At long last I finally dove back into my A4. Armed with my premonition from a dream and a deep desire to hear the engine purr, I set out to find the source of the awful noise and dead misfire.
With the noise coming out of the right bank, I started by taking off the valve cover on that side. Per my dream, I checked the clearance between the intake cam and the lifters, but it was to no avail as everything was within tolerance. I did notice (through luck) that the engine had stopped PERFECTLY on Top Dead Center for cylinder 1. My exhaust cam on bank one, which is driven by the timing belt, was dead on the money. Perfect. My intake cam, however, looked a little off.
So, as the timing procedure outlines, I checked the number of chain links between the intake and exhaust cams (see photo above) and realized I was at 14 links rather than 16. Boom! That solved the misfire concern. But what about the noise???
I thought to myself that regardless of what the noise may be, I had found something that had to be corrected. The course forward would be to re-time the cams on bank two, check compression, and reevaluate. And that’s exactly what I set out to do.
I removed the bearing caps for the intake cam and compressed the cam chain tensioner hoping to have enough wiggle room to make the needed adjustment. I didn’t. Then I loosened the exhaust cam, but still no dice. Ultimately the timing belt, cam gear, and timing cover (behind the cam gear) came off to make the correction.
With the cams out I decided to check the lifters again for good measure. What I found was an intake lifter on cylinder two that did NOT want to move. This was the area with the noise!! With a little persuasion the lifter came free and I found debris (almost like a dried up engine sludge) between the lifter and the bore in which it travels. It wasn’t much debris, but it was enough to prevent the lifter from freely traveling. Boom! Here was my noise!!!!!! I cleaned all the contact surfaces, lubricated them with new oil, and confirmed there were no more restrictions.
At midnight I was finally ready to hit the key, and to my delight the engine was quiet as a mouse once the lifters pumped up. Needless to say I’m very happy to have the A4 road ready. And, with the all-wheel drive drivetrain, I can weather through the snow to EXAIR for your application needs all winter long.
Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE
Also, about the name – I acquired a VW Jetta much in the same way I came to own this A4. When I towed the Jetta home my son saw the crunch in one of the fenders and named the car “Crunchy”. This one, being very clean and sporty, has been named “Freshie”. Because he’s fresh.