Thermostat Wahler or AISIN

Spend slightly extra and get a quality OEM Wahler thermostat.

I still changed my thermostat to an Aisin unit for peace of mind, so far so good.

I just bought two thermostat related parts off rockauto that are both Aisin yesterday.

I have installed them in two rebuilt, and they are working perfectly fine

Got the Wahler on my 2008/2011 and it was identical to the MB part except the area that had the MB logo on the original one was ground out.

It's a very easy thermostat to replace, I just did it a couple days ago on a 2008 Hyundai Sante Fe with the big 3.3l V6. The gasket comes with the OE Aisin thermostat, too, making it even easier.

I've replaced my thermostat with a new wahler one and I have the same problem which is that it openes at around 70°C and cools my engine to almost 50°C, from what I understand the thermostat is mechanical and electronically assisted to open faster/wider

I just replaced the original thermostat at 90,000 miles because at highway speeds it would run slightly cold and took a while to warm up from cold. The new wahler replacement takes just as long and will actually run cold intermittently when not on highway. Occasionally it won’t deviate from center on the highway.

My tstat is wahler. People said that it was better than Mahle. But I found it similarly poor.

Thermostat was ALSO replaced when the water pump was, with a Wahler unit. Guess I got 10k miles out of it?