engine noise

[mickey]

hi gang.i've done loadsa research on this forum,to establish whether this question has been answered elsewhere,and although a couple get close,nothing definate,so here goes.........94 auto turbo diesel,low mileage,runs as smooth as silk,but:every now and again she sounds throaty.the turbo is whistling reassuringly,and the sound doesn't seem dependant on engine temperature.the oil is new,nothing leaking and not noticably smoking.when it is throaty,it can be heard at idle,and whilst moving,which would eliminate a binding brake putting additional load on the motor.it sounds a little like an exhaust blowing,and is accompanied by a vibration which can be felt under the footwell,sort of kicks in between 1000 and 1500 rpm,dissapears,then kicks in again at 2000......the noise is exhausty,but everythings tight down below.on lifting the bonnet,the motor might sound a little more tappetty,but like i said,the noise can dissapear,only to return just when you think its blown some crap off an injector or something.the airfilter housing is secure,so,i'm sort of scratching me head....just to add,when she is sounding sweet,the turbo sounds more whistly at low rpm,but may just be masked by the grumble at other times.no vibration or resonation in footwell or go peddle at other times though,just whilst throaty.can last 3 or 4 days,then fine,about 50/50 at the moment....any ideas?....by the way,again!tick over fine.

[djcazyp]

Had what sounded similar to what you describe in my TD 406 Taxi- which was the cam belt pre tensioner.

[TonyN]

Just a thought, check your air filter, Milner send some out last year that didn't fit properly, and moved around in the air box.

[mickey]

thanks guys..the cambelt was done a few months ago,i'm not saying it isnt the tensioner,i'll certainly get it checked....................the filter,yeah,saw some posts on the forum re filters..i did notice at one point that the sensor had come out,you know,the electrical thing that plugs in just behind the housing.that made it quieter when i popped it back in,making me think it was some sort of induction noise,especially as she growled at 2000 when i assime the turbo was kicking in.since then i've had my ear to that area,but it sounds like an overall increase in volume rather than specific to the air system....its a pig to describe guys,sorry for the confusion......best i can say,is the sound is similar to the exhaust resonation you get,when it first starts to blow.it feels like that too when it vibrates through the floor.i suppose the only reason i notice it,is because sometimes it sounds as smooth and sweet as silk....its not road surface,wind causing additional load,brake sticking.....i think is an engine noise,making the exhaust sound harsh.......i will change the filter today though,wouldn't be a bad thing.thanks guys.

[Guest]

Check the flange between the turbo and the exhaust - three studs and nuts. This mat be slightly warped and causing an intermittent blow at this area. Feel around (don't burn yourself) when the engine is sounding noisy.

Cheers

[crazybitch]

hi gang.i've done loadsa research on this forum,to establish whether this question has been answered elsewhere,and although a couple get close,nothing definate,so here goes.........94 auto turbo diesel,low mileage,runs as smooth as silk,but:every now and again she sounds throaty.the turbo is whistling reassuringly,and the sound doesn't seem dependant on engine temperature.the oil is new,nothing leaking and not noticably smoking.when it is throaty,it can be heard at idle,and whilst moving,which would eliminate a binding brake putting additional load on the motor.it sounds a little like an exhaust blowing,and is accompanied by a vibration which can be felt under the footwell,sort of kicks in between 1000 and 1500 rpm,dissapears,then kicks in again at 2000......the noise is exhausty,but everythings tight down below.on lifting the bonnet,the motor might sound a little more tappetty,but like i said,the noise can dissapear,only to return just when you think its blown some crap off an injector or something.the airfilter housing is secure,so,i'm sort of scratching me head....just to add,when she is sounding sweet,the turbo sounds more whistly at low rpm,but may just be masked by the grumble at other times.no vibration or resonation in footwell or go peddle at other times though,just whilst throaty.can last 3 or 4 days,then fine,about 50/50 at the moment....any ideas?....by the way,again!tick over fine.

Have similar with mine, but never found anything, suspected an injector getting clogged or not as good as it should be, but same as yours wont do it when you want it to and runs realy smooth other times

[mickey]

flange,nuts,studs and now crazybitch,am i in the the right forum? thanks again though,first to crazy,for making my problem seem somewhat less serious,and now to andy,who's tip i will now check for,if i can find the bits..my problem is,i sound more mechanically adept on screen than in reality,but in saying that,the guys on this forum gave me the confidence to change the radiator,something i couldn't imagine doing in a million years,and it worked out just fine.i only regret that i cannot put as much into this site as i've taken from it,but maybe that will change in time.

[Guest]

flange,nuts,studs and now crazybitch,am i in the the right forum? thanks again though,first to crazy,for making my problem seem somewhat less serious,and now to andy,who's tip i will now check for,if i can find the bits..my problem is,i sound more mechanically adept on screen than in reality,but in saying that,the guys on this forum gave me the confidence to change the radiator,something i couldn't imagine doing in a million years,and it worked out just fine.i only regret that i cannot put as much into this site as i've taken from it,but maybe that will change in time.

The Turbo on the 3 litre is down the side of the engine on the driver's side, bit of a bu**er to get to. Probably best to get at it from underneath. Should be the 3 studs and nuts only (If it is anything like the 2.4 exhaust connection and after all the turbo is the same so I am hoping it is right.

Just trace up the exhaust pipe to it's front end and the connection will be there.

Cheers

[mickey]

just to say,time ran away with me,didn't get a chance to check out your tip andy,haven't got a garage,peeing down with rain and dark.i'll do the filter change and look at the turbo to exhaust bit over the weekend as things are gonna be hectic till then,ok,ok,i know,5 minute job,but i want to look at everything carefully when i can set aside some time.......................... .............drove to the dentist earlier,opened door of car,gently revved it,and felt the resonation under the pan,but,also noticed there seemed to be a little more hesitation,i mean its probably always been like it when running throaty,but i was listning extra carefully because of crazy's mention of the injectors...anyway,out of the dentists,fire the motor up,oooh,sounds nice,drive it home,open door,rev it,listen,and yes,definatly more instant on the footpedal.so,now thinking maybe blocked injector,making it sound a little like a missfire.i run it with redex,but i guess it can still clog,i do tend to run in overdrive,which barely gets the motor over 2200.whats so annoying is the inconsistency.anyways,i'll keep you posted,ta for the help so far.

[mickey]

just a quick progress report,for those that may have similar probs,now,or in the future....checked the bits,ie exhaust to turbo flange,tensioner and filter,all ok.engine running fine,but still with resonation in the footwell....today,started it up,and immediatly felt it was going to be a good day..hadn't thought about it before,but she starts smoother on a good day.on a bad day,she would growl on start,then the rpm would drop back to normal tickover...drove off,no resonation,smooth as silk.when i say the vibration is in the footwell,its because when i felk it last,i took my heal off the floor,the sensation vanished,so it wasn't in the accelerator pedal.also,when the resonation is there,on revving the engine lightly at standstill,there is the vibration as the revs fall,it really does feel like an exhaust blow,but cannot find anything....now i've noticed the oil level has dropped again.i check it at least every other day,always right on the mark.two weeks ago it dropped 4 mm on the dipstick.i didn't top it up,just kept an eye on it.took it on a 100 mile round trip,checked the level next morning,it was back up to the mark,and stayed like it for a few days.when i check it,its from cold,first thing,i wondered if the cold snap we had,made the oil contract maybe.anyway,reasonably mild today,but the level is down again.....no blue smoke on start,tickover or acceleration,no leaks around the filter etc and oil pressure reads fine......so still baffled.i'll keep you updated.