Thermostat Change: The Good, the Bad and the Annoying

Lex4TDI4Life

Top Post Dawg
Joined
Jun 22, 2006
Location
NorCal
TDI
2001 Golf-Ute TDI GLS 5spd Manual
So I got around to replacing my thermostat today. I orded a new coolant flange as the pins inside the old ones frequently break when removed. That most certainly happened when I removed mine :)

The annoyances occurred when I tried to place my new thermostat into the new flange. I just could not seem to mount the t-stat inside the flange. The idea is to insert the tstat and twist it onto the two retaining pins. After looking at the old t-stat i saw what the problem might have been:

OLD Thermostat:


NEW Thermostat:


As you can see, the old thermostat has a lot more room for the retaining pins to slide into. The new one has no room at all.

The bad thing was that I ended up breaking the retaining pins in both the old AND new coolant flanges. Without those retaining pins, it becomes very difficult to mount. I had read in another thread that I could just mount the t-stat to the flange with a little rtv silicone. I could not find any in my supplies, but I did have some leftover "Right Stuff" gasket maker from when I did my friend's oil pan. I used a very very small amount smeared around the mounting surface on the flange and pressed the T-stat onto it and held it a few minutes so that it would stay put. I then installed the flange/t-stat and went about my business.

The good thing is that my engine will finally get up to 190F. While cruising, it was only hitting between 158-170 with the old t-stat. This also appears to have effected my milage. My first trip with the new t-stat was up several MPG.

Here are the questions:

Is that even the right thermostat? Am I retarded or is it truly impossible to mount one of those onto the flange pins? I don't see how it would even be possible.

Is anything in danger from using the Right Stuff gasket maker to rig this thing into place?
 

Lex4TDI4Life

Top Post Dawg
Joined
Jun 22, 2006
Location
NorCal
TDI
2001 Golf-Ute TDI GLS 5spd Manual
anyone else have trouble installing the above thermostat, or am i just an idiot?
 

mctdi

Veteran Member
Joined
Dec 10, 2004
Location
se WI
TDI
2010 Jetta
Lex4TDI4Life said:
anyone else have trouble installing the above thermostat, or am i just an idiot?
I was able to get the 0-ring to hold the stat inplace. And this does not make you an idiot.
 

MOGolf

Top Post Dawg
Joined
Jun 27, 2001
Location
underneath something
TDI
2001 Golf GLS TDI Reflex silver, rough road suspension and steel skid plate, 2004 Passat Variant, Candy White, rough road suspension and geared balanced shaft module, and much, much more. 2016 LR RR HSE TD6, 2019 Jaguar I-PACE
I have a Wahler brand here that looks like that. It will not fit properly into the flange.

I have a MTC brand here and it will work.

I also have a VW boxed one and of course it fits.

This is why I decided to always get the "genuine article" or get a look at the replacement before purchase.
 

Lex4TDI4Life

Top Post Dawg
Joined
Jun 22, 2006
Location
NorCal
TDI
2001 Golf-Ute TDI GLS 5spd Manual
Good to know I'm not an idiot or crazy (yet) :cool:

I was able to place the o-ring on the block, but my fat fingers couldnt hold the t-stat in place while pushing the flange on. I had to mate the two prior to installation.

I got the t-stat from one of our trusted vendors. I am going to shoot them an email regarding this. It's no big deal to me; I was eventually able to make it work. It would be nice to help the next guy down the line from having this confusion, however.

Thanks, everyone!

MOGolf said:
I have a Wahler brand here that looks like that. It will not fit properly into the flange.

I have a MTC brand here and it will work.

I also have a VW boxed one and of course it fits.

This is why I decided to always get the "genuine article" or get a look at the replacement before purchase.
 

mctdi

Veteran Member
Joined
Dec 10, 2004
Location
se WI
TDI
2010 Jetta
Lex4TDI4Life said:
Good to know I'm not an idiot or crazy (yet) :cool:

I was able to place the o-ring on the block, but my fat fingers couldnt hold the t-stat in place while pushing the flange on. I had to mate the two prior to installation.

I got the t-stat from one of our trusted vendors. I am going to shoot them an email regarding this. It's no big deal to me; I was eventually able to make it work. It would be nice to help the next guy down the line from having this confusion, however.

Thanks, everyone!
Just had a thought, use a string or wire to pull the stat in place on the housing [string goes through housing and out hose end], locate on block, bolt down, drop one end of the string and pull other end to remove string.
 

Lex4TDI4Life

Top Post Dawg
Joined
Jun 22, 2006
Location
NorCal
TDI
2001 Golf-Ute TDI GLS 5spd Manual
mctdi said:
Just had a thought, use a string or wire to pull the stat in place on the housing [string goes through housing and out hose end], locate on block, bolt down, drop one end of the string and pull other end to remove string.
This is why I hang out on this site! Great idea!
 

larithmos

Veteran Member
Joined
Feb 7, 2004
Location
MN
TDI
2002 Golf
I just got mine in the mail today and I am seeing that I will have the same problem. Good idea with the string though, that is what I am going to do.
 

Kfir

Well-known member
Joined
Jan 31, 2007
Location
South NJ
TDI
'03 Jetta Wagon "Marge", 5-Spd, 130K+,
How-to?

Hi, i've looked ut cant find it...
Can anyone point me to a "T-Stat Change" how to thread?
I have a '03 Jetta Wagon.
 

SheeB

Veteran Member
Joined
Jul 8, 2007
Location
Ottawa, ON
TDI
2001 Jetta GLS Manual
Kfir said:
Hi, i've looked ut cant find it...
Can anyone point me to a "T-Stat Change" how to thread?
I have a '03 Jetta Wagon.
Hmm, was looking for the samething and checked Wingnuts list but nothing there for thermostat changing how-to.
 

dubvulture

Veteran Member
Joined
Jan 21, 2004
Location
Tunkhannock, PA (NorthEast)
TDI
04 Golf GLS 5 spd. black/black
You are not an idiot. I just went through the exact same thing with the exact same thermostat from a frequently used vendor from this site. I ended up not putting in the new one yet because I wasn't sure if it was the wrong part or perhaps defective. I sent some pictures that look exactly like yours to the vendor. They assured me that the thermostat wasn't damaged, that's just the shape. And that it won't affect the performance of the thermostat even though it's not locked onto the tabs.

I'll be putting my new one in this weekend. mctdi, great idea for using string as a helper. I'm definitely going to try that. Thanks.

BTW, this was in no way meant as knock at the vendor, they are a great company, with very helpful and knowledgeable people.
 
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