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Patrick of M
11-15-2018, 10:32 PM
I bought a Mahle one, supposed to be one of 2 types that were OEM. Was I mistaken ? Stupid PITA. What is the 100% original thermostat and do I have to go to MB and pay MB prices for the pleasure of having a thermostat that last more than 12 months?

Midwestdrifter
11-15-2018, 10:54 PM
What are your symptoms? Have you double checked the dash gauge with an IR gun? You likely know what you are talking about, but for others who might find this thread.

Patrick of M
11-16-2018, 06:31 AM
Symptoms are the same as last fall. Canít stay hot unless running down the highway and even then sits at 78C instead of 82. Itís not even really cold yet but at 0C it is taking way too long to even get to 60. Iíve had aftermarket thermos give flawless performance for decades. It is unlikely that the gage is awry as it is tracking and behaving generally as it should. Iím pretty tuned into the the engine heat via the cabin heat, and 60C in the engine feels warm but not hot from the vents. Last year after the replacement all these symptoms went away. I contacted the eBay seller, and amazingly they are sending me a replacement (although Iím sorely tempted to go MB and pay them god knows how much for a thermostat that lasts).

Midwestdrifter
11-16-2018, 02:27 PM
I would be curious to see a test and autopsy on the removed unit. Good luck!

Aqua Puttana
11-16-2018, 02:43 PM
I would be curious to see a test and autopsy on the removed unit. Good luck!
+1

A visual inspection of the internal rubber seals at least. Is the there a jiggle valve? If yes, is it functioning?

A heated water bath test is probably less worthwhile, but if done be certain to not remove the sensing element out of the housing. It will pop apart when heated out of the housing.

:cheers: vic

Patrick of M
11-17-2018, 02:12 PM
Last year when I changed the thermostat I examined the old one, the internal rubber seal and adjacent metal face that it seals on where all in good condition. The only explanation I have for the previous failure is that the spring was not holding the seal tight against the face. Presumably, as it is the only spring in the assembly, this spring modulates with temperature, my guess is that it loses temper and eventually stops holding tight and allows a certain amount of coolant to slip by. This would explaing the slow but eventual heat up and the slightly low final temp. When I get a new one I will try to analyze the spring tension of the new against the old.
Iím thinking that maybe a generic thermostat was put in a Mahle box, there are no actual indications on the thermostat housing as to its origin.
The eBay seller certainly refunded me my $ very quickly, no questions asked.
Next, who has replaced a thermostat and had reliable results and what brand/merchant was it?

Aqua Puttana
11-17-2018, 02:24 PM
Europarts SD?

Wahler

https://europarts-sd.com/thermostatwhousing2002-2006.asp

vic

MillionMileSprinter
11-17-2018, 03:02 PM
I sell the oem thermostat on my website:
https://www.millionmilesprinter.com/product-page/thermostat
I also have a video discussing the thermostat and a tip on how to remove it on my Instagram and Facebook.
https://www.instagram.com/p/BqIRj0cne7T/?utm_source=ig_share_sheet&igshid=aiz07978t4jz
https://www.facebook.com/pg/millionmilesprinter/videos/
On my Facebook page it's the video entitled "Why pay more for the same product?"
I currently have over 70 videos and add more every week!

billintomahawk
11-17-2018, 03:07 PM
Mahle from a different source.

https://www.idparts.com/thermostat-t1n-p-4329.html

bill in tomahawk

billintomahawk
11-17-2018, 03:16 PM
I sell the oem thermostat on my website:
https://www.millionmilesprinter.com/product-page/thermostat
I also have a video discussing the thermostat and a tip on how to remove it on my Instagram and Facebook.
https://www.instagram.com/p/BqIRj0cne7T/?utm_source=ig_share_sheet&igshid=aiz07978t4jz
https://www.facebook.com/pg/millionmilesprinter/videos/
On my Facebook page it's the video entitled "Why pay more for the same product?"
I currently have over 70 videos and add more every week!

MMS,

That's a great video on the thermostat.
Now I know.
Loved the pro tip.

Nice work.

bill

Woodythesprinter
11-17-2018, 05:16 PM
Thanks for sharing, I was about to buy one so I'll reconsider

NelsonSprinter
11-18-2018, 04:32 AM
Last year when I changed the thermostat I examined the old one, the internal rubber seal and adjacent metal face that it seals on where all in good condition. The only explanation I have for the previous failure is that the spring was not holding the seal tight against the face. Presumably, as it is the only spring in the assembly, this spring modulates with temperature, my guess is that it loses temper and eventually stops holding tight and allows a certain amount of coolant to slip by. This would explaing the slow but eventual heat up and the slightly low final temp. When I get a new one I will try to analyze the spring tension of the new against the old.
Iím thinking that maybe a generic thermostat was put in a Mahle box, there are no actual indications on the thermostat housing as to its origin.
The eBay seller certainly refunded me my $ very quickly, no questions asked.
Next, who has replaced a thermostat and had reliable results and what brand/merchant was it?

What spec coolant are you using?

Patrick of M
11-18-2018, 01:24 PM
Yeah I got there as well, and it’s is a possibility. Last year I put in long life presumably HOAT for Mercedes some Canadian Tire brand that they no longer sell. This year IN AUGUST when I did my waterpump, the Canadian Tire brand is no longer available and a new brand was on the shelf OEM brand, Euro 1 the full strength supposedly for MB. There’s was no HOAT written on the container but I trusted they were not bs ing me. Looked it up online turns,out it is OAT!
So I may have mixed OAT and HOAT (but only 10-15% as i drained the system pretty good during waterpump as i had to do the Ac condeser in the cooling pack)
I would be surprised if 10 months of OAT or 2 months of 15% HOAT/85%OAT would cause a seal to fail, but I’ll know soon.
I’m a bit pissed that the OEM Euro 1 is not HOAT as it clearly states on the front that it is for Mercedes, and from what I can tell Mercedes has been using HOAT for the last 15-20 years.
I have written CT and OEM, and obviously a full flush (possibly chemically flush) is in my future.
Flushing the engine in the winter is less than ideal as well.
The whole long life coolant thing is pissing me off. Seems I crack into coolant systems at least once every 3 years with older vehicles, maybe universal coolant is the way to go, less bs, just change every three years or when servicing.
Live and learn.

Nautamaran
11-18-2018, 04:06 PM
Sorry to hear you were mislead...

Valvoline’s Zerex G-05 is available at NAPA Canada.
Concentrate is about $22/gallon, 50/50 for $18.

But... it was behind the counter in their warehouse, with a couple of OAT blends out front touting recommendations for Mercedes... Maddening!

-dave