D3 4.0tdi any issues ??

[roberto]

thinking of buying one as a cheap run-around
any issues with this old engine and gearbox?
thanks

[ainarssems]

The biggest issue with 4.0TDI is intake manifolds braking down with age and sending bits into engine which kills engine. In most cases engines are not repairable and not economical to replace which means cars are written off. Intake manifolds cost over £1k each so not economical to replace as preventative measure either. In my opinion warranty is a must if you go for 4.0TDI unless you can find one which had manifolds replaced recently.

[roboblob]

I am wondering if anyone has ever tried taking off the manifold and adding a fine light heat resistant mesh over the gasket and refitting as a safety net as such just in case bits fall off.

[roberto]

oh dear
is this why there cheap now £5,000 ish for a £55,000 car new
well breaking for spares would make a bit of money back i suppose if it went wrong
put me off a bit that i must admit

the heat-resistant mesh sounds like a plan but how hard is it to do i wonder

[webs289]

We use zylon mesh on the F1 cars airbox to stop rubbish getting in, bonded with high temp glue. My have a go with that option soon to prove the theory. I also thought of making some mods to an already damaged unit with composites if i can get one :-)

[ainarssems]

Depends how close to head swirl flaps are, if they are protruding from manifold when open mesh will get in the way. What about vibration, it might be OK for short distances in F1 but will it survive 50k miles? If some bits get loose and rattle around they will surely wear through sooner or later. It will also reduce airflow and power, increase back pressure and make turbo work harder, less efficient, increase charge temp. Many diesels are known to clog intake manifolds with carbon build-up from EGR+engine breather system so it could clog up mesh at least on the swirl flap side as airflow is lower on that side most of the time.

[webs289]

I take your point about reduced airflow once the mesh has a coating of muck and oil deposits on it. But surely on the side of of broken parts bouncing around then that is the idea of the mesh to stop them before they do go into the engine, hopefully youwill notice the reduced torque and investigate the problem, finding the broken pieces en route so to speak. Maybe not a completely well thought out plan to start off with, although i think it would last quite a while.....50k, note so sure about that, but as i have only 11k left to the "dreaded engine failure" of 100k then could be worth a go :-)

[Goran]

Why not get someone to remove the swirl flaps for you. I read some BMW 330D guys got their swirl flaps removed. I'm not sure what that would do to performance.

[ainarssems]

Removing swirl flaps will not affect full throttle performance as they are fully open at high load. They are there for fuel economy and emissions at idle/part load. What they do is partially close one of intake channels in manifold for each cylinder so that airflow amount and speed is different in each channel, this causes air to swirl more as it enters the cylinder, mix better with fuel and result in cleaner combustion. At WOT they are open to get more air almost like if they were not there.

I know they unbolt in BMW's and end up in engine, not sure if that's the parts that get sucked in 4.0TDI' as there are also throttle flaps and I have heard people blaming the fact that manifolds are plastic so maybe plastic fractures and send bits in engine. If it's just swirl flaps then it could be simple solution. If they are getting loose it might be possible to service them, use thread lock on any bolts and screws or weld them together or possibly replace by custom made parts if they wear out. It's a bit harder if manifold itself fractures and breaks down.