Another SC intercooler leak after only 3,300 miles

[ModItNow]

So as the title says I just went through a leaking intercooler repair and only 3,300 miles ago! It was a mess as I needed a full carbon clean because I drove too long with the leak. Coolant was everywhere and even the injectors needed to be pulled to get cleaned. New o rings were installed and even the intake manifold pulled for a proper cleaning. I took advantage of the SC getting pulled and had a S4Matty blower installed with new intercoolers I bought from AudiUSAParts.com with part number that's ends in "R".

Had all this done at 46,600 miles and now I have 49,900. Cyl 3 plug looks bad and coolant reservoir is low (pics attached) Plugs were installed at about 37,500 miles. BKR8EIX gapped to .025"

On top of that cyl 1 plug had gas on it which I'm told is an injector failure!

I have a AWE coldfront without the pump which is a divorced set up. I'm thinking my issue is having a divorced system and too much pressure building up. Just seems like I should not have another cracked intercooler already. Not sure how the possible injector failure plays into it or if there is anything else going on. I had a friend take a log about a week ago and noticed cyl 3 and 5 had some correction. This could have been taken right before or after the issue started, not sure.

Is the solution as simple as having a vented cap? This is a huge PITA and it's my daily driver. Any possible suggestions would be appreciated!

Thanks!
Marco

20190425_115943.jpegScreenshot_20190425-144112_Gallery.jpeg

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[bhvrdr]

I dont want to add to your confusion on how to try and reduce the chances of serial IC failures but just to offer a datapoint...

I've had 3 different 3.0T cars. Two of them have been dual pulley with divorced hx setups. The Revo reservoir is pretty much identical to your AWE one. Ive run the car hard to redline just about daily doing 20mph to 100mph WOT runs on backroads I take daily. A fair amount of drag strip duty which involves heat soaking the car to all hell in the staging lanes then beating the piss out of it down the track.

Ive yet to have an IC failure or a cat failure.

Am I jinxing myself by typing this? Not sure. I definitely fear it will happen any day but thus far, nothing.

Why am I lucky and others not? Maybe it really is luck. Maybe there's something else besides just divorced vs not divorced setups and adding pressure reliefs. Not sure.

I can say that I have run any pulley ratio from 2.85 to 3.5 on these setups but 90% of my time has been on a 3.16 pulley ratio. That may help limiting the amount of boost through these cores. It may also help that I am religious about monitoring IATs. I keep IATs on my gauge screen at all times. It would only be a rare instance of testing a new cooling setup where I would see IAT above 70C. Almost never. Maybe it helps that I generally am successful in keeping IAT at 65C or well below even during all the torturing of the car. Not sure on that one either. I also live in south florida. So is it easier on the metal IC cores to always be going from warm weather to HOT iats vs people up north who could be going from 30 degree cold metal cores to 150 degree IATs. Not sure either. I know Loe used to go through IC cores like they were candy and he lives in FL too so not sure. Just helping to think out loud with you.

It may very well be dumb luck on which cores can take DP power and for how long.

Mike

[maty360414]

I dont want to add to your confusion on how to try and reduce the chances of serial IC failures but just to offer a datapoint...

I've had 3 different 3.0T cars. Two of them have been dual pulley with divorced hx setups. The Revo reservoir is pretty much identical to your AWE one. Ive run the car hard to redline just about daily doing 20mph to 100mph WOT runs on backroads I take daily. A fair amount of drag strip duty which involves heat soaking the car to all hell in the staging lanes then beating the piss out of it down the track.

Ive yet to have an IC failure or a cat failure.

Am I jinxing myself by typing this? Not sure. I definitely fear it will happen any day but thus far, nothing.

Why am I lucky and others not? Maybe it really is luck. Maybe there's something else besides just divorced vs not divorced setups and adding pressure reliefs. Not sure.

I can say that I have run any pulley ratio from 2.85 to 3.5 on these setups but 90% of my time has been on a 3.16 pulley ratio. That may help limiting the amount of boost through these cores. It may also help that I am religious about monitoring IATs. I keep IATs on my gauge screen at all times. It would only be a rare instance of testing a new cooling setup where I would see IAT above 70C. Almost never. Maybe it helps that I generally am successful in keeping IAT at 65C or well below even during all the torturing of the car. Not sure on that one either. I also live in south florida. So is it easier on the metal IC cores to always be going from warm weather to HOT iats vs people up north who could be going from 30 degree cold metal cores to 150 degree IATs. Not sure either. I know Loe used to go through IC cores like they were candy and he lives in FL too so not sure. Just helping to think out loud with you.

It may very well be dumb luck on which cores can take DP power and for how long.

Mike

We should meet up Mike, I'm living rn on South FL, Coral Gables and do some runs

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[bhvrdr]

We should meet up Mike, I'm living rn on South FL, Coral Gables and do some runs

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Awesome. Im moving this month nearby but going nuts with it so this summer definitely.... lets hit pbir on a Friday testntune

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[maty360414]

Awesome. Im moving this month nearby but going nuts with it so this summer definitely.... lets hit pbir on a Friday testntune

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What is PBir? Palm Beach? That's so far from where I am. Wanna do some Mexico runs

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[killer_s4]

Im close to coral gables as well. If yall meet up let me know.

[maty360414]

Im close to coral gables as well. If yall meet up let me know.

I can meet with you since your close

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[TruS4]

This is why i did the self bleeding intercoolers that dump back into my divorced reservoir

[fx_warrior]

Could of sworn I read in one of the facebook groups that the new IC's are a problem and to get the older ones, which ever parts numbers those may be.

[theweebabyseamus]

This is why i did the self bleeding intercoolers that dump back into my divorced reservoir

Self-bleeding heat exchanger you mean?

[ModItNow]

Thanks Mike. I don't know but my luck is no bueno lol

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[ModItNow]

Could of sworn I read in one of the facebook groups that the new IC's are a problem and to get the older ones, which ever parts numbers those may be.

Could be, my original ones lasted me 24k miles on DP. Only thing I changed was ported blower with those "R" revision intercoolers. I only have a 183mm crank pulley 3.17 ratio

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[brs2c]

Could of sworn I read in one of the facebook groups that the new IC's are a problem and to get the older ones, which ever parts numbers those may be.

I was told the opposite, and to get the R’s cause they are better made. Does anyone have a definite answer on what is the best revision?


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[Loe]

it's due to pressure build up in the system when the pump shuts off. If you install a bypass line, you'll see fluid jump up into the line. I've been running for almost 4 months without issue ever since I installed a bypass line on my reservoir (i recently had my S/C removed + cores for inspection). The fluid contained in it goes back into the reservoir as soon as the pump turns on.

[brs2c]

it's due to pressure build up in the system when the pump shuts off. If you install a bypass line, you'll see fluid jump up into the line. I've been running for almost 4 months without issue ever since I installed a bypass line on my reservoir (i recently had my S/C removed + cores for inspection). The fluid contained in it goes back into the reservoir as soon as the pump turns on.

My AMS system keeps the pump on for a little, after the engine is turned off. Do you think this helps any?


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[Callandor]

it's due to pressure build up in the system when the pump shuts off. If you install a bypass line, you'll see fluid jump up into the line. I've been running for almost 4 months without issue ever since I installed a bypass line on my reservoir (i recently had my S/C removed + cores for inspection). The fluid contained in it goes back into the reservoir as soon as the pump turns on.

Can you expand on this? A bypass from where to where? Any chance you could write a short DIY?

[ModItNow]

it's due to pressure build up in the system when the pump shuts off. If you install a bypass line, you'll see fluid jump up into the line. I've been running for almost 4 months without issue ever since I installed a bypass line on my reservoir (i recently had my S/C removed + cores for inspection). The fluid contained in it goes back into the reservoir as soon as the pump turns on.

Thank you Loe! This sounds like a promising fix, how do you hook up this bypass line?

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[cspcrx]

My AMS system keeps the pump on for a little, after the engine is turned off. Do you think this helps any?


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I have the same question also its not divorced so that may help as well?

[Jflow23]

I have the same question also its not divorced so that may help as well?

I think a divorced system may also provide this pressure release benefit...depending on what reservoir you run. My divorced reservoir is more like a surge tank and I don’t believe it’s completely air tight. It doesn’t have to be because the s/c coolant loop won’t get that hot on its own where the coolant has to be pressurized to avoid boiling.

I’ve been running this way for almost 30k now...

[cspcrx]

I’ve had my AMS system in place for also 40k miles with no issues but I don’t push my car as hard as others. Doesn’t seem like there is a common denominator with those who see them fail.

[Loe]

i'll take a picture some time this week and post what I did, but what a relief (pun intended)

[SteveYem]

What are the symptoms of leaking SC intercooler(s) other than some amount of coolant loss detected at the reservoir? For a couple years, approx. 25k miles, I have been dealing with rough/hunting idle, decreased gas mileage, decreased power output, poor throttle response, some mysterious coolant loss and some oil consumption. Some people say all signs point to PCV failure, others say it's due to excessive carbon buildup on the intake valves. I am taking the car to a shop next week to have the PCV and thermostat replaced, as well as to have the intake valves cleaned. I have asked them to inspect the SC intercoolers for leaks while they have the SC removed.

The few times I have scanned for fault codes I have found none. Do my symptoms sound indicative of SC intercooler leak? Would a leaking SC intercooler be evident via pressure test of the coolant system? Basically time is money and I only really want to take the car into the shop for a 2 day service one time, so if I can kill multiple birds with one stone on this visit it would be ideal.

EDIT - For reference my car is a 2015 S4 with 56000 miles, with original PCV, tstat and waterpump installed. I have not carbon cleaned the intake valves previously.

[scls4]

My AWE cold front divorced set up runs for like 5 mins after I shut the car off and it runs anytime I do anything (like open a door, etc) which is overkill but I'm approaching 50K miles (tuned for 40K) with no coolant issues / leaks.

[RWD2quattro]

Bummer Marco, what the heck are you running HCL .

[ModItNow]

i'll take a picture some time this week and post what I did, but what a relief (pun intended)

Haha looking forward to that. Don't want to fix my car until I have a fix for it!

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[ModItNow]

What are the symptoms of leaking SC intercooler(s) other than some amount of coolant loss detected at the reservoir? For a couple years, approx. 25k miles, I have been dealing with rough/hunting idle, decreased gas mileage, decreased power output, poor throttle response, some mysterious coolant loss and some oil consumption. Some people say all signs point to PCV failure, others say it's due to excessive carbon buildup on the intake valves. I am taking the car to a shop next week to have the PCV and thermostat replaced, as well as to have the intake valves cleaned. I have asked them to inspect the SC intercoolers for leaks while they have the SC removed.

The few times I have scanned for fault codes I have found none. Do my symptoms sound indicative of SC intercooler leak? Would a leaking SC intercooler be evident via pressure test of the coolant system? Basically time is money and I only really want to take the car into the shop for a 2 day service one time, so if I can kill multiple birds with one stone on this visit it would be ideal.

EDIT - For reference my car is a 2015 S4 with 56000 miles, with original PCV, tstat and waterpump installed. I have not carbon cleaned the intake valves previously.

Easiest way to find out is look at cyl 3 plug, always leaks onto it

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[ModItNow]

My AWE cold front divorced set up runs for like 5 mins after I shut the car off and it runs anytime I do anything (like open a door, etc) which is overkill but I'm approaching 50K miles (tuned for 40K) with no coolant issues / leaks.

I don't have the pump, maybe I should think of getting it?

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[ModItNow]

Bummer Marco, what the heck are you running HCL .

Dude, the only thing I changed was ported blower. Been running the same set up for a long time. 183mm crank, NGK Iridium plugs, AWE coldfront without the pump

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[SteveYem]

Easiest way to find out is look at cyl 3 plug, always leaks onto it

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Would I be looking for a pool of coolant, or some residue? If the latter, what does the residue look like?

[ModItNow]

Would I be looking for a pool of coolant, or some residue? If the latter, what does the residue look like?

Residue on the actual spark plug

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[cspcrx]

My AWE cold front divorced set up runs for like 5 mins after I shut the car off and it runs anytime I do anything (like open a door, etc) which is overkill but I'm approaching 50K miles (tuned for 40K) with no coolant issues / leaks.

my AMS does this as well. Not five minutes but a minute or two for sure.

[bhvrdr]

my AMS does this as well. Not five minutes but a minute or two for sure.

The ams unit acts like you cut the pwm signal i believe. Youll see a softcode for coolant pump. This is same as how my pump behaves with the pwm cut. No issues for me either.

[ModItNow]

Sounds like I might need a pump, in what location do you install this? Or should I try the pump mod first?

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[RWD2quattro]

Pump mod is the least expensive (cut a wire) but you will always have a soft code but you can install a switch for on/off, up to you. If you install a switch, you can leave pump running for a few minutes after shutdown to help with cool down. Call EPL and see if they can ramp up coolant pump speed on start up or keep on for a few minutes during shutdown. My AMS pump starts up anytime I touch the car and shuts down after 3 minutes, I think the byproduct of that cycle helps prevent IC failures. By the way, I'm still on my original IC's going on 94K miles.

[m1k3d3]

it's due to pressure build up in the system when the pump shuts off. If you install a bypass line, you'll see fluid jump up into the line. I've been running for almost 4 months without issue ever since I installed a bypass line on my reservoir (i recently had my S/C removed + cores for inspection). The fluid contained in it goes back into the reservoir as soon as the pump turns on.

Isn't the factory cap designed to release that pressure at a certain point?

[ModItNow]

Pump mod is the least expensive (cut a wire) but you will always have a soft code but you can install a switch for on/off, up to you. If you install a switch, you can leave pump running for a few minutes after shutdown to help with cool down. Call EPL and see if they can ramp up coolant pump speed on start up or keep on for a few minutes during shutdown. My AMS pump starts up anytime I touch the car and shuts down after 3 minutes, I think the byproduct of that cycle helps prevent IC failures. By the way, I'm still on my original IC's going on 94K miles.

Damn 94k! Yeah makes sense, I bet having the coolant circulating through for a few minutes after helps with cooling everything down. Maybe I'll look into the pump that AWE uses since I have that system.

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[ModItNow]

Isn't the factory cap designed to release that pressure at a certain point?

No sure but we have a divorced system (SC separated from the engine coolant loop) so we would be looking at something custom. What Loe did (bypass line connected to the reservoir) sounds promising

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[ModItNow]

Here's what my plug looked like 20190425_115943.jpeg

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[theweebabyseamus]

Isn't the factory cap designed to release that pressure at a certain point?

The main cooling system, sure. But not the divorced s/c cooling loop.

[The_Bamboozler]

That plug certainly looks a bit off. Were you able to take off a plug that was far away from #3 to compare?

The orange bits on the ground electrode would make me think the coolant has contaminated the combustion chamber.