View original topic: Thermostat Housing Rear View Pics
Timwhy Fri Jan 07, 2011 4:14 am

Any one have clear pics of the TH from the rear of the engine. I am putting together
a box of parts to replace once it gets warm again(several month away).
Last Jan I bought the GW SS coolant pipes along with as many replacement hoses
as I could, but did no put them on as of yet. I bought a new TH & cover and will
get a new thermostat. What else should I replace with reguards to the TH?
I already have the distribution tower and new T's for the rear heater. I read temp
After reading all the posts and threads about the TH & cover removal, I did not see
any pics of the TH rear view. Just wondering what I will be up against if for example
the bolts break off or are messed up at the head. My plan is to unbolt the TH and
bolt up the new unit but things seldom go that smooth.

James 93SLC Fri Jan 07, 2011 8:23 am

Personally I'd just get a piece of cardboard and shimmy underneath with a flashlight. Access is pretty well unobstructed other that the axle shaft. That way you can see exactly what your dealing with as far as bolt (I believe socket head cap screws) condition and location. I think the only thing on the backside is a temp sensor. While under there, pre-treat the bolts with some PB Blaster.

Oh, and go ahead and replacing that TH housing. It sees the most heat from direct contact with the head and becomes brittle.

Timwhy Sat Jan 08, 2011 8:11 am

James 93SLC wrote: shimmy underneath

Well I did the Shimmy this morning and took some pics. Here's what the camera saw.
I looks as if my Thermostat Housing is a leaker, all wet from the pictured hose?
Kind of hard to tell but still disconcerting. I can't get up under the van at the moment
to have a better look see while the engine is running, but that got to be coolant.

Kind of from the top

New TH position of the bolt holes to the block, one bolt is longer than the other.

All sides of the TH

GrindGarage Sat Jan 08, 2011 8:41 am

those t-stat housing mounting bolts can be a real PIA. They are cap head make sure you use plenty of liquid wrench and make sure the inside of the hardware is clean before you insert your tool. I spent almost 5 hrs fighting one of those bolts and that was with my van on a lift. I ended up banging a 12 point socket over the cap head and using a torch to get that sucker out. Replaced both bolts with normal metric hardware in grade 8 from my flaps. Have Fun!

James 93SLC Sat Jan 08, 2011 8:48 am

GrindGarage wrote: those t-stat housing mounting bolts can be a real PIA. They are cap head make sure you use plenty of liquid wrench and make sure the inside of the hardware is clean before you insert your tool.

An old trick to making sure the tool doesn't slip and round out the bolts, is to put a dab of valve grinding compound on the tip of the tool. It gives the hex a bit more "bite" and lessens the chance of stripping.

I wouldn't even bother reusing that housing. Judging from the corrosion on the therm cover bolts you'll likely end up destroying it anyway.

autostick73 Tue Jan 18, 2011 7:23 pm

It looks as if the thermostat in the diagram is going in upside down. I looked in my Bentley book and it shows it with the gasket ring up. I am asking this because I replaced mine and now I have coolant coming out the side where the top housing bolts to the bottom.

Timwhy Wed Jan 19, 2011 3:12 am

Just got my new thermostat in the mail yesterday, so I snaped a few more pics.
Here is the unit installed with the cover on. Gasket is on top of the thermostat.

Next serie of pics are jut the way it looks on the outside as well as inside with the cover

On a side note. I am trying to get all my parts ready for went I do my coolant component changes.
The thing about ordering these parts is I believe the thermostat is the only item that
comes with a new gasket. the two sensors do not and they also do not come with the
circlips to hold them in the TH. A little FYI ask the supplier if something comes with an
item or is that an additional part to be ordered. Also new bolts do not come with the
TH for the cover. I have tried twice to get these M6 X 18mm bolts from the VW dealer here and both
times they have screwed up the order. Went to Lowes and bought M6 X 20mm stainless
steel hex bolts as well as M6 X 20mm allen socket bolts. I think that I will be returning
the allen socket bolts and keep the SS. Also you can get the M8 X 50mm and M8 X 60mm
Stainless Steel bolts at Lowes for the TH to the block. I wished I had gone there before I
spent almost $5 for the 60mm bolt from VW?

mordeaux Sat Jun 18, 2011 7:57 am

Informative pictures. Very helpful.

One of the last photos shows and O-ring on top of the Tstat. I assume the flat seal is for underneath the Tstat. My new housing from Van-Cafe did not come with an O-ring for the topside of the Tstat and the VagCat diagram doesn't show one either. Is there supposed to be one there?


tencentlife Sat Jun 18, 2011 8:19 am

The exploded drawing above does show the t-stat and o-ring upside-down as a grouping. There must be an o-ring and it must go in the hole after the t-stat, which goes in the hole spring-down. Those last pictures show the right way to install it.

There are round and square-section o-rings, either type works fine, no sealant is needed. The OEM Wahler t-stats normally come with a new round-section o-ring in the box. When the cover is bolted down the tapered ridge on its underside pushes the o-ring out against the inner surface of the hole and seals off the whole lot.

What flat seal? Could you mean that you got a square-section o-ring?

mordeaux Sat Jun 18, 2011 2:22 pm

Yes, square section O-ring is what I mean. Thanks for the lucid reply, Chris. The job is done.

jaggedline Fri Jun 20, 2014 9:04 pm

Great info.
Did you have any issues getting the clips for the temp sensors into the GW housing? I am have one heck of a time getting them back in.
Any tips?

IdahoDoug Fri Jun 20, 2014 10:18 pm

Double check that a previous owner did not leave an old O ring behind, or an edge of it - making the new O ring too thick and the clip hard to get in.


jaggedline Sat Jun 21, 2014 10:00 am

IdahoDoug wrote: Double check that a previous owner did not leave an old O ring behind, or an edge of it - making the new O ring too thick and the clip hard to get in.


Old O-rings are definitely not present. What appears to be the issue is the density of the new rings. I can not get the clips aligned passed their entry points. This applies to both the temp ii and standard coolant temp sensor, so I know I am just looking at things wrong. RAWR!

I am going to warm up the rings in a little temperate water and see if this helps this morning, if not... I may be back with photos of the offenders to hopefully generate some chatter and shine some light on my inadequacies.

Feeling so stupid that this simple job is turning into a headache haha.

jaggedline Wed Jun 25, 2014 5:50 pm

This is all taken care of now. Thanks for taking the time to reply. Local Euro part source sold me the wrong o-ring for the temp II sensor. Lesson learned: do not space ordering everything from a single, credible source; i.e. GW.

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