Hello. My car currently has 203,000 miles on the odometer and a rough idle that gets rougher by the month. I’m positive that the rough idle is caused by valves that are out of adjustment: the last time I had the valves adjusted was when the car had ~120,000 miles on it. My question is whether having the valves adjusted now can cause any valve damage, such as the valves burning up, and whether any special procedures need to be observed during the adjustment due to my neglect to have it done earlier?
Thank you.
If this problem is caused by valve lash that is too tight then it’s too late to do anything about it.
Before assuming that you have a serious problem here, a little diagnosis should be done.
Easiest, quickest thing to do is have a vacuum gauge connected. This only takes seconds and will reveal in a few more seconds if there is a valve problem or not.
If a valve problem appears to be evident, then it can be verified by running a compression test, which is also easy to do.
A rough idle can also be caused by an ignition miss, vacuum leak, etc. Hope that helps and don’t panic just yet.
Typically if a valve adjustment is neglected its the exhaust valve lash adjustment getting to tight do to valve and seat wear. This causes the valve not to seat completely on the seat, which burns the valves.
Your car is very old and very high mileage (eg well worn).
I would simply have the vehicle diagnosed by a mechanic. Don’t mention the valves unless specifically asked. Telling a mechanic this will only lead to paying for a valve adjustment they may or may not have anything to do with the issue at hand.
Between 120,000 and where you are now, there isn’t a lot of wear on the valve face. I don’t believe the problem was caused by neglect. So, if you are adjusting valves, be sure to go closer to the widest gap setting and stay away from the narrowest one. You could still have a bad valve or two but only a compression check will help you find out.
I bet it still has a carburetor too…Your rough idle MIGHT be valve related, but don’t bet on it…I have a feeling the valve adjustment is the LEAST of your problems…
I’m sure it’s fuel-injected. My 1990 Accord had PGM-FI.
I’ll second the diagnostic route . . . get a good mechanic to go over things . . . OK’s suggestions are a good starting point . . . see if you have more simple and direct causes to the rough idle than jumping to the valve adjustment conclusion. 203,000 miles isn’t that much and this isn’t an old car . . . by any means. Much depends on how you drive it and maintain it. My Accord is an '89 and has just over 490,000 miles on it. And it runs great. I check the valves every 30,000 or so and can tell you that the adjustment has been minimal. Vacuum lines getting old and brittle would be my first guess. BTW, this is fuel injected, '89 was the last year for Accords with carbs, some had them, some didn’t. Rocketman
Thanks for all the good advice! I’ll schedule a visit to my local mechanic and let you know the verdict. Thanks.
In New England 203k/15 years old is quite old. Typically the body is well rusted and bumper starts to sag beyond the rust forming around the wheel wells.
Anything past 8yrs/150k is extremely variable with vehicles. More expensive items start to fail that some deem maintenance other repairs. Some people have few issues but the likelyhood goes way up. At that point it turns to a combination of luck, driving style/type and maintenance habits all three being equal as far as longevity.