Is there a way to know without actually checking them?

 

If you have clatter or a tapping noise, that could be a sign of out-of-adjustment valves.

But I don't know how you could determine valve clearance without popping the valve cover and inserting a feeler gauge.

 

It should be checked and the adjustment completed if needed every 30,000 miles. The injectors are so noisy you likely won't hear the valves.

Even if you're not going to do it, at least check with feeler gauges to make sure they're not going to choke out the engine, they tend to tighten over time.

***Many recommend the bent tip feller gauges, I personally found it MUCH easier to use a single, loose straight blade that's been removed from the sheath with the others.

 

It's a pain to do and although I'm not at 30,000 miles yet I have no plans to touch it until I get somewhere north of 60,000 miles.

 

My mechanic, otherwise known as the car whisperer, says mine will need it around 100k miles. I'm at 75k. I trust him since he's told me multiple times I don't need work I asked him about.

 

If they're too loose, you'll hear louder tapping than usual. If they're too tight, the tapping will be less. Unfortunately, unless they are extremely out of adjustment, listening to them won't tell you much. I'm waiting till Honda says it's time, and then I'll adjust them.

 

I've seen a few people quote estimates on when to get the valves adjusted and around the 100K miles mark is most commonly mentioned. You can do them sooner if you want but you probably shouldn't do them later.