In case if your New Year resolution is to lower coolant operating temperature
 

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Update 12/31/16:

3 sold, 2 left. $92 free shipping.

This topic been covered zillion times but general consensus is that 108 C operating temp in M62TU is great for the fuel economy and emissions but not so great for plastic cooling components.

For those who remember the High school Physics classes, more heat = more pressure so it's 2 enemies against the cooling system.

I've sold about dozen of these, mainly on ebay and E39 forum and than my supplier in Europe run out. They're back in stock and have batch of 5 coming in about 7 days.

One is sold, four are still available: $92 including free shipping.

Direct fit to any E53 X5, E38 740i and E39 540i with M62TU engine. This is mechanical thermostat that opens at 88 C and you'll see average running temp of around 88 C-92 C vs. 108 C.

In order to avoid CEL you simply connect 10 OHM resistor to disconnected OEM thermostat DME wiring connector.

This thermostat came originaly on E38 740D and here are some specs:

https://catalog.mahle-aftermarket.co...lterId=1164537

It is genuine Mahle / Behr brand made in Germany and it comes with o ring included.

PM if interested.

Thanks.

I've looked into this before and is definitely something I'm going to do. 108deg running temperature makes me very nervous and uncomfortable! Sourcing the right thermostat however was proving tricky.....they were even on back order from BMW with no available date when I last looked.

I got a few part numbers too for various possible options although ultimately I'd only really be happy with a genuine thermostat for reliability - I was looking into other options as the BMW ones didnt seem readily available...

90Deg :
BMW 11531704704

95Deg :
BMW 11531702279

88Deg :
BMW 11 53 2 248 542
BMW 11 53 1 715 254
BGA CT5003
FIRST LINE FTS473.88
MOTORAD 603-88
TRISCAN 8620 24388
VEMO V20-99-0161

You are aware that "genuine" is elusive word. While there are BMW parts that are proven to be better quality than aftermarket, when it comes to thermostats it's not so clear.
I have the "genuine" BMW thermostat in my 540 and it's of course made by Behr. I don't believe in first quality BMW Genuine vs second quality aftermarket as some claim.
Sure, it does apply sometime when you compare let's say Genuine BMW vs URO but if the manufacturer is known to produce parts for the maker and it's not a illegal copy, I don't have problem buying it.
Anyway, about dozen people are running Mahle / Behr and I had no complaints. Time will tell, but another benefit IMO is of course no electrical connector which can be a separate issue with coolant leaking at and in rare cases traveling to DME wiring loom.

Oh totally aware.....however after being burnt several times with aftermarket thermostats (one in my BMW 330d a couple of years ago) unless I'm sure that it is a quality brand such as Mahle/Behr then I wouldn't entertain buying it. Completely false economy and definitely more hassle. Definitely prefer parts that you can fit and forget about rather than having to revisit them again because they have failed prematurely. Least with a genuine part you're probably 99% sure that this won't need to happen.

Please can you PM me details of your European supplier as I'd definitely be interested in one of these.

Is that the same thermostat that needs to be carefully drilled to fit correctly? Or is this plug & play with the added resistor?

Fuel economy, ha! can't get much worse that 13 mpg!

Plug and play with added resistor.

PM sent

3 sold, 2 left.

Is there a part that would do this for a 2005 4.4 x5?

The pressure is too much! :yikes: lol

Logic 7 modified thermostat. I have one here on a shelf waiting to go in when I do my cooling system refresh. Unfortunately it's pretty expensive for a thermostat. But if it saves other components in the future I suppose it pays for itself.

Coller Thermostat | BMW LOGIC7