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Thermostat OEM Audi or AISIN
I have an 06 Audi A3 2.0T Sportback with just over 105k miles; recently replaced the thermostat, spark plugs and coil packs. Other than being in need of some new brakes and a bit of cosmetic love, she's running strong.
Pros: running strong
Cons: needs new brakes
Vehicle:
Audi A3
Mileage: 168981 km
Hard to say if it’s directly OE to Subaru, but I use Aisin thermostats and water pumps on every Subaru engine I do, they function the exact same and are equally as reliable as the original equipment, not to mention these thermostats are $15 on amazon compared to $40 from Subaru.
Pros: equally reliable, functions same as OE
After doing some research I found that AISIN is likely the supplier for the Subaru OEM thermostats so I ordered them off of Amazon (sold and shipped by Amazon) and they appear to be just that. They were close to the same price and are made in Japan. AISIN THF-007/009 appear to be true OEM Subaru thermostats for FB20B
Pros: true OEM quality, made in Japan
Part number: THF-007/009
Pick up the AISIN OEM version of your thermostat. It's pretty cheap so no reason not to get the best one instead of some cheaper alternative. Also you can test the function of your thermostat before doing the change by putting it in hot water. You can check the specs of the one you use, but for the AISIN one for my 2012 civic (9th gen), the thermostat starts opening at 170 and is fully open at 190.
Pros: OEM quality, good value, accurate opening
Vehicle:
Honda Civic
I still changed my thermostat to an Aisin unit for peace of mind, so far so good.
Pros: peace of mind, good performance
Vehicle:
Lexus
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
Pros: perfectly fine operation
Recently had the exact same issue on a 14 a6 ended up being a DOA t stat I compared the shaft length on the new t start to the 2nd new t stay and sure enough it protruded out about a mm further just enough to not seal properly causing the over cooling after the swap no more issues.
Pros: no more issues
Cons: over cooling
Vehicle:
Audi A6
Had this happen to our 2018 Q5 a few months back, 35k miles on the SUV. Thermostat issue plus some other stuff.
Vehicle:
Audi Q5
Mileage: 56327 km
Aisin THF-003 thermostat was used (I believe this is what I'm regretting). It's like the thermostat isn't opening? Everything else seems fine - it's clearly getting hot. Little to no heat at idle. No circulation = overheating of the engine. Is the replacement thermostat stuck shut?
Cons: thermostat not opening, overheating engine, little to no heat
Vehicle:
Subaru Impreza
Part number: THF-003
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Which thermostat to choose — OEM Audi or AISIN?
If choosing thermostat across many manufacturers, check the part ranking. If your choice is down to two brands, the PartReview part comparisons help.
We compare thermostat across these categories:
- PR Score.
- Overall ranking.
- Vote balance.
- Average rating.
- Number of reviews.
- Feature ratings.
- Car owners’ choice.
Which thermostat are better — AISIN or OEM Audi?
In March 2026 on PartReview, thermostat AISIN were overall better than OEM Audi.
- OEM Audi received a PR Score of 75 out of 100, and AISIN scored 83 points.
- OEM Audi ranked 7 in the overall ranking, and AISIN ranked 5.
- The average rating is higher for AISIN (4.3) than for OEM Audi (4).
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Thermostat AISIN have better feature ratings than OEM Audi:
- Overheating - owners believe, that this property for OEM Audi is better than AISIN.
- Slow warm-up - drivers claim, that this property for AISIN is outperforms OEM Audi.
- Cabin heat - reviews suggest, that this property for AISIN is preferred to OEM Audi.
Which thermostat are more popular — OEM Audi or AISIN?
Thermostat OEM Audi and AISIN were equally popular according to data in March 2026.
By vote balance, thermostat AISIN surpassed OEM Audi:
- For OEM Audi, the ratio of positive (27) to negative (9) votes is 18 votes.
- For AISIN, the ratio of positive (26) to negative (5) votes is 21 vote.
By number of reviews, thermostat OEM Audi surpassed AISIN:
- For thermostat OEM Audi there are 11 reviews: 7 positive, 3 neutral, 1 negative.
- For thermostat AISIN there are 10 reviews: 8 positive, 1 neutral, 1 negative.
Which thermostat do car owners prefer — OEM Audi or AISIN?
In March 2026, according to PartReview, thermostat OEM Audi and AISIN have not taken top places in car-specific ratings. You can help by adding your review about these manufacturers.
Other comparisons of thermostat
If this comparison didn’t fully answer your question, there are many others on PartReview.
For example, comparisons of thermostat OEM Audi with: MotoRad, Wahler, OEM Volkswagen, Mahle, OEM Mazda, MOPAR, MISHIMOTO, Gates, OEM BMW, OEM Nissan.
Also available: comparisons of thermostat AISIN with: MotoRad, Wahler, OEM Volkswagen, Mahle, OEM Mazda, MOPAR, MISHIMOTO, Gates, OEM BMW, OEM Nissan.
You can also see who is better among other thermostat manufacturers: Wahler or MotoRad, OEM Volkswagen or MotoRad, Mahle or MotoRad, OEM Mazda or MotoRad, MOPAR or MotoRad.