A4 2.0t AWD Automatic Wagon - Water Issues

[audicted20v]

Hey Guys!

The car was driven through hurricane Matthew and while driving across some moving water on the road the car began to slip or misfire. The water was probably 1/2 foot deep, I pulled over drained the intercooler pipes which had oil on the passenger side and milky oil on the drivers side. About a half of a water bottle on each side. I checked the air filter and it was dry. Car idles fine. From a dead stop you can accelerate as fast as you want to go and it drives normal. If you accelerate to around 40 MPH, it will start to slip or miss and when trying to hold speed the RPMs drop 500 revolutions and go back up. There are no lights on and nothing in the memory for fault codes. After letting it sit and run for 45mins to an hour, it missed/slipped less. Replaced the spark plugs and 2 coil packs(that was all that was available last Sunday) and it didn't change anything. I dropped it off at a shop and they advised to replace the turbo. Turbo replaced, same issue. Turbo was bad but wasn't the problem. The did a leak down/ misfire detector and nothing came up. Has anyone had a similar issue or have any ideas? The shop isn't sure where to look next and neither am I. Kicker now is the car is 800 miles away from home.

[miA4]

Hey Guys!

The car was driven through hurricane Matthew and while driving across some moving water on the road the car began to slip or misfire. The water was probably 1/2 foot deep, I pulled over drained the intercooler pipes which had oil on the passenger side and milky oil on the drivers side. About a half of a water bottle on each side. I checked the air filter and it was dry. Car idles fine. From a dead stop you can accelerate as fast as you want to go and it drives normal. If you accelerate to around 40 MPH, it will start to slip or miss and when trying to hold speed the RPMs drop 500 revolutions and go back up. There are no lights on and nothing in the memory for fault codes. After letting it sit and run for 45mins to an hour, it missed/slipped less. Replaced the spark plugs and 2 coil packs(that was all that was available last Sunday) and it didn't change anything. I dropped it off at a shop and they advised to replace the turbo. Turbo replaced, same issue. Turbo was bad but wasn't the problem. The did a leak down/ misfire detector and nothing came up. Has anyone had a similar issue or have any ideas? The shop isn't sure where to look next and neither am I. Kicker now is the car is 800 miles away from home.

If you drove it in deep water, you may have bent a valve if water got into the engine via the intake. Did you do a compression test on all cylinders?

[audicted20v]

They did a leak down test and didn't find any differences between each cylinder. The water wasn't high enough to really get to the air box. It was pretty much at the bottom of the bumper but I did check the air filter and it was dry. I also checked the tube to the throttle body right after and other then the normal oil residue, dry.

[miA4]

They did a leak down test and didn't find any differences between each cylinder. The water wasn't high enough to really get to the air box. It was pretty much at the bottom of the bumper but I did check the air filter and it was dry. I also checked the tube to the throttle body right after and other then the normal oil residue, dry.

With the leakdown test, you were able to distinguish that the cylinder is able to hold pressure. I would still perform a compression test to verify. Although you didn't find water, doesn't mean it wasn't taken into the intake duct. Also, if you found milky oil, I would suspect that the HG may be the culprit as well.

[pezgoon]

Well you keep saying slipping, did you change the tranny fluid? The transmission is vented as is rear diff and if you didn't do those I would suggest changing fluid in both, it is always suggested to do that after any water crossing in any vehicle

How'd water get in the ic's if it didn't reach the air cleaner?? They are a sealed system


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[audicted20v]

@miA4 - Thanks for your input! I'll see what the shop says tonight. What does HG stand for?

@pezgoon - It is either slipping or misfiring, the car is 800 miles away from home so I did what I could macgyver style and then handed it over to a European shop. The vent is at the top of the trans/diff and has a cap. The water was to the bottom of the bumper max and driving through it under 5 MPH. I am not sure if the milky oil was from going through the water or just moisture trapped but ICs can have cracks in them that do not affect driving but let water in when submerged. I wouldn't consider them a sealed system. I will check with the shop to see if they did anything with the trans today though! I asked them to look at that Thank you!

[pezgoon]

Ah I didn't realize the ic's could be cracked and the computer wouldn't see the boost leak. Ya I would suggest changing our tranny and diff fluid, it isn't cheap but especially if your having slipping issues (I'm assuming automatic right) then that's what I would point to, if manual then your clutch obviously was submerged and what it would need I am not sure (I don't know all that much about clutches)

I know that the pickups I owned the manuals specified that water that was to the midpoint of the rim (which is about the height of the bumper on ours) required changing of the fluids in tranny and diff asap as water can penetrate through the vents and the seals even though at the half way point on the rims the tranny wouldn't be submerged

Hg=headgasket


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