Coolant leak from front of engine

[catchupmustard]

04’ Allroad coolant leak is clearly leaking from the front of the engine, and running down the oil pan.
I don’t think it’s secondary water pump bc it’s not leaking after turning the car off or is their pooling under the air manifold.
I recently changed the thermostat and that did look like it was my culprit. However it wasn’t.
The water pump didn’t look like it was bad or leaking- could it have been that? Is there anything else that would cause a leak from down the front of the engine to the oil pan?

[hoganalley]

04’ Allroad coolant leak is clearly leaking from the front of the engine, and running down the oil pan.
I don’t think it’s secondary water pump bc it’s not leaking after turning the car off or is their pooling under the air manifold.
I recently changed the thermostat and that did look like it was my culprit. However it wasn’t.
The water pump didn’t look like it was bad or leaking- could it have been that? Is there anything else that would cause a leak from down the front of the engine to the oil pan?

When I had this, the o-ring around the thermostat was not seated properly. If it's down the front, my first suspicion would be the thermostat o-ring and then the water pump gasket or thermostat housing gasket

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[jbain2]

Not much else on the front of the block besides the thermostat and water pump that would leak coolant. Turbos are on the side. Other coolant connections are on the front lower passenger side or lower drivers side of block. Other stuff is around back.


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[rah253]

It happened to me 3 month back, same symptoms. Could not find it but it gradually got worst. Ended up being my water pump.

[PaperToast]

when you have this fixed, install the aluminum tstat cover, no mas leaks

[catchupmustard]

So I just replaced the tstat and housing and leak is instill leaking.
If I do the water pump, can I just order the water pump and re use my tensioner? I only ask bc my timing belt kit was just done 30K miles ago and the belt and everything else looks good to go, so I guess what I’m asking is why do a complete $300 timing kit? If I can just reuse the tensioner, and just order a new WP? How’s that sound to you guys?

[jbain2]

when you have this fixed, install the aluminum tstat cover, no mas leaks

This. But I’m guessing with it being an 04 it already had one.

I think you could get away with just doing the pump but frankly the timing belt is relatively inexpensive. I would just do that.


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[Grainreaper]

My car sprung a seeper, but from the right front corner ahead of the engine, gotta pressurize and look for the leak, hope it's just the temp sensor... Fun fun fun!!

[glennda5id]

Buy or rent a coolant pressure tester. This will identify the leak without the motor running so you can find it easier.

[4xaudi]

Buy or rent a coolant pressure tester. This will identify the leak without the motor running so you can find it easier.

This is how I found the pinhole in one of my turbo coolant lines.

[Grainreaper]

Pressure tested mine, I have a leaky end tank on my radiator.

[AR-77]

its the oil cooler housing.

[ecbo0m]

I did a full TB/WP job and coolant seeped afterward. Turns out the replacement aftermarket plastic thermostat housing developed a crack in the weld between the two halves and would only leak when the coolant was at temp. When cool, the system passed pressure test. Definitely check thermostat housing.

[rah253]

So I just replaced the tstat and housing and leak is instill leaking.
If I do the water pump, can I just order the water pump and re use my tensioner? I only ask bc my timing belt kit was just done 30K miles ago and the belt and everything else looks good to go, so I guess what I’m asking is why do a complete $300 timing kit? If I can just reuse the tensioner, and just order a new WP? How’s that sound to you guys?

I would redo your timing belt at the same time if i was you. I understand that you did it 30K ago, but the parts are not that expensive for that and if you already have the know how just do it, you got most of it out for the water pump anyways...

[Calif_Kid]

So I just replaced the tstat and housing and leak is instill leaking.
If I do the water pump, can I just order the water pump and re use my tensioner? I only ask bc my timing belt kit was just done 30K miles ago and the belt and everything else looks good to go, so I guess what I’m asking is why do a complete $300 timing kit? If I can just reuse the tensioner, and just order a new WP? How’s that sound to you guys?

The timing belt has a mileage limit, but also a time limit which I think may be 5 years, so I'm not sure how long ago you changed the timing belt, but would be good to do everything. Personally, I had changed the timing belt on my A6 2.7T due to a leak from the thermostat housing, and the housing was plastic, so I replaced it with a metal one. After say 8K miles, I had a slight coolant leak start, and when I took everything apart, I found that the leak was from the thermostat gasket, and that rubber gasket was squarish in shape vs the round shape of the new gasket. This time, I also put a little sealant on the thermostat gasket, in addition to the slight amount on the water pump gasket.

PS - if needed, there is install info on ECS like http://bd8ba3c866c8cbc330ab-7b26c6f3...elt_DIY_r2.pdf plus on videos like JHM at https://youtu.be/0LnpfiG1XzY
- Jim

[timmyflash]

check the clamps on the hose that goes to the thermostat housing. Those things lose their tension after a while and if you have recently taken the housing off that could be a possible cause. Definitely go with aluminum thermostat housing regardless and i would go ahead and do a timing belt, valve cover, cam seal job "while you are in there."