Pics of coolant migration preventative measure.

Jackmc · January 14th, 2002, 14:28

Hi all,

At our recent West Coast GTG the tech at Capistrano VW explained to us a method for getting a "heads up" on a coolant leak before it becomes a major coolant migration problem.

Below you'll see the connector that must be removed.

Here it is removed and you can see the two prongs where coolant can leak out of the bottle and into the connector.

Here I am now drilling a small (1.2mm) hole into the underside of the flange but outside of the bottle!

As you can see it might be better to remove the hose next to the expansion tank to have better access. After you drill the hole just replace the connector and now if coolant starts leaking from that point you will know it's time to replace the bottle and you won't have coolant migrating up that cable harness and into the main harness of the car.

Jimmy · January 14th, 2002, 14:51

Excellent! "one picture = 1000 words".

Turbo Steve · January 14th, 2002, 17:35

Thanks Jack! [img]images/icons/smile.gif[/img]

This clears things up for me because for some reason, I was thinking the hole actually went completely through the reservoir bottle and this would depressurize the cooling system a little.

Jackmc · January 14th, 2002, 17:41

Yes, you are just adding a "weep" hole like on a waterpump.

When you see coolant trickling down then you know the expansion tank has failed and needs replacement which is much less costly than what could happen if the coolant were to migrate up that cable.

The tech at Capo had that very thing happened recently and I don't know if this is something he came up with or if it's a suggestion from VW but it couldn't hurt to have that hole there.

He suggested a .030-.040 hole but when I put one in that small the plastic seemed to close up when I withdrew the drill bit. Going up to the larger 1.2mm (about .047") gave me a hole that stayed open nicely.

[ January 14, 2002: Message edited by: Jackmc ]

Turbo Steve · January 14th, 2002, 17:48

P.S.

Jack:

Could you please elaborate a little more or refresh our memories about the replacement of seals in order to prevent coolant migration? Thanks.

-steve

golfstream · January 14th, 2002, 18:56

<blockquote>quote:<hr>Originally posted by Jackmc:
He suggested a .030-.040 hole but when I put one in that small the plastic seemed to close up when I withdrew the drill bit. Going up to the larger 1.2mm (about .047") gave me a hole that stayed open nicely.<hr></blockquote>

Thanks for passing that tip along, and for the pictures. I'm definitely going to make that mod. I think I'm going to drill the hole, then take a thin, hot wire to "melt" the hole open.

Thanks again,

-Mel

golfstream · January 14th, 2002, 18:58

<blockquote>quote:<hr>Originally posted by Turbo Steve:
P.S.

Jack:

Could you please elaborate a little more or refresh our memories about the replacement of seals in order to prevent coolant migration? Thanks.

-steve<hr></blockquote>

Steve,

Sounds like he was indicating that the seals are in the bottle such that, if they fail, you get a new bottle.

-Mel

paul_cat · January 15th, 2002, 06:42

Just a thought, but you could use a hot nail to pierce the hole rather than drill it; that way the hole will be clear and won't "close back up" when you remove the drill bit. Probably faster and easier too. Just heat the nail with a lighter and push it through.

Old Navy · January 15th, 2002, 06:47

As soon as I can re-assemble the Jeep, I've had to remove the driverside seat for repairs, I'll will be doing this to the NB. Man is this forum great. [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

Jackmc · January 15th, 2002, 17:17

The Capistrano VW tech mentioned that there are some o-rings as a last line of defense but I didn't see them on the bottle. Usually, the type of leads I saw are molded in during manufacture of the bottle.

There might be a seal in the connector itself and that is likely since he said that the connector and cable is so hermetically sealed that coolant easily flows up the length of it to cause damage instead of just dripping out!

Jackmc · January 15th, 2002, 17:21

<blockquote>quote:<hr>Originally posted by paul_cat:
Just a thought, but you could use a hot nail to pierce the hole rather than drill it; that way the hole will be clear and won't "close back up" when you remove the drill bit. Probably faster and easier too. Just heat the nail with a lighter and push it through.<hr></blockquote>

I thought of that too, but when I thought a second time my imagination went like this--you heat up a small nail, stick it into the soft plastic which then absorbs the small amount of heat contained in the small nail, the nail gets glued to the bottle, then you break the bottle trying to get it free or burn up your engine compartment trying to apply heat to the nail stuck in the bottle!

But, if it works for you, let us know.

[img]images/icons/grin.gif[/img]

BoraTdi · January 16th, 2002, 05:46

Question: whoever has had a problem with "coolant migration," what symptoms did you notice other than the obvious fluid leaks? I have had 3 MAFs fail, my transmission occasionally does funny things, and my speedo needle has jumped up and down a couple of times in the last month.

Jackmc · January 16th, 2002, 13:49

The tech at Capo said that they looked into the coolant migration problem when a customer came in complaining of seemingly unrelated electrical problems.

I don't recall what these were but you should be able to check if your car is sending fluid up that cable by removing it and inspecting for fluid. There should be none.

nuke · January 16th, 2002, 15:04

According to the TSB on the subject, the coolant wicks up to the instrument cluster and damages the connectors and electronics there.

It's a really scary looking TSB too.

BoraTdi · January 17th, 2002, 07:00

$HIT! Anybody got a copy of the TSB? I really wish we still had access to these things. I have the same symptoms, weird electrical crap. I'm gonna check it at lunch.