Check Engine - Thermostat - MBWorld.org Forums

Dec 6, 2006 | 03:28 PM

PDC

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2006 SL65 ///AMG - GONE BUT NOT FORGOTTEN: 2005 E55; 2002 ML55; 2001 CLK55; 1992 BMW 850i; 1991 M5

Check Engine - Thermostat

I have one of Patrick's 160 degree thermostats installed in my 05 E55. I think it went in in September. The car runs great and the temp stays either dead-on at 80 degrees or one bar above/below. I live in Kansas City and we had our first blast of winter this week. I drove to and from work with the outside temp in the 20s and the car was fine - one bar below 80 after warm-up. Today was about 40 degrees out and I had to make a highway run of about 40 miles. I was cruising between 80-85 mph and at that speed, the temp stayed below 80. I parked the beast for about an hour and when I got back out to fire her up, I got a "Check Engine" light. I was going to the dealership anyway to have new tires mounted and my tech said the code came back for "faulty thermostat." He remembered putting in the lower temp thermostat and cleared the code out for me and indicated that he wanted to wait a week or so to see if it came back. After the tires were mounted, I fired her up, no CEL, and drove back to the office. Any others out there with Patrick's thermostat have any CEL issues in colder weather? Could it just have been the extended highway trip with only 2200 rpms on the tach, but 80 mph 30 degree air blasting over the radiator? Is this particular error message likely to clear itself out in warmer weather? I love the cooler stat and don't really want the hassle of swapping it in every March and out every November. Any thoughts and ideas greatly appreciated.

Dec 6, 2006 | 03:47 PM

jamusa

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I also have the 160 degree thermostat installed,but no problem thus far.Of course i have not yet experience any problem.....because the weather in my area have not fallen below 40 degrees as yet.
Did you loose or gain performance that you could tell?

Dec 7, 2006 | 10:46 AM

PDC

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2006 SL65 ///AMG - GONE BUT NOT FORGOTTEN: 2005 E55; 2002 ML55; 2001 CLK55; 1992 BMW 850i; 1991 M5

No (noticable) effect whatsoever on performance. Again, temp was one bar below 80 the whole way back to the dealership - all highway - and she just pulled and pulled. Had another cold snap last night - it was 12 this morning - warmed up the beast, ran a couple of errands that required shutting the car off and re-starting twice and NO ERROR CODE!!! Maybe it was just a gremlin, or maybe I will need to have my service tech clear that code out 2-3 times each winter. It would be worth it for the benefits of the cooler T-stat during 80-100 degree summer days. We'll see.

P.S. Had Pirelli P-Zero/Nero M&S tires installed yesterday and stepped up to 275s in the rear. My dealership had a helluva time getting the rears mounted; said it was difficult to fit the 275-35 on a 9" wide rim. I've never heard of such a thing before, I thought 9" was plenty of real estate to mount a 275(?)

Dec 7, 2006 | 03:51 PM

Grumpy666

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Quote:

Originally Posted by PDC

I've never heard of such a thing before, I thought 9" was plenty of real estate to mount a 275(?)

It depends on the diameter of the wheel and the aspect ratio of the tire. For example, a 20" wheel with a 0.30 aspect ratio tire needs a wider rim than a 17" wheel with a 0.45 aspect ratio tire (to mount the same width tire).

Dec 7, 2006 | 03:55 PM

e55 baller

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W221 S65 AMG

My car threw a CEL and the dash said error with thermostat or something. Happened when I was driving down a 4 mile mountain at 70mph off the gas in 30 degree weather without being on the acclerator for 3 minutes. The temp was seriously like 4 bars below the 80 cutoff. Must have been too cold.

Dec 7, 2006 | 05:10 PM

chiromikey

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'03 E55, Range Rover Sport Supercharged, Ducati 748R

are you getting an actual cel or just an error code? i've had an error code for a "theremostat temp below threshold" ever since the intall but never got an actual cel.

Dec 8, 2006 | 10:07 AM

whmorris

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Info + Additional question....

My '03 lit up the CEL last weekend (it's been fairly cold around here too). It turned out to be the thermostat. Mine is still stock, so not quite the same situation as you're describing, but it makes me wonder if the infamous ECU flash affected the trigger point for thermostat problems? Interestingly, there was another '03 E55 at the dealer that had the same problem the day I dropped mine off. And supposedly the thermostats are on national backorder now too... sounds kind of suspicious that they run out of thermostats in the first winter after the ECU flash.

While I was driving it on the freeway with the CEL on, my supercharger cut completely out for a mile or so, then came back on and didn't flake out again. I've been feeling like the car had lost some of its high-end power for a while now, but this is the first time I've ever had the supercharger completely cut out on me. It felt like I was driving a 300HP car (probably was!). Now for my question... after replacing the thermostat the dealer found that the Air Charge Circulation Pump (part # 00050000386) is also malfunctioning. Is this the same thing as the IC pump that several people on the forum have had replaced? Could it be responsible for moderate loss of power under normal driving conditions?