106 1.5 Diesel Keeps Snapping Downpipes

Retrogamer

Bit of a strange one this. I've a few ideas in my head that might be causing it, but wanted to post to get other peoples views.

Dad's 106 1.5d. 105k miles on the clock, unknown service history before we owned it but doesn't burn any oil.

It cracked a downpipe a good few months ago
Downpipe was replaced and when it was replaced, the friend who fitted it said manifold bolts were loose also.
All torqued up and fine for a few weeks. Then brand new downpipe cracked again. 2 days later after driving like this, the mid section cracked and snapped completely. No rust / corrosion at either bit either. Clean breaks.

Dad's friend noticed where the bolt joins the downpipe to the engine to secure it was really slack. So bolt had slackened, causing downpipe to vibrate and crack.

Fitted down pipe number 3. Look underneath with engine running and vibrating really badly again. Few days later bolt loosens itself due to excessive vibrations and few months later downpipe has cracked again.

Engine mounts "feel ok" but not 100% sure the best way to test them. Put it in gear and tried pulling away with handbrake on and checking movement of engine and feeling for any clunks ect. All seemed fine, but not 100% certain.

The only other thing i can think of causing the vibrations through the engine could be the engine running rough. It sounds really chattery in the mornings and if you rev it hard when cold (i don't make a habit of this, was just to test) it shoots out a fair bit of soot from the exhaust. I'm wondering if maybe one or more of the injectors isn't firing correctly and is causing the engine to run rough and vibrate too much?

Any ideas from anyone else, as a bit stuck just now and it's getting annoying changing downpipes all the time.

forgotmyname

Engine mounts shot. Engine moves backwards and forwards more than it should putting stress on the exhaust.

motorguy

forgotmyname wrote: »

Engine mounts shot. Engine moves backwards and forwards more than it should putting stress on the exhaust.

+1

There may also be an upper steady bar on these - cant remember.

Retrogamer

It seems to be excessive vibrations causing the metal to fracture.
We put the car in gear with the handbrake on and tried to pull away backwards and forward testing the mounts and watching the engine. No clunks or excessive movement.

Not sure how you determine rough running on a non ECU'd diesels though or if the method above is suitable for testing engine mounts.

vaio

my vote goes to engine/gearbox mounts too with a side bet on missing exhaust mount.

As for a cure...probably the cheapest option is a flex joint assuming the worn mounts aren't causing any other problems

Retrogamer

Wouldn't worn mountings cause clunking when slowing down or pulling away? Looking for suggestions other than engine mountings or any other suggestions how to test them?
Visually they all look fine and the engine doesn't appear to have excessive movement when pulling away

As a precaution i may change them but will have to be non OEM as it's still a guess at this time.

Prothet_of_Doom

Ah yes the old PSA 1.4/1.5 normally aspirated Diesel. Lucas DPC pump probably. 45 bhp ? They will probaballly run on veggy oil, from a chip shop, IIRC.

Anyways up, they vibrate like mad, are the most rattley peice of engineering ever to have been made, (They must have been bad, they sold them to rover who fitted them to the 115D - metro to you and me) and you should go to a dealer and buy new engine and exhaust mounts all round.

Where are you getting your exhausts from ? Try and see if you can get one with an extended warranty.

Retrogamer

Prothet_of_Doom wrote: »

Ah yes the old PSA 1.4/1.5 normally aspirated Diesel. Lucas DPC pump probably. 45 bhp ? They will probaballly run on veggy oil, from a chip shop, IIRC.

Anyways up, they vibrate like mad, are the most rattley peice of engineering ever to have been made, (They must have been bad, they sold them to rover who fitted them to the 115D - metro to you and me) and you should go to a dealer and buy new engine and exhaust mounts all round.

Where are you getting your exhausts from ? Try and see if you can get one with an extended warranty.

Getting the exhausts from ebay just now as only £27 a piece from there. Always breaks at the same area as well and doesn't appear to be manufacturing problem with them

Mounts from Peugeot are pretty expensive. I can fit them myself but they're just shy of £200 for the engine alone. If i knew 100% it would solve it, i'd get them but it's just a guess just now.

The 1.4d with the alloy blocks made 45bhp if i remember, but this is the later 1.5 one with the cast block and 58bhp.

1.5 came with both Lucas and Bosch pumps but i don't know the difference visually between both fuel systems. I think plan a this stage is euro car parts for mounts and then if still having problems start looking at injector issues as the diesel chatter is a bit louder than i remember my older 106 diesel being.

westwood68

That's a bosch

http://smg.photobucket.com/user/yellow_spider/media/106/tud5_later_bosch_pump_engine_bay.jpg.html

the object to the front right of the engine with the cable (throttle cable?) attached is not evident on the Lucas at the location

forgotmyname

Is the downpipe bolted to the bottom of the engine?

Are the exhaust rubbers all fitted properly? No bodged ones that stop the exhaust moving?

Slowly_does_it..

Can I ask if the gear stick moves excessively forwards or backwards if you accelerate and then slow down in the same gear? (no braking, just using the engine to slow you down) - When my engine mount undid itself this was the first thing I noticed. Also agree with a rattling engine not doing much good to the pipes, but they should last longer than that!