Hi Everyone,

My 2008 4cyl LX-P Accord suddenly lost all power and went into limp mode when I was climing a hill several hours away from home. Got it towed to a garage where they said it needed a new plug, coil, and VTC solenoid. After charging me $500 for that stuff they said it had a burnt exhaust valve on the #3 cyl, and it would be another $2300. I finally got it trailered to my home and I confirmed that it has 0 compression on the #3 cyl, and normal compression on all other cyl. I have worked on motorcycles for years and replaced timing belts etc. so I am going to tackel this job on my own. I have been following the service manual and I am replacing the VTC solenoid, coil, timing chain, head gasket, and valve seals. I took the rocker arm assembly out yesterday and noticed that the tappets on the rockers have some noticible wear (you can feel the wear with your finger tips), so I guess I will be replacing them as well. Is there anything else I should be replacing?

Does anyone have any advice or notes about this that might suggest that it might not be an exhaust valve, or that I should check something else while I am in there? I bought a borescope but I can't get it to angle around so I can see the valves properly. I put some paper over the exhaust pipe and noted that it seemed to suck the paper in as it fluttered back and fourth.

Much appreciated!

 

Fixed the issue. Turned out to be a burnt exhaust valve on #3 cylinder. All exhaust valve seats were bad on both the valves them selves and the heads. All exhaust valves needed to be replaced and seats on the heads were re-ground. Problem was caused by burning oil (about a quart every 1000) over 150,000 miles. Burnt oil residue collected on the exhaust valves eventually preventing a good seal and causing valve overheating issues.

Everything replaced that I can remember - tappits, exhaust valves, timing chain, and a few other small bits.
Work done that I can remember - New exhaust valves, reseated all valves, ground head, valve clearences, cleaned carbon from heads exhaust and intakes.

Now the engine runs like new.

 

Looks like the rings were leaking. Did you fix that issue?

1qt of oil every 1000 is considered normal and generally not a cause for concern. Did you leak test the other valves before the repair? How did you know they weren't sealing? I assume all of the valves in that cylinder weren't sealing,yes? Ive never seen burning oil cause a seating issue,Im more inclined to think there was another problem.

Good job,either way.

 

Thanks for you feedback!

I compression tested all of the cylinders before I took everything apart and the compression was good on all other cylinders, but when I removed the exhaust valves I noticed there was pitting and buildup and my best guess is that it is caused by burning oil. I know that 1 quart every 1000 miles is within the Honda allowable tolerances for the latest generation of engines but excess burnt oil will naturally leave deposits. It is my understanding that Honda is using a lower friction piston ring to improve gas mileage at the expense of burning oil.

Hopefully I fixed the problem but if not I'll dig deeper. For now everything seems to be in good working order, good compression and plug inspections look good.

 

I would recommend regular engine flushes for the next few oil changes. Oil rings carbon up allowing oil consumption.