replacing original plastic thermostat housing

diesel steve

Veteran Member
Joined
Mar 23, 2009
Location
southfield,MI
TDI
1996 b4v
I will be changing my timing belt and water pump soon and I was told there is a better choice of the thermostat housing then the original plastic one that cracks. I think it may be aluminum from a different year VW that can be substituted. Does anyone know what the part number is and from what year and car it came from? Does it have to be modified? thanks.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
All A1 chassis cars used the cast AL elbow. It's not going to be a direct swap, based on how the hose connection is made.

-Todd
 

thechoochlyman

Vendor , w/Business number
Joined
May 7, 2015
Location
Campbellsville, Kentucky
TDI
1997 B4 Sedan
I was approached a while back to machine one from aluminum. Never got off the ground very far though. But I'm glad you posted this, it's something I intend to look back into soon.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Hmmmm.... interesting.

In a day or so, I'll be swapping the wp on my B4. I can post a pic of the plastic vs. AL elbow, if needed.

-Todd
 

Steve Addy

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Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
The big problem is that the Mk1 (and early Mk2) aluminum thermostat cover is barbed to accept a hose whereas the B4/Mk3 TDI engine uses a 90 degree coupler off the thermostat cover as a transition to the lower radiator hose. It's the same way on the opposite end where it connects to the radiator, there's a coupler that fits on the plastic radiator flange instead of a direct fit hose barb.

If a person wanted to replicate the fittings in aluminum it would be complicated because of the plastic couplers currently used.

Steve
 

vanbcguy

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Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
The plastic stuff isn't all that bad if you run VW coolant and replace it preventatively. Say every timing belt interval... Probably wouldn't hurt to replace the thermostat at the same time. Power steering belt would already be off, that's 30% of the labour right there.

Sent from my XT1097 using Tapatalk
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Does the elbow have issues? I'd personally like to see the entire thing as one piece.

That clip/o-ring connection is odd.

-Todd
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
Does the elbow have issues? I'd personally like to see the entire thing as one piece.

That clip/o-ring connection is odd.

-Todd
The Cascade piece seems to be of decent casting quality, but both the O-ring groove and retaining clip groove are wider (040" & .030", respectively) than the OE piece (depth is OK). That could result in more axial movement of the elbow relative to the outlet nipple, possibly affecting sealing ability, although I haven't installed mine yet nor know of any incidence of leakage with this part. Also the bolt hole ears are a little skimpy at their outer edges and look ripe for cracking at that point if over-tightened.
 
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thechoochlyman

Vendor , w/Business number
Joined
May 7, 2015
Location
Campbellsville, Kentucky
TDI
1997 B4 Sedan
Have to wonder how much extra $$ for what would be gained? Would it be worth the work it takes? Not tossing cold water, just asking.
I guess it just depends on how reliable you want all your parts to be. Something I'm always thinking about is how much longer VW or aftermarket manufacturers are gonna keep bothering with making all these cheap plastic replacement parts until it's no longer worth it. That's been my primary motivation for developing billet parts.
 

Diesel_Aggie

Veteran Member
Joined
Nov 3, 2005
Location
College Station, Texas
TDI
1996 B4, 1996 B4V
I would certainly be interested in upgraded parts. I don't mind spending money if a repetitive replacement item is eliminated. The correct billet parts should last 50 years.
 
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