P026A code and intercooler buildup

[Tom in PT]

2013 Passat TDI SE, 28,00 miles
I have had a series of P026A codes and have been getting fouling of the IAT sensor at the top of the intercooler. So, I removed the hose from the bottom of the intercooler and a good a mount of greenish/blackish gunk had accumulated, which I cleaned up with shop towels.

Should I attempt to flush/clean the entire intercooler and can that be done without removing the intercooler from the engine?

 

[740GLE]

+5 years and 28K? Less than 6K a year? or new car to you?

Seeing the IC is water to air, it's gonna be a rather large messy task to remove the unit from the car, I'd say empty from the bottom and clean as best you can.

Time to do more driving!!!!

 

[Tom in PT]

^ I bought the car new March 2013. I am leaning towards draining the coolant and removing the intercooler for cleaning. There is not much you can do from the bottom in terms of cleaning the heat exchanger structure itself.

 

[740GLE]

Def a good project and a proper way to clean it, a coolant flush prob wouldn't hurt with heater cores clogging up as a common issue.

Good luck.

 

[flyboybob]

at 170k miles on the clock i've now cleaned my intercooler 6 times due to the turbo compressor seals leaking a significant amount of oil (approx half pint per 10k miles) into my intake.
***
the first time the map sensor got fouled with oil (at around 100k miles if i recall correctly) i removed the intercooler. brought it to a radiator shop (mac's) to have it cleaned (aqueous cleaning) and leak checked. after they were done i still wound up cleaning it myself (with mineral spirits) to get out what they left behind. all said n done i wouldn't ever bother removing it again for cleaning.
****
now on a regular basis i clean the charge air cooler in the car. i remove the lower hose and plug the bottom of the intercooler w a size 10 1/2 hard rubber stopper ($2.98 @ ace hardware). then i remove the map sensor from the top of the intercooler (without removing the 4 wire connector which i've found to be fragile). then, using a flexible funnel, i CAREFULLY fill the intercooler (AND ONLY THE INTERCOOLER!!!!) w mineral spirits (approx $14.00/ gallon @ the home despot) thru the map sensor hole. let it sit for a few minutes then drain (easy to mod the rubber stopper w a valve to make draining painless). blow dry w compressed air (w a rubber tipped air nozzle thru the map sensor hole). then reassemble bottom hose and sensor....job done.
******
i can complete the cleaning in the car in under an hour. that's compared to 4-5 hours it takes me to remove n reinstall the intercooler. LOTS less hassle and WAY less risk of damaging the intercooler (i've found those small diameter hose connections to be fragile and a PITA to remove/install hoses on).
*****
HOWEVER, CARE MUST BE TAKEN NOT TO GET THE SOLVENT IN THE INTAKE MANIFOLD!!!
overfilling w solvent (say by holding the funnel too high) to the point that it enters a cylinder thru an open intake valve will cause damage to your engine (think liquid hydraulic lock).
******
so....just sayin...
if you're careful there is another way.
*****
bob.

 

[Tom in PT]

Thanks Bob. I was hoping you would weigh in. I like your cleaning idea and will try it.

 

[flyboybob]

hi tom!


pm sent.


bob.

 

[Tom in PT]

Well, I used flyboybob's method with mineral spirits and it worked good. I did not have compressed air so used a powerful vacuum, hose at the bottom of intercooler with towel wrapped around it for a tight fit and sucked out the vapors and a little more solvent from the intercooler.

If you use this method, let the solvent drain for at least 10 minutes and wipe it all up before and after vacuum/compressed air.

And follow flyboybob's commandment to not overfill the intercooler with solvent. I used a clear transparent tube attached to funnel so I could see if the solvent was up to the level of the air sensor hole and stopped well before then -- I did 1 flush of about 1 Qt., Will repeat at next oil change in 6 months.

 

[flyboybob]

oil fouled MAP/IAT was prelude to turbo falilure

wanted to bump this thread and let folks reading it know that this issue (oil fouled intercooler/MAP-IAT sensor) preceded turbocharger failure in my car.
******
i stopped cleaning my intercooler. when the check engine light came on again for this code (P0111 IAT implausible signal) i checked and reinstalled the oil fouled MAP-IAT sensor and took my car to VW.
******
long story short VW replaced the sensor and then my turbocharger (took two visits) under terms of the "dieselgate fix" extended warranty.
******
i'll post details of the turbo failure/replacement separately but wanted folks reading this thread to know that this happened to me. i believe that these issues (oil buildup in intercooler, "dieselgate fix", turbocharger failure) are related.


bob.

 

[sntil1968]

Hey Bob

was there any hoops you had to jump through to get your turbo replaced?

I have a 2014 Passat with 52k and it’s starting to do this.

thanks Scott

 

[flyboybob]

Scott,

i’ll apologize in advance since this reply will likely be too long :/

the short answer is yes....there were some ”hoops...to jump through” before vw replaced the turbo in my car.

the first time this happened to me (at 80-100K miles on the odo IIRC) i read the code w VCDS but i didn’t know what or where the MAP/IAT sensor was. so i took the car to the dealer to see what they had to say. they explained that the sensor needed to be replaced AND the sensor connector needed to be rewired. their quote was $800 for that work and they said it would probably be more depending on what they found as a cause. the dealer service adviser argued that the car was beyond the warranty period and i would be on the hook for all of this repair. i said “no thanks” and paid them $150 for the “diagnosis”. i found a replacement sensor on the web for about $60. i found the connector terminals at digikey for 75 cents each, made a terminal removal tool and rewired the connector myself. i found the ”green gunk” built up in intercooler inlet duct and went thru the 4-5 hour remove/replace process to get the thing “cleaned” and leak checked. the car was out of service in my driveway while i smartened up enough to fix it but i figured i had dodged a bullet.

but then the problem returned in about 12K miles. that’s when i started cleaning the charge air cooler in the car at each oil change. i guessed that the little bit of oil that the car was ”using” between oil changes was leaking past the turbo compressor seals and fouling the intercooler and the MAP/IAT sensor. that belief was confirmed for me when i took pictures (using a borescope) of the compressor inlet which showed a small amount of oil there as well as some foreign object damage on the compressor blade leading edges. but at that time there was no evidence that the compressor blades were hitting the compressor housing.

fast forward about 5 oil changes/intercooler cleanings when it’s my turn to get the ”dieselgate fix“ (at around 150-160K miles IIRC). after the “fix” the car didn’t run nearly as well as before. it seemed more labored in all driving modes, used more fuel, ran hotter and scared me a couple of times when it couldn’t get out of it’s own way merging into traffic. and since the “fix” extended the warranty, i decided to stop cleaning the intercooler. within 15K miles the sensor was fouled again. the dealer replaced the sensor under warranty but refused to replace the turbo saying that there needed to be more evidence of a failure (turbo related code or obvious turbo failure) before they could replace it under warranty.

so i drove off toward home (20 mile trip from the nearest dealer) and twice on the way i heard the turbo “howl”. the noise was unmistakeable to me even tho the radio was on and it was the first time i’d heard it in this car. i heard that “howl” twice the next day and then drove directly back to the dealership. i told them what i had heard and that i was afraid to drive it thinking the turbocharger might fail and take the engine with it. i told them to keep it until they could figure out the problem. the next day I got a call from them. a technician had confirmed the noise on a test drive. upon inspecting the turbo they found evidence of a failure (contact between the compressor wheel and the housing). the service advisor said that they were replacing the turbocharger under warranty (even tho there was no stored turbo related code in the ecu).

so you see i got lucky. turbo replaced at about 165K miles under warranty without a check engine light. coulda turned out much worse than that if the thing had failed before the dieselgate fix. now at just over 200K on the clock the car runs great. the dieselgate fix is double edged imho. i believe it stressed the turbo to failure in my car....but also extended the warranty to fix it for me.

i wish i could tell you that you could just drive it to the dealer and that they’d fix your car without a hassle but that has not been my experience. ymmv.

bob.

 

[sntil1968]

Bob

thank you so much for this help. With only 52k on my car and starting to have to clean the sensor I am a little worried.

I’ll take it to them just to get the ball rolling at least.
Scott

 

[oilhammer]

The CKRA turbocharger already got a warranty extension of 10 years, 120k miles, before Dieselgate ever happened. Although coverage for one may only be for outright failure like they often do, and not any excessive oil buildup in the charge air tract. The wording they use is "Engine lacks performance, Shaft of turbine fan of turbocharger broken or seized". Which is exactly how I have found all the dead ones I came across. They even look exactly like the picture they show.

They have an updated part.

 

[flyboybob]

Scott,

a few comments:
—good idea to take your car to vw to fix the sensor when it sets a code.
—oilhammer is correct! looks like you’re covered under both warranties (dieselgate and turbo extended warranties). i was already beyond 120K before the turbo warranty extension iirc. the dieselgate warranty gave me the confidence to stop monkeying w the sensor and intercooler myself.
—i now worry less and drive more knowing that i have the dieselgate warranty in place. i believe this is good advice for you too. maintain it well but let vw fix it under warranty when it screws up.

my plan when I bought my ‘12 passat was to own it for 10 years then turn it over and buy something new. that 10 years will be up in september of 2021. even w all the issues i’ve had with my car i’m still enjoying it. in fact i’m having some difficulty finding something i like as much to replace it with.

sounds to me like you won’t have a problem getting to 10 years old on your car.

bob.

 

[sntil1968]

Update

i have had it to the dealer several times and they have replaced the map sensor three times and the intercooler has been changed out twice. They tell me the goop that it is collecting can only be from two things. short tripping can cause this i'm told and the turbo going bad can cause this as well.

The car gets driven 70 miles round trip to work and the closest town to me is over 8 miles so it never gets short tripped so that leaves the turbo failing as the culprit. The dealer agrees that the turbo is probably the issue but it is not throwing any turbo codes and also I am being told that the turbos for this car are on back order from over 6 months ago.

I guess for now I keep taking it back to them for new intercoolers. My problem is that I no longer trust this car to do long trips in. Who knows when the turbo is going to give up.

 

[oilhammer]

I have a nice 2003 Jetta TDI I am refurbishing that won't ever do any of that, if you are interested in something reliable for long trips.

 

[flyboybob]

hi Scott!

just read your update….sorry (but not surprised) that vw still hasn’t fixed this for you :/

i remember worrying about what i would do if my turbo failed out of warranty. that was before my “dieselgate fix” and after 120K on the odometer (so outside of any turbo warranty). that anxiety was no fun but i never felt like the car would let me down on a long trip. in fact i took several 1600 mile (out & return) trips during that period without issue—but i always made sure to note where the nearest dealer was located and kept my towing insurance paid up

i find it odd that they keep replacing the intercooler when all it really needs is a cleaning. and of course what you really need is a turbocharger to fix this permanently. but vw probably couldn‘t do that at the moment anyway since the part is back ordered everywhere i checked today (do a search for p/n 03L253010J).

i feel your pain but wouldn’t know how to advise you about it. my turbo didn’t last long after:
-the “dieselgate fix” tune was applied
AND
-i stopped cleaning my intercooler.

and after vw replaced my turbo, i stopped using their “fix” tune.

now with 210K on the clock, my car is running so well that i’m thinking of changing my original plan and keeping it for more than ten years (at least until i can find something i like driving as much as this car).

the only reassurance i can offer you is my own experience—my turbo gave me plenty of warning that it had failed. i heard it howl above the radio blaring. it howled like that half a dozen times in the approx 50 miles i drove it to get it back to the dealer (and never threw a code). so i no longer believe that these things ALWAYS fail suddenly or unexpectedly or catastrophically. ymmv.

bob.

 

[jafische]

... left behind. all said n done i wouldn't ever bother removing it again for cleaning.
****
now on a regular basis i clean the charge air cooler in the car. i remove the lower hose and plug the bottom of the intercooler w a size 10 1/2 hard rubber stopper ($2.98 @ ace hardware). then i remove the map sensor from the top of the intercooler (without removing the 4 wire connector which i've found to be fragile). then, using a flexible funnel, i CAREFULLY fill the intercooler (AND ONLY THE INTERCOOLER!!!!) w mineral spirits (approx $14.00/ gallon @ the home despot) thru the map sensor hole. let it sit for a few minutes then drain (easy to mod the rubber stopper w a valve to make draining painless). blow dry w compressed air (w a rubber tipped air nozzle thru the map sensor hole). then reassemble bottom hose and sensor....job done.
******
i can complete the cleaning in the car in under an hour. that's compared to 4-5 hours it takes me to remove n reinstall the intercooler. LOTS less hassle and WAY less risk of damaging the intercooler (i've found those small diameter hose connections to be fragile and a PITA to remove/install hoses on).
*****
...
*****
bob.

I just did exactly what you suggested at ~143,000 miles. And replaced the Boost Pressure Sensor 03G906051E for ~$20 on eBay (OEM-exact markings as my original sensor). I will add, you are right about a valve would be nice on that rubber stopper!

Prior to putting any mineral spirits in, I wiped out the bottom with some rags. Best I could estimate, there was about 1/2 cup of black oil in the bottom of the intercooler. I wiped out as much as I could from the bottom of the intercooler. I also wiped out the L-shaped hose that made that connection at the bottom. That hose was clean.
My intercooler took about 1/2 gallon of mineral spirits before reaching the boost sensor hole. When I released that cleaner, after about 10 minutes... it was black as oil. Wiped out the bottom with rags. Repeat process with second 1/2 gallon. Much cleaner. Decided to stop there and reassemble.

So far, after clearing the Fault Codes with VCDS, P026A has not come back.
Thank you for your write up!
Jeff

 

[flyboybob]

hi jeff!

sorry you’re having to deal w this issue too….but glad your car is back on the road.

the first time i cleaned my intercooler without removing it from the car the solvent went everywhere when i drained it. that’s when i knew i’d need to mod the stopper with a valve. here’s a picture of that mod:

36F0DE08-8170-4882-8E07-8B314E7D1C7D.jpeg

• flyboybob
• Nov 10, 2021

1/4” FNPT gate valve added to a #10 1/2 hard rubber stopper using a 3/8” hose adaptor.

the valve & pipe nipple were refugees from the scrap pile. i threaded a hose adaptor into the valve and pushed that thru a 3/8” hole i drilled in the rubber stopper. i can think of simpler ways to mod the stopper to make draining the solvent easier—i just used what i had lying around to make what you see in the picture. and altho i haven’t needed to use it since VW replaced my turbo, i‘ve decided to keep this tool as long as i have my passat….just in case.

bob.

 

[jafische]

hi jeff!

sorry you’re having to deal w this issue too….but glad your car is back on the road.

the first time i cleaned my intercooler without removing it from the car the solvent went everywhere when i drained it. that’s when i knew i’d need to mod the stopper with a valve. here’s a picture of that mod:

36F0DE08-8170-4882-8E07-8B314E7D1C7D.jpeg

• flyboybob
• Nov 10, 2021

1/4” FNPT gate valve added to a #10 1/2 hard rubber stopper using a 3/8” hose adaptor.

the valve & pipe nipple were refugees from the scrap pile. i threaded a hose adaptor into the valve and pushed that thru a 3/8” hole i drilled in the rubber stopper. i can think of simpler ways to mod the stopper to make draining the solvent easier—i just used what i had lying around to make what you see in the picture. and altho i haven’t needed to use it since VW replaced my turbo, i‘ve decided to keep this tool as long as i have my passat….just in case.

bob.

Great valve kit on the stopper. I bet I have those exact same spare parts in the garage! It did make a mess for sure. And I was jumping out of the way!
The second flush, I was able to crack the bottom of the stopper open from the top side of the car. It went much better.

Do you think the root cause is the turbo failing? I believe I am out of the warranty. I recall a 139,000mile limit on mine (but that may be for everything but the turbo.... I recall there was a special rider for the turbo)

 

[Tom in PT]

There is a special extended warranty for the turbo, above and beyond the dieselgate warranty. It might have been for 10 years or 100,000 miles, but I am foggy on the details of it.

I think some condensation in an intercooler is "normal". Accumulation of oil, not the condensation, might indicate failing seals on a turbo and an imminent failure. My condensation is a green goo, some oil but not a lot. I am not worried about it since I am at 47,000 miles on my car, and have some time left on the dieselgate warranty.

Two thumbs up on flyboybob's rubber stopper with drain valve!

 

[oilhammer]

The CKRA's extended turbo warranty was to 120k miles, not sure of the time limit (if there was one). This is of course of no real use anyway, as there have not been any new turbochargers for these available for about a year now.

The CKRA's latest wallet-crushing events seem to be both valve covers barfing oil all over the place, or the sudden and with no warning explosive loss of coolant from the plastic oil filter housing, that is also the pass-through for the oil cooler. And as an extra "feature", they can also spew coolant straight into the oil, so you milkshake the engine and blow it up without even knowing! YAY!!!

 

[oilhammer]

Hah... I literally just added another CKRA Passat to the "waiting for a new turbo indefinitely" list. Man these cars are turning out to be real piles of crap.

 

[TurboABA]

Maybe VW will just end up buying them back at some point..... sucks for all the owners.

 

[jafische]

whoa whoa... wait a second @oilhammer ... are you saying I am driving a ticking time bomb with 143k miles?

 

[jafische]

whoa whoa... wait a second @oilhammer ... are you saying I am driving a ticking time bomb with 143k miles?

And I should seriously think about getting rid of it before it becomes an anchor...?

 

[oilhammer]

I certainly wouldn't recommend anyone depend on one as their only means of transportation, that's for sure.

 

[jafische]

There is a special extended warranty for the turbo, above and beyond the dieselgate warranty. It might have been for 10 years or 100,000 miles, but I am foggy on the details of it.

I think some condensation in an intercooler is "normal". Accumulation of oil, not the condensation, might indicate failing seals on a turbo and an imminent failure. My condensation is a green goo, some oil but not a lot. I am not worried about it since I am at 47,000 miles on my car, and have some time left on the dieselgate warranty.

Two thumbs up on flyboybob's rubber stopper with drain valve!

So, when I was wiping the lower intercooler out initially with my fingers... it did seem like it was a dark green slime. I though that my old eyes were just playing tricks on me. But, glad you mentioned it. When I did flush it out, hard to tell now... was it dark dark green or was it black. My mind just assumed oil and maybe translated it to black in color. Hopefully.... mine was just dark green condensation slime. I have about 143,000 miles on it, and it has never been cleaner or replaced. So hopefully it is not impending failure. And this will give me time to find a new car (while not under duress).

 

[AverageAndy]

The CKRA's extended turbo warranty was to 120k miles, not sure of the time limit (if there was one).

The time limit is 10 years, starting from the vehicles original in-service date. Also, it is a "which ever comes first" sort of deal.

 

[oilhammer]

Well since there are not many CKRA's 10 years old yet, I'd say that is of no concern. Probably some are pretty close, though, not sure when the 2012s landed. A few 2012s could be 10 years in service by now.