, one just started howling. In process of sourcing replacement wheel bearing now... lol

 

I've been on the brink of giving up on our R56 but for some reason I cant bring myself to give up

 

I have the metal pipe and new thermostat and all good. Just on my second thermostat with about 138K on the R58 JCW. My original thermostat went at like 80-90k had the bremmen parts thermostat so far and its been on and off a bunch of times testing prototypes all the time on my car.