Fast Coolant Leak

Tiny
TYAZZ
  • MEMBER
  • 1999 VOLKSWAGEN JETTA
  • 170 MILES
The Jetta leaks coolant fast from behind a pulley loacted just above the oil pan. I can not find any wet spots anywhere around it, but it leaks fast from behind it. The pulley is the largest pulley involved with the serpentine belt. Maybe crank shaft pulley. I dont see coolant in the oil yet, but im sure itll work its way through the oil pan gasket eventually.
Saturday, February 18th, 2012 AT 5:45 PM

15 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Probably the water pump here is a guide to help confirm the pump and a step by step guide with diagrams below to show you on your car.

https://www.2carpros.com/articles/car-is-leaking-coolant

and

https://www.2carpros.com/articles/water-pump-replacement

Image Reference:

1. To upper radiator
2. 0-ring (Always replace)
3. Coolant pump
4. Clip
5. Engine Coolant Temperature (ECT) Sensor (G62), with ECT Sensor (G2)
6. From expansion tank
7. Connector flange
8. To heater core
9. From expansion tank (vehicles with automatic transmission)
10. 10 Nm (7 ft lb)
11. Bracket
12. From heater core
13. From expansion tank (manual trans.) or ATF cooler (automatic trans.)
14. Coolant pipe
15. Oil cooler
16. To lower radiator
17. 20 Nm (15 ft lb) plus /14 turn (90°) Always replace
18. Generator (GEN) bracket
19. 30 Nm (22 ft lb)
20. Poly-ribbed belt

Check out the diagrams (Below). Please let us know what you find.
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Saturday, February 18th, 2012 AT 7:15 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Water pump. Don't worry, coolant can't leak into the oil pan
through the oil pan gasket.

To replace the water pump, you need to remove the timing belt. So
be sure to install a new T-belt & tensioner as well.
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Sunday, February 19th, 2012 AT 12:04 AM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
I dont have the know-how to do this myself. Is it even cost effective to have the water pump and timing belt changed on a 99 Jetta with 180k miles in fair condition?
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Sunday, February 19th, 2012 AT 6:14 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Just to make sure, we are talking about the A4 model VW Jetta, right?
Should look like this:

If the car has been maintained/serviced regularly, it will still
have quite a bit of life/years left! Many variables obviously,
but it would sell for more money (should you decide to sell it)
if the leak were repaired! :-)

Take it to a VW Specialty shop for an estimate. Prices can
vary, so you might want to see two shops. Don't just take my word
for it and phone for an estimate. Since I can't see the leak, my
best guess at this time is water pump.

The 1.8T, 1.9TDi, 2.0 & VR6 engines will all have water dripping
from behind the big crankshaft pulley when the water pump leaks.

Good luck!
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Sunday, February 19th, 2012 AT 6:26 PM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
Before I go and buy these parts and pay someone to do it. Could it be the crank shaft pulley seal? Or would that be oil leaking out?
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Sunday, February 19th, 2012 AT 6:31 PM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
And yes thats what the car looks like.
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Sunday, February 19th, 2012 AT 6:33 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Sorry about the late reply. Had a phone call.

Crank shaft pulley will leak oil, not coolant. What engine is in
your car?
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Sunday, February 19th, 2012 AT 7:00 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Don't buy any parts until you have someone verify where the leak
is coming from!
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Sunday, February 19th, 2012 AT 7:01 PM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
The engine is a 2.0. Ok, il have it verfied first. But I took the undercariage covers off, the oil pan cover, and the engine covers and could not find any wet spots at all. I couldnt even find any moisture on the top side of pulley.
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Sunday, February 19th, 2012 AT 10:13 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
The water pump has a small "weep" hole. Coolant can leak from it
depending on engine temperatures & pressure.

It might not leak until the car has been run to fully warm state and
then as the engine cools, coolant will start to run out.

Attached is a picture that shows a trail of coolant from the pump
town to the crankshaft sprocket.

Diesel engine picture. But your w/p is in the same place.
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Sunday, February 19th, 2012 AT 10:46 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
One more.
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Sunday, February 19th, 2012 AT 10:51 PM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
Thanks. This leak though leaks weather the car is running or not. Its a slow drip with the car off, and a very fast drip with it running. So fast that the coolant resevior will empty out in ten minutes.
Regardless, im going to have it diagnosed to know for sure.
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Monday, February 20th, 2012 AT 1:17 AM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Yes, have it looked at and post back your finding!
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Monday, February 20th, 2012 AT 1:20 AM
Tiny
TYAZZ
  • MEMBER
  • 56 POSTS
It was the water pump leaking. If I could do it myself it woulda cost $170 for water pump, thermostat, and timing stuff. Since I couldn't, $700. Thanks for the help guys. Ima get to posting my next problem with this car.
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Thursday, March 1st, 2012 AT 11:33 AM
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
Glad we were able to be of help. Glad it's fixed now.
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Friday, March 2nd, 2012 AT 4:57 AM

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