I replaced it at around 140,000 miles. It did not fail, but I thought it was running a little too cool, maybe 160°. So I changed it and the temps went up a few degrees, maybe to 165°. Both were 80° thermostats. So the old OE thermostat probably was still okay.

__________________
Len
'59 220S Cabriolet-SOLD and living happily in Malta
'83 240D 351,500 miles original owner-SOLD
'88 560SL 41,000 miles - totaled and parted out
https://sites.google.com/site/mercedesstuff/home
'99 E300 turbo 227,500 miles
'03 SLK320 40,000 miles - gave to my daughter
'14 Smart electric coupe 28,500 miles
'14 Smart electric cabriolet 28,500 miles
'15 Smart electric coupe 28,000 miles

I replaced mine in the 206k mile range. I really can't complain given how long it lasted.


---
I am here: http://maps.google.com/maps?ll=34.621074,-118.193512

__________________
2013 Volkswagen Jetta Hybrid SEL Premium (Sparky)
http://badges.fuelly.com/images/smallsig-us/193500.png

It's a car not a science experiment! Open the throttle!

Replaced mine at 140,088 miles with a Behr. Still had the original housing so replaced that too.

Now the Behr is quick to heat to the first thermostat mark 60C but takes some 6 or 7 minutes to get to 80C but will maintain 80C in sub 0 weather. Will replace with a Wahler. I understand both brands have an excellent reputation.

I think I may have cooked it when the temperature went 3/4 of the way to the 100C mark while on cruise with the air blasting going up a 15 mile grade on Interstate 15. It was advised to turn off air conditioning at the base of the hill.

I have always had the belief that you could reach 100C before and damage was done and that a thermostat or engine and it would fail open at 120C. I suspect that I have a partial fail resulting in a fast opening. New Wahler thermostat ordered now if it would only warm up outside.

__________________
1999 Mercedes E300TD daily driver sold at 238K miles 106K miles were mine, rust worm got it :-(
2006 Mercedes CDI new daily driver! 56,000 miles May 2016 now 85,625 Apr 2018 and Apr 2019 101,000 miles Apr 2020 109,875. March 2024 135,250