76 votes
I had a bad thermostat and it's only indication was the temp rising when going up hills under sustained load.
I had this year ago, thermostat was stuck closed, so coolant couldnt go to big circle and into cooler, it went up after 10 minutes of highway driving up to 115° (obd temps) on dash it wasnt that much
I used the genuine part as there is no desire to redo it again too soon.
It has been two weeks since the repair without issues, so I am going to call this one solved. If I was paying for this out of pocket in the future, I would only replace the thermostat and not the pump as that is what was closing and causing the issue.
Original was stuck open, replaced with new VW which now appears to be stuck closed. ????. Fortunately I have recently acquired a new OE thermostat on clearance for jollies.
I did the timing belt water pump thing on my MK4 last year, and shortly after the test drive with fresh genuine VW antifreeze and while patting myself on the back for a job well done it occurred to me that I hadn't changed the thermostat. Sure enough a month or so ago when the first of the really cold whether started around here the temp gauge would only get to about halfway to normal during a trip to town and back. I tried the ol' cardboard in the grill routine for a couple of days until I got a chance to change the thermostat and that brought things back to normal.
After getting mine back together, and filling it back up with coolant, i found the new thermostat from the dealership was stuck wide open and the car wouldn’t get over 110*F.
I've got a 13 sport with 135k miles on it. Only ever done oil changes, spark plugs, 12v battery and a thermostat. Other than that it’s been stupid reliable.
Sounds like your water pump is working, but maybe your thermostat is stuck closed? Have you tested the thermostat?
mine is also a problem an my car is 1.5 yrs old. Sometimes the temp gauge acts as if it is -40C outside even if it is a couple degrees above freezing. Often the car will take 4-5minutes to get near base idle when it is cool outside, but when it's really cold, sometimes it takes 30seconds and there is no way it's warmed up. Can also smell coolant anytime I open the hood. Sad.
Write your review about thermostat OEM Volkswagen
Help others - share your experience with this part.
Voted AGAINST engine oil RAVENOL on the rating page
The brake pads OEM Alfa Romeo got the first review!
The brake caliper OEM BMW got the first review!
The brake pads OEM Infiniti got the first review!
For wiper blades PIAA already 100 reviews.
For battery Energizer already 25 reviews.
In the rating best water pump already 12 brands participate!
In the rating best timing belt already 13 brands participate!
In the rating best head gasket already 3 brands participate!
In the auto rating oil filter for Volkswagen Passat already 5 brands participate!
In the auto rating brake pads for Mazda 5 already 10 brands participate!
In the auto rating tires for Subaru Outback already 50 brands participate!
For cabin filter Fram already 25 reviews.
Voted AGAINST engine oil RED LINE on the rating page
Voted AGAINST engine oil PENNZOIL on the rating page
The brand is registered in Germany. Official website: https://www.volkswagen.de/.
In March 2026, PartReview users have a mixed opinion of OEM Volkswagen thermostat.
PR Score — 73 out of 100, based on 24 reviews and 76 votes. 16 positive reviews, 4 neutral reviews, 4 negative reviews. Average rating — 3.6 (out of 5). Vote balance: 56 up, 20 down.
In the ranking of the best thermostat this part is at position 1 ahead of OEM Nissan and Gates.
Users also evaluated the qualities of OEM Volkswagen thermostat:
See which car brands and models owners choose OEM Volkswagen thermostat for. Below are car-specific ratings where this part is in the Top-3:
There are 14 comparisons of OEM Volkswagen thermostat with other manufacturers on PartReview.
In particular, see which thermostat are better: OEM Volkswagen or Motorcraft, OEM Volkswagen or OEM Honda, OEM Audi or OEM Volkswagen, MOPAR or OEM Volkswagen, OEM Volkswagen or AISIN .
