The Sea Foam treatment worked so well I decided I would try Liqui Moly Diesel purge treatment. I ordered four cans from TDI Parts on Friday night and they arrived here on Monday afternoon. (I get my oil and filters for the Jetta from TDI Parts too.)
If you read any of the VW or Mercedes diesel message forums you’ll find a many people that praise Diesel Purge. Some of them have been Mercedes diesel mechanics for a long time. I figured they all can’t be crazy so I would give this stuff a shot in the BJ42. The engine has 260k+ miles on it and I have no idea if the previous owners ever tried to clean the fuel injection system. It was running better after doing a treatment with Sea Foam so I wasn’t expecting too much of an improvement from the Diesel Purge. Boy was I wrong.
I followed the general guidelines for doing a purge at the TDI Club forum. Basically the idea is to swap in a temporary fuel tank to run the engine from and fill that tank with Diesel Purge. It’s pretty easy to do this on the old Toyota 3B engine in the BJ42. I ran 1 liter of Diesel Purge (two cans) through the engine sitting in the driveway. Then I reconnected the fuel tank lines and took it for a drive for 20 minutes to flush any Diesel Purge that might still be in the fuel system.
Some people have noted that Diesel Purge can get into your engine oil and break down oil’s lubricity resulting in increased piston ring wear. So I changed the oil just to be sure there wouldn’t be any problems. (I only got about 75 miles out of that oil since the previous change.)
I’m a Diesel Purge believer now. This stuff works wonders on an old engine. It starts up great even when very cold and with minimal smoking. The idle is much smoother now. The engine is quieter. It’s pretty amazing actually. It’s a whole different vehicle now. I think I’ll do it again this summer when the temperatures are higher and see if it makes a difference then too.