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-   -   Audi Q7: Coolant has mixed with engine oil & triggered a plethora of issues (https://www.team-bhp.com/forum/technical-stuff/213568-audi-q7-coolant-has-mixed-engine-oil-triggered-plethora-issues.html)

Hi All,

I have been Audi Q7 (2011 model) 3.0 V6. It was working fine till last week with almost no issues.

Last week, the coolant sensor lit up mid-drive. So I pulled over and checked the coolant level after letting the car cool down for about 20 minutes.



The coolant had turned completely brown. My coolant is generally green. So I knew something was wrong. Quick google suggested that the engine cylinder head gasket must have been damaged allowing coolant to mix with engine oil.





So I sent the car to garage on a flatbed and he confirmed the google knowledge. Over the period of next 6 days, he got the engine cleaned thoroughly, coolant box cleaned, pipes replaced, coolant and engine oil replaced.

After I received the car, I observed that engine temperature was unusually high. It is generally around 60 whereas, it was 90 now. I checked with Garage and he said that since all coolant is just added, it will take time to circulate and engine will cool down. I had my own doubts on this theory but proceeded nevertheless.

Next day, after driving approximately 45km at constant speed of 120, three indicators started beeping consistently all of a sudden.







So I stopped the car and opened bonnet to cool the engine before I check coolant or engine oil. To my horror, the car engine was surrounded by white smoke and was making sounds (similar to Diwali crackers, patt, patt type). Here is the video of the car. If you observe closely, you can see the smoke. The sound (patt patt) is lost in the surrounding noises but was very prominent.

https://youtu.be/SC56Tze5zwQ

I again loaded in onto flatbed and took it to Garage. By the time I reached garage, the engine had cooled down. So no noise or smoke was present. Drove with garage folks again for 5 km and the sound+smoke was back prominently. The mechanic said this is due to faulty water pump and is investigating the same. Few other trusted mechanics are saying that either oil pump is gone or the whole engine is history now.

I am waiting for analysis from mechanic and estimates. Anybody faced a similar issue? What this could be?

Also, is is worth keeping this car now? Few mechanics are saying that since the head cylinder gasket was gone, it's only few months from engine seizure. Is there any truth to this claim? I got this car pretty cheap (around 4.6 lakh INR). So I don't mind selling it at first quote I get but my son and daughter have an emotional connect to car so would want to keep this if the car is going to survive this episode.

I don't own an luxury car so can't really tell by seeing the images of the warning lights. But from what you have explained it seems like the gasket was not installed properly leading to leaking of engine oil and the oil must be dripping on hot metal which is making it smoke and maybe the reason for engine temperature being high and could trigger different sensors too.

The brown colour indicates that oil has mixed with the coolant. This is usually the result of a seal failure (cylinder head gasket, water pump seal, oil cooler, etc.)

This is serious and you should get the car checked thoroughly by a competent person.

Was the head gasket replaced at all during the first time?

Secondly, the pat pat sound happens when the engine overheats. The white smoke is the oil in the combustion chamber or could be water mixing with the oil and burning. Head Gasket could be culprit again.

If i was in your situation i would have the head skimmed,replace the head gasket,check the thermostat or replace if needed,inspect or replace the water pump if required,replace all fluids after proper flushing and use the car.
Cars do overheat and this is what is done as mentioned above. It solves the issue. Why sell it if its in good condition except for this small hitch which can be rectified.
Just my personal opinion.

If you have the time (and budget) to spend on the mechanics and spare parts you can keep the car for emotional reasons.
However if you need a reliable vehicle and do not have the time fot a love affair with your mechanic then you are better off cutting your losses and selling this vehicle.

Either the first repair was not carried correctly or the problem was mis diagnosed. It is not necessarily the head gasket that caused the initial problems. It could be the turbo or perhaps oil cooler if your car has one.

Whatever you do, I would not take it back to whoever fixed it first time. Because obviously he did not fix it correctly. In fact it looks like he made it worse, I hate to say.

So you really need to get somebody to look at this and do a proper diagnosis. Depending on what the problem is, you can make a call on what to do.

Good luck
Jeroen

Sorry to hear about your issue. I had a similar issue on my Volvo XC60, although my issue was Coolant mixing with the Gearbox oil due to a failure of the Cooler.

Check link - https://www.team-bhp.com/forum/techn...-000-km-3.html

https://www.team-bhp.com/forum/attac...lant-tank.jpeg

Did you get your car checked out from an authorised Audi workshop ? I'll be really surprised if the they did a wrong diagnosis. If the diagnosis was correct the first time, further damage could have been avoided. If the head is damaged it is probably best to sell it as engine damage will cost more than your purchase price.

I had car repaired at a local garage initially. It is now with German Experts. These guys are apparently the best of the lot in Abu Dhabi.

First impression that the QC gave was that probably engine itself has some issues. However, he will perform a detailed analysis and let me know about the exact issue and whether this can be fixed or not.

I just realised you were based in AD. How many kms has the car run after you bought it and in total ? Just asking as I have heard from a couple of Volvo technicians that cars and SUVs there are usually high mileage.

I bought this car when it has around 143,000 km on it. Currently it has crossed 225,000 km. As per the folks at Audi service center, this generation of Audi is supposed to last without any major issues till about 300,000 km.

I'm guessing the problem with the head gasket was the tip of the iceberg. My initial guess is that the coolant and the oil have mixed. But there's a whole other story that was probably not discovered by the initial mechanics.
Sorry to say, this reason is absolute bollocks. If the driving conditions were as usual, the temperature should have been 60 for a healthy engine.

If it's a serious problem with the engine or the turbo, I wouldn't think twice about letting the car go considering it's age and mileage. No point spending big $$$ while having a worry in the back of your mind.

And you should be able to get your hands on another used/new car pretty easily in the UAE.

The Audi dealership in Abu Dhabi is well known for its atrocious pricing not to mention incompetency. I own a 2014 Audi A6 which I bought new,now it is at 140000kms.The service experience with the dealer has been a nightmare.German experts are all right though. To which workshop were you taking your Q7 to previously?

Just adding my observation, most(to my knowledge) Audi and VW cars have a pink coolant, it's what is recommended by the factory but you say you've had green, which (according to the internet) isn't as good as the pink one. This could have caused the overheating I think.

I could be wrong though.

I hope the mechanic actually finds the cause and fixes it, it's a lovely car and if you don't mind putting some more money and time it will give you more memories to cherish

All the best!

You've got a Audi Q7 3.0 TFSI at the cost of a Maruti Alto.

And you thought you got a great deal??

Obviously the guy who sold it to you was out to make a fast buck and you fell for it!!

Repair this car??? Considering the symptoms don't even bother!!

Sell it to the first guy you can find and run away as fast as you can.