Replaced original Tstat and have same result as others - PeachParts Mercedes-Benz Forum

EricSP · #1 10-25-2008, 09:04 PM

My car used to run at a tad over 80c . After having a overheating issue I replaced my faulty Tstat with one from Autozone. I'm getting the same results as others. It runs consistently at 100c now.

After reading 2 good threads I realize it must be the brand. The original was a wahler Tstat.

Is it worth buying a new OEM Tstat ?

Also where can I buy an OEM Tstat?

79Mercy · #2 10-25-2008, 09:06 PM

Get one from Phil. Get a 79C t-stat. DON'T use any autozone junk on a MB.

MBeige · #3 10-25-2008, 09:09 PM

Fix your overheating issue first.

85 DSEL · #4 10-25-2008, 09:17 PM

I'd just buy one from the MB dealer in your neighborhood...

Not THAT expensive...

79Mercy · #5 10-25-2008, 09:21 PM

karugs if it was running at 80C steady before he replaced the t-stat then it must be a bad t-stat that he bought, not a problem with the car.

MBeige · #6 10-25-2008, 10:12 PM

He had an overheating issue prior to replacing the thermostat...

79Mercy · #7 10-25-2008, 10:20 PM

Sorry I missed that sentance. I stand corrected.

MBeige · #8 10-25-2008, 10:27 PM

Autozone sometimes sells Walher T-stats, sometimes the Duralast brand, sometimes Behr. You have to know which one you got. I think I have a Behr on mine, been a long time since I replaced it.

If that was what's causing the overheating issue then get the right one. When my T-stat got stuck open I would cruise close to 100C on the highway, which was weird because of the added air flow that should reduce the operating temp. Now without any accessories on my gauge reads a hair below 80C which is VERY surprising, as before it would usually be a hair over 80C. I've never replaced the T-stat between those times.

EricSP · #9 10-26-2008, 01:20 AM

Who is Phil?

Cr from Texas · #10 10-26-2008, 02:05 AM

Go to the top of this page and click "BUY PARTS" then "FASTLANE". You'll see Phil's phone number. Without them, this forum would not exist. Support the forum and buy from Fastlane.

EricSP · #11 10-26-2008, 10:50 AM

Thanks!

There are 2 choices Behr or Germany I'm not sure which one to buy.

The amount of threads dealing with issues with Tstat replacements is amazing. All of the replacement Tstats seem to run at about 100c or higher . It really is insane.

There should be a sticky on some threads dealing with this situation. People are buying various other parts in hopes of fixing the car from running at 100c or higher.

http://www.peachparts.com/shopforum/showthread.php?t=193569

http://www.peachparts.com/shopforum/showthread.php?t=213203

#12 10-26-2008, 02:42 PM

If your car is consistently running at that temperature, it is not the T stat!

Plus, they almost always fail in the open position, not closed.

Fix the problem right instead of throwing T stat after T stat at it.

Have you done a citric acid flush?
Are you running the correct coolant?
How old is the radiator?
Is the fan clutch nice and tight when hot, or is it getting loose?
Water pump leaking (unlikely)?
Expansion tank cap creating a good seal?

EricSP · #13 10-26-2008, 03:03 PM

My car never runs hot. Only after changing the old Tstat has it been running like this.

I have flushed the rad in July. I use the G-05 fluid. The fan clutch is perfect. I have no leaks in my system.

Brian Carlton · #14 10-26-2008, 03:05 PM

Quote:

Originally Posted by EricSP

My car never runs hot. Only after changing the old Tstat has it been running like this.

I have flushed the rad in July. I use the G-05 fluid. The fan clutch is perfect. I have no leaks in my system.

When you replaced the thermostat, did you remove the upper radiator hose and completely fill the head with coolant?

nhdoc · #15 10-26-2008, 04:01 PM

You also ought to run it unpressurized for a couple of days (cap set at first detent) so any air bubbles can purge themselves. If you fill it and run it with the cap closed it can become airbound because the bubbles expand when heated and can't move.