Common Problems for the 3.0t (Supercharged) Engine in a B8 or B8.5 S4

[Paul@ShopDAP]

We worked with an Audi Tech to put together an article for the 3.0t Community. This engine is very wide spread across a ton of Audi models. While the 3.0t is a pretty solid engine, like any vehicle there is a possibility for problems.

Check out this list for a few things to look our for on your S4

[BucDan]

Thanks for the link! A great insight summary for new owners like me.

[WeeKenny]

You missed one, oil cooler failure causing oil and water mix to gather in the expansion tank but no sign of water in the oil. This is actually a common issue in all Audi’s with a coolant to oil cooler. On the 3.0L it’s bolted to the block down next to the sump rather than under the oil filter housing like most others.

[ZGskibum]

You might also address the phantom, slow loss of coolant with no visible leaks that defies pressure testing and plagues some significant percentage of us


Sent from my iPhone using Audizine

[hilmar2k]

You might also address the phantom, slow loss of coolant with no visible leaks that defies pressure testing and plagues some significant percentage of us

That's funny, I had that exact issue on my C6 A6 4.2.

[BucDan]

You might also address the phantom, slow loss of coolant with no visible leaks that defies pressure testing and plagues some significant percentage of us


Sent from my iPhone using Audizine

Wait, what? Can you expand on this?

Can't find anything on the oil cooler, either.

[tech30six]

Wait, what? Can you expand on this?

Can't find anything on the oil cooler, either.

That's cause it's NOT a common issue. In 5 years at the dealer...seen it 3 times.

Sent from my LG-H915 using Audizine mobile app

[tech30six]

You missed one, oil cooler failure causing oil and water mix to gather in the expansion tank but no sign of water in the oil. This is actually a common issue in all Audi’s with a coolant to oil cooler. On the 3.0L it’s bolted to the block down next to the sump rather than under the oil filter housing like most others.

See above.

Sent from my LG-H915 using Audizine mobile app

[catalyst686]

Great article, glad you're taking the time to do all of this.

[ZGskibum]

That's cause it's NOT a common issue. In 5 years at the dealer...seen it 3 times.

Sent from my LG-H915 using Audizine mobile app

Well, there's this:

https://www.audizine.com/forum/showt...t=coolant+loss

and this...

https://www.audizine.com/forum/showt...t=coolant+loss

oh, and this...

https://www.audizine.com/forum/showt...t=coolant+loss

well, plus this one, of course...

https://www.audizine.com/forum/showt...t=coolant+loss

I could go on but wouldn't want to belabor the point.

I've also experienced the issue in both B8 S4's I've owned. Neither ever successfully diagnosed. I suspect (but don't know) the issue is that the pcv valve leaks under certain driving conditions that aren't replicated in a stabdard pressure test.

[WeeKenny]

See above.

Sent from my LG-H915 using Audizine mobile app

It happens a whole lot right across the Audi / VW ranges, a quick Google will show you that. You personally may not have seen many but it does happen and the S4 is no exception as it shares the oil cooler design. My S4 has this happen and the dealer mechanic diagnosed it in 3 seconds flat having seen it often before on various Audi’s.

[JonS4]

We worked with an Audi Tech to put together an article for the 3.0t Community. This engine is very wide spread across a ton of Audi models. While the 3.0t is a pretty solid engine, like any vehicle there is a possibility for problems.

Check out this list for a few things to look our for on your S4

I think this is a good list with excellent explanations but the regular carbon clean is worth mentioning. I realize it is more a maintenance item and is part of the secondary air system warning issue but none the less, it is a major pia to do or pay for.

[Upstate Audi]

Very interesting article. I've been having problems on my C7 A6 now where I've been having to add a quart of oil every 1000 miles or so. Does anyone have any more information about the bad PCV valve? Is there any way to test if this is for sure the reason why my car is burning so much oil, and how much does it usually cost to have replaced?

[schirm]

Very interesting article. I've been having problems on my C7 A6 now where I've been having to add a quart of oil every 1000 miles or so. Does anyone have any more information about the bad PCV valve? Is there any way to test if this is for sure the reason why my car is burning so much oil, and how much does it usually cost to have replaced?

No information, but my car was burning a quart every 1,500. PCV valve fixed the issue for me. Its covered under warranty if you burn over 1 Qt every 1,600 or something like that.

[BucDan]

Well, there's this:

https://www.audizine.com/forum/showt...t=coolant+loss

and this...

https://www.audizine.com/forum/showt...t=coolant+loss

oh, and this...

https://www.audizine.com/forum/showt...t=coolant+loss

well, plus this one, of course...

https://www.audizine.com/forum/showt...t=coolant+loss

I could go on but wouldn't want to belabor the point.

I've also experienced the issue in both B8 S4's I've owned. Neither ever successfully diagnosed. I suspect (but don't know) the issue is that the pcv valve leaks under certain driving conditions that aren't replicated in a stabdard pressure test.

I'm losing coolant slowly right now, and the local shop mechanic did the pressure test, only 1 psi drop after 1 hour when the engine cooled. So could be the oil cooler and/or the pcv.... Hmm... Or even the supercharger intercooler. I'll have to read those links.

I probably have a bad pcv, blegh. I bet the shop I went to, purems in San Diego, probably aren't strangers to this, but it looks like a pricey job.

[Bartlett]

No information, but my car was burning a quart every 1,500. PCV valve fixed the issue for me. Its covered under warranty if you burn over 1 Qt every 1,600 or something like that.

It's 1qt for every 1,000 miles. So, I'm not quite sure how they covered that for you :P

[Stwaven]

You might also address the phantom, slow loss of coolant with no visible leaks that defies pressure testing and plagues some significant percentage of us


Sent from my iPhone using Audizine

Mine had this. Decided to do the water pump, t-stat and PCV as preventative maintenance when I did my carbon cleaning. No more loss of coolant over 10kmi later.

[BucDan]

Does the issue of the phantom loss ever come back after replacing the faulty pcv?

[Upstate Audi]

No information, but my car was burning a quart every 1,500. PCV valve fixed the issue for me. Its covered under warranty if you burn over 1 Qt every 1,600 or something like that.

Sadly my car is way out of warranty so I'd probably have to pay out of pocket.

[kudlajz]

You might also address the phantom, slow loss of coolant with no visible leaks that defies pressure testing and plagues some significant percentage of us


Sent from my iPhone using Audizine

I am experiencing this issue right now. I have a '15 S5 with 18k miles on it and coolant was constantly mysteriously disappearing into thin air (or so I thought). No leaks under the car, nothing. Turns out it needed replacing the pressure control valve (PCV). Good thing is that it's "only" around $200. Hopefully it will make the issue go away.

[S4'ed]

Don't forget about the separating lower crank pulley problem with the 3.0T...….

[mercedesinfarct]

my thermostat failed, at work so can't watch the video. Was that mentioned? Also the oil consumption issue. Audi told me that I didn't have a problem.