Which thermostat to buy that will last.

Henrick said:

OK, then do you have at least a clue who is the OEM thermostat supplier for VW?
I don't remember the source but I have in my notes that OEM supplier (for TDI-PD engines, at least) is Wahler. It seems my notes are wrong

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No, I don't have a clue. I just wanted to see if you guys had installed the Wahler successfully and found it to be identical to the VW, because the picture clearly shows they are different thermostats. It could be that the poster got the wrong Wahler, or that Wahler just manufacturers a different thermostat for VW.

I can almost guarantee that Wahler's can be installed successfully and work, otherwise IDparts wouldn't still be selling them...

I think what I might do is install the Wahler stat in one Jetta and go to NAPA or O'Rielly for an aftermarket/generic one and run both a couple years and see which one stays at what temp. Why not??

Hey guys, not sure if this will be noticed since this thread is old, but I'm left feeling more confused after reading this than before. I have a 99.5 Golf ALH that needs a new thermostat. If I go to 1stVWparts.com, the one that has 1.9 tdi listed on it is 14.64
https://www.1stvwparts.com/catalogs.html
There are others, but none say for "tdi"
World Impex lists one for 48.79, it says "genuine," but it is the wahler if I understand this thread correctly, which isn't the right one... right?
So, which is the best one, the "genuine" oem, to order. That will last and fits perfectly.
Don't mean to be a pain, just confused. Also, what else should I order? A flange? An O-ring?
It would be great, but not necessary, if someone just gave me a link to exactly what to buy.
Thanks
Scott

I am currently using the $14.64 thermostat from First VW parts and am happy so far, however, I have only had it installed for a few months, so only time will tell.
It arrived in a genuine VW box, and appears to be of higher quality of the one that I pulled, if that helps any. Don't forget to buy a new O-ring and probably some coolant.

jettawreck said:

I think what I might do is install the Wahler stat in one Jetta and go to NAPA or O'Rielly for an aftermarket/generic one and run both a couple years and see which one stays at what temp. Why not??

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Sorry, my follow up was in a different post. The OReilley one never made/kept tempature. Changed it out in a couple days and have been running the Wahler. So far so good. It makes it to 190 after 30 miles of my commute if its above 10F with the radiator and grille both covered. Best I've done so far in any of the Jettas.
It (Wahler) isn't "OEM" because the tabs inside the coolant flange don't work with it, but they relly aren't that critical for installation.

That's still a long time.. Mine makes it to the 190 mark within 10 miles, even on the morning where it was -8F.. I have no grille/radiator covers of any kind..

TDIJetta99 said:

That's still a long time.. Mine makes it to the 190 mark within 10 miles, even on the morning where it was -8F.. I have no grille/radiator covers of any kind..

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190 mark, or 190?

Mine makes it to the 190 mark around 160.

the mark.. I'll have to run VCDS next time it's really cold and see how long it takes.. I know after about 15 miles, the thermometer in my center vent will reach 175...

TDIJetta99 said:

the mark.. I'll have to run VCDS next time it's really cold and see how long it takes.. I know after about 15 miles, the thermometer in my center vent will reach 175...

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Mine enters/touches the 190 mark at 163F.

eb2143 said:

This isn't really correct.
Genuine VW parts: See what T_D_I_Power said. VW does not necessarily make something directly because it's stamped VW.

OEM: Original equipment manufacturers are the manufacturers of original equipment VW-stamped VW P/N parts.

I have heard of issues with non-VW thermostats. A search should turn something up. I've heard of aftermarket German not fitting correctly. I would stay genuine VW from 1stvwparts.com.

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This is true, most all the parts for these cars as well as most are not made by the manufacture. If they did no one would be able to by one because of cost. Can you imagine a plant for almost every part on and in the car. The vender code on the part will tell you who made it. And parts for these cars are made all over the world.

I also had issues with some aftermarket stats.

All my cars, and all my customers' cars, get genuine VW thermostats, no questions asked. None of the aftermarket ones (no, not even the ones frm Germany) are as good as the originals.

So far I'm doing pretty good with my aftermarket one.. I'm using a BEHR 92C one at the moment.. Cost me $16 and came with the o-ring..

Edit.. Here's the one..

This is from 1stvwparts.com.

Is this the real deal?

THERMOSTAT [Part# 044121113]
Quantity:

Volkswagen
List Price:$20.00
Your Price:$14.64

Looks like the real deal.. Genuine 87C (188F) thermostat. Impex shows it for $49 so even after the shipping/handling charge it's still really cheap for OE..

madrean said:

This is from 1stvwparts.com.
Is this the real deal?
THERMOSTAT [Part# 044121113]
Quantity:
Volkswagen
List Price:$20.00
Your Price:$14.64

Click to expand...

Thats what I run, so far it is good.

sweet, i'll have to get me the parts together.

thanks

I installed the Wahler one from IDparts in my 04. had to break the tabs to reuse the housing . Interesting enough after removing the housing the T-stat was completely closed and no coolant would come out but it still slightly opened when it was warmed ( coolant temp never exceeded 165F).

madrean said:

This is from 1stvwparts.com.

Is this the real deal?

THERMOSTAT [Part# 044121113]
Quantity:

Volkswagen
List Price:$20.00
Your Price:$14.64

Click to expand...

this is for the gasser , it should work though

It won't. It will go in, it just won't regulate the coolant temps correctly. I think this is why so many aftermarket stats don't work correctly on TDIs, because they sell you one for the gas cars.

I'll bite.. what's the difference between a 87C gasser thermostat and an 87C diesel thermostat both for a 4cyl mk4? Thermostats don't care what kind of fuel the engine uses.. They only regulate coolant temp..They are physically the same dimensions.. Heck the 2.slows even have the same thermostat flange as an ALH..

oilhammer said:

It won't. It will go in, it just won't regulate the coolant temps correctly. I think this is why so many aftermarket stats don't work correctly on TDIs, because they sell you one for the gas cars.

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care to explain why ? they are both rated for the same temp . I have ran lower temp thermostats in earlier VWs and had no issues with them.

i've been using the 92C (197F) units in the ALH cars for a while and they work VERY well, especially in cars that live on the highway.. You wouldn't believe the heat output with 200F engine temperature, LOL. They also work well for WVO cars to keep system temps up where they need to be.. I'll usually use the 87C t-stats in the more modded cars..

The temp stamped in the stat is just when it starts to open. Place a new OEM VW TDI stat and a new OEM 2.0L stat in a pot of water side by side, turn the heat up, and watch.

The other thing is the size of the opening, as well as how it is designed to flow coolant (the water pump impellers are different gas/diesel) at a given RPM.

Probably splitting hairs, but still, VAG built around 10 million cars last year, if they could have saved 2 cents on half of them by using a different thermostat, they probably would have.

Both gas and diesel cars have 12v batteries, too, but they are not always the same battery.

Well, I did a little digging at my local VW dealer, and the 044-121-113 is listed for the ABA, ALH, 1Z, AHU, BEW, 1.5NA, 1.6NA, AAZ, BHW, 83-85 Quantum Turbodiesel, 87-93 Fox, and 82-83 Audi 4000..

And just for kicks it fits/functions in my big block chevy as well...

So part number 044121113 turns out to be for both gasoline AND diesel..

The newer EA113 gas engines use the 050 prefix thermostat, not the 044. (I did some digging right in front of my face ). When I mentioned the different water pumps, I was in context of the EA113 engines, not the EA827, sorry I should have made that clear.

Out of curiousity, though, I want to perform some tests next week. I have both the 044 and 050 OEM thermostats on the shelf, honestly never looked all that closely at them. And I can easily get both Wahler and Behr brands from Worldpac, and probably a Stant from the local generic parts dump. While I know the non-OEM ones generally will not twist-lock properly into the necks (you have to break the tabs off), and I know they seem not to hold the [real] temps as steady over time, I am wondering how well they perform in a side-by-side comparison.

I'll try and post some pics, but my camera is old and my skills in that department are rather lacking...

is the 050 the same temperature rating as the 044?

I just stuck the comment about my big block in there since they will work with just about ANY 54mm thermostat.. The smallblocks and a lot of ford V6's use 54mm stats as well..

Yes, the 050 is the same temp as the 044. I thought I had both on the shelf here, but I don't. I am going to order some more in today and take a better look at them.

It may just be that the ALH/BEW/BHW one is just shaped a little differently to lock into the tabs, because most of the EA113 gas engines' necks for some reason do not have those tabs (which really sucks on some models).

oilhammer said:

Yes, the 050 is the same temp as the 044. I thought I had both on the shelf here, but I don't. I am going to order some more in today and take a better look at them.

It may just be that the ALH/BEW/BHW one is just shaped a little differently to lock into the tabs, because most of the EA113 gas engines' necks for some reason do not have those tabs (which really sucks on some models).

Click to expand...

i checked the factory one from my 04 and a wahler one. the opening is wider on the wahler but I don't think it will make a big difference on how the temps are regulated .

Dealer is out of thermostats now, go figure.... we've had a cold snap here recently. Be in tomorrow.

I read this thread with interest, and with a history of good and bad thermostats. A Standt one I put in my 91 Jetta (IDI engine) cost me a cylinderhead gasket. It broke apart, burying the disc that serves as a valve, into the impeller intake port, where it fits perfectly.

Since then I've been buying mostly Behrs, one Wahler (which I didn't like the construction of), and one from VW. Te Behrs that I ended up with were identical in appearance to the VW, but that may not be the whole story.

Autohausaz, where I have bought various VW parts from lists two Wahlers and two Behrs for my 99.5 TDI. The listing goes something like this:

Wahler OEM 80C $11.11 056121113A
Wahler alternate 71C $9.44 056121113E

Behr OEM 87C w/gasket $14.48 044121113
Behr alternate 87C $9.70 056121113D

Since I have many gaskets on hand, I am thinking of replacing the thermostats in my 99.5 and 03 ALH engines with the Behr alternate. Not only do I like the additional heat output in the winter, but I find the engine temps are simply more stable when set higher. I figure that the temp climbing and dropping during various levels of power output only stresses the head gasket for an earlier failure.

Since this discussion had little mention of Behr thermostats, I figured I would ask.