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While changing a clutch cable I noticed quite a bit of oil around the joint between the turbo and the intercooler ducting. When I took off the pipe there is quite a bit of oil inside the pipework.
The car drives ok and there doesnt seem to be any loss of power, where do you suppose the oil is coming from and what are my turbo's chances.
Oh and hello to you all !!!

Some oil will always 'carry over' in the airstream from turbo's (even quite new ones) but it is a problem if there's loads of oil but you'd know about this as it will be blowing blue smoke out the back.

It's quite normal even my HDi does it quite a bit.

Welton wrote:Some oil will always 'carry over' in the airstream from turbo's (even quite new ones) but it is a problem if there's loads of oil but you'd know about this as it will be blowing blue smoke out the back.

It's quite normal even my HDi does it quite a bit.

Mmmm welton you should know better by now ..... Sheepshank, it is not normal as in " supposed to" You have leaking Turbo seals and it will only get worse. The oil does not "carry over" in the air stream but a very faint mist over time in the inlet manifold can occur. This will sit in the bottom hose and will continue to accumulate until you get fed up. It is caused by a number of reasons - pure wear and tear, using flushing oil between oil changes, failing to clean the small line filter, using the wrong oil. In general you will probably get fed up of the mess before it fails completely it will not blow through to be burnt by the engine - it's to high to get carried up through the intercooler, if it did you would notice uncontrollable engine run away as the oil is ingested and burnt as fuel - it's an oiler, it uses oil as a fuel - yes really, it used to be a common occurrence in the old days when they used oil filled filters. If you keep an ear on the tone generated by the turbo you can just let it run - if you notice any change in the tone - get it done, the worst that can happen is a disintegrated Turbo and maybe loss of your CAT plus lots of oil everywhere.
Scary eh.

thanks for the prompt help..feel a little better now. i will keep an eye on the prob and an ear too but tell me longintooth where would i find the "small line filter"? thanks again.

I agree with Welton, oil in the turbo pipe (If no running problems, or large amount of smoke present) is quite normal, normal as in nothing unusual, I see this all the time.

I used to have a Citroen Xantia that always had oil in the turbo pipe, never gave me any problems in the 80,000 miles we did in it.

Sheepshank wrote:where would i find the "small line filter"? thanks again

It's situated on the feed pipe that goes into the block - just undo the pipe and withdraw slowly.

jasper5 wrote:I agree with Welton, oil in the turbo pipe (If no running problems, or large amount of smoke present) is quite normal, normal as in nothing unusual, I see this all the time.

I used to have a Citroen Xantia that always had oil in the turbo pipe, never gave me any problems in the 80,000 miles we did in it.

With greatest of respect to Welton - he is not a qualified engineer with experience and if that's your opinion , neither are you my friend.

Right, I had a quick Google and it seems like a small amount of blow-by is not perfect but acceptable (possibly due to the nature of the seals, no rubber seal would exist here so they seem to use some sort of ceramic affair). Basically, if the engine is using oil then worry. Just to make things even more interesting ("may you live in interesting times" - Chinese curse) it's not just that the engine will run on sump oil, it could run without the engine management's rev limiter in place: apparently the con rods on Landrover TD4s let go at about 11,000rpm

I've seen oil in the turbo pipe on the Landrover TD4 as well, Rover 75 too (same engine).

In my 30 odd years experience as a qualified motor engineer and foreman mechanic, I have noticed that a small amount of oil in the turbo pipe does not amount to a serious problem, as I said before, providing there are no running problems or excessive smoke from the exhaust.

steve_earwig wrote:Right, I had a quick Google and it seems like a small amount of blow-by is not perfect but acceptable (possibly due to the nature of the seals, no rubber seal would exist here so they seem to use some sort of ceramic affair). Basically, if the engine is using oil then worry. Just to make things even more interesting ("may you live in interesting times" - Chinese curse) it's not just that the engine will run on sump oil, it could run without the engine management's rev limiter in place: apparently the con rods on Landrover TD4s let go at about 11,000rpm

That's right Steve, there is a big difference between a small amount of weep and oil accumulating in pools in the air ducts and that's why I mention the run away affect although not likely in this arrangement - the hoses will rot first. It will get worse and the oil is being sucked through from the compressor side and being pushed from the Exhaust side of the Turbo Impellor with exhaust gas carbon build up.

You have to be very careful what's on some website forums - so much twaddle and myths. On one site someone describes the oil pressures in a Turbo that are out of Kilter with reality. The oil pressure delivered to a turbo is not high but the volume is and that's why there is always a larger drain pipe back to the sump. The reason is that the oil has to remove heat quickly and that as little pressure as necessary is exerted on the seals to form a path for oil. Two types of seals are used one is carbon disc which is not favoured because of the higher resistance to the impeller, the other is dynamic steel rings as used on pistons and in all automatic gearboxes. These are favoured on high performance units. The faster the Impeller spins the better the seal but what you don't want is high pressure differences either side of the seal especially one side pulling and the other pushing. Engines with Turbos should not have low idle rates because there is more inclination for the seals to leak more and if the shaft is getting bung up with exhaust gas carbon it is possible for the impeller not to spin if the idle is too low - on the 406 the impeller is going very fast on idle because it is designed for high torque at low speeds - that is why a wastegate is used to control the higher end speeds. As with Piston rings, some oil as to be maintained on the surface of the seal to prevent wear and also to plug excess but just as with excess wear on piston rings the same applies to Turbo seals.

Just thought you might be interested.

Longintooth wrote:With greatest of respect to Welton - he is not a qualified engineer with experience and if that's your opinion , neither are you my friend.

jasper5 wrote:In my 30 odd years experience as a qualified motor engineer and...

Give it a rest you two. It's getting very tiring reading your bickering


Also, my tubby was chucking oil through the throttle at pretty much the same rate at 180k as at 100k with no ill effect bar a manky ICV+piping. Additionally there's been loads of diesel+tubby owners on here going "i noticed a bit of oil in the charge pipe/intercooler/throttle body/..." so yes I'd say a small amount of oil is perfectly normal on the 406.

Give it a rest you two. It's getting very tiring reading your bickering

No argument from me there

FIN