Another coolant leak thread

greggyc1

Veteran Member
Joined
Jun 23, 2004
Location
Columbia, TN
TDI
2001 New Beetle Cool White
Two years (20k miles) ago I had my timing belt done and they replaced my water outlet and thermostat at the same time as it was stuck open and I had no heat. No issues all this time. Last Friday just as I arrived to the hospital for my shift, my temp light came in flashing and beeping at me. I was stopped in a hill so I thought it was just positional and it went off when I leveled off. Next morning drive home no problems and tipped the tank off when I got home. Drove back to work next night, same thing happened. No puddles under the car 01 beetle TDI BTW. Went out to the parking garage during the night to check oil to make sure it wasn't pudding or level high but that was all fine. But on the passenger side I noticed a drop hanging from the edge of the belly pan. I touched it and it was pink so I knew it was antifreeze. I topped the tank off again and left it unsealed so it wouldn't pressurize on my 50 miles drive back home. Car did fine, it was 20F outside. I didn't lose any antifreeze on that drive. So tonight it's 40f outside and I was able to get under him to look. It has obviously lost coolant in the front but I can definitely rule out the head gasket and the radiator and nothing is coming out of the timing cover nor is the timing belt wet so not the water pump. I can see a "blood trail" coming from above and where it has come down and crossed the oil pan and it is directly beneath the water outlet thermostat housing. So I tightened the cap and went for a drive on a nearby highway that's 65mph and came back home. With the belly pan off it blew elsewhere under the car but I can see it has squirted from somewhere. The passenger side rad fan motor had a few drops in the back of it, the AC compressor was wet and pink, and a couple of pipes were wet...all in the front. I suspect the water outlet gasket or something in that vicinity. Oil cooler hoses are dry.
During my 10 mile drive I lost about 1/2 inch of coolant. I'm going to attach a couple of pics, don't know if they will show very well on here. I would really like to fix this myself if I can find it. Next step is a pressure test but I don't really want to buy another tool I will likely only use once and for the price that money could go towards someone else fixing it. I just did my clutch myself but I didn't touch anything in the cooling system during the process. I just do not know if any other places it could be leaking from. The hoses were dry before I went for my drive tonight and now there's just a small amount from the spurt on a couple.
Well I can't figure out how to attach a pic at this moment...it's been awhile 😔.
 

GlowBugTDI

Veteran Member
Joined
Jul 20, 2018
Location
Cambridge, MN
TDI
2001 Beetle GLS TDI (BIODSL). 01 original Glow Bug TDI (sold)
Check the hose that goes from the coolant resivior to the metal crack pipe. Feel for wetness or bulges I recently. Went through a similar issue and had multiple leaks. One was that hose bulging and pin hole leaking onto the block very slowly. Couldn't see it even while running, but it eventually burst and then I was able to fix it.

Some auto part stores will loan out tools, maybe you can find one with a pressure test kit.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI the winter water wonderland
TDI
More than I need, less than I want
You can have people guess, but nobody is going to find it but you. Keep cleaning and drying it off until you find it. Or save time instead of money and get your hands on a pressure tester. Coolant tube above the T-stat is a likely spot also.
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
Also check the pipe that comes out of the radiator and has the small-diameter connection to the reservoir hose. That one can crack inside the hose end and it will only leak under pressure -- until it blows off at some point and ruins your day. The good news is they're cheap and even the major parts stores usually have them.
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
... Coolant tube above the T-stat is a likely spot also.
This is where the hard line (small diameter metal pipe runs close to the top of the block around from the back of the engine, across the front, and then straight into the block in a secret location behind IP pump where you can't see it unless you already know it is there. It is just above where the thermostat fitting is. As such, the leak makes you think the t-stat connection is leaking. It will also stealthily run down the block and migrate to many places. This is my vote anyway, but everything jmodge says is correct. It just takes time and looking with diligence. Good luck. These can drive you nutty.

Cheers,

PH
 

greggyc1

Veteran Member
Joined
Jun 23, 2004
Location
Columbia, TN
TDI
2001 New Beetle Cool White
I rigged up a pressure tester using a gauge, a ball valve, and my air compressor. I drove my car about 10 miles on a 65mph highway, came home and I connected to the return port on the tank and plugged the line. I SLOWLY added air until the cap popped off at around 24 psi and just let it sit for a bit. It didn't lose pressure and I was beginning to get discouraged but finally I began to see a drip, then a small stream. I went up top to look around but it's so hard to see behind. I reached in and kinda wiggled the water outlet and I saw it squirt out around it unmistakably. So I'm going to order an aluminum one from ecs tuning. My tstat is only two years old, should I go ahead and replace it while I'm at it or just reuse and go on? Its German made, not Chinese. I'll get a new gasket. I found an incidental leak beginning to show around the temp sensor. I've had to change that before so I know what to do there, a new o ring should fix that. Everything else was tight as a button under there.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
An O-ring will come with a new Thermostat.
Changing the O-ring at the Temp Sensor will be much easier now than later when the system is full of coolant.

For what it is worth, in July/August, 2014, I drove from Rockford, Illinois to Alaska and back to the Kentucky with the coolant system not pressurized. The ALH in my Vanagon performed just fine pulling a popup camper, no overheating. The hose to the pressure gauge came loose. So, rather than having to do some major work under the dash, I drove on day after day with no problems. So, this is good info to know. The OP here has also proved that the coolant system of the ALH is capable of doing it's job without being pressurized.
 

greggyc1

Veteran Member
Joined
Jun 23, 2004
Location
Columbia, TN
TDI
2001 New Beetle Cool White
Swapped the thermostat housing out and changed the o ring and all is good again. I highly recommend the aluminum water outlet from ecs tuning.
 

Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
I had the same leak recently. The O-ring was maybe 7 years old. The rubber was hardened, and it just wouldn't seal any longer. I thought I was stuck on a Sunday afternoon when I finally found out where the leak was from, but amazingly, my local Autozone had an O-ring in stock.

Brett
 
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