Rattling noise

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

Post Reply
Mark Wilson
Bongonaut
Posts: 29
Joined: Fri Jul 13, 2018 9:58 am

Rattling noise

Post by Mark Wilson » Sun Aug 30, 2020 8:36 pm

My 2.5 diesel has recently developed a clattering or rattly noise from the engine, possibly further forward, rather as though something is loose. Haven't found anything obvious yet, but the odd thing is that the noise disappears once it is warmed up. Bit of an impossible question, but can any of you think of anything which could stop once the engine is warmed up?

Mark
User avatar
Northern Bongolow
Supreme Being
Posts: 7713
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: Rattling noise

Post by Northern Bongolow » Sun Aug 30, 2020 10:20 pm

Front crank pulley ?.
User avatar
Tessie
Bongolier
Posts: 128
Joined: Fri Jan 15, 2010 12:51 pm
Location: Yorkshire

Re: Rattling noise

Post by Tessie » Sun Aug 30, 2020 10:58 pm

Northern Bongolow wrote: Sun Aug 30, 2020 10:20 pm Front crank pulley ?.
I agree that would be the first thing to check, could be the bonded rubber between the double pulleys that has worn.
Never run out of road, traction and ideas at the same time.
Mark Wilson
Bongonaut
Posts: 29
Joined: Fri Jul 13, 2018 9:58 am

Re: Rattling noise

Post by Mark Wilson » Mon Aug 31, 2020 8:23 am

I'll take a look this morning. Would replacing the pulley be a major job, and is it safe to drive for a hundred miles or so? Going away for a couple of nights this week, won't be popular if I have to cancel...
User avatar
JulesMartin
Bongolier
Posts: 216
Joined: Fri Oct 04, 2019 11:15 am
Location: Rainham, Essex

Re: Rattling noise

Post by JulesMartin » Mon Aug 31, 2020 10:03 am

I think it's about 35/36 mm bolt holding the pulley on so you'll need that size socket. I'm sure the more expert will give you the exact size. then the pulley is held on with a woodruff key so levering will eventually get it off. but worse case you may need a puller. the pulley drives your alternator, A/C and power steering pump so if it does go en route you'll lose all of that immediately, you may also lose the belts along with possible damage of the pulley itself flying free. unless you can get the job done before you go away I'd advise not going to far with it. Other thing to check could be the turbo heat shield coming lose. A bolt snapped on mine and that rattled away like a good un! I can't recall if it did stop when it got hot. definitely explore and determine what it is before a long journey.
Martin
1996 2.5 TDi Silver pop top unconverted
rita
Supreme Being
Posts: 3284
Joined: Tue Sep 15, 2009 7:11 pm

Re: Rattling noise

Post by rita » Mon Aug 31, 2020 10:54 am

Just wondering, why if it is the crankshaft pully the noise goes away when the engine is warmed up ??
phil 1
Bongonaut
Posts: 81
Joined: Thu Dec 15, 2005 6:56 pm
Location: north devon

Re: Rattling noise

Post by phil 1 » Mon Aug 31, 2020 1:58 pm

Try spraying a little water on the drive belts before you start attacking the bottom pulley. Mine makes a rattle/squeaking noise when cold sometimes a quick adjustment of the belts and all is good :)
Image
Mark Wilson
Bongonaut
Posts: 29
Joined: Fri Jul 13, 2018 9:58 am

Re: Rattling noise

Post by Mark Wilson » Mon Aug 31, 2020 9:47 pm

Thanks all. Couldn't really identify any problem with the pulley, but I'll have it checked out. When I investigated this morning, though, I realised that although the noise went away, it wasn't really warmed up, just settled into a smoother rhythm after a minute or so. Which leads me to suspect a loose piece of tin such as the turbo shield as mentioned above. Be a few days before I can get another look (unless I have to in the middle of a field in the Yorkshire Dales...)
User avatar
JulesMartin
Bongolier
Posts: 216
Joined: Fri Oct 04, 2019 11:15 am
Location: Rainham, Essex

Re: Rattling noise

Post by JulesMartin » Tue Sep 01, 2020 12:02 pm

Well as long as it gets you there. there are few other places better to break down I'm sure and if it ain't broke don't try and fix it always rings true for me. Have a nice few days away.
Martin
1996 2.5 TDi Silver pop top unconverted
Mark Wilson
Bongonaut
Posts: 29
Joined: Fri Jul 13, 2018 9:58 am

Re: Rattling noise

Post by Mark Wilson » Thu Sep 03, 2020 8:31 pm

Well, we did have a good couple of days and no break down. The noise has, however, got worse and I've now been under the van and into both engine covers without finding any loose tin. The crankshaft pully theory is definitely winning at the moment, but I don't fancy this as a DIY, so fingers crossed it makes it the thirty miles to Bongo Spares for MIchael to have a look. Although, like Rita, I don't understand why the noise changes once it has warmed up/settled down. Many thanks for all the help.
User avatar
Northern Bongolow
Supreme Being
Posts: 7713
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: Rattling noise

Post by Northern Bongolow » Thu Sep 03, 2020 11:49 pm

Maybe the rubber bonding is splitt apart, rattles when cool, the as it spins the 2 rubber coated surfaces get hot and tacky and improve the drive.
Maybe.
Look for a how to fix etc link by author (me) it shows how they can fail.
Mark Wilson
Bongonaut
Posts: 29
Joined: Fri Jul 13, 2018 9:58 am

Re: Rattling noise

Post by Mark Wilson » Tue Sep 15, 2020 12:40 pm

Now sorted. Embarrassingly it was just a slipping belt or belts, but instantly diagnosed and fixed (no charge) by Michael at Bongo Spares.

On the plus side it gave me an excuse for one of the best morning's cycling I've had for a long time. Fabulous countryside and great roads between Rishworth and Rochdale, providing you like hills! And I came home with a very reasonably priced set of Mazda tailgate curtains to match the blinds.
Post Reply

Return to “Techie Stuff”