Carbon Build Up

[traygarb]

The dealer has told me I need a carburator cleanout stating the valves are badly coated. My car had only 40K miles. They are saying the carburator cleanout is part of my standard recommended maintenance at 40K. I have put 91 or 93 octane since buying and I have definitely run the RPMs up to blow out the carbon. I cannot find anywhere in the forums where carb cleanout is standard maintenance at 40K and most people report getting to about 75K before having to do it. Yes, I have symptoms but isn't 40K early for this.
2021 GTI SE.

 

[Diggs24]

 

[El_bigote_AJ]

We talking Webber? Holley ? or quadrajet ?

Yes 40k is pretty early and and a good sign that your PCV system is failing or failed, esp if you’re getting driving symptoms

 

[JC_451]

They are definitely lying about it being recommended at 40k.

Is the car down on fuel economy or power?

 

[jay745]

The interval isn't an exact science. It's all related to your driving habits, short trips will cause early build up, driving like you stole it all the time will keep the carbon away. Done enough carbon cleanings to say it's not uncommon for build up to be bad at 40k.

 

[traygarb]

They are definitely lying about it being recommended at 40k.

Is the car down on fuel economy or power?

Idling like crap, engine light on, starts blinking, then EPC light comes on and car sounds like a 1970 beetle and looses power. Shutting it off is only way I can stop the sequence.

 

[scrllock]

Have seen other DI cars need it by 40k. If you have warranty (i assume you do, with a 40k '21 going to the dealer), then the other potential causes (bad injector, coilpack, failed piston ring, etc.) would be covered. But it's definitely a common cause for misfires. A boroscope on the valves would confirm it and shouldn't add much time. Worst case you confirm it's carbon, best case they're wrong and it's something else they should be on the hook for.

 

[traygarb]

The interval isn't an exact science. It's all related to your driving habits, short trips will cause early build up, driving like you stole it all the time will keep the carbon away. Done enough carbon cleanings to say it's not uncommon for build up to be bad at 40k.

I do "drive it like I stole it". That's the fun of having it I drive 75% highway, 75 + mph. I use the correct gas. This car had been problematic since I got it. Dealership is trying to soak me for a grand+. I think it should be under warranty because something is wrong with cylinder 3. Dealer doesn't agree, telling me carb cleanout is recommended as service at 40,000. So, there are two things happening here.

 

[traygarb]

Have seen other DI cars need it by 40k. If you have warranty (i assume you do, with a 40k '21 going to the dealer), then the other potential causes (bad injector, coilpack, failed piston ring, etc.) would be covered. But it's definitely a common cause for misfires. A boroscope on the valves would confirm it and shouldn't add much time. Worst case you confirm it's carbon, best case they're wrong and it's something else they should be on the hook for.

Injector replaced in October, 6 mos later plug is so fouled, nearly not firing at all. Coil packs still good. No leaks around rings.

 

[traygarb]

They are definitely lying about it being recommended at 40k.

Is the car down on fuel economy or power?

Power

 

[scrllock]

Injector replaced in October, 6 mos later plug is so fouled, nearly not firing at all. Coil packs still good. No leaks around rings.

Assuming it's a stock car, the fouled plug sounds like either a ton of idling and/or a bad PCV. But the actual mechanical issue at the moment is likely going to be solved with a walnut blast.

I do "drive it like I stole it". That's the fun of having it I drive 75% highway, 75 + mph.

Lots of highway driving doesn't help if it's at low rpm/load. You could probably cake a valve in 30k if you did nothing but drive at 85mph in a 7-speed.

 

[swcrow]

We talking Webber? Holley ? or quadrajet ?

Yes 40k is pretty early and and a good sign that your PCV system is failing or failed, esp if you’re getting driving symptoms

Definitely Edelbrock

 

[tigeo]

I do "drive it like I stole it". That's the fun of having it I drive 75% highway, 75 + mph. I use the correct gas. This car had been problematic since I got it. Dealership is trying to soak me for a grand+. I think it should be under warranty because something is wrong with cylinder 3. Dealer doesn't agree, telling me carb cleanout is recommended as service at 40,000. So, there are two things happening here.

The gas has nothing to do with this issue as the fuel never touches the valve. It's the oil vapor through the PCV. It's just a maintenance item.

Holly 4 barrel.

 

[imthanick_a]

There's been plenty of jokes made here, but I'm saying this genuinely. If you aren't aware that your car doesn't have a carburetor, please trust someone else to take care of your maintenance.

 

[dtfd]

I think the question here is:

Is the buildup the cause of long highway trips under light load (essentially idling while moving) or is the buildup the cause of a PCV issue. One is a driving habit that VW probably wouldn't cover, the other is buildup caused by a faulty part which means VW should replace the PCV and clean what the old one left behind.

Murray's Carbs