install thermo-tee fitting w/o leaks

Gothmolly

Veteran Member
Joined
Feb 3, 2005
Location
Providence, RI
TDI
2002 Golf
My thermo-tee fitting on the fuel filter is ... wiggly, and it seems as if air could get in where the hose slides over the tee, despite the clamp.

Dabbing some grease on that junction, the air bubbles all but go away.

How do you ensure a good mating surface/seal?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Nictane fuel filter uber kit
Nictane.com

or search for ditzel mod.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
I wrap the nipples on the T with Teflon pipe tape. I know it is not fully compatible with diesel fuel, but once you force the hose on and clap it down, it will last until the next filter change...
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
I suspect that after 15 years hoses are starting to get a little less pliant. Should have seen the hose that I pulled from my diesel generator- it was B1 hose and at the ends it was like hardened, caramelized taffy, with some thin metal added!
 

Gothmolly

Veteran Member
Joined
Feb 3, 2005
Location
Providence, RI
TDI
2002 Golf
It's always been a bear to remove the hoses from the fuel filter, maybe last time I beat them up? I'm seeing a constant stream of tiny bubbles coming into the clear line.
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
I try to work around the T when changing the filter. Silicone spray will soften rubber hoses.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Just replaced the fuel filter on a new to a co-worker '03 Jetta. I find the hoses get "stuck" on the filter and need to be gently twisted to free them up before pulling off. But the filter tee went in fine (OE filter made by UFI), and no bubbles or leaks.
 

Gothmolly

Veteran Member
Joined
Feb 3, 2005
Location
Providence, RI
TDI
2002 Golf
I might pick up a new T next time I make a idparts order. For those of you who grease things to keep them airtight, are you greasing the T before inserting it into the hoses & clamping, or are you putting the hoses back on it, then covering the joint with grease?
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Just a light coat on the O-rings. Grease won't stop any leaks, it just keeps the rubber soft.
Sometimes the tee will hairline crack.
 

Gothmolly

Veteran Member
Joined
Feb 3, 2005
Location
Providence, RI
TDI
2002 Golf
So your experience is that air is sucking in around where the T fits into the filter housing, not the hoses themselves?

I've always found the T fitting into the housing to be somewhat 'loose' even with that mouse-ears wire clamp thing holding it in. Is it supposed to have any play?
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
So your experience is that air is sucking in around where the T fits into the filter housing, not the hoses themselves?

I've always found the T fitting into the housing to be somewhat 'loose' even with that mouse-ears wire clamp thing holding it in. Is it supposed to have any play?
Yes, I've never had the hoses leak that I've noticed. There always seems to be some "play" in the T fitting and o-ring connection. Some heavy grease has been the solution for mine. Yours and others results may vary, as they say.
 

Gothmolly

Veteran Member
Joined
Feb 3, 2005
Location
Providence, RI
TDI
2002 Golf
Yes, I've never had the hoses leak that I've noticed. There always seems to be some "play" in the T fitting and o-ring connection. Some heavy grease has been the solution for mine. Yours and others results may vary, as they say.
Thanks - again, heavy grease on the T as it goes into the filter, or just heavy grease covering the whole thing once its in the filter? Like, a giant blob?
 

hey_allen

Veteran Member
Joined
Nov 25, 2006
Location
Altus, OK
TDI
2000 Jetta TDI
Usually just a light smear around o-ring portion of the T, before putting it in the filter.

You might also look at the T and make sure that the bottom of it is not getting loose. Mine separated along the joint where the o-ring portion was bonded to the upper housing, leaving the o-rings, the check valve, and spring in the filter when I removed the top of the T. Old plastic that had hardened, and finally gave up.
 

red16vdub

Veteran Member
Joined
Aug 26, 2013
Location
(617) City of CHAMPIONS
TDI
03 JSW 5spd
As usual people over think most of this stuff, you really shouldn't put grease on the o-rings. Lube it with diesel fuel, it's no different than doing and oil filter. Same principal.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
As usual people over think most of this stuff, you really shouldn't put grease on the o-rings. Lube it with diesel fuel, it's no different than doing and oil filter. Same principal.
I haven't over thought it. It did/does make a difference on more than one occasion. Your results can and perhaps will vary.
It doesn't take a lot, but a light lithium type grease didn't fix it. Pretty heavy wheel bearing grease worked every time. Applied some over the o-rings after they are installed and the T fitting shaft. A little bit usually oozzes out as the T is inserted.
 
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