Can Faulty Radiator cause of Auto transmission leak?

[Bal B7]

Hi All,

My A4 B7 has decided it wanted some attention so decided to leak auto transmission oil into the near side of the engine bay.

The near side was covered in oil, it looked as if the oil had shot up from the 'drive shaft' area and managed to reach the coolant header tank as liquid was dripping from it { may have been coolant fluid}

i cleaned as much oil as i could to trace it back but did not see any direct sources for the oil.

The car engaged gears fine, there was no sign of 'mayo' in the oil cap or dip stick. {no lights on dash}

 

Wasn't able to get the car towed home so took a slow drive back after rush hour was gone.

It drove ok but as it eventually came to a stop, it then seemed to struggle to pull away {likely due to the lack off transmission oil}

once it was back home, checked the oil again and it was fine, checked the header tank and it was full of mayo, a sure sign oil had mixed with the coolant.

 

Did some research online and didnt get any luck so decided to strip the coolant system as it would need flushing. 

One but of advice I got was to check the flow of the radiator. I blocked off the return flow and filled the radiator with water and could see it slowly seeping out of the oil feed and return points.

 

From My diagnosis it seems that the radiator has failed and caused the oil feed lines to the gear box to over pressurise.

The part im struggling with is finding where the oil has escaped into the engine bay from the autobox.

Has anyone had a similar experience or know where I should look next?

The plan now is to install a new radiator after flushing the coolant system, top up the auto box with new fluid {not sure how much it takes}

Any advice would be appreciated

thanks 

[Steve Q]

Not sure on your situation but regarding gearbox oil change, here's a link: 

https://www.audizine.com/forum/showthread.php/414061-B7-A4-Tiptronic-ATF-Replacement 

Plus I think the gearbox takes around 5-6L of oil. 

[Bal B7]

27 minutes ago, Steve Q said:

Not sure on your situation but regarding gearbox oil change, here's a link: 

https://www.audizine.com/forum/showthread.php/414061-B7-A4-Tiptronic-ATF-Replacement 

Plus I think the gearbox takes around 5-6L of oil. 

Thanks Steve, I'll take a look at this.

I'll report back once I've swapped the radiator and further checks

[Steve Q]

27 minutes ago, Bal B7 said:

Thanks Steve, I'll take a look at this.

I'll report back once I've swapped the radiator and further checks

Good luck with the work and further diagnostics. Please keep us posted on how you get on 🙂

[Bal B7]

Update on repairs, I drained the coolant tank and gear box of the creamy mayo, installed a new radiator and put everything where it belongs.

 

My issue now seems to be that it has no throttle response. It seems to be hunting for revs also.

 

Is there anything I should double check that could be causing the issue?

 

Thanks

[Steve Q]

Glad you sorted the radiator. Regarding no throttle response, could it possible that the 'fly by wire' accelerator pedal be causing your problem?

They are just a variable resistor connected to a pedal really. So it could be the pedal sensor. It could also be the throttle body. 

this is me assuming its a manual of course. If it's an auto then I'd think it's connected to the previous problem. And I'd assume it's the CVT gearbox. If it is a CVT gearbox I've seen issues where hesitation on acceleration is caused when the box isn't warm enough plus other issues. If you Google Audi CVT gearbox problems you'll see what I mean. 

I Also known on the b8 the diverter valve is known to fail on them causing the issues you're experiencing. But not 100% sure if that affects the b7. 

[Bal B7]

Hi Steve, thanks for the info.

Mine is an auto, I didn't do the filter change as you advised reason being that my auto box does not have a sump, the filter is actually inside the rear bell housing. There is a secondary external filter on mine.

 The hesitation issue is there when the car is cold or upto temp. The revs in D or R will go up to 3k but little to no drive. I think you're right about the throttle issue being linked to the gearbox issue.

The diagnostics check didn't pull any codes (used Snap-on unit) the throttle switch it self response as should but the engine does not.

We ran through all the systems on the engine and they work fine, I also removed and cleaned the throttle body.

Due to the age of the A4 and potential costs I'm actually considering letting it rest and finding an alternative daily driver.

I may have a look at the diverter valve and see how complex it is to repair.

If nothing else this post will hopefully help others in future with similar issues.

[Steve Q]

Sorry to hear you're looking at letting it go. It's often the complicated issues that kill off older German cars. 

[Bal B7]

I'm looking at possibly getting a B7 S line quattro as a replacement.

 

Am I right to assume the manual audi's don't use the radiator to cool the gearbox oil like the auto's?

[Steve Q]

11 minutes ago, Bal B7 said:

I'm looking at possibly getting a B7 S line quattro as a replacement.

 

Am I right to assume the manual audi's don't use the radiator to cool the gearbox oil like the auto's?

I don't believe so, but can't say for 100% certain

[Stevey Y]

19 hours ago, Bal B7 said:

I'm looking at possibly getting a B7 S line quattro as a replacement.

 

Am I right to assume the manual audi's don't use the radiator to cool the gearbox oil like the auto's?

Hi the manual gearbox fitted will not use a cooler as they run on proper Gutsy oil which only needs changing every 50k, thats why I chose a manual for my cab I have changed the oil twice plus the clutch assemblies are cheaper £1400 manual £2000+ for the auto DSG, the prices are so high because the Barstewards at Audi won't release the patents for aftermarket.

Steve.

[Bal B7]

Really appreciate the help guys, I don't really want to give up on trying to fix it but time is tight so may have to unfortunately let it go as spares or repair. Hopefully someone has a spare gearbox they an swap into it.

 

[Steve Q]

4 hours ago, Bal B7 said:

Really appreciate the help guys, I don't really want to give up on trying to fix it but time is tight so may have to unfortunately let it go as spares or repair. Hopefully someone has a spare gearbox they an swap into it.

 

You're welcome, glad we could help 🙂 sorry you'll have to get rid of it. 

[Ianswebb]

This has certainly peeked my interest. Although I have no symptoms, off the back of this I'm going to do some digging around and clue myself up. 

Anyone know if Elsawin is still the workshop go to, or am I 10 or so years behind?

Ian  

[Bal B7]

Is yours having similar issues as mine? 

 

Mine started out feeling as if it was developing a slight miss fire before blowing oil out from the passenger side of the engine.

I'd recommend checking the quality of the coolant and if possible a quick look at the gearbox oil.

[Ianswebb]

23 hours ago, Bal B7 said:

Is yours having similar issues as mine? 

 

Mine started out feeling as if it was developing a slight miss fire before blowing oil out from the passenger side of the engine.

I'd recommend checking the quality of the coolant and if possible a quick look at the gearbox oil.

Fortunately I haven't got any symptoms, but I am a big fan of the CVT and maybe over sensitive to it's fragility.

I need to do a coolant change anyway as it looks like my thermostat is knackered (engine temps doesn't get much above 70c when on the move), although I'm nervous of changing right now as I'm not entirely sure the cooling fans are operating. I'll be sure to use the correct 'G' number though.

Gearbox oil is genuine Audi stuff as I didn't feel comfortable using anything else, which I changed about 4,000 miles ago. 

Ian