lannarebirth Posted February 22, 2011 Share Posted February 22, 2011 I drive a 7 year old Isuzu D-Maz p/u. When idling in Neutral it will intermittently make a chattering noise and the switch back to running silently. I went to isuzu dealer and he says that it is normal. My wife's brother who operates a car leasing company and services about 100 cars/trucks a month says the timing belt/chain is going out. Does anyone know if either of these diagnoses is the correct one, or if not what might be causing this noise. For my part I would have thought it had something to do with the clutch assembly but I'm not particularly mechanically inclined anymore. TIA for any replies. Link to comment Share on other sites More sharing options...
transam Posted February 22, 2011 Share Posted February 22, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. Link to comment Share on other sites More sharing options...
lannarebirth Posted February 22, 2011 Author Share Posted February 22, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. About 275k km's, timing blt changed once before. Been making this noise for about 40k km's, that's when I checked with Isuzu and they said normal, though it never made that nise before. I think I'm using 10-40 though it might be 10-30, changed about 3k km's ago. Thanks Link to comment Share on other sites More sharing options...
lannarebirth Posted February 22, 2011 Author Share Posted February 22, 2011 (edited) Oh, and the reason I thought it might have something to do with the clutch assembly is because if I depress the clutch and release it the chattering stops. Then it starts again in another 40 seconds or so. then it stops by itself after a minute or so than 40 seconds later it starts again. Depressing the clutch makes it stop chattering. Doesn't appear to be any vibration associated with it, just a chattering noise. Edited February 22, 2011 by lannarebirth Link to comment Share on other sites More sharing options...
transam Posted February 22, 2011 Share Posted February 22, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. About 275k km's, timing blt changed once before. Been making this noise for about 40k km's, that's when I checked with Isuzu and they said normal, though it never made that nise before. I think I'm using 10-40 though it might be 10-30, changed about 3k km's ago. Thanks I ask about oil cos if a thin/light grade you might be down on oil pressure at idle Sounds like it's well overdue for a belt change. Not sure about your ride but Toyota belt change is 100,000 km. If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise. The clutch, hmmm, interesting, sounds like one of those probs where an ear must be present . Link to comment Share on other sites More sharing options...
lannarebirth Posted February 22, 2011 Author Share Posted February 22, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. About 275k km's, timing blt changed once before. Been making this noise for about 40k km's, that's when I checked with Isuzu and they said normal, though it never made that nise before. I think I'm using 10-40 though it might be 10-30, changed about 3k km's ago. Thanks I ask about oil cos if a thin/light grade you might be down on oil pressure at idle Sounds like it's well overdue for a belt change. Not sure about your ride but Toyota belt change is 100,000 km. If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise. The clutch, hmmm, interesting, sounds like one of those probs where an ear must be present . I agree, it's overdue for a timing belt change and I'll get that done tomorrow. I'm just guessing that won't make this noise thing go away. Link to comment Share on other sites More sharing options...
transam Posted February 22, 2011 Share Posted February 22, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. About 275k km's, timing blt changed once before. Been making this noise for about 40k km's, that's when I checked with Isuzu and they said normal, though it never made that nise before. I think I'm using 10-40 though it might be 10-30, changed about 3k km's ago. Thanks I ask about oil cos if a thin/light grade you might be down on oil pressure at idle Sounds like it's well overdue for a belt change. Not sure about your ride but Toyota belt change is 100,000 km. If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise. The clutch, hmmm, interesting, sounds like one of those probs where an ear must be present . I agree, it's overdue for a timing belt change and I'll get that done tomorrow. I'm just guessing that won't make this noise thing go away. When you push the clutch pedal the force does pull on the crankshaft, there are thrust bearings on a main bearing web to keep everything from moving, you could have a bit of wear on these bearings which moves the crank a fraction and when the clutch is released everything floats again. Just guessing though, need to hear the noise. Link to comment Share on other sites More sharing options...
kartman Posted February 22, 2011 Share Posted February 22, 2011 Noisy clutch thrust bearing. Link to comment Share on other sites More sharing options...
transam Posted February 22, 2011 Share Posted February 22, 2011 (edited) Noisy clutch thrust bearing. Yep, could be. If really bad to make big noise then usually you will feel it through the clutch pedal in you foot, vibration. Edited February 22, 2011 by transam Link to comment Share on other sites More sharing options...
lannarebirth Posted February 24, 2011 Author Share Posted February 24, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? How long has it been doing it ? What grade oil are you using and when did you last change oil and filter ? Doubt it the clutch as in neutral it's locked up, unless the clutch fork is flapping about. About 275k km's, timing blt changed once before. Been making this noise for about 40k km's, that's when I checked with Isuzu and they said normal, though it never made that nise before. I think I'm using 10-40 though it might be 10-30, changed about 3k km's ago. Thanks I ask about oil cos if a thin/light grade you might be down on oil pressure at idle Sounds like it's well overdue for a belt change. Not sure about your ride but Toyota belt change is 100,000 km. If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise. The clutch, hmmm, interesting, sounds like one of those probs where an ear must be present . I agree, it's overdue for a timing belt change and I'll get that done tomorrow. I'm just guessing that won't make this noise thing go away. I guess I never did change the timing belt as it hasn't got one. I changed the various fan/pulley belts. It has a timing chain and there is no proscribed replacement schedule. Just says "lifetime". I had them change the throw on the clutch pedal., which helped alot. I mentioned the thrust bearing and they said "maybe" but not too bad yet. Thanks everyone. Link to comment Share on other sites More sharing options...
ignis Posted February 24, 2011 Share Posted February 24, 2011 (edited) How many KM's has it done. Has the timing belt been changed at the correct interval ? That is a new one ?? since when did a D-Max have a timing belt? If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise How do chains get stretched ? Known problem is the fuel pump on the 2.5 models, = engine intermittent clatter when idling in heavy traffic. If it is this problem = No or little acceleration when it clatters. Do not buy a new fuel pump the new ones have a engine cut out = far worse.. If it happens a lot, or the orange light comes on, stop for 10 mins, unscrew the top on the fuel pump, turn key 5 times, screw top back on, your OK to go again. Edited February 24, 2011 by ignis Link to comment Share on other sites More sharing options...
transam Posted February 24, 2011 Share Posted February 24, 2011 How many KM's has it done. Has the timing belt been changed at the correct interval ? That is a new one ?? since when did a D-Max have a timing belt? If a belt fails it can be catastrophic, if it is stretched it can put timing out a tad and cause noise How do chains get stretched ? Didn't no DMax had a chain, do now , learn something every day. Timing chains do stretch, thats why most modern rides with chains have tensioners, takes up the slack so no noise, some do not, especially American V8's. Most rides do have a replacement interval for chains. Way back when l fooled around with tuning mini's the timing chain was a problem with stretch and clattered because stretched, the Cooper S had a double row link to sort that out. There are different types of chain, link type and roller, and true roller type. True roller mainly for performance stuff. Link to comment Share on other sites More sharing options...
Lickey Posted February 24, 2011 Share Posted February 24, 2011 Gearbox chatter, just up the engine idle 50/100 rpms and it will go away,, Link to comment Share on other sites More sharing options...
lannarebirth Posted February 25, 2011 Author Share Posted February 25, 2011 Gearbox chatter, just up the engine idle 50/100 rpms and it will go away,, Ok, so I read this and think to myself, "yeah, I wish it was that easy, but I'm not that lucky". So my daughter calls to pick her up from school. I'm stopped at the traffic light idling in Nuetral at 725 RPM and the chattering starts. I figure "what the hell" and take the revs up by 100 RPM and the noise stops. Lickey, you're a genius. Thank you so very much, I'm going to get that adjusted tomorrow. Link to comment Share on other sites More sharing options...
Lickey Posted February 25, 2011 Share Posted February 25, 2011 Thanks Lannerbirth, its the the 1st time anyone has said this in 5 years on this forum, Just to get a bit more tecnhical, rev counters are useually driven by the alternator, when the diode and brush boxes get a little worn they are not completely accurate, so by increasing the revs at tickover, you might or not be going against the manufactures rec specs for your vehicle, At 7 years old a lot of things will be worn, Its possible that your truck could have a leaking/dribbling injector at idle, causing an inherrent vibe through to the gearbox, but if it drives ok, and no black smoke under acceleration, dont worry, Cheers, Lickey.. Link to comment Share on other sites More sharing options...
Lickey Posted February 25, 2011 Share Posted February 25, 2011 LB, forgot to add, when increasing the idle speed, you must allow a little more time after pushing the clutch pedal down before engaging a gear, perhaps count t o 5 then shift, this gives the input shaft time to stop and engage gear with no grating ect, thats from a standstill, moving , normal, change as you wish.. Lickey Link to comment Share on other sites More sharing options...
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