bsherwoo

As timing would have it, I developed a coolant leak on the drivers side of the engine between the alternator and oil filter right about the time the timing belt should be changed.

Posting last week, consensus was that the leak was due to the thermostat somehow as they go bad with time. So I'm taking care of the coolant leak and timing belt change at the same time.

The pictures below is of the thermostat housing removed from the side of the engine. What is that metal arm outlined in yellow? It seems to enter the metal sheathing and have bits of black plastic poking in.

Is this the real cause of the leak? The housing for the thermostat looks fine from what I can tell.

Thanks,
Ben

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QuattroFan02

Wow, I have no idea what that is, I don't remember seeing that on mine. What year is your car?

bsherwoo

2005 1.8T Avant. No modifications.

Mrider

I have also had a coolant leak lately. But with all the rain, I have not been able to locate the leak. Could you describe the leak a little more. Maybe take a pic a little further out.

TIA

bsherwoo

side of the oil pan by the electronic sensor. It started above the metal lip at a point unseen between the alternator and the oil filter.

I've also heard of leaks form the back of the engine at the rear coolant flange.

MikTip

What he wrote ^^^ ;o)

diagnosticator1

It's held in place by the bolt at the upper end of the curved arm. The plug is sealed with an O ring. If there is any sealant on the plug (looks like there is black rtv on the inside,)besides the O ring, the O ring won't be able to function as a seal properly. You need to remove the plug, replace the O ring, and don't use ANY sealant of the O ring! O rings must be free in the grove to seal reliably. There is a TSB on the plug leaking. Email; your address and I can send you a copy PDF.

Improved plug Part No: 06B 103 033 A

Aarononymous

brittle over time so replace the whole thing. Who told you to replace the t-stat?

QuattroFan02

I did, and mine was leaking when I replaced it @ the time I did my T-belt.

bsherwoo

Part # 06b-103-033-a "Plug"

It was fairly simple to install with a little twisting and nudging. The old one was the same plastic material too. As you can tell from the picture, the older plug was really worn down. The bits of black that I thought were plastic was really the o-ring.

After the replacement, I took off the plastic impeller water pump, and many of the fins were worn down half way, broken off. I can only assume all these little broken pieces of plastic are now in the radiator blocking things up. Is there any way to flush the system with a hose?

Thanks for the guidance. Hopefully this can help someone else if they have a similar leak.

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