Mystery Coolant Loss

[tko123]

My buddy's '90 van is losing coolant but he can't figure out why. In the past two weeks he's lost about a gallon. Recently, his temperature gauge went above the mid point and the warning light activated. He shut down the engine until cool and made it home. There are no obvious drips that would indicate a hose leak etc. I told him that I'd put some thought to it since I have a '90 as well and we've team up on various problems over the past couple of years with success. This one has us stumped.

Would this be a faulty head gasket? Suggestions on how to proceed?

Thanks
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'90 Vanagon
'72 Squareback
'66 Bug
VSC706

[heidi85ho]

is it possible that your friend could have missed coolant coming out of the overflow tank? this will happen when the main coolant tank cap goes bad. when hot it will surge back thru the cap and escape thru the overflow tank. you can loose a fair amount of coolant this way.

[jmranger]

http://www.thesamba.com/vw/forum/viewtopic.php?t=431407

Good luck,

JMR

[phatveedub]

It could be that the trans cooler has gone south and coolant is being fed into the tranny - not good at all. Do not drive until you sort it out.

[Ahwahnee]

Coolant can also depart via the tailpipe and may appear as white smoke or may not produce smoke at all. Either way there is a distinctive sweet smell in the exhaust.

[peaceful warrior]

Just out of curiosity, was the coolant recently changed? Maybe the system is not purged of air.
Bentley, my friend.
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"Two things are infinite: The universe and human stupidity; and I'm not sure about the universe." Albert Einstein
"Notchboy" says "Man up!"
"Tram" says " My bus is bigger than your bus."
66 13W Deluxe, 68 Westfalia, 87 Syncro.
TOOB Member #15
Brian

[tko123]

Nope, no coolant coming from overflow tank. I think the trans cooler is only a factor w/ auto transmission. He's been watching for exhaust smoke but none so far but I will pass along the sweet smell. The coolant was changed over a year ago and properly bled.

The link below was intriguing and I think I'll recommend a leak down test tomorrow.

Thanks everyone for the guidance.
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'90 Vanagon
'72 Squareback
'66 Bug
VSC706

[IdahoDoug]

Pull up the rear carpet before doing the leak down test as that test requires some time to do properly. Also, a simple test for coolant leaking into cylinders (usually happens if compression is also getting into the coolant as your leakdown test will check for) is to pull the spark plugs and keep track which cylinder they come out of. If one is markedly cleaner than the others you've got a coolant leak at that sealing ring - steam cleans the plug very quickly. Plugs are 5 minutes to pull.

DougM
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Terry Kay]

Get a coolant pressure tester on the Van.It'll tell you pretty quick if & when there is a leak--and where it is.
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T.K.

[iltis74]

Pressure test for sure, but be aware they are not fool proof. I've messed with two vehicles. not vanagons, that wouldn't leak off a single pound of pressure in an hour no matter where you pressured up from, but were going through coolant and driving me nuts. One finally became an obvious bad hose, the second left me stranded on the highway a couple weeks ago when the block heater started hemorrhaging. It was hard to get upset though, I had been under that thing enough recently that just knowing what it was put a smile on my face. It was always just spotless. If it is intermittent at this point, it could be a matter of just catching it at the right time, but hey, it'll eventually make itself known.