Hi, I’ve got a 2012 S3 with DSG. (CDLA Engine) I’ve got a coolant leak from a plastic coolant housing. It sits on the right hand side of the head, above the gearbox and houses the coolant temp sensor. It’s a 3 bolt flange and seals with an o ring. I’ve replaced the seal and housing but it still leaked. I’ve tried using high temp silicone to help but it still leaks. Has anyone seen this before? And have you managed to fix it? Help would be much appreciated.
Coolant Leak
- Thread starter Simon Bramley
- Start date
The plastic flange warps over time. Only way to fix it is to replace the whole thing. New bolts, new o-rings, and clean the mating surface to the block. Torque it properly as well because too much and you'll crack the plastic.
Don't use RTV or any other sealant because over time the sealant exposed to the heat and coolant will dissolve and clog up your system. Radiators nowadays have tiny tiny channels so they could get clogged and the water pump bearings aren't designed to get gummed up by RTV.
Don't use RTV or any other sealant because over time the sealant exposed to the heat and coolant will dissolve and clog up your system. Radiators nowadays have tiny tiny channels so they could get clogged and the water pump bearings aren't designed to get gummed up by RTV.
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I’ve got a different o ring, it’s slightly smaller in diameter, but thicker. So I’m hopping the thickness will cure it. The seal land on the head was pitted and I got most of it off, but I’ll give it another rub down and let you know if this works .
Hi, I didn’t put much on to be fair and I only put it on the face of the head to try and get an extra seal if the o ring was still weeping. I don’t like using it but i had to try something. However it’s not worked twice, and like you say when I’ve taken the housing off after I’ve used it, it’s never bonded so I won’t bother again.
Could you perhaps tell me what connects to the smaller tubes on the flange. I just picked up this a3 wagon and was all torn apart. I have the small tubes right across from each other with no hose to attach on either side
