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Water leak | Possible cause found

3722 Views 42 Replies 7 Participants Last post by  Raul_MX
Hello guys, good day.
This is just to tell you that I think I might have found the cause of my water leak. I was able to take my bug to the shop, crawl under it and look for dripping. Found nothing out of the possible places. Flange dry, water pump area dry, water block seals dry... there was a small drip-drip below the passenger's side of the chassis... mechanic told me to turn on the A/C, blow on cold high... then the dripping started... same area... he told me to check the passenger's footwell area, inside the cabin... it was dry... this lead us to believe it was the heater core going bad and making me lose my water fast. I did notice that I had to top off my coolant deposit more and more often when my AC was on... so this matched the behavior I noticed when trying to find the leak.
1. Is this normal/to be expected on the new beetles?
2. how common is this?
3. how can I tell for sure this is the part to blame?

1. Replace heater core
2. Lose my heating and loop the inlet/outlet hoses, till i got enough cash to replace the heater core.

Emphasis on question 3 above... any leads? any more tips to pinpoint the location?

Best regards to all and thanks for writing this message.
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I would pressure test the system (it should be obvious then); as noted in other threads, you can get a pressure test kit or make your own, using the stock tank cap/valve to connect to a pump. If you don't have the cash for the repair; bypassing the heather, until you do... makes sense.

More info: http://newbeetle.org/forums/1-8-liter-turbo/78553-2000-beetle-mystery-coolant-leak.html
Thanks much for the reply... and another question.. is the heater core to blame despite the passenger's footwell area being dry as dry can be?
We are guessing/theorizing, at this point; that is why you need to pressure test the system, to properly diagnose the problem. I haven't had this problem or replaced my heater core yet but it sounds like it is coming from the right area. Test the system; right now, you are flying blind without pressuring the system. Test, troubleshoot with hard cold facts and then, repair based on those facts... done! Successful, diagnosis/repair! :)
Put your HVAC on defrost, turn the fan on high. You'll know immediately if your heater core is bad. Smell, and fog on the windshield.
You surely won't need a heater on April 18th! :) Yes, I will be there. Fredericksburg Texas baby. :party.

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Hello guys... followed the wisdom in the advice above...
Took the TS to a radiator shop.
They pressurized the system. No dripping.
They connected the heater core back, pressurized the system, no dripping.

They checked the car underside, fittings, hoses, inside the cabin for the common failures, no dripping, no nothing. No traces of green coolant, no traces of rust residue... so... their verdict was the darned recovery tank CAP. So... after 8 dlls for the radiator shop fees, 7 dlls for OEM new cap... now on to check if no more loss of coolant appears. Will check the next 5-10 days. No more loss? then g13 + destiled water will follow. Thanks everyone and yes... Fredericksburg next April 18th! I will take my air cooled beetle tho, but lets meet!
...and they pressurized the system about 7 times before reaching the veredict.

They told me that when the cap is the one that fails, the water evaporates and leaves no trace... these were my symptoms.
Interesting conclusion from the troubleshooting steps; keep an eye on your coolant levels and let us know, if the replacement cap... end up fixing the problem! I have to top off; my system, from time to time... maybe its my cap! :)

I know; there are special adapters to the pressure test the cap, did they do that and it failed the test?

Assenmacher FZ36 Cooling System Cap Adapter
Part Number: ASSFZ36

Radiator Cap Adapter Volkswagen Beetle
SKU#: ST12036
The machine that tested the caps was broken; could not test it... but they were certain the cap was the culprit... however.. they told me to top off, replace the cap and monitor. If more problem occur, to take the car again and search for the elusive leak... monitor phase begins :)

... and since heater core is connected, all systems are GO!
I'm glad you found what the problem is! Keep us posted if things change! :)

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WEll.. following up this store to a closure...

I replaced the reservoir cap with a new cap and filled it up. This morning, I got the red light beeping again.

Waited a few min till things cooled down... opened up the reservoir to fill up only to find that there was not water missing. Same level I left it the night before. So i wondered... "could the red light on the dash was for letting the driver know there was low level of coolant AND /OR that the water was hot..."

So... no need to top off, started the car, no red light...

I think this could be the thermostat not performing(?). I will replace and keep monitoring.
Coolant level switch is bad. Red flashing light thinks it is low on coolant. But its not.
As far as I know, but you have to replace the whole coolant reservoir. Switch is inside, on the level device.

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The sensor being bad makes sense; was there any trouble codes?

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Will VAG com this dude today... see what spits out!...

any particular block setting on vag com to check?
Went to the radiator shop again as my expansion tank was empty again!... we tested the car, ran the usual diagnostics... we did noticed the steam coming out of the exhaust... and now that i think of it... no matter what the weather is like... no matter how long i've been driving... there is always steam coming out of my exhaust... any thoughts? Radiator shop tells me this is linked to my water loss as the cooling system checks out ok...
I'm no expert on NB, but from every other experience I've seen like that, it's head/head gasket related.
... that is what I'm afraid of...

been doing some research here on the .ORG and some users reported also hard time starting the car (no crank at all, just wont start) and my TS started doing that last week.. not every time, but hit or miss...

oh dear... time to diagnose some more and break the piggy bank (knock on wood!)
If the head gasket is suspect; I would do a compression test or even better, a leak down test. Leak down testers are pretty cheap; at places, like harbor freight.

Cylinder Leak-Down Tester
Pittsburgh Automotive - item#94190

Cylinder Leak-Down Tester


The chemical based combustion leak testers; maybe even better...

possibly; a loan tool at Autozone or buy at most auto parts stores:



Videos: ignore the block sealers!
http://www.youtube.com/results?search_query=head gasket block tester&sm=3
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well.. just went outside and found out that now I have Chocolate milk flavored oil... the new cap made the fissure/problem more evident.

Thanks for the information, repairs are next

The TurboS is now in my garage, and my air cooled trusted friend is out from storage... that will keep me moving till this guy is off from the repair shop.

On the lighter side of the story... hey! I found my leak! (or.. where my coolant was going)
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