Did I cause the valve damage?

Did I cause the damage to the engine valves by adding a fuel injector cleaner, run a tank of gas, then adding an octane booster?

Engine now needs valve job.

Not if you were using the normal parts store stuff. Doesn’t Honda require periodic valve lash adjustment?

No, that would not do anything. By ‘valve job’ do you mean removing the head and refinishing the valves and valve seats (a very unusual thing to do these days), or just adjusting the valves? What are the symptoms?

I doubt the valves were damaged by fuel injector or octane booster, but we need more info.

How many miles are on this car? How old is the car? Do the valves need adjusted or repaired?

This makes me wonder, why are you putting octane booster in the tank? This product is a ripoff. Just buy the kind of gas required for the car. Using fuel injector cleaner isn’t such a waste of money in my opinion, but opinions will vary on this.

She’s a 2005 w/83K mi. I’m the third owner. CEL came on after weekend of driving in pouring rain. Honda Maintenance Mgr checked and said car had “missed” and recommended some octane booster as perhaps some water had gotten into gas tank. So, since products were on sale, I bought two for one and used cleaner, ran a tank of gas, then booster. Have not told husband about cleaner and booster, was afraid it was my fault.

Two tanks later car began running rough and lost 4 mpg. Honda Mgr diagnosed Loss of pressure on 3rd cyl. Took to reputable local mechanic. He says valves are “stretched?” and thinks will have to replace all 24.

I’m not fussing over having to have valves done, just wondering what would cause this. I drive the car energetically, but no where near the ability of the vehicle. Does “high performance” mean “high maintenance”?

Well, this is still confusing…you might post this on an S2000 forum, there are plenty of folks that drive the tires off these, I’d just be surprised if ‘valve stretch’ was the result…but who knows?

You’re the 3rd owner. It’s hard to figure anything out under those circumstances, unless you know the other 2 owners. My guess is that at least one of them abused the car.

I’ve put the last 20K on it. Owned it for 1 1/2 yrs.

Just don’t understand what forces would stretch the valves.

Do you have the owners manual for the car?
If it does, can you go into it and see what it says in the maintenance section.

Look for anything about valve adjustment.

If your car needs to have periodic valve adjustments, this can be the cause of the issue. If it doesn’t, then you will need to have a compression test and a leakdown test in order to determine which cylinder is the issue, and what the problem might be.

Chances are, nothing you did caused the issue, and I would be very suspect that all the valves need to be replaced after only 83k miles on this engine.

One last thing - Valves don’t stretch.
The valve face can wear away, and the valve seat can wear away. When this happens, the valve clearance tightens up, and the valves will need to be adjusted back into spec by replacing the valve shims/buckets.

This is a normal issue with most car engines, but manufacturers get around this bit of maintenance by installing hydraulic valve adjusters in the engine. If your car has hydraulic valve adjusters, then there’s not much that can be done.

A third opinion is your best recourse.


I think this has mechanical adjusters, picture I saw looked just like those on the Honda 550/4 I had a “few” years ago!

Is the reputable local mechanic a Honda specialist? Your motor uses a rather complicated variable valve system. Something in the system that moves and times the valves may be out of timing or broke. This could cause a loss of compression in one or more cylinders. I feel you need someone who really knows and understands this particular motor to confirm the diagnosis.

Until you know what it going on I’d avoid or minimize running the motor to reduce the risk of doing more damage.

Actually, yes, I am using a Honda trained mechanic. He works a “paying” job 4 days a week and works on Hondas 3 days. He’s taking it to a machine shop to check on the seating of the valves. All four cylinders have loss of compression. Is this a timing chain issue?

I’m still asking–what could cause this?

So you’re sure the valves are adjusted to spec? For all 4 cylinders to be low, that’s unusual. A timing chain issue shouldn’t cause this kind of thing.

There is an answer, but it will involve taking apart the top of the motor to get to the bottom of this. Honda is several “generations” ahead of other manufacturers in the development of variable valve systems. They pioneered the concept on racing motors then in motorcycles and finally in production cars. There are complicated and that’s why I suggest a Honda specific mechanic.

I believe the valves in that motor do require manual adjustment, but not that frequently. So, the starting point it to check if the values are ajusted and fall in or out of the specified tolerances? Then are they opening and closing to the correct degree? Then are these movements properly timed?

I think something has broken, or worn, or become loose or disconnected in the valve train. What that something is will take visual inspection.

If the valves can be adjusted, ADJUST THEM!! Then run a REAL compression test with a pressure gauge…The gas additives did NOTHING, good or bad…

It looks like you could not have caused the problem.

Thank you! I just wanted someone to tell me I didn’t hurt my “baby.” All I can tell you guys is I am using a very reputable Honda trained mechanic who has let the engine cool before testing pressure on the next cyl. He is taking it to the machine shop this weekend to check the seating on the valves. He says there is pressure loss on all four and other than a small tick, idling, you wouldn’t know there is a problem, but there is also a loss of mpg.

We have decided “to do it right”, use Honda parts and have it fixed correctly, as I really do enjoy this car. I’ll report back when job is complete and let you all know what the final verdict was. Thanks for all your input and support.

“Just don’t understand what forces would stretch the valves.”

The valves are held against the cylinder head by springs. The only force that could stretch them would be the force of the spring. It could also be that the spring has collapsed a little. It seems unlikely to me, too. I don’t think the mechanic could tell that the valve stems were stretched unless he removed them and measured them.