Thermostat for 2000 MB E430

[HTSS_TR]

My E430 with almost 140k miles has original thermostat, the current oil is a mix of 5qt M1 0W20 and 2qt M1 0W40.

When I drove the car last Sunday on highway at speed around 68-70 MPH the coolant temp was around 82-83C and 85-88C on city streets, the OEM thermostat is 87C. When it had M1 0W40 some years ago the coolant temp was 85-90C on highway and a little higher on city streets at around 88-93C.

Should I change the thermostat now ? There are 3 aftermarket brands: Wahler (German), Stant and Beck Arnley. The price is between $22 to $38, OEM at dealer is $89.

The price is a little high because it is included in a housing. Below is the Wahler, the others are similar.

 

[bepperb]

You're a lot more proactive about maintenance than I am if you change a thermostat out because it's running 5% cooler than you remember it running a few years ago. IMO if the nominal temp is 87 your numbers are right on.

I hope it's at least easy to get to.

 

[HerrStig]

You might get faster warmup. Otherwise it is a small variation.

 

[HTSS_TR]

Actually the coolant is warm up faster with thinner oil, it's used to be about 3-4 miles of city driving to get to 80-85C, now it is less than 3 miles.

May be the thinner oil lubricates so well such that the engine is running a little cooler.

May be I just buy one thermostat to keep it as spare, and keep an eye over the coolant temp gauge, to make sure that it never get lower than 70-75C after driving on highway for 5-10 miles.

 

[Trav]

Your thermostat is within specs but if i were to buy a new one it would be Wahler. Stant has been putting out some real iffy stuff over the past few years and Beck & Arnley is a toss up, sometimes they have OEM in the box other times god knows.
Wahler is a well known quality brand.

 

[CATERHAM]

Yes it sounds like you're T'stat is sticking.
Having said that, 82-83C coolant temp's are not bad especially during the summer months and if you're not doing mostly short trips.

 

[Garak]

If it's anything like my old Audi, stick with the factory thermostat, both in brand and temperature range - the Wahler 87 C. If it's easy to change, go for it.

 

[HTSS_TR]

Originally Posted By: Trav
Your thermostat is within specs but if i were to buy a new one it would be Wahler. Stant has been putting out some real iffy stuff over the past few years and Beck & Arnley is a toss up, sometimes they have OEM in the box other times god knows.
Wahler is a well known quality brand.

Bought "Used" Beck&Arnley from Amazon for $7 with some other parts for free shipping. The actual thermostat is Wahler made in Germany, looks like new in a slight damaged open box. But who cares about the damaged and opened box ?

Took a chance that the "cheap and used Beck&Arnley thermostat" may be an unknown brand made in China, but pleasantly surprise that it is a new and brand name part made in Germany, it also came with gasket too.

It's amazing that the thermostat and its aluminum housing can be purchased for so cheap.

 

[Trav]

Awesome deal! Thats the thing with B&A they are a repackager so it really is a roll of the dice, i would say 80% of the stuff i have got from them has been OEM or better brands.

 

[HTSS_TR]

This is the first I ever bought from B&A. I had no idea what I may get from B&A, so most of the times I bought parts from a known brand name.

Since Amazon is easy on return, I took a chance and it turns out to be a good deal.