TDI intake cleaning

The design of the VW TDI (Turbo, Direct Injection) diesel engine has an EGR valve that, by design, sucks dirty sooty exhaust, and injects it back into the intake to help reduce NOX emissions.

The problem with this is oily fumes from the CCV (crank case ventilation) system can combine with carbon particles (soot) from the EGR system to form a black sticky tar in the intake system. This eventually starts restricting the amount of airflow into the engine, resulting in gradual power loss as the vehicle ages and the intake clogging becomes worse. Over time the car suffers from lack of power at higher engine speeds, and in the worse case, the car will detect excessive intake back pressure and go into 'limp home' mode, disabling the turbo. This has happened to me many times on the highway, and is very annoying. More or less, I figured it was time to clean the intake manifold.

BBW made an unscheduled appearance in the BeerMuda Triangle this weekend. He was in the area for a business trip so figured he might as well come over. It was great to have company in the garage and a working laptop. BBW would look up the how-to on the web, ordered parts for his new bike, fetched beer, and took pictures of the project.



A great resource for TDI VWs is Fred's TDI page. They have a great FAQ that anyone who has a TDI or is considering one should read. The procedure is descriobed in detail there, but some forum users have gone a bit further. This guy even took videos!

Anyhow, it wasn't that bad of a project, just tedious. I took the hood off the car to make it easier to work on.

After a few hours, the intake came out and it was DIRTY
One port was almost 50% clogged!

It took a couple hours of scraping, two cans of carb cleaner, a soak in a vat of solvent, but eventually it was cleaned out.

I was happy!



After breathing solvent fumes all day, scraping out sludgy soot, I was getting pretty tired. The reinstallation procedure is pretty tedious:

Eventually the project was DONE, and it was time for a test drive:

We found a intercooler hose clamp that I forgot to fasten, and it blew off. The car ran like crap without the turbo, very sooty and stinky. We fixed it and took it for another spin around the block. I couldn't tell if we got the massive increases in performance, maybe because the head is still partially clogged with sludge? (can't clean that while its in the car, and i was certainly not pulling it off myself)

Anyhow, the project was a success!