Vanagon Coolant Issue

[The Big Cheese]

The overflow tank in my 85 1.9 Vanagon is filling up pretty quick. Below is a picture of the tank after 30 minutes of driving:

I also noticed that the overflow tank seems to be leaking from the top?

Should the overflow tank be filling up this much?

Also, I'm now all of a sudden having to sometimes push on the gas pedal to get the engine started. This seems to be a separate issue and related to a bad Temp sensor?

[jlrftype7]

I would say put a pressure gauge on the expansion tank and see what the pressure is building to from the engine running for that 30min, but not everyone can easily source the tool and adapter for that.
How old is your expansion tank cap, the Blue one or something else?
If it’s bleeding pressure and not holding it back, you can get overflow into the overflow tank.
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'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[Ahwahnee]

This is a classic symptom of a head 'gasket' failure that allows combustion gases into the coolant. That in turn forces coolant out of the system and into the expansion tank - sometimes to the point of fluid overflowing out those openings at the top that you show.

It doesn't have to be that but the symptoms fit pretty well. When everything cools down is there a pocket of 'air' in the top of the pressurized tank?

There is a chemical test for this issue - it uses a liquid that changes color if combustion products are present.

[The Big Cheese]

[borninabus]

maybe Ahwanhee is just trying to scare you because this is also a classic symptom of a failed (or failing) pressure tank cap. new caps are now available again at your friendly local VW dealer for about $60; accept no substitute.

another thing that can cause this is overfilling the system by reving up the engine and "topping off" the expansion tank.

my suggestion would be to get a genuine cap, or PROPERLY test your current cap, give it a good bleed & see how it acts. if the problem persists, then further action is required.
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88 Van WBX, A/T - 13 JSW TDI 6M/T - 2012 Touareg TDI Sport

[Ahwahnee]

[borninabus]

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88 Van WBX, A/T - 13 JSW TDI 6M/T - 2012 Touareg TDI Sport

[Abscate]

[mikemtnbike]

Got an old guy in my neighborhood that likes to come over and watch me work on my van. When I first got it, I had a bad pressure cap, but was checking the head gasket leak. No color change, I'm feeling good. He says, hey you want to see how those work? Takes a big drag off his smoke, exhales into the tester, instant color change.
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[E1]

Is the red light light flashing and the temp showing suddenly hot before you think it could possibly be hot?

That's a factor to the below, but it doesn't always happen unless the overflowing coolant drops the level enough to expose the sensor to air.

This happened to us on our first test drive after purchase, and resulted in my first thread here. I freaked when reading "head gasket," partly as we had accompanying bubbles in the overflow tank at idle.

I added two bottles of Subaru coolant conditioner also, but if memory serves that was to make me feel better as we were about to live on the road and out of patience in general.

I've since had a couple caps fail, bubbles and all, and new Blaus stopped the issue.

So if so or even if not, start by replacing the blue cap. Van Cafe has the Blaus back in stock, as I learned in person yesterday, the "other" blue ones that also sometimes come in black have not been fruitful for us.

So it may be too early to chatter your teeth. Good Luck!
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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

[tencentlife]

Read these:

https://intrepidoverland.com/bad-coolant-pressure-cap-or-bad-head-gasket/

https://intrepidoverland.com/testing-coolant-pressure-caps/
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https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[The Big Cheese]

I ended up ordering a replacement cap this morning from GoWesty. Is the Van Cafe BLAU that much better?

Hopefully it’s just the cap but I would like to run the tests for the leaking head gaskets. Could you guys provide some information on this test?

Also, what coolant conditioner is recommended?

[jlrftype7]

[VicVan]

[crazyvwvanman]

VW Dealer list for the cap looks like $56. Better be real good.

Mark

[borninabus]

[crazyvwvanman]

Ok, you talked me into it. Just ordered one from the DEALER. Hope it is the real deal.

Mark

[thewump]

[E1]

Blaus cost $17.
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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

[vegpedlr]

It was a gasket issue on my old van. Passed the first chemical test anyway. While I was experience all these thrills I got the GW cooling system pump and tester which proved to be very handy. Pressure test the cap, the system overall to look for leaks, and bleed the system.
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1985 Tintop 4 sp GW 2.3 “Connie”
2006 Mk V GTI 2.0 FSI “Penelope”