405 TD 'clonk'

Hi Folks,

I recently aquired a '94 405 TD estate, and barring a few minor problems it seems to be o.k. - it's remarkably rattle and smoke free for a 140k mile car (I suspect much of the mileage was done on the motorway)

One of the minor problems is a 'clonk' noise when lifting off the accelerator. I assume that this is a dodgy engine mount or similar, allowing the engine to move slightly, but anyone with ideas about common culprits, or sensible ways to diagnose exactly what it might be will win my eternal gratitude and half a mars bar I found in my desk drawer this morning.

Cheers, Albert

Reply to
Albert T Cone
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mmmmmm Mars bar My first port of call would be the engine mounts, as you say. The top one normally has far too much play in it IME, and the bottom one can become a bit too 'squidgy' as it gets old and not really do much. Not sure of the exact arrangement of the front suspension on a 405, but on a 205 there are 4 bolts (2 each side) that hold the front subframe to the actual underbody that can come loose/fall out and cause clonking - worth checking that. One more thing is to check that the turbo isnt banging on the heat shield on the bulkhead, again this was a 205 problem i had, i'd imagine its quick unlikely in a 405 due to the extra space, but you never know (although this may actually be due to worn engine mounts).

Hope that helps

Carl

Reply to
Carl Gibbs

in news: snipped-for-privacy@individual.net, "Carl Gibbs" slurred :

Oh ah.... Hadn't thought about the turbo hitting the heat shield - presumably if that's happening, then it's going to be stressing the exhaust quite a bit - bad thing, I reckon.

Cheers Carl - I'll send the Mars bar by PayPal.

Albert

Reply to
Albert T Cone

In my old 205 it used to clonk when i reversed for that reason. Then i blew up the engine and put a new one in with a slightly bigger turbo and it just rested against the sheild. A few precise adjustments with a lump hammer soon had that sorted! I'd imagine it would stress the heat sheild more, that would definately give way before the exhuast!

Wooo hoo

Reply to
Carl Gibbs

Hope the mars bar is still up for grabs. Another thing to check is the bushings in the wishbone as when these are worn excessively they can make the noise you are talking about. Check if the car has had a recent service including the replacement of these bushings if not another way of checking is jacking up the car at the front and check if there is any play when you push and pull the front wheel out and in if there is excessive movement then theres your problem.

Reply to
hig_gti

in news:41b4a2f9$1 snipped-for-privacy@alt.athenanews.com, hig_gti slurred :

Carl's got the first half of the mars-bar, so I reckon you're in luck for the second half :-) I can either paypal it to you or attach it to an email....

Thanks for the suggestion - when I had the wheels off recently, I did try to find play in the bushes in the wishbone, the ball-joint and the drop- links. As far as I could tell, all were apparently clonk-free. When these bits went on my 205 I could usually feel play, except the bottom balljoint - I needed to use a crowbar to see movement in that, but there are none of the other symptoms of bottom ball joint wear, so I don't think that's it. Hmmm.

Cheers, Albert

Reply to
Albert T Cone

"Albert T Cone" wrote: > in news:41b4a2f9$1 snipped-for-privacy@alt.athenanews.com, hig_gti > slurred : > >  > > "Albert T Cone" < snipped-for-privacy@yahoo.com> wrote in > message >  > > news:Xns95B7818B9115A224267@130.133.1.4... >   > > > Hi Folks, >   > > >

Aw well worht a try. Well keep us informed on whats happening wouldn?t mind finding out whats wrong with it sounds like a real mystery

Reply to
hig_gti

Hi,

I had exactly the same thing on my 94 405 GTX TD estate - and it turned out that the pivot bolt had fallen out of the alternator, allowing it to nod forward and touch the radiator. How it didn't damage the plastic radiator header is beyond me - total luck, I think - fitting a new bolt solved the problem, and also stopped the engine from looking as though it had broken a mounting and moved forward onto the radiator all in one piece.

I'll pass on the Mars Bar, nice offer tho.

Philip

Reply to
<philipfaeunst

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