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Losing Coolant slowly

3083 Views 68 Replies 9 Participants Last post by  Flerky
Hey everyone,

So I recently purchased a 2015 Touareg TDI and have noticed that it's losing coolant. Every few days I'm having to add coolant but not a whole lot. It gets just below the minimum line and so I add more. I've added 3-4 times now since purchasing 3 weeks ago. The temp while driving never gets above 200-205 even during long trips so no overheating issues yet.

Where could this slow leak be coming from? EGR? Oil cooler? Water pump (I would assume I'd lose more if it was the water pump). Also would these issues be covered by the extended emissions fix warranty? Just wondering whether I should bring it to a VW dealer or to a good locally known VW mechanic.

Is there something I could look for myself? Are any of these issues easy enough fixes or just best to take it to a dealer?
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Can I figure out if the Oil cooler is leaking with VCDS? Would the exact temp gauge be a little higher or something that I would be able to diagnose? Or anything visually to look at around the engine?
Doubt any variables in vagcom would be of help. Look for obvious leaks at this point
I was wondering though ... wouldn’t oil temp module show that it’s a little hotter than normal in VCDS?
I mean it just looks like oil more than coolant and a couple times I pulled the scope out it had oil on it, not coolant.
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what about the possibility of that being oil and fuel mixed? do you think you’re seeping oil and leaking a small amount of fuel from the fuel injector seal area?
savagesoot is right. its the oil cooler. I've had mine replaced twice now. first time the dealer did it and it failed 1,000 miles past the warranty. second time went to the indy shop so far so good.
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how do you start to figure out the oil cooler is leaking? just to give me an idea of what i’d be asking the dealership to specifically check out?
We had a similar issue with our 2014 TDI. It turned out the be the EGR for us. Not a cheap fix.
I’m starting to suspect my 2015 might have an issue going on similar to this. I started another thread about loosing coolant and I thought it was coming from my water pump however the dealership didn’t find any leak, even while they pressure tested the coolant system. How do I essentially start to figure out if it’s this issue related to the EGR?
Why would you tell to the dealer where to look? They should know where to look. When you are losing coolant from oil cooler or EGR, there is always residue because G12 contains glycol which does not evaporate. After some time it will look like red sludge. Oil cooler and EGR are in the same area, so every leak will be visible between heads.
when coolant leaks does it disintegrate rubber gaskets and seals? I recently had other work done to gaskets between the exhaust manifold, cat downpipe, and fuel injector seal on 1 of the injectors.
If does, they would not be used in cars at all. Rubber seals are resistant to oil and fuel, only heat is a problem.
Thankyou. Okay so what do you think would have gone wrong when they initially did the diesel emission settlement software fix? The moment they did that it caused many of the seals around my engine and exhaust (mentioned above). The acelleration was even more laggy and it skipped or puttered a lot more until the dealership repaired the fuel injector seal. Something went wrong on day 1 of the emissions software compliant fix. It also had some boost pressure leak fixed last time at the dealership along with all the other work to exhaust and fuel injector seals
That could be coincidence. One this is sure...emission software fix is not good and engine will behave weird. I would recommend ECU chiptunning. New map will replace this ****ty emissions fix and engine will perform a lot better than before.

There are two seals. One (at bottom) made from copper and second (approx in the middle) is classic o-ring. These coppers seals will fail after some time anyway. At this point, its recommended to replace all of them at once (on all injectors). That's quite cheap job.
you say replacing all 6 fuel injector seals, both the copper and classic o-ring are relatively cheap fix job? I will look at doing that in a couple years as they literally just went in there an repaired the one they could replace under the warranty while they were doing all that work.
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