Bent Valve, Not Covered by Warranty?

[CMan]

I'm looking for some advice, comments, etc.

My car is currently at Honda having the valves in the head replaced due to a bent valve in cylinder #3. The car is a 2006 with just over 58k miles on it. Per the dealership, the work is NOT covered under the 5 year / 60k power train warranty. When asked why it is not covered (since the engine is part of the power train), they told me that Honda will not cover bent valves because, as they put it, "valves are only bent due to an overrev".

Now I've read enough on these boards and others to know that valves do get bent by overrevs. And I know that 9 times out of 10 (if not more) the owner of the car will say the did not overrev their engine. But, I have NEVER overrev'd my engine - I'll swear on whatever makes you feel comfortable, but I have NEVER overrev'd my engine. And, I do know the difference between a mechanical overrev and hitting the rev limiter.

So, my question is this. Is there a way to bend a valve without overrev'ing the engine? Also, doesn't the computer record when an overrev occurs? Maybe not date/time, but that one occurred (the dealer is telling me it doesn't)? And lastly, if Honda cannot prove that an overrev occurred (other than to say that the only way a valve can be bent is by an overrev), shouldn't the repair work be done under warranty?

I've already sat down with the Service Manager and will be contacting American Honda today about it, but I'm curious what others think.

Charles

[dfws2k]

there can be mechanical defects that cause a bent valve, to say that only one thing causes a bent valve is a lie, IMO

[ryanmatic]

Don't AP2s record over-revs, anyway? They shouldn't see any record of an over-rev if they check, then.

[Goku]

sadly since the warranty says its not covered, its not covered. Doesn't matter how it happens, defect or abuse. Sure there are other ways to bend a valve with out over rev. How it happens in this car I don't know. Perhaps someone else drove your car? But with this its something your going to have to pay for. Good luck.

[desmo4]

The timing chain jumping teeth could bend valves too.


Jonathan

[repiv]

A mechanical over-rev is generally the way to bend valves but it's not the only way. You can mis-shift and catch it before it goes over redline BUT, I've always felt that the rate at which the revs climb can contribute to factors that will make the valve meet the piston. We now have evidence that point towards cracked or sunken retainers if the revs climb very rapidly due to a mis-shift. You don't necessarily have to over-rev to cause damage. This same principle can apply to bent valves.
Like Desmo said, the timing chain jumping a tooth can also cause problems and we all know that the timing chain tensioner on this engine can be an issue, however, on an '06, that might be hard to prove.
Another way to bend a valve is as a result of a very bad valve adjustment. If the clearance is set too small or there is no gap, then it's quite conceivable that a valve can strike a piston, again, if the revs climbed fast enough and high enough.
If you ever ran very low on oil and you revved it quickly to redline (either under power or by mis-shift), a valve can be sticky and not return as fast as it could.
I'm sure there are other ways. That's all that comes to mind now.

[s2kobsessed]

hydrolocking can bed valves... Water doesn't compress so easily :LOL:

[Glider Guider]

I'm looking for some advice, comments, etc.

So, my question is this. Is there a way to bend a valve without overrev'ing the engine?

Charles

My 2003 needed a partial valve job at a mileage a bit over 100,000, if my recollection is in gear 3 valves and seats were involved.

I don't think the engine was ever overreved. The only way I could think of to do that is to accidentally downshift from 6th to 1st instead of 6th to 3rd at freeway speed. I had done that a couple times, but am pretty sure I always caught it in time to avoid an overrev. Also, my engine's symptoms didn't start abruptly.

As the miles built up I began occasionally getting an intermittent Check Engine light that extinguished without intervention. I figured it was probably for evaporative emissions because it usually turned on in a particular traffic jam in Hayward on warm days, when I could smell everyone else's exhaust VERY well. The prevailing wind in this traffic jam is a tailwind. The check engine light went off after I'd driven enough miles or trips afterward.

As time passed the frequency of the check engine lights increased until it eventually stayed on solid. A check at the dealership showed a notable compression loss in one cylinder and slight declines in two others. The dealer's theory was possible buildup of soft carbon on valve seats. Dismantling the heads showed need for minor machining and parts replacement but nothing very radical. It might be due to just plain aging and mounting miles.

I'm currently on the high side of 130,000 miles with then engine running like new. When I've checked gas mileage carefully it still shows an average of about 26.0 on my mostly-freeway routes.