I was wondering if anyone has seen this type of metal degradation? It looks like some form of electrolysis. This is a vehicle we have serviced since new. All maintenance done on time. We did a timing belt and tune up last year. I don't remember seeing anything like this when the plugs were replaced. Today, my technician removed the valve covers to replace the gaskets, adjust valves and install a new VVT spool valve. One of the spark plug tubes is oblong, almost like it got hot and malleable.
I posted this on that other site, but I know a lot of the expertise is now here. Anyone seen this?
I have seen that on J35's in the past. Not often, but often enough that I caution customers about valve cover replacement when going in for the first valve adjustment. Every time I've seen this phenomenon, it's been the rear valve cover. Never the front. I always chalked it up to casting defects? But I hadn't considered electrolysis.
I’m just speculating on electrolysis.
I've seen it a lot on those type of valve covers. Aluminum, magnesium Most of them from prolonged oil service intervals is always the middle one where most of the heat from the cat is. Replace valve cover and that ignition coil and or spark plugs on the affected cylinder. The coil boot on that affected cylinder is most likely damaged
No misfires, I have service records of 6000 mile oil changes going back to when the car had 8000 miles. 0w20 oil. coil boot is fine.
Honda with maintenance minder system suggest to replace the engine oil at 15% life left, most customers let it go to negative values. Oil level low less lubrication more friction more heat.
As I said. We change her oil every 6000 miles. She goes by the sticker we put in her window. She has never seen 15% oil life on this vehicle.
I have the same things on the 2010 v6 Accord (rear) cover, we fixed the oil leak - replaced valve cover gaskets, and missed the first time bad cover itself.
Thanks for the input. These were not leaking. The VVT Spool valve was.
Had a 2010 honda van with some of that under where the tube seal went but no warping or holes. I was changing the cam and rocker since the cam went bad. I was replacing the gasket since I was taking it apart. Makes me wonder if the coil is damaging the valve cover with electromagnetic energy. Warn plugs would make the coil work harder and cause Higher KV.
That cam is ugly. I would have put a motor in that car. Where did all that pitted metal go?? As far as your hypothesis on the electro magnetic field, I think something like that is going on.
All the other cam lobes looked good and the engine ran well except at 2500 rpm there was a ticking noise in that valve cover. I changed the rocker to be safe, but the roller did not look bad.
A couple things come to mind on this engine. This is purely speculation though. I’ve seen coils on these melt from being held on by the pcm. This essentially overheats the coil. I’ve also seen spark plugs loosen on these over time and allow exhaust gases up into the spark plug well. Normally when that happens if it’s left long enough you end up with problems with the spark plug threads in the…
I’ll check the service history on Monday. I don’t think so. We did the plugs around 100 k and it has 109k Now. I didn’t see any sign of combustion gases leaking. I’m wonder now if there may be a Corona effect at the bottom of the coil body?? similar to what you see on the plug porcelain? Just a guess.
I’ve seen that happen many times on those magnesium valve covers, even with proper oil change history and even with properly fastened spark plugs. I can’t explain why, but yes the holes get egg shaped and partly turn into grey powder and get all buggered up, sometimes damaging coil rubber seals. I’ve seen them so bad you can stick a pocket screwdriver through the valve cover, so I think if you…
Thanks. I showed the owner pictures of the covers. I told her she may need them replaced if they start to leak. She needed the car today, so we put it together. No leaks. But I don’t like the looks of that back cover. The labor isn’t too bad. If it was one of the vehicles that required 4 or 5 hours, I may have convinced her to leave it and let me get a new cover.
we seen this kind of thing on 2 Nissans. 1 was much worse than the other. 120k on 1 , 140 on another. we found some used valve covers and they already had a very small evidence of the same situation. battery cables were in bad shape, three of the boots were in bad shape we clean all the engine grounds and hope for the best
We see it fairly often and not just on Hondas. Now that I think about it, all have been higher mileage cars. You have started another research project for me. As if I need another one. Here is a link that I have not read completely, but will at least begin to explain a few things. energy.gov/sites/prod/fil….pdf
The on-board computer system continuously monitors engine operating conditions such as engine temperature, ambient temperature, vehicle use, speed, and time. The system will count down the vehicle’s oil life based on these conditions to determine when an oil change is necessary. Based on the 6kmiles intervals you mentioned, it could be past due at times. What I would do from now and on monitor…
I have a theory, could be way off mark. Short trips or long trips? Short trips may not be letting valve cover get to full temperature properly. There may be hot spots and cold(relative) spots. After a short trip shut down the hot spots on the valve cover can get hotter while the cold spots are cooling causing a large temperature difference across the valve cover. On long trips the engine…
My $ is on dissimilar metals causing galvanic corrosion around the tubes.
We are a honda/acura shop in my experience the j35s seem to do that the most, in fact it happened to me on my 2008 accord. Went to repair oil leak on spool valve and found the valve cover was deteriorating at the number 2 cylinder tube seal. 250 dollars later, oem valve cover came with tube seals and gasket. The car has 180k and those plugs had been in around 60k. I think the grounds on this car…