first, my appologies for my bad english and the inappropriate technical terms I might use.
In Summer 2001, after 120.000km (75.000mls) with my '93 Discovery tdi, I got my intercooler and turbo replaced - according to the mechanic (BMW - dark times) some valve got burned so both couldn't be fixed. Later (autum 2004) after 198.000km (124.000mls), I was again suffering of missing power and really, really black exhaust gases. A newly found LR-specialized mechanic told me, that the intercooler was just jammed with the remains of the exhaust gases and that this could be fixed by rinsing it. So, after they rinsed the intercooler all seemed to be well - but just for 200km (125mls). Now, again, there's no power and the exhaust gases are dark black.
So I'm suspecting, that there's something else wrong with the engine. Has anyone an idea what could be the cause? I will appreciate any comment or hint what to check to find or rule out the real problem.
It may be that your intercooler is filling with oil. This may be coming from the turbo oil seals. You do look after your turbo by idling the engine before shutting down to let it slow down and cool every time, do you not?
Wolfgang's Tdi must be a 200 one (I think he quoted that it is a 1993 model year) so it SHOULD not have EGR (Exhaust Gas Recirculation) but then again the EGR point is something that is worth checking.
Wolfgang does your can have a black sound deadening cover on top of the engine coming from the factory? If yes then most probably your Tdi is a 300 and it SHOULD have EGR. Another thing to check so as to establish whether your vehicle is fitted with a 200 or a 300 Tdi engine is to check how many belts it has for the ancillaries (the alternator, power steering pump and if fitted the air condition compressor) If it has a big, long, fat one (no dirty thoughts please) for the power steering pump and the alternator then it is a 300Tdi. If it has two small and thin ones (one for the power steering pump and another one for the alternator) then your engine is a 200Tdi.
You can also check the type and form of the air filter housing. If the air filter housing is looking like a barrel then it is a 200Tdi, if it is rectangular, almost square actually, then it is a 300Tdi one.
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Now for the black smoke and intercooler stuffing.
Have you checked the condition of your air filter's element? Sometimes when the air filter gets TOO dirty you may end up producing black smoke from your exhaust when you press the accelerator pedal to pick up speed and acceleration.
From your description I would also suspect damaged oil seals or maybe damaged bearings on your turbocharger. May I suggest you remove the hose leading from the turbocharger to the intercooler, cleaning it up and the re-installing it and having a drive?
If you find lots of oil after about 100 Km then most probably the oil seals and bearings inside your turbocharger are gone and need either to be replaced (hopefully) or you will be in need of a new or reconditioned turbocharger unit.
ONE POINT OF ATTENTION.
If you end up repairing OR replacing your turbocharger be EXTRA CAREFUL on priming the new/repaired turbocharger with fresh engine oil right before you start the engine for the first time. A lot of turbocharger specialists or car mechanics FORGET (?) to do so (just because it is time consuming) and the result is premature but significant wear on the new seals and bearing due to the turbine spinning dry until the engine's oil finds its way through the oil feeding hoses to them (the seals and bearings). If they are primed in advanced they spin freely and well lubricated and this ensures a proper start of operating life for them.
Another thing to make sure is the check with them that the turbocharger's turbine is balanced after they replace the seals and bearings.
Sorry for not being specific: Having two belts and a barrel shaped air filter housing the engine looks like an 200Tdi.
If I got you right, there SHOULDN'T be a EGR. Just out of curiosity: What sort of problem with the EGR could lead to the effect I described?
The air filter's element was the first thing I checked - it looked pretty dusty so I replaced it but with no remarkable effect.
Okay, I will clean the hose and look for oil after 100+km.
The warning you made, that experts and mechanics don't really care about their custumers engines somehow frightens me, because I made similar experiences. Why is it so hard to get real service when the other way round I have to pay real money?
All right, I'll check and clean it.
Do I get this right: If the breather pipes aren't clean then the (oil) pressure in the engine rises and somehow (?) pushes oil out of the block into the intercooler?!
I must admit that I wasn't aware that letting cooling and spinning down the turbine is so crucial for the lifetime of the turbocharger. (Huw, in another answer to my posting, also pointed that out.) Albeit being unaware, I normally have some slow paced 1-2km before reaching my destination.
Just to get a better feeling: How long should the engine idle to cool and spin down the turbine?
Thanks, especially Pantelis for the detailled reply.
After a long journey, maybe two minutes straight off a motorway but with your 1km slow pace end to a journey, just 15 seconds or so should be good. Stalling an engine under load can kill a turbo also. Newer turbo's will be water cooled but I don't think that these were fitted to either 200 or 300TDi engines. At least, I am certain that they did not have the modern facility of water pumping through the turbo for a period after engine shut-down. Even this type should not be stalled and should be idled for at least 10 seconds in order for the turbine to slow while oil is still flowing through its bearings.
People who manage to kill turbochargers will find that cylinder heads soon follow to the scrapheap.
Your problem could be something entirely different of course.
I've often heard some people state this but it's never really seemed vital to me, is there any firm evidence that this is really required unless you rev the engine high just before switching off or stall it at high revs? If the revs are extremely low and the engine is idled even for a couple of seconds before shutdown I'd have thought that the turbo wouldn't be moving significantly as it doesn't spin at a significant speed unless the engine is revving at about 2,000 RPM (estimated - no rev counter) under load. You certainly don't hear it spooling up if you rev it to over 2,000 RPM in neutral.
The advice I've had from mechanics on the Landy and my other cars (all my cars have turbos) is that you don't really need to worry about it unless you shut off the engine when the turbo is spooled up (which requires high unloaded revs or medium-low loaded revs), and you should idle the engine for 30 seconds to a minute if you have been ragging the engine like crazy as the turbo heats up and the oil can carbonise if it's not being circulated.
I've only had one turbo fail so far and that was on a car that's done just over 100,000 miles, six previous owners and is of a type that would have been ragged hugely by all six. It also gets so hot you can see the glowing exhausts at night casting an orange glow on the ground. Certainly not the case with the landy or the old audi TDi.
It is not vital. It is advisable for long term reliability at best and short term reliability at worse. No one forces anyone to treat anything mechanical properly and many don't and some of these complain loudly about the cost of their motoring.
In normal use all that it takes is the time it takes to apply park brake, release seat belt, check for open windows, straighten wig etc. -
10 seconds or so. If the engine has just operated at a high power factor then extend this to the about a minute.
Yes!
Hot abusive shutdown is not the only problem affecting turbos. Those who insist in applying high revs at start up have the same problems with turbo bearing wear.
Those who cannot see the sense (or have so far been lucky in avoiding damage) in allowing oil to circulate both at start up and shut down might like to investigate those devices that use the normal engine oil pressure to provide a reserve of 'high' pressure oil which is automatically released during these critical moments.
This one I already knew, from my friends Renault R5 alpine turbo, back in the eighties :-) He killed one turbo, not listening to the previous owners hints.
Do not worry. I see the sense. I know (so far) how this stuff works, just did not realize that it also applies when parking the car. But one never stops learning!
I used to run an American-built tractor with an Exhaust Gas Temperature gauge. Shutdown on that was specified in terms of temperature. It's not just oil in the bearings, it's letting things cool down. As I recall, it tended to work out as you describe. Maybe a bit longer, but it was a big engine.
It is just in the nature of this discussion group to provide help and assistance to fellow LR enthusiasts around the world so I did nothing more than what all other fellow members and listers would do.
Unfortunately I managed to erase your posting with the question you had for me so I would like to kindly ask you to repeat it and I hope I, or another lister, will be able to provide you with some useful input.
Take care and Happy New Year to everybody in the group. Pantelis Giamarellos LAND ROVER CLUB OF GREECE
On or around Mon, 03 Jan 2005 16:37:07 +0000 (GMT), "Dave Liquorice" enlightened us thusly:
not only turbos, either - apparently, quite a few Commer 2-strokes were killed by not letting 'em cool down enough after hammering up the then-new M1 at the heady speed of about 45 flat out and the pulling into the services. In that case, it was a hot-running engine and if shut down too hot then the thermal stresses damaged the head.
'course, at the time, most of the wagons had Gardner or AEC or Leyland engines that were flat out at about 1800 rpm, or if you had more money a Rolls 220. I don't know what the 2-strokes (Foden had one an' all, dunno if it was related or separate design off hand) ran at but it was faster and hotter than "normal" truck engines of the day.
Aye, gas turbine engines in helos etc run down to "idle" and leave them there for a minute or longer before switching off.
Strikes me that with the amount of automagics that are in modern vehicles that they ought to shut themselves down as and when they sense they are ready. The most I've seen of this is the occasional car that keeps it's fan running after the engine has stopped.
I guess there would need to be an "emergency" stop button as well somewhere in case you really wanted the thing to stop *now* or if the automagics failed...
My understanding was that the commer two stroke fitted in trucks was the ts3, another opposed piston engine with no head. I have never had anything to do with these engines but they seem to have had a reputation for blowing up. I think it is much the same design as the multi fuel engine in a 434.
In general two stroke diesels sound like they are about to burst because they have twice the firing strokes.
I once drove a detroit V8 two stroke and the noise scared me.
Due to my (obviously) limited technical knowledge I will probably not be able to contribute to as much as I take from this group, I'm sorry. So the least thing I can do is express my gratitude. But yes, lurking around here for some time, I found this group both very helpful and entertaining.
Here's a repost of my posting (hope it don't gets scambled). My last question, how long to idle the engine to cool down the turbo, started some discussions - intersting...
Cheers, Wolfgang
Hej Pantelis, hej David!
Pantelis Giamarellos wrote: >
Sorry for not being specific: Having two belts and a barrel shaped air filter housing the engine looks like an 200Tdi.
If I got you right, there SHOULDN'T be a EGR. Just out of curiosity: What sort of problem with the EGR could lead to the effect I described?
The air filter's element was the first thing I checked - it looked pretty dusty so I replaced it but with no remarkable effect.
Okay, I will clean the hose and look for oil after 100+km.
The warning you made, that experts and mechanics don't really care about their custumers engines somehow frightens me, because I made similar experiences. Why is it so hard to get real service when the other way round I have to pay real money?
All right, I'll check and clean it.
Do I get this right: If the breather pipes aren't clean then the (oil) pressure in the engine rises and somehow (?) pushes oil out of the block into the intercooler?!
I must admit that I wasn't aware that letting cooling and spinning down the turbine is so crucial for the lifetime of the turbocharger. (Huw, in another answer to my posting, also pointed that out.) Albeit being unaware, I normally have some slow paced 1-2km before reaching my destination.
Just to get a better feeling: How long should the engine idle to cool and spin down the turbine?
Thanks, especially Pantelis for the detailled reply.
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