New sound from my turbo diesel
 

I have owned this car for over 20 years, so I know what the diesel normally sounds like. But today, I noticed that it was noisier than normal and the sound was not the usual klakety klack of the diesel.

I probed around with stethoscope, but so far haven't found any specific source of the noise. It seems to come from everywhere!

This link is from engine bay

https://dl.dropboxusercontent.com/u/54783344/MVI_2019.AVI

and this one from side of car (less normal engine noise)

https://dl.dropboxusercontent.com/u/54783344/MVI_2020.AVI

Any ideas?

Plan is to adjust valves, because that job is due anyway, but not sure that is the problem.

though i haven't experienced it myself, i understand that different engine oils can affect the sound significantly.... did you change the oil? if not that, and not the valve adjustment, i guess i would check the injection timing next. those are my thoughts - good luck.

I'm on my phone so wasn't able to listen (if this is way off base), but did you check around the manifold gasket with the scope? If the power is the same, first place id start is exhaust system. Maybe you are developing a leak, or a piece of the gasket blew out, though that would be an obvious noise, a very small leak could sound odd

I did change the oil recently, but used same oil as before. That was a couple of weeks ago. Really only noticed noise today. I did fill up with diesel today at busy Esso station but hard to imagine anything wrong there.

Exhaust is a possibility that I should look at.

I checked rotating items with stethoscope. Alternator is quiet but funnily, bracket it mounts on was noisy. PS was quiet and A/C is not running. I did probe engine and got nothing unusual. Fan not touching anything. Air cleaner solid on its mounts.

Car still seemed to be running fine with no noticeable loss of power. Not even any significant smoke.

I noticed some air bubble in the plastic fuel pre-filter. There was always a small bubble, but there were now a couple and larger. Wonder if it could be air getting in with fuel that causes noise?

I would start first by disconnecting all the belt-driven accessories and seeing how it sounds then.

Are you talking about that hiss noise? If so it is for sure an exhaust or intake leak....start by removing the breather and inspecting everything....

It's the sort of chirping sound - higher pitched than the normal diesel sound. Almost like a bearing that needs some oil.

I will remove the air cleaner and check if I can see anything obvious.

Mine's doing exactly the same noise but it goes away when the engine warms up...

2x what rscurtis said.

Okay, I don't know what it is.

However, thinking it through a bit: If you heard it in the alternator bracket, through the stethascope, that suggests to me it is coming through the block or from something else close by that would resonate through the bracket.

So I wonder:

How old is the water pump? (Was it you who said on another thread you still have the factory one in place?)

How many miles since the timing chain was changed?

Do you recall, were the guide and tensioner replaced when the chain was done?

Just some thoughts until Roy or John get around to listening to it....

It was peculiar that the alternator was quiet and it's bracket noisy. I will have another look at that. Will also double check engine mounts. Need to buy a gasket before I do valves. Suppose I could put old one back, so may do them tomorrow if I can't find source of sound.

Will also try with listening tube instead of stethoscope.

I think it is still the original, but not 100% sure because of engine change out. see below. I know they had it off because of bolts leaked when I got car home. I did check pump housing with scope but no noise from there.

Engine was replaced with used engine about 95k km ago (in 2001). Head rebuilt, block resleeved new chain, new rings etc etc. Most external parts were moved over. Invoice is not in too much detail. Shop just did what ever was needed. All done by a good mechanic in Etobicoke (Euro Cars). I wish he was closer, I would like him to hear the engine. Unfortunately no-one around here that I know of who really knows these engines.

Sometimes you have to drive them until they get worse in order to find the source. I've had that with wheel bearings, for example. The noise just isn't pronounced enough to track it down at first.

The suggestion to drop the belt and try it is excellent - an often overlooked diagnostic process on pretty much any car. That eliminates a whole suite of potential racket.

I missed if it was a manual or auto trans. Either one has the potential of failing bearing/bushing on the input. Stuff spins even when the wheels aren't.

Good luck
Dan

Sounds to me like something on the utility side rather than an internal engine related problem. (Assuming the sound on the videos is a faithful reproduction)

tink tink tink...

immediately after a fuel stop...

I'm going with bad fuel/filter issue causing a weak injector to ping.

do you have new clear lines? any chance there is air in the lines?

put your stethoscope on each injector and see if you can isolate which one... send it to greazzer...

oh, and WOW your motor idles smooth!

x2 (or x5 rscurtis post :D)

Now listening to it, it sounds like an accessory bearing somewhere to me.

I had a long standing light noise like that on my 240, went on for months. Finally it got louder as dan stokes points out, I had to wait for it before I could really identify what was wrong.

Here is a thread with a few videos of my noise 2 months in, and the alternator it turned out to be. Was charging normally

http://www.peachparts.com/shopforum/diesel-discussion/342802-failing-alternator-bearing-noise-video.html

Id go around checking all the accessories