If im not mistaking one of the most common issues for the R56S (N14) is the thermostat failure. Why does it fail, what is the problem that causes it to fail?

 

It's a plastic part, which heats up, expands and leaks. Lots of good info in this DIY thread on the R56 thermostat here as well.

 

Thanx PelicanPars but... if its plastic and heats expands it bla bla bla, how come BMW didn't fix the issue? With my little knowledge, id replace the plastic and fit in there a metal part, or some kind of plastic that would endure more!

 

That would be a question for them unfortunately. Although it is a common failure and issue for the R56, thermostats are wear and tear items on any car.

 

On any car? I had no idea! But i do know from a friend, that Peugeots 207 RC, never have the thermostat issue (although tey use the same part). And the reason is due to the fact that the water temp on their car maxes at a lower degree (around 90 if i remember correctly) so the plastic will not wear out as it does fail on the R56S!

 

There is an aftermarket housing seal that is far superior to OEM. My indie wrench replaced it about 50K miles ago and it still holds water. If interested, I'll find out what he used. The housing and thermostat he used were OEM but he said he used a different seal.

 

A seal? Like silicone you mean?

 

sorry, no, the *seals* on thermostat *housings* are not wear and tear items on "any" car.

 

Why would Mini create a more reliable part when the thermostats are selling like hotcakes? For every owner of an R56 in just 100,000 miles you'll go through 2-3 thermostat housings, we all know this is where Mini/Mini dealers make their money. People continue to buy unreliable cars and as long as people are willing to do that Mini won't change a thing.

 

I have changed mine few thousand miles ago and the code says Thermo stuck open on the new one...So May have to change again...I have a faulty Thermo..from the dealer..Yeah! such a PITA to change...urgh

 

Temp sensor thermostat is a common problem with both N14 and N18 engines. Ours failed and replaced at 4k, 30k and 48k miles.

The last time it was replaced the car was out of warranty but Mini dealership replaced it a no charge.

I like driving this car because it reminds me of driving a go-cart but I'd swear if my wife didn't enjoy her mini as much as she does I'd be trying to get her into something else reliable.

 

- it fails because it is plastic

- which means there is a great business opportunity for someone to make a nice metal on that would last forever

- however if we look at the GEN1 S coolant overflow tank which was (is) a failure prone plastic item: a nice metal replacement costs a 'decimal place' more than the plastic so not a big seller . . . altho the tank is A LOT easier to replace (changing it 3 times is still only a 15 minute job while a therm' on a GEN2 means removing several things for access). A 'last forever' thermostat housing COULD be a winner . . .

 

exactly. If a metal replacement was $1500, or even $500 would they sell?

 

not seeing a lot of interest in it . . .

someone with an MBA, please tell us what the necessary price would be for a winner!

 

Funny when you consider people crying about VW's emissions troubles while Mini's known faulty temp sensor problems could potentially leave you or your family member stranded. And Mini only solution is to keep replacing them with the same over engineered part!

 

Its not over engineered, its under engineered. It is poorly designed. They typically do not leak at the gasket. Mine did not and from reading, thats not common at all. They typically leak at the seam or crack at the high stress 90 degree inside mold point, which is where mine leaked. The crack only opens when the tstat is hot. A machined metal one would have to be multiple parts, with more seals because The design tries to do to many flow connections at the same point, especially for the turbos. A better plastic rsurgery designed more intelligently, or a total redesign with mutliple parts in different locations which requires more and different hoses would be the smart design.

For instance, the thermostat block itself could be machined with a replaceable tstat with the temp sensor and tstat sensor machined and 3 larger hose connections (inlet, outet, and pump suction) and the bleed. The suction to the water pump, turbo cooling and heater core would then have to be separate manifold, as well as the other heater line to the radiator, requiring some different hose designs, and especially a redesigned replacement for the incredibly stupid water tube. The rad connections would be the same. Between the design costs and maching, and new hoses, etc, it would easily be a $2000 kit in order to be profitable. A hot shot machinist and welder could make a one off in a few days.

 

This metal replacement for the R52 demonstrates it isn't that expensive
https://www.ecstuning.com/News/MINI_...006_2007_2008/

 

That's a very simple 2 hose cast and face machined design. Very nice, for what it is, and in line with other simple designs. The R54/55/56 design is far more complex, and includes 2 electrical connections, a bleed, 2 bracket bosses and 6 hose connections. If it was that simple, it would have already been done. For sure it is possible, but not anything in line with that type design.

 

I just recently got in the mail a class action lawsuit again BMW and this thermostat failure issue. It took long enough!

 

Thermostat or water pump? Eveyone else has only gotten a water pump class action suit. It doesn't mention the thermstat at all.

 

I replaced mine thermostat housing (cracked) with a new MINI one and it stuck open as well....had to do the job all over again....

 

Hamtup, is a 2011 R55 S or 2014 R60 S included in the class action suite? Is there a URL or contact information so I can get on the list?

Thanks!