Tic/Tapping Noise When Ideling?

[one2another240]

I've been reading through some related topics where this noise is described at higher RPM's but mine is only when ideling at 750. At cold start there is no sound when ideling until it settels in at 750. It's a tic or taping, with perhaps a faint rubbing or vibrating like sound. At first I thought it was comming from the fan or belt drives and have thus far ruled them out. The noise seems to be comming from under the valve cover. Any ideas?

[niznos]

I had this problem a while back in my SOHC, and I think I adjusted the timing and it went away. It may be a ping at idle disguising itself as a tic. Hope it helps you.

[santa109]

mmmh, that sounds alot like what my own 92 LE does. you can only hear it at idle when the car is warm, when you rev it, there's no weird sound. I too thought it might be coming from the belt accessories area (water pump, etc) but upon closer look, it seemed like it was coming from the front of the engine, under the valve cover. Took it to the dealer today and was told it's the timing chain rubbing against stuff inside. Haven't got an estimate yet...but that's an expensive job..

[MyCarIsWack]

someone told me that my valves needed to be adjustedactually a few ppl, but eh i dont think its that

[one2another240]

Thanks for the info thus far guys, yes, mine sounds to be comming from the front also. I'm going to adjust the timing and inspect the chain. Santa109, let us know how things go along with yours. I'm going to start checking these later today. Hopefully an adjustment will do the trick.Along with valves, I've also read in some other topics to look for loose or bad rocker arms, lifters, or for a loose rod bolt (at crank). Will check back here for more later, thanks again all.

[USCS14DUDE]

I have the same problem in my 95 240 and i was also told it was the valves. These motors are built with such tolerances that after awhile the valves just tap. It seems far worse on mine in the winter when its cold. Annoying buti live with it for now.

[navysnail]

you guys need to check the timing chain, it is a very common problem with 240's and will ruin the engine after a while.

[240dreams]

i thought tapping was natural. Dont injectors or spark plugs make a tapping noise? The timing chain is more that a tap its a freakin nasty rattle. i had it and it killed my KA and opened the doors to my SR.

[navysnail]

yes the timing chain is a very bad rattle, its loud. clicking is normal as the injectors click. if its not the injectors though...

[one2another240]

Finally got around to looking into this further, checked the valves and everything measures out fine. The noise does seem to be comming from the timing chain (likely slack?). It's not very loud, can't really hear it even when in the car with the windows down, maybe faintly when you listen hard. Even with the hood open it's not like a loud ratteling or rubbing, but more of a slight rub. As far as adjusting the idel, I'd have to set it at around 900 to 950 before the noise disipates, but if it's the timing chain wouldn't this just be disguising the problem? I'm not quite sure if this is even something to be concerned about yet? However I am going to take it to a recommended shop to get some opinions. If anyone else has additional input here be sure to let us know.

[santa109]

ok, got the nissan dealer estimate...ready? 1600$CAN (over 1000$US) for parts and labor (9 hours). I know it's a big job, but damn, this is kinda ridiculous..I'm probably gonna have it done somewhere else tho and get it doubled checked by a trusted mechanic.

one2another, mine does the exact same thing, if I up the idle ever so slightly, the sound disappears. And I too can only hear it with the hood popped up, or maybe with the hood down at night with no other cars around and really trying to hear it.

and mine isn't a loud rattle either. My older 89 has the infamous 2-3 secnods "start up" chain rattle and the sound on my 92 LE is nowhere similar to that one.

Since the sound goes away when the engines turning a little more, could it be that oil pressure builds up and that the tensionneers on the chain are activated by oil pressure (or so I've heard?). Then maybe only the tensionneers need to be replaced?

[BadMojo]

Since the sound goes away when the engines turning a little more, could it be that oil pressure builds up and that the tensionneers on the chain are activated by oil pressure (or so I've heard?). Then maybe only the tensionneers need to be replaced?

That's a reasonable assumption. The tensioners are operated by oil pressure, and as you rev up the engine, oil pressure increases. If you have a weak tensioner and your chain is in decent shape, you could get away with just a ~$60 tensioner.

I guess the key is to try to isolate where the noise is coming from. If its coming from the upper chain guide area and not from lower in your engine, then you should have a pretty easy time removing the two upper guides and replacing a tensioner.

I'm having the same problem with my '93 240SX. I'm going to start off by checking my oil pressure this weekend and if that is within spec, I'm going to see if I can find out where the chain is hitting. If it's the lower chain, well...that's gonna suck.

[santa109]

From what I can tell after about 2 weeks of really trying to pinpoint the origin, mine seems to come from the upper part of the engine, crossing fingers that it is only the upper chain rubbing.

[cvex]

I notice that before my oil change it was just regular conventional oil, the motor is smooth and quiet as a lexus. After I put in semi-synthethic oil, man it sounded like a diesel engine, ticking and tapping. Crap, I need to change it back .

[one2another240]

All very interesting... Santa109, hope you are going for a second and third opinion if it's gonna be that much. Hope it's just a bad tensioneer for both our sakes.

A mechanic who listened to it today said just drive the car, it's got a lot of miles left as is (whatever all that means). I'm more interested in hearing what the shop I'm taking it to tomorrow has to say, they're very reputable, trustworthy and fair pricewise.

Interesting this last comment, the wife took the car for an oil change about 3 weeks ago. My wife, bless her heart, is one of the biggest suckers for coupons and bargains. Used her auto pass card for a $9.99 oil change service at Firestone. They put in Kendall GT1 synthetic oil. Anyway, I started noticing this noise shortly after this oil change. And also, when I checked the oil after the service it was well above the H line. My wife only puts 2 things physically in the car herself, gas and her rear end, and I sure hadn't added any oil or oil treatment since the change. Seems I didn't complain enough when I called Firestone that day. Guess I'll have to change it to conventional also right after I shred my wife's auto pass card.

[Luke]

Back when I had my KA, I removed the two guides from my upper timing chain, the noise was gone. Cost: free.

[one2another240]

Another verdict in today, this shop told me pretty much the same as the other, not to worry about it unless it gets a lot louder. These guys also often work on higher end cars, Mercedes, BMW's, Jaguars and the rest, so a 240 at 140K miles probably doesn't seem much to be concerned about in their world. Anyways, come thursday the cars are getting a weeks vacation while my wife and I are in Cancun surveying the beaches for errr aah, sand crabs. :icesangel

[scorsone]

I have the same sounds with my 91. My plan is to let it go and save for an sr.

[Bloodstone]

Take your valve cover off and look at the bracket that's above the middle of your timing chain. Most likely your shain is bouncing up into it. If that's the case, replace your chain. And buy a book. If you can't do it yourself, then take it to a shop. NEVER take it to the dealer. I think they're trained to feed you a line of bs from the moment you walk through the door. The upper chain should cost no more then $90, and the lower should be no more then $80. Most liekly you only need to do the top. About 3 hours time, and some messy hands.

[Arrow]

IMO, I believe that you should change your oil back to the organic blend... I have had a similar problem with my car and the cause was low oil pressure. Put 10W-30 in it and the problem went away (it had 5W-30 in it before). I could be wrong but I believe that the synthetic oil is thinner and that if you put it in a car that has been running organic it can cause leaks and thus your oil pressure can/will drop... Just my opinion... Hope it helps.

[SHIFTrl240]

yeah i have this problem too. but it seems like it comes from the injector area. it is very loud...

[MaxType 240]

Open your valve cover and remove the guide. It's been known to crack. If a part traps into your rotating assembly, you're engine is toast. See the cracks on mine:



It's a 30min process at most. It did help reduce the tapping but I'm gonna replace the tensioner too.

[Bigrolla]

i had my guide removed also made a great difference

[projeckDspdStar]

i have the same problem. I never realized until i turned off my music one late night. i hope its just the tensioner or the guide.

[sil80drifter]

is the startup rattle really infamous? i've had that after a while after replacing my timing chain/tensioner etc on my SOHC. maybe te tensioner got clogged again?

sil80

[Bigrolla]

remove the guide its easy and cant hurt to try

[sil80drifter]

i have an SOHC. no upper guides there. so it's gotta be my chain.

doing the timing chain kit replacement this weekend. PIA but gotta be done.

sil80