How to diagnose bad PCV on 4.0T?

**ABlazeski** · 02-28-2022 08:01 AM

Was just wondering how you can tell if the PCV on your car is bad or not I saw some things online that if your oil cap has suction that means your PCV is bad. I believe my car does but it doesn't show any other signs of a bad PCV wanted to see if this is normal or something I should be worried about.

**MattyMarkey** · 02-28-2022 08:30 AM

Some suction is normal when removing the oil cap while running. The difference being the amount of effort needed to remove the cap - it will be harder if the PCV is failing/ has failed. You will also have excess oil burn and need to add oil more frequently between changes. Many times there will be a higher-pitched "whistle" while the car is running.

IF you want it covered by the extended warranty through Audi, you will most likely need a CEL or Fault Code. Having a relationship or just a cool dealership may help, if you don't have a CEL, but have other symptoms.

**THCarpenter** · 02-28-2022 11:18 AM

easy answer:

does your Audi have PCV.....if so....yes its bad and needs to be replaced

**rabbitdog** · 03-01-2022 02:54 PM

Tried the CEL light to get a fix at my dealership for warranty and they said the CEL have to go with the whistling sound to match the TSB symptoms for them to repair it.

**Evandoe** · 03-09-2022 07:43 PM

Sorry to revive this thread but ive been wondering what the pcv is on the 4.0t. Is it the oil separator attached to the IC or is it the crank case vent valve at the bottom of the V covering the oil screen?

**phats7** · 03-10-2022 05:52 PM

When mine failed it made a loud whistling noise. Also I read about the gas cap trick and tried that. I had to use a good amount of power to get the cap off.

**Optimus247** · 03-14-2022 04:05 AM

Originally Posted by phats7

When mine failed it made a loud whistling noise. Also I read about the gas cap trick and tried that. I had to use a good amount of power to get the cap off.

I think that was the Oil Fill cap ... NOT gas cap ... for evaluation ...