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Car Forum / Honda Cars / December 2005What is this ticking noise?
I have a '92 Honda Civic EX with 156k miles. It runs fine and doesn't give me any problems. The oil was changed about 500 miles back. I hear this very fast ticking noise on about the first five blocks in the morning. Then it stops. It's coming from the motor and some one else probably wouldn't notice unless I pointed it out. When I start the car, it idles at about 1500 RPMs. About three or so minutes later, it is at around 1100 or 1000 around five minutes. Now if I take off, I don't hear this noise. I imagine the noise is the engine turning at higher RPMs because the oil has not heated up yet and it takes more effort to turn the cam. Once the motor heats up, everything is well lubricated, hot and so it runs very smooth. But what could this noise be? Also, do I actually need to wait until the car idles down to 1100 RPMs each morning? I've read that about 30 seconds of warm up time is just fine. My car is just below 1500 RPMs at 30 seconds. To me, that doesn't show it has warmed up at all. What's the general concensus on this? Thanks, Brett > I have a '92 Honda Civic EX with 156k miles. It runs fine and doesn't > give me any problems. The oil was changed about 500 miles back. > > I hear this very fast ticking noise on about the first five blocks in > the morning. Then it stops. It's coming from the motor and some one > else probably wouldn't notice unless I pointed it out. Sounds like the valve lash (distance between rocker arms and valve stems) is set a bit on the high end of the spec. This is very common. It's better to be on the high end of the spec than the low end--too small a clearance can cause valve damage, IIRC. Googling will yield some discussion of this. You hear it first thing because the valve parts are not warmed up and so are relatively contracted. As they warm, they expand, and that clearance reduces. Check your manual's maintenance schedule for how often the valve lash is supposed to be checked (and so possibly adjusted). Though I ignored my 91 Civic's for 150k miles (out of ignorance), then checked it. All was fine. But don't do as I did. It is risky. Valve damage is expensive. I got lucky. > When I start the car, it idles at about 1500 RPMs. About three or so > minutes later, it is at around 1100 or 1000 around five minutes. Now > if I take off, I don't hear this noise. I think that's because, when accelerating quickly while the engine is still pretty cold, the higher RPM makes the ticking harder to detect. The rate of valve opening and closing will depend on RPM, after all. > I imagine the noise is the > engine turning at higher RPMs because the oil has not heated up yet and [quoted text clipped - 5 lines] > each morning? I've read that about 30 seconds of warm up time is just > fine. I've read the same. Only in the rare times the temperature has been below 10 degrees F have I ran out and warmed up my 91 Civic for five-to-ten minutes. I don't know if that's necessary, even in really cold weather. My Civic is doing fine after 14 years and 172k miles, over half of which were driven in the Northern U.S., with its abysmally cold winters. So how long do you usually let your car warm-up during the various seasons? I guess the conclusion is that it is much better to allow the engine to idle down. This way, you elimate all valve lash and probably a few other things you weren't aware of. Do you agree? Thanks, Brett > So how long do you usually let your car warm-up during the various > seasons? I live out west in a much milder climate now. Lows in winter during the day are, at the very worst, around 25 F. And that's rare. Also, I have a garage. So these days I never purposely let my Civic sit and warm up upon leaving my house. When I go into the mountains to ski, and the car is exposed to the elements and extreme cold (teens or worse, degrees F), sometimes I'll give it a minute or so, tops. I don't know if that's really necessary. (If there's a sheet of ice built up on my car, that's different, but that's of course a special situation and not really your main concern, I think.) > I guess the conclusion is that it is much better to allow the engine to > idle down. No, I don't think that's necessary at all. The engine control system senses several parameters (air temp, coolant temp, etc.) and deals with the car being cool. The engine is tough enough to take it, IMO. I don't think one will squeeze more life out of one's car by letting it sit a few minutes, idling in the driveway, before leaving. Engine oils are better than they were a few decades ago, as well. (Certainly synthetic is a vast improvement! I don't use synthetic, but I would if my car were new or just had its oil lube system thoroughly cleaned. Not that anyone bothers with the latter.) At most, by warming up the car first, I figure one's muffler might last longer. They rust prematurely when one goes on only short trips, as you probably know, not allowing sufficient heating to evaporate away accumulated condensation in the exhaust system. > This way, you elimate all valve lash One is more likely to eliminate all tapping, perhaps. But again, I don't think a little tapping is going to affect the valves' life by much at all. I base this on reading about it on the web. People generally say get it in spec, and better to tap a little than not at all. Off the top of my head, I don't know whether eliminating /all/ the valve stem-rocker arm clearance at normal engine operating temperatures is desirable or by design. > and probably a few > other things you weren't aware of. Do you agree? No. The engine control system (and thermostat) senses yada yada (see above) and adjusts fuel flow, coolant flow, and RPM etc. so as to achieve ideal conditions in a reasonable amount of time. Also, I think the engine valve design is plenty tough enough to deal with a bit of tapping, as long as the lash is still in spec. (Else the spec for the lash would be more exacting.) Keep checking back. Many of the regulars are busy during the day and do not get to the group until later. > I have a '92 Honda Civic EX with 156k miles. snip > When I start the car, it idles at about 1500 RPMs. About three or so > minutes later, it is at around 1100 or 1000 around five minutes. snip > Also, do I actually need to wait until the car idles down to 1100 RPMs > each morning? At normal op temps, it does idle lower, like 750 RPM, doesn't it? The normal operating idle RPM will vary by car model and year, but I would think your 92 Civic EX normal operating idle RPM was closer to my 91 Civic's (about 750 RPM, for a 1.5 L engine). It drops below 1000 when I put it in gear. Yes, probably 750 perhaps a little lower. Thanks, Brett > it takes more effort to turn the cam. Once the motor heats up, > everything is well lubricated, hot and so it runs very smooth. But > what could this noise be? valves ever been adjusted? thats a start. another possibility is "piston slap" which is not harmful, just an annoyance. I haven't had the valves adjusted but it sounds as though I can go until the car is sold (200k?) without any problems. They'll want an arm and leg to check any of this so I'll keep avoiding it. Thanks, Brett > I haven't had the valves adjusted but it sounds as though I can go > until the car is sold (200k?) without any problems. They'll want an > arm and leg to check any of this so I'll keep avoiding it. its really not too difficult, if you have a set of 1/2" sockets (or at least one to turn the crank pulley) and a few metric wrenches to get the valve cover off and do the job. oh- and a feeler gauge and spark plug wrench:) i think a flathead screwdriver is also used on the valve adjust bolt. |
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