Thermostat housing question

I am in process of changing out the thermostat while doing TB change. There is a plastic sleeve that fits over the end of the T stat housing and a rubber o-ring fits between them to form a seal. I ordered a new housing unit from IDparts but it did not come with a new seal. I am guessing it is not a reusable item but where can I get one and what do I ask for? This is not the O-ring that is used with the actual thermostat. Found this diagram on another post. It's item # 16 below. Not a mechanic and couldn't do this without the forum. Thanks in advance.

E.Allison
98 Jettea TDI

When I did mine, 40k ago, I got a new thermostat housing from idparts, and a new elbow from the dealer. I also had to order the o-ring separately from a local dealer.

If you can wait a little, for shipping during the holidays, I would order your parts from http://1stvwparts.com/ It's the Auburn Wa dealer and offer excellent service and pricing.

Tony

Thanks for the info. I will try that avenue. Surprised they didn't offer it with the t-stat housing.

I believe that o-ring pictured is in the couple piece that the radiator hose attaches to. It in turn attaches to the thermostat housing with a spring clip. If you run into a problem it can probably be reused(I did) make sure to lubricate it with antifreeze first. Mine hasn't leaked.
My car isn't here right now so I'm working from memoryeek

You are right Veedubyoo. The other end of that sleeve attaches to the lower radiator hose. Am afraid to reuse since that area is pita to get to and don't want to go digging into it was I get everything buttoned back up

eallison
98 jetta tdi

I just replaced a coupler like that on my Passat, the one at the lower radiator hose/radiator it kept popping off and draining my $$ G12. I just replaced everything but probably was just the spring clip that was bad.
The O-ring# was 1H0-121-687-A cost $2.07 at my stealership.
When I did my water pump though I reused that o-ring...although I think your approach is safer...