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Suspects for leaking coolant appearing in the valley:
- PCV Oil Separator
- Thermostat
- Thermostat cross over pipe and o-ring connections
- If this is a 3.0T then leaking black plastic bleeder screws on each of the supercharger intercoolers
If the engine has been overheated due to low coolant then recommend to replace all the above while the intake / blower is removed as these parts get cooked.
Last edited by AudiAllTheWay; Dec 26, 2023 at 07:54 AM.
Suspects for leaking coolant appearing in the valley:
- PCV Oil Separator
- Thermostat
- Thermostat cross over pipe and o-ring connections
- If this is a 3.0T then leaking black plastic bleeder screws on each of the supercharger intercoolers
If the engine has been overheated due to low coolant then recommend to replace all the above while the intake / blower is removed as these parts get cooked.
It's the 3.2. Thermostat and croosover pipes were changed last year. I will look into the PCV oil separator. Thanks
Unfortunately, the oil separator problem is not well understood and people regularly take the intake off and don't thoroughly inspect it. I have not seen the thermostat housing leak on a 3.2 yet but it is within the realm of possibility. Depending on model year you have either a plastic(later model) or aluminum (earlier model) oil separator housing. Make sure you order all of the seals when you do that job, if you have the aluminum one, the PCV tube that inserts into the oil separator housing has two seals, a molded rubber seal on the face, and an oring around the tube body. The oring part number is hard to find, I think it took me an hour to figure out the first time I did one, it did not appear in any of the parts diagrams I had including my version of ELSAWin.
Since it's a 3.2, take a look at the vacuum pump as well, if it is leaking you can get a cheap seal kit from RKX(RXK?) off eBay/etc that reseals the entire thing, much cheaper than a new pump.
Correct, they leak copious amounts of oil. I haven't seen a single one that wasn't leaking when >100k miles/10 years! The seal kits are an easy fix for what becomes a very significant oil leak. Always worth doing it if you have the car apart and notice it leaking.
Just updating this thread. I found the PCV oil separator was leaking badly. Unfortunately, there are also coolant leaks in the front of the engine. Added to that, there are numerous oil leaks including the timing chain cover in the back. I have decided to cut the cord and sell it for whatever I can get for it. The car has 221,000 miles and still drives like it's new. I have had it for 11 years with little trouble. About a year ago I had AC problems which are fixed, but the leaks are too numerous. Thanks to everyone for such good information. I will not be leaving the forum as I also have a Q3.
Probably not the timing cover leaking in the back, it's the oil filter housing. Very common. Timing covers are just sealed with silicone, if those were leaking you could pull them off with minimal effort but I really doubt they are leaking unless they've already been off before and someone screwed up when applying the silicone. If you chose to go the repair route you can do all the top end seals including cam girdles, with new chain tensioners/guides, thermostat, reseal the vacuum pump, etc, literally every leak source above the oil pan and front/rear main seals for under a grand in OEM parts easily. It does take a week's worth of evenings to finish the job if you haven't done it before, though. Also you'd need to rent or buy the holding tool for the cam phasers and cams but they are pretty inexpensive for the 3.2 nowadays. Every 3.2 I've done this job on has ended up with zero leaks, and also ran much better since I also cleaned the intake valves/flaps and throttle body. It's a rather satisfying repair job.
Coolant leak sources on the front of the engine are thermostat, cross over pipe and water pump. Reach down and wiggle the water pump pulley and if there is any shaft play then replace.
Oil leaks at the rear upper covers solution is R&R the covers plus a tube of sealant. Can replace the upper tensioners while open.
Understood if it is time to sell but simply to note these fixes are DIY friendly.
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