We have seen a lot of strange and scary things with regard to vintage iron. We have also seen a number of very pleasant surprises. We can’t recall a roller coaster ride of highs and lows quite like this recent Vanagon episode.
It all started with the conclusion of the major interior work. This meant that the van was ready for a test ride. I filled it with AV Gas and some Sea Foam as always on a new-to-me vehicle just to get a good starting point. In this case, the gas tank and fuel lines were new as well, so the injectors and the cylinders would get the good stuff. So here we go:
Sat 7am – Start and runs fine after a month of sitting while interior work was done. It is filled up with AV Gas. Take it for a run over a couple of highway exits. 35 miles. Runs great. Back to the garage.
Sat 2pm – Decide to finally install the new injectors from Marco. These are higher performance injectors and very well regarded for improved spray pattern, solving running issues and delivering superior fuel mileage. Installed them and then did a brief startup and idle. Starts fine and idles, no noticeable difference, but was not expecting any either.
Sun 7am – 24 hours after the first run, we decide to go for a more extended run. Starts fine but there is immediately a knock. A loud and clearly mechanical knock. It does idle even with the knock. I shut down and check things hoping that I have somehow done something stupid the day before. Nothing obvious. Oil levels are fine. Scratch head. Look some more. Brief start and listen again. Sounds bad. What could I have possibly done in changing injectors? Scratch head. Knowing these machines, I fear the worst. I pay a visit to The Samba, source of all VDub knowledge. There is a real mix of threads from plug wire mixup to catastrophic engine failure. I upload a brief video and post a new topic.
Sun 10am – 6 replies to the topic, and none of them suggest catastrophic failure. Most point to the hydraulic valve lifters getting stuck. Several say “mine does that sometimes”, and several say to just drive the thing for a while and it will go away! I am not convinced. To me it sounds worse than just a valve, and driving it more as a remedy is the opposite of all my instincts. The initial video does not do the sound and vibration full justice, it is deeper and more forceful than it appears.
Sun 12noon – I finally decide that if this is rod knock, or some other major failure, an engine swap is on the cards. With some major apprehension, I decide to drive it gently as was suggested. 5 minutes, same. 10 minutes, same. I start the return loop, and then suddenly sometime between 15 and 20 minutes, it is gone! I get out and open the engine compartment to check. There is the same engine, purring like a content kitten. It seems even smoother than I recall before all of the drama. I keep driving, wanting to see if it returned. I stopped to top up with regular gas. I stopped and got some marvel mystery oil. I drove an exit on the highway. I drove around town. Nothing but smooth quiet running. The second video here is only 20 minutes of running time later than the first, with no other intervention of any kind.
Clearly, the collective experience of The Samba was correct. As disturbed as I am about a vehicle sounding that bad and then that good, I have to now update the mental database with another entry. Of course I need to address the root cause, but this was a class in comparative valve train dynamics. Lesson one. In this particular case, the sound, vibration, and harshness of a stuck lifter on a Vanagon, is equal to something much more catastrophic on most other vehicles I have owned. Lesson two. An amazing coincidence of timing will seriously mislead your diagnostics. Lesson three. Being laid back and rolling with what seem like serious knockout punches is a critical VW Bus owner attribute. I should know this by now. Lesson four. The collective wisdom is collectively wise.