# Coolant Leak



## Strictly4Boost (Feb 21, 2009)

This weekend I bought a beater a 2006 Volkswagen Jetta 2.5 with 196k. Manual Transmission.

When I started to work on the car, I noticed thermostat and brake light blinking.

I added brake fluid which was low, the light went away. There was no coolant in the reservoir, so I added to the mark. The light went away. I also scanned and got 2 codes. p0332 and p0420.... (knock sensor & Catalytic Converter).

Drove around for a little bit and then checked the coolant, it was low, so I added again. Now what I did realize was coolant leaking on the passenger side but underneath the control arm and also in a hole where the passenger seat would be above. I've looked everywhere and can't pinpoint where its coming from. I removed the coolant reservoir to also see if it was cracked, but I don't see anything. I've looked near the water pump, and hoses. Is there something I am missing?

Ps: Car does not overheat and temperature gauge sits in the middle, just loses coolant. Previous Owner was clueless and stopped servicing the vehicle 2 years ago and added regular green coolant instead of g12 :banghead: Just hope its not a head gasket issue.

Some pictures


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## Master_P (Feb 10, 2012)

When did you completely flush out the old green stuff and refill with G12/G13? Pics show green liquid.

First and foremost, you must identify the leak source. Try adding UV dye to the coolant bottle, and trace the coolant lines with black light.

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## Master_P (Feb 10, 2012)

Oops. Just realized you said you just bought the car.

Step 1 - flush the green stuff out. Replace with distilled water. Add UV dye.
Step 2 - find the leak
Step 3 - fix the leak with new parts.
Step 4 - flush the UV dye out with 5+ gallons of distilled water.
Step 5 - add 50/50 G13.

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## Strictly4Boost (Feb 21, 2009)

Master_P said:


> Oops. Just realized you said you just bought the car.
> 
> Step 1 - flush the green stuff out. Replace with distilled water. Add UV dye.
> Step 2 - find the leak
> ...


Thanks for replying,

I flushed all the green stuff out and let it sit. It took a while. I will add water and UV dye and go from there. I will need to buy a black light.

Is there a difference between G12 or G13?


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## Master_P (Feb 10, 2012)

The differences between G12 and G13 should be of no significance on a 2006 2.5L Jetta.

I suggest you study the coolant loop system so you can pinpoint the leak easily. 

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## Hate-Trix (Sep 30, 2011)

Did tou check the water pump?

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## Strictly4Boost (Feb 21, 2009)

Hate-Trix said:


> Did tou check the water pump?
> 
> Sent from my SM-G930W8 using Tapatalk


I looked to see if anything is leaking from the water pump, I see a little tiny bit of mold dark white but dry. Starting to think if I should just go ahead and change it since i'm putting in new coolant.

Today I ran the vehicle on jack stands. Water only. I bought the UV Dye and g12 coolant but it got dark outside so i didn't bother putting it in yet.


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## Master_P (Feb 10, 2012)

Don't put the G12 in until you fix the leak.

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## Hate-Trix (Sep 30, 2011)

Strictly4Boost said:


> I looked to see if anything is leaking from the water pump, I see a little tiny bit of mold dark white but dry. Starting to think if I should just go ahead and change it since i'm putting in new coolant.
> 
> Today I ran the vehicle on jack stands. Water only. I bought the UV Dye and g12 coolant but it got dark outside so i didn't bother putting it in yet.


When mine went and did the same. Left a trail down the block. And it was like a pink jell. 

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## Master_P (Feb 10, 2012)

If the leak is on the passenger side, then there's the few places worth inspecting.

You've already checked the expansion tank. On the bottom of the tank is a small rubber hose with an elbow. It connects to a metal pipe. Inspect that hose.

The metal pipe steers coolant towards the front of the car, then hits another rubber hose with an elbow. Inspect that small hose.

At the top of the expansion tank is a rubber return hose. Inspect that hose.

Inspect the heater core hoses at the firewall. There's a small hose that goes to the metal return pipe.

Inspect the top of the transmission. Coolant here could mean a leak with the coolant distributor housing.

Use a black light to inspect the thermostat housing for UV dye. Better to do this at night. Any dye will light up and be easy to see. Access is very tight. Inspect the oil cooler hose. That would be a major PITA to replace.

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## Strictly4Boost (Feb 21, 2009)

Master_P said:


> If the leak is on the passenger side, then there's the few places worth inspecting.
> 
> You've already checked the expansion tank. On the bottom of the tank is a small rubber hose with an elbow. It connects to a metal pipe. Inspect that hose.
> 
> ...


Thanks, The top hose on the reservoir was a little loose, and the bottom doesn't look like it was clamped on correctly. I replaced the reservoir and cap since I have an account with a VW Distributor at work. Heater core looks good, inside the car no coolant smell or signs of coolant. 

Looks like I have a very tiny small leak like a tiny drop from the water pump seal. Spoke with a friend and he told me to do a compression test before I even replace the water pump, since I have no records of anything. I think my friend has a compression test tool, would you know the size of the spark plug?


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## Master_P (Feb 10, 2012)

Strictly4Boost said:


> Thanks, The top hose on the reservoir was a little loose, and the bottom doesn't look like it was clamped on correctly. I replaced the reservoir and cap since I have an account with a VW Distributor at work. Heater core looks good, inside the car no coolant smell or signs of coolant.
> 
> Looks like I have a very tiny small leak like a tiny drop from the water pump seal. Spoke with a friend and he told me to do a compression test before I even replace the water pump, since I have no records of anything. I think my friend has a compression test tool, would you know the size of the spark plug?


A compression test kit should include the proper adapters for the spark plug socket; however this will not help identify your leak. If you have a tiny leak at the pump, UV dye will show it.

Let me know how you go about swapping the coolant pump. The official procedure calls for securing the engine/transmission on a joist/cherry picker, removing both motor mounts, and pushing the engine towards the drivers side. Supposedly, this is the only way to get enough room to unscrew and remove/replace the pump.

This process seems like a huge hassle. The motor mount bolts are TTY and one-time use, and there are many bolts to replace. Finally, IMO it seems excessive to disconnect the engine and transmission for a coolant pump swap. I really don't like this method, and am looking for a better way.

I will probably swap the pump out of our 07 2.5 Jetta in the coming months. I plan to improve access to the pump by removing the:

-intake manifold and fuel rail
-all serpentine belts, tensioners, and both idler pulleys (going to replace them anyways)
-t-stat housing (going to replace it anyways)
-alternator
-passenger headlight (not sure if this improves clearance?)

Hopefully with all that stuff removed, the pump should come out easier, but I won't know for sure until I'm knee deep in there.

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## Strictly4Boost (Feb 21, 2009)

Master_P said:


> A compression test kit should include the proper adapters for the spark plug socket; however this will not help identify your leak. If you have a tiny leak at the pump, UV dye will show it.
> 
> Let me know how you go about swapping the coolant pump. The official procedure calls for securing the engine/transmission on a joist/cherry picker, removing both motor mounts, and pushing the engine towards the drivers side. Supposedly, this is the only way to get enough room to unscrew and remove/replace the pump.
> 
> ...


I want to do the compression test just to see if its worth even working on this engine.

I'm afraid coolant could be going through the exhaust manifold into the catalytic converter. I have a catalytic converter light on as of now. There is no smoke at all. I just want to be sure :laugh:

Also there is a diy for the water pump removal. Looks like you will need a diy for removing the belts. ( Removing Pass. Tire, and Side Access Panel). Then the diy for removing the water pump consists of 2 jacks. One on the engine and one on the transmission. Remove the mounts, lower transmission, and raise engine. You can do the water pump from the top. I think its okay to re-use the bolts.

here is the diy for that http://volkswagenownersclub.com/vw/showthread.php/21187-water-pump


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## Master_P (Feb 10, 2012)

Strictly4Boost said:


> I want to do the compression test just to see if its worth even working on this engine.
> 
> I'm afraid coolant could be going through the exhaust manifold into the catalytic converter. I have a catalytic converter light on as of now. There is no smoke at all. I just want to be sure :laugh:
> 
> ...


A better test would be a leak down test. As long as you can get each cylinder to TDC, this will not only tell you if there's compression loss, but _where_ the loss is happening. A compression test is only helpful if it yields good results, but it's fast and easy.

I've seen that water pump DIY. It's similar to the process I outlined, as it requires manipulating the engine laterally. Let's say you place one jack stand under the engine oil pan, a second jack stand under the transmission oil pan, and then remove both motor mounts. You will have room to replace the pump, but how do you realign the engine and transmission back into the mounts without a cherry picker? Two floor jacks? I think that's extremely risky. Balancing that much weight spread across a large area, with two floor jacks requires a lot of care and patience. Plus, you need to put a 2x4 between each jack and oil pan, and between the jack stands and oil pan, or the jack/stand will damage the pan.

If you try this method, please let me know how it goes.

Now, I'd rather take several components out if it affords me added room to swap the coolant pump. I don't like the idea of resting my engine and transmission on jack stands, even for a little bit. To me, that's like putting a heavy $6,000 flat screen TV on a folding table (something I did in my younger/naive days...) :laugh:

I disagree with reusing the engine mount bolts. Once a TTY bolt is removed, it should be discarded. This will impact the clamping force of the bolt.

Excellent serpentine belt & pulley DIY: 
http://forums.vwvortex.com/showthre...-Accessory-Belts-Tensioners-and-Idler-Pulleys

Lower tensioner/belt how to:
https://www.youtube.com/watch?v=XsMTR37NL_o

Upper belt how to:
https://www.youtube.com/watch?v=qKC0wqei1us


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## Strictly4Boost (Feb 21, 2009)

I was able to do the compression test over the weekend. Autozone rents the tool for free, just have to give them 40 something bucks and they'll return it to you when you bring it back to them.

Here are my results

Cylinder 1 = 170

Cylinder 2 = 174

Cylinder 3 = 175

Cylinder 4 = 179

Cylinder 5 = 195


Here are pics


Cylinder 1 










Cylinder 2









Cylinder 3










Cylinder 4










Cylinder 5


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