Help! BOILING Coolant Expansion Tank? + leak [SOLVED]

[E1]

Thanks Kamz, Whoops.

But can you say, fer sher, that I was addressing *the same* Flapjack?
(Asking for the second cousin of a friend’s friend)


Flapjack, that’s a normal position. We’ve rarely run below straight up except for a short drive, and/or a cool day, and/or other low heat-producing variables. If any air’s left, you might see it drop a little lower once the air’s all gone.
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‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[flapjack]

Well, I guess I THOUGHT things were fixed... but now I'm back with a mysterious leak.

After driving about 15 minutes with my sparkly brand new cap, (okay, I've actually been driving around a few days with my new cap, but this is from stone cold after not driving a few days) I pulled into the parking lot of harbor freight (yep, to buy auto tools) and upon my return to the car I noticed a tiny leak under and a small pool of coolant.

Here's where things get strange: the REFILL tank which I had previously filled was now empty. But where was all the coolant? The small pool under the car was not even close to the amount that was in the refill tank... I opened the deck lid, set it down, and lo and behold about an inch air gap at the top of my PRESSURE tank.I could see coolant had leaked under the pressurized tank on the metal bracket. Here's what was weird:

Hoses? Bone dry. Tank? Bone dry (as far as I could feel, anywhere around, that being said I could not feel all the way under). And especially the TOP of the tank was super-dry. No liquid on the cap, hoses, etc. The WEIRDEST part?

The FOAM on the underside of the deck lid, right above the pressurized tank was SOAKED with coolant, so much that when turned on it's side it was dripping coolant out of the foam. Now, how does that make any sense? The top of the tank BONE DRY but the foam practically in contact with the top of the tank soaked in coolant?!?! :')
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1990 Multivan "Sacagawea" [Burgundy]
It's not a slow car, its a fast house.

[Ahwahnee]

Were it mine, I would be testing the coolant for combustion products (i.e. checking for a head leak into the coolant).

A leak that forces 'air' into the coolant will push coolant into the fill tank until it overflows out of the top (as you drive). As the engine cools down it will suck coolant back from the fill tank until it is empty and then suck air leaving a pocket of air in the pressurized tank.

[jimf909]

[sanchius]

Have you tried using a coolant system pressure tester to locate the leak?

I consider these to be a required tool when owning any older vehicle: https://www.harborfreight.com/radiator-pressure-tester-kit-63862.html

I have used this so often, on many different cars, and it has saved me many times the initial $90 purchase price finding and fixing coolant leaks over the years.

The nice thing is you are working with a cool, rather than a hot, engine.

And you'll smile every time you break it out and use it because you know you've become the next level of steely-eyed Vanagon mechanic for whom coolant systems no longer hold any mysteries.

You can also use it for pressure bleeding brake systems solo.

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[djkeev]

[flapjack]

[flapjack]

[Vanagon Nut]

Sounds like leak is in engine bay somewhere but if rear heater is present, check for leaks, coolant smell at rear heater.

If leak is at expansion tank and coolant pools at an area, after tank heat causes some of that fluid to evaporate off, mystery ensues.

x2 on getting an analysis of coolant.

Neil.

coolant fluid level sensor, was on my '88. You can see remnants left after coolant burned off. I don't recall if tank had cracks or seal at sensor or sensor was at fault.

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1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[sanchius]

[flapjack]

[sanchius]

Thanks for following up to act on and pictorially document the outcome of our guesses.

Perhaps JBWeld will work, but given that the bottle both flexes and is under pressure, I wouldn't trust it at all. This is one of those items that will put you on the roadside in seconds when it goes, so it's worth renewing. There are lots of $10-$35 replacement plastic bottles available. If you are in this for the long game, aluminum is the way to go: https://www.google.com/search?q=aluminum+vanagon+overflow+bottle

After a few years, one comes to learn that renewing/upgrading every bit of any Vanagon system is the best way to increase your reliability. Then you realize that also applies to all the other systems: fuel, electrical, drivetrain, engine, etc.

I'm getting there, but it can take awhile. See my spreadsheet below.

The biggest help is to become very skilled using TheSamba's advanced search. I've found info and how-tos on everything I've worked on somewhere in the TheSamba archives, with the exception of one or two things that I subsequently documented.

Finally, if you find the advice and info you are getting here valuable, click that gold star membership link below to throw in a little $$$ help keep all this going.
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The Syncro years (2005-16) - The 2WD years (2017-23) - Westy & WBX rebuild spreadsheet - Sanchius & Tuna: The Video
Your gold star membership keeps this awesome list going!

[djkeev]

Agree! ^^^

If you buy one cheapy plastic tank, get two because you will most likely be needing it sooner rather than later.
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Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[DanHoug]

there is not an adhesive that will stick to expanding and contracting polypropylene... the tank material. only emergency temporary fix is to 'weld' the cracks with a stick of polypropylene base material and a torch. but that is folly because if you are showing *any* cracks at all, your tank has failed and needs replacement. new ones are made of poorer material than VW used back in the day and can blow out with a goiter when hot and under pressure. or the threads soften and the cap or level sender blows out.

if you have your van for the long run, cry once and buy the aluminum tank and move on hardening your other systems, like the coolant tower. the reliable operation of the overflow tank is worth it alone. on my recent 4,400 mile trip, i didn't check the pressure tank level once, because i KNEW the overflow tank level was reliable.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[E1]

The advice to buy two tanks is good, and maybe two sensors. I was able to JB Weld a damaged nipple on the overflow tank, but there’s no pressure on that.

If your intention is to keep the van for a long time, you might just shoot the wad and get the metal one. I’ve read they can leak, too but cannot say how common that is — or which tank has from time to time.

One thing I do like about the plastic tank is it being the weak point and first to fail in an extreme-pressure situation — instead of hoses or head gaskets.

On the coolant pressure test kit, we recently bought one sight-unseen and there’s like 15-20 pieces. We only need the one attachment, plus one for the master cylinder I’ll likely never use. If having several cars, and/or a garage or space, then it makes more sense to me. For the few times it's needed, it just takes space.

I’ve never bled a master that way, but it does make sense — and is necessary if doing it alone. I presume you need almost no pressure and that too much is dangerous to the reservoir.

Honestly, after buying the kit I miss the stupid-simple of the Go Westy pump — and may buy another if we never go the metal tank route (the pump leaks but lasted a full decade). What I don’t know is if the GW one is only usable on a blue cap.

Hope the tank crack is your only issue until 2037.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[do.dah]

While I don't think gluing/epoxying the pressure tank is a valid option,, IF I were to attempt such a stunt,, I'd use something like "Mr Sticky's" under-water or vibra-bond epoxy, or at the very least, a plastic focused epoxy, NOT JB Weld.

No epoxy is gonna get you moving again as fast as replacing the tank, after all, you hafta let the epoxy set up for at least a day, even the 5 minute stuff.

[E1]

Why the other brands, are they more flexible, or bite better, or?

JB working or not greatly depends on where a crack is, and if it experiences any flex. On the OP’s tank, there’s no flex there and should work long enough to get another tank, if not forever.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman

[Ahwahnee]

In my experience JBWeld doesn't adhere to plastic. It needs some 'tooth' but even roughing up the plastic doesn't seem to help much.

As noted, a weld can often work (for awhile). Strips of milk bottle plastic can be used in an emergency, but this isn't an emergency.

OP needs a new tank.

[4Gears4Tires]

[E1]