Changing out coolant pipe seal

npdimonte

Veteran Member
Joined
Jan 17, 2008
Location
Bolingbrook, IL (Chicago area)
TDI
2003 Jetta GLS TDI, 5spd
I have a '03 Jetta and I'm in the middle of replacing the O-ring on the coolant pipe that goes into the block, near the thermostat. So, does anybody have the part number for this O-ring, the O-ring for the coolant outlet flange and then for the seals (cooper washers) for the oil supply line connecting to the oil filter.

Thanks,
Nick
 

sisyphus

Veteran Member
Joined
Dec 8, 2008
Location
Appleton, Maine
TDI
99.5, '01 A4 Jetta sedans, 5 sp box, Hamman mod, Joey mod, Bilsteins, 2.00" lift
I did this a couple months ago. If its an ALH, the seal can be had via the stealership, because the coolant pipe should be ordered by VIN number of your car. It's like, 80 bucks. There are two seals, round or square in section. Which one you need depends, again, on your vin number. The rubber seal is another $2.50 or so.
As for the copper washers, you can reuse them. First, however, you must anneal them. Heat them up to glowing red and drop them into a container of cold water. This softens the copper so it seats again. When you torque down the oil fitting it will work-harden the copper, but it can always be re-annealed in the future.
The only trouble I had doing this was coming to grips that I had to dismantle half the engine compartment to get the damned thing out. Then puttting the new one in almost drove me insane. I ended up cutting the electrical connector bracket off the front, getting the pipe in, and then welding the bracket back on. It was easier than trying to shoe-horn it in there with that on it. If you're over that step, good on ya. If not, well, there you go. Hope you have a welder.
 
Last edited:

npdimonte

Veteran Member
Joined
Jan 17, 2008
Location
Bolingbrook, IL (Chicago area)
TDI
2003 Jetta GLS TDI, 5spd
I did this a couple months ago. If its an ALH, the seal can be had via the stealership, because the coolant pipe should be ordered by VIN number of your car. It's like, 80 bucks. There are two seals, round or square in section. Which one you need depends, again, on your vin number. The rubber seal is another $2.50 or so.
As for the copper washers, you can reuse them. First, however, you must anneal them. Heat them up to glowing red and drop them into a container of cold water. This softens the copper so it seats again. When you torque down the oil fitting it will work-harden the copper, but it can always be re-annealed in the future.
The only trouble I had doing this was coming to grips that I had to dismantle half the engine compartment to get the damned thing out. Then puttting the new one in almost drove me insane. I ended up cutting the electrical connector bracket off the front, getting the pipe in, and then welding the bracket back on. It was easier than trying to shoe-horn it in there with that on it. If you're over that step, good on ya. If not, well, there you go. Hope you have a welder.
That's great idea with the copper washers, I never knew you could do that.
In regards to removing that pipe, what a pita that was. Would never have believed that it would have been so difficult.

I was thinking of cutting the oil line and then reconnecting it with a coupler, which would allow for future removal if need be. Should be able to fine something to do this.

Will be checking the stealership since I seem to have a square washer for the coolant tube and have been unable to find it online.

Thanks,
Nick
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
Or you can do what I did and just reuse the old seal after helping it with some silicone plumbing sealant.

I had an '88 Fiero for several years. Never should have sold it - it was a hoot to drive.
 

npdimonte

Veteran Member
Joined
Jan 17, 2008
Location
Bolingbrook, IL (Chicago area)
TDI
2003 Jetta GLS TDI, 5spd
I've been restoring it since '07, just had it painted and will start rebuilding the engine soon. Hopefully will be on the road next summer. And I agree, it is a hoot to drive.
 

npdimonte

Veteran Member
Joined
Jan 17, 2008
Location
Bolingbrook, IL (Chicago area)
TDI
2003 Jetta GLS TDI, 5spd
For future reference, the part numbers for the seals are:

1) n0138123; Banjo washer for turbo oil feed line, need two.
2) 06b121687; O-ring for hard pipe to engine block (behind thermostat).
3) 037121688; O-ring for coolant flange to cylinder head.
4) 037121687; O-ring glow plug coolant flange to coolant flange. (optional)

With shipping (USPS) I spent less than $8 from idparts.com.

Also, for added sealing, I used a gray sealant at the block to pipe connection, around the pipe between the o-ring and the metal lip.

I believe my leak developed due to some corrosion on the block surface were the o-ring has contact with it. Used a very fine sand paper to clean surface.

This job is a pain in the ass, but I think I can do it much faster the next time if need be. This is what I would do after draining the coolant.

Remove the following:
1) Air filter box
2) vacuum reservoir
3) Oil dip stick tube
4) coolant flange/glow plug coolant flange
5) disconnect all electrical connectors from main harness attached to the coolant pipe, including the glow plug harness. Move to the front, to get it out of the way.
6) all hoses to the coolant pipe
7) oil banjo screw
8) two bolts mounting pipe to block

At this point you should be able to side the pipe out of the block, but you may have to break free the seal if it was corroded as mine was. I used a bar near the 90 degree elbow to help me, little to no effort was needed.

Now the tricky part, how to remove pipe with that darn oil line in the way. Well, as I moved the pipe to the right I lifted the oil line up so the bracket on the coolant pipe could pass. Continue to move it far enough to the right which allowed me to rotate the pipe so that the ends would be facing up and with the oil line above the 90 elbow of the pipe. You may have to lift the oil line up to accomplish this. At his point the pipe could be removed by pulling it out between the fuel injection lines and the oil line while lifting the oil line as needed.

I removed my pipe because I noticed rust forming on it, so it was cleaned up and repainted. This also gave me more than enough room to clean the block surface were the o-ring mates.

Installation is the reverse.

Note: I did remove the oil sending unit only because I thought it was in the way, this may not be necessary to remove.

Hope this helps someone,
Nick D.
 

Randall

Veteran Member
Joined
Jun 22, 2008
Location
Kansas City
TDI
1998 & 2000 new beetles
The oil line to the turbo is easy to deal wtih. Some of the bolts on the vacume pump are a PITA. It's no fun to do that job. I had to do it on a 98 just a few weeks ago. Seems like you keep taking crap apart.
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, 99 MK4
Hate to resurrect this thread but oh boy!! this was a pain in the you know what!!!! Having a braided turbo line would have made this job much easier. Also, if you have a 99, make sure you use the right o-ring. I failed to check this and I had to wait until I received the right one.
For future reference, the part numbers for the seals are:
2) 06b121687; O-ring for hard pipe to engine block (behind thermostat).
Here is the "early" A4 o-ring at idparts
and the newer one
 

red16vdub

Veteran Member
Joined
Aug 26, 2013
Location
(617) City of CHAMPIONS
TDI
03 JSW 5spd
Hate to resurrect this thread but oh boy!! this was a pain in the you know what!!!! Having a braided turbo line would have made this job much easier. Also, if you have a 99, make sure you use the right o-ring. I failed to check this and I had to wait until I received the right one.

Here is the "early" A4 o-ring at idparts
and the newer one
I believe the coolant temperature sensor uses the same o-ring as the coolant hard pipe on 2000, and 99 Alh tdi’s .
 

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
The Coolant Temp sensor uses an O-ring that is "round" any way you look at it.

The steel re-turn coolant pipe to the back of the water pump housing (down under the IP) uses a round-type O-ring with square shoulders! There is a difference, thus, why not use the correct one and only do the job once.

On the ALH engine in my Vanagon, I have reused the OE rubber several times with some hi-Temp RTV. However, in my case, the steel pipe was modified for the engine install and is much easier to remove.
 

BakoTDI

Veteran Member
Joined
May 5, 2005
Location
Bakersfield, CA
TDI
Jetta, 99 MK4
The steel re-turn coolant pipe to the back of the water pump housing (down under the IP) uses a round-type O-ring with square shoulders! There is a difference, thus, why not use the correct one and only do the job once.
Well, for the hard pipe, I actually tried both cause I ordered the wrong one first. On my 99, the one with the square profile did NOT let the pipe slide into the opening. So I had to reorder the one with the round profile. IdParts asks that you call them with your VIN to make sure you order the right one. I had to extend my downtime due to this...during a holiday weekend.
 
Top