I do 3-4 km and I get the water heat icon. First it turned yellow, and a few minutes after, it turned red. When I open the hood and check it, I notice that there is no coolant left!!!
1. Can this be the Thermostat?
2. Can oil leaks (I see few drops) be also due to the thermostat?
3. Are there 3rd party, no plastic thermostat housings on the market ?

 

Assuming the water didn't go into the oil - there are several spots where things leak.

Most probably the crossover pipe? Being plastic is not the issue - it's just seals getting bad over time.
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So the seals is what usually is the problem and not the replacement of the whole housing?

 

Maybe. Though I would never recommend just doing the seals.

 

Is it normal to change the thermostat housing so often? Ive changed it after 50K km

 

Your car is now 13 years old. Parts are aging out.

N14 thermostats are crap. I doubt I ever got much more than 30K miles on the replacement ones.

Change the water pipe and the expansion tank after five years of service (more or less). Both are way cheaper than a tow truck. Or replacing an overheated engine.....

 

How can a new part be aging out? What do u mean?

 

Are you refering to thermostat housings bought from BMW, OEM housings by manufacturers who BMW actually sources parts from, third party manufacturers who claim "OEM" quality or third party manufacturers whose products are cheaply available on ebay, etc.?

Note that products made by one manufacturer may differ in quality depending on lifecycle iterations (of the parts) as well as whether they were made for BMW or for aftermarket retail channels.

FWIW: The expansion tank in my 2010 LCI is now 11 years old, as is the water pipe (both fitted at factory). They are no leaks. The thermostat housing was changed in 2017 but only because it did not allow replacing the integrated and not individually accessible temp sensor which had failed (the new, BMW fitted housing has separate access to the temp sensor).

@genik : Judging by several reports of (cheap?) aftermarket thermostat housings failing after a relatively short time I'd recommend biting the bullet and getting it from BMW. If you fit it yourself or have an independent garage do the work, I'd go safe and also replace the water pipe at the same time with a quality aftermarket part (i.e. not bought through BMW). The extra work and the price for the water pipe are minimal compared to the work and costs for the thermostat housing.

All this of course on the presumption, that the thermostat housing itself has a leak or is not working as it should. Note that the main seal between the thermostat housing and the engine can be replaced separately (I recommend seals made by Elring). So the first thing you need to do is hunt down the actual leak rather than start by replacing the (edit: second) most expensive part in the chain besides the engine itself (i.e. the thermostat housing).

 

Hi giorgos, thanks for the full reply 😊
No the thermostat housings I’ve changed we’re never purchased by the original BMW service, so they could be OEM or any other kind.
Still though, is there any knowledge that the original BMW part does not have such an issue? I mean that they tend after a few km of use, to corrupt, due to the heat and loose cooling fluid etc. That’s what I’ve been told by the non bmw technicians… suspicious statement or truthful?

 

All I can say is that the factory fitted thermostat housing in my Mini had, besides the failed temp sensor, no other issues at 7 years of age. The replacement has been fine since, both in function and tightness. This includes two, each several hundred mile long trips at over 40 degrees C (over 104 degrees F) ambient temperature.

 

Maybe the cooperS (mine is the S) raises higher temp and makes more damage?

 

I would be very very interested to read comments from 2008 N14 R56S owners, regarding the Thermostat issue and how often has it needed to be replaced!

 

2009 MCS here,

Imho - If you get 70K miles on a thermostat housing, you are lucky. Moving fwd, I'm planning to replace (thermostat-housing, water-pipe, and water-pump) every 60K miles as a regular maintenace replacement of a wear item. No fun being stranded due to failure of one of these cooling system components.

W

 

The thermostat is a tricky item to add to your maintenance list. Mine went out at 120k miles, some only go 50k miles. What should be the change interval? My suggestion is to wait until it fails, then change it out. They are designed to fail open, so it will always provide cooling, just not efficient cooling.

As for the issue of losing coolant, I can't see how that is related to the thermostat housing; maybe the gaskets, but not the actual housing. If you are losing coolant, something else catastrophic is going on. Not sure how you could prevent that by adding an item to your regular maintenance intervals.