Thermostat 02 TDI

[POWERSTROKE]

How do you replace these? Do you need to drain the radiator? Or can you just pull it off and replace it? Any step by step or better yet YouTube videos?

 

[Curious Chris]

I never drain the radiator. Yes you loose some coolant. Take off the upper hose, 2 bolts and remove. Since it is a 2002 you might want to buy the coolant flange as they get brittle over time. And if it breaks when you take it off you will be unhappy if you do not have one. Mine broke when I replaced my thermostat. This one https://www.idparts.com/thermostat-housingcoolant-flange-alh-038121121-18230-p-653.html

 

[oilhammer]

Two bolts. That's it. Super easy.

Get a new flange, put the new o-ring on the flange, and twist lock the new thermostat to the flange and bolt it back on. You can drain the radiator if you like, but you'll still lose some more when you take the thermostat off usually.

 

[POWERSTROKE]

So I’ll lose fluid now matter what. Might as well just change it and just replace without draining the radiator. Thanks.

 

[flee]

Guys that have exceptionally clean engines have been known to catch the coolant
that drains down the side of the block and reuse it.
Me, not so much...

 

[shoebear]

Two bolts. That's it. Super easy.

Get a new flange, put the new o-ring on the flange, and twist lock the new thermostat to the flange and bolt it back on. You can drain the radiator if you like, but you'll still lose some more when you take the thermostat off usually.

I agree that you should replace the flange with the t-stat. There are two fingers in the flange that hold the t-stat during reassembly, and it's practically impossible to get the old t-stat out without breaking the fingers. While it's possible to install the new t-stat without the aid of the fingers, it's difficult, and then you can never be certain that everything is lined up so that the gasket will seal properly.

Here is the flange for your car at idparts. Beware of aftermarket ones -- some do not have the fingers (URO, if I recall).
https://www.idparts.com/thermostat-housingcoolant-flange-oem-alh-038121121-p-3402.html

If you use an aftermarket t-stat, the geometry/construction may not work that well with the fingers. The OEM t-stats from VW are very expensive, but Behr is the OE manufacturer, and you can get the same t-stat as VW (but without the logo) from AutoHausAZ for $12+shipping):
https://www.autohausaz.com/pn/056121113D
Disclaimer: It has been a few years since I bought one from them. Apparently Behr has been purchased by Mahle. I assume this is still the exact t-stat I have bought before, but it's hard to tell from the photo; it looks a little different, but it may still work fine with the flange fingers.

 

[AndyBees]

I use a vacuum to pull out the coolant. I generally lose no more than a pint.

The Autohausaz T-stat will not fit into the Plastic Coolant Flange. What you see in the pic is not what they will send you. I have about five of those T-stats. I called and never could get it thru the numbskull's head how the T-stat fits into the coolant flange and what they are sending out is not what's in the pic. So, to use them (those I have on the shelf), I use a Drimel to modify the inside of the coolant flange.

I just checked one of my previous orders. The T-stat linked above is the same as those I have had issues with (same part number). The metal across the top is too wide to go in the fingers of the Coolant Flange ....... Trust me!

 

[shoebear]

The Autohausaz T-stat will not fit into the Plastic Coolant Flange. ... The metal across the top is too wide to go in the fingers of the Coolant Flange

Good to know. That used to be a good way to get the OEM t-stat cheap. Now I wish I had stocked up more. Have you found any other source? Or did Mahle just screw up the t-stat and it's not available anymore except from VW (until they run out)?

 

[oilhammer]

Calorstat brand is what I have been using for a while now. Like the Behr, they look and fit exactly the same as the OEM ones they just do not have the VAG logo and part number. They come with an o-ring too.

 

[shoebear]

Calorstat brand is what I have been using for a while now. Like the Behr, they look and fit exactly the same as the OEM ones they just do not have the VAG logo and part number. They come with an o-ring too.

Thanks, Brian. Happen to have a part number handy? I couldn't find a direct match listed on https://www.calorstatbyvernet.com .

Otherwise, the genuine VW part number is 044121113. MSRP is $50, found it on eBay for $29 incl shipping.

On edit: Found THIS which looks like the VW t-stat except for the gold color. They claim OE mfr. $15+shipping ($11.34 for 1 or 2 to Colorado Springs). I ordered 2 of them and will let you know how they fit the flange fingers when they arrive in about a week.

 

[oilhammer]

They give a number of TH6273.87J, which actually crosses to the VAG number of 03G-121-113-A (for the BRM) but they are the same. That is one of those instances where VAG has a newer part number prefix for a newer engine, but did NOT change it for the older ones.

 

[shoebear]

They give a number of TH6273.87J, which actually crosses to the VAG number of 03G-121-113-A (for the BRM) but they are the same. That is one of those instances where VAG has a newer part number prefix for a newer engine, but did NOT change it for the older ones.

Thanks, Brian!

Looks like AutoHausAZ has them on sale now for $10 ea + shipping.

On edit: Nope! Autohaus cancelled my order... says they're out of stock and can't get more.

 

[POWERSTROKE]

I bought the skit from I’d parts that included everything. It fit well and took about 15 minutes with draining the radiator. Not too shabby. I didn’t breK the original housing either.

 

[shoebear]

I bought the skit from I’d parts that included everything. It fit well and took about 15 minutes with draining the radiator. Not too shabby. I didn’t breK the original housing either.

Cool. idparts is a quality vendor. Good for you not breaking the fingers.

 

[shoebear]

Found THIS which looks like the VW t-stat except for the gold color. They claim OE mfr. I will let you know how they fit the flange fingers when they arrive in about a week.

They arrived today. They are BorgWarner Wahler 4264.87D, and they don't fit. What I got is different than the photo on their website. Requesting a return/refund. You can see photos of what they sent HERE.

 

[IndigoBlueWagon]

That thermostat will fit, it just doesn't click into the flange.