300tdi still smokey

[piper109]

I'm a bit discouraged :-(

I would fog up the neighborhood shortly after start up and move off. I thought it was valve stem seals so I replaced them with green Elring seals (head in place). There does seem to be an improvement but not as much as I was hoping for.

Heres what happens.

Start up engine, no smoke. Pull away, no smoke. Let foot off accelerator pedal no smoke. Accelerate again it smokes profusely and engine seems lumpy. It clears after a couple of hundred yards and seems fine after that but if I follow someone driving really slowly for a few miles, it smokes when I accelerate.

Its a 300tdi Disco with about 170k miles but engine was supposedly rebuilt about 20 k ago and it has a replacement AMC head. Car does not use much oil, perhaps one liter in two thousand miles max. Turbo was also rebuilt within 15k miles at a place where they install a bigger impeller and shaft feels good.

Any ideas what could be causing this smoke?? What should I be looking for next? Its not really a big deal I suppose buts its embarrassing and I'd like to fix it.

Strangely when I am at 3000 ft above sea level its a lot worse than when I am at 3-500 ft.

Thanks, Steve

[Jon W]

I had a problem like this, on my 200tdi, it worked out to be the timing was moving, as my front pulley have come loose and worn the keyway, so the timing would advance and retard accelerating or on engine breaking, hence a lot of smoke. Problem resolved with chemical metal for the worn key way and new woodruff keys.

So have a check of the timing and front pulley.

Jon

[moose]

what colors the smoke? Blue?

does it smell of unburnt diesel?

if its lumpy and missing could be the timing is out...

[Off Road Toad]

A liter of oil in 2000 miles is quite alot, mine doesn't use that much over 12,000 miles!

Regards the smoke, are the tamper evident seals still in place on the injection pump? if not then it could be someones messed with it and that could make it smoke, is it black smoke or blue or some other colour?

Steve

[v8bertha]

And another idea for you...

I had this smoking issue on my old 300tdi 110, but it was only noticeable in low box. So for example you'd be descending a hill in 2nd low using the engine braking, then you'd get to the bottom and give it some beans and I'd get a big cloud of blue smoke that would clear after just a couple of seconds. It was more noticeable at altitude.

I never got to the bottom of it as I sold the vehicle and it was a fair few years ago now, but I vaguely remember a very clever spanner-wielding friend saying something about turbo seals?

Oh, and that's a lot of oil to be burning!

[cackshifter]

When you take your foot off the accelerator the engine continues to pump air as if it was being fuelled, but there is not so much energy to drive the exhaust turbine, so you'd tend to generate a bit of vacuum in the inlet manifold. If the turbo was rebuilt a bit back, was the intercooler ever cleaned out? Maybe it is drawing oil from in there that was deposited by the old turbo? It does sound like oil is somehow being sucked in from somewhere, so it could only come from valve seals (just done) turbo seals (done a bit back but hopefully OK), or maybe a breather, where the oil separator isn't working. Worn rings would tend to cause smoke continually under load. I'd have a peek at the intercooler and the oil separator before getting too upset; it only needs a couple of drops of oil to make a big cloud.

Nigel

[piper109]

Thanks Gents for some really good comments.

I transplanted this engine and gearbox into my Disco about 8000 miles ago. At that time I cleaned out the inter-cooler but I have not cleaned it out since. I can discount old oil but not oil that might have accumulated since. I have run the engine with the hose to the intake off and throttled up to check for oil etc and it seemed dry...at least when I did that. The intake seemed dry too, perhaps the slightest suspicion of oil. Its a good idea to check/clean the intercooler again and give the turbine/oil separator breather a cleaning out. I have not done that. I have however checked the hose the other end where it goes into the hose between the filter and the turbo and there is just a small oily deposit, what I would expect from a breather.

The smoke is pale blue and I'm pretty sure its oil I'm burning, not excess fuel. I used to ride a Scott Flying Squirrel so I am familiar with burning oil. I also kind of feel like oil is getting sucked in somehow and I don't yet know where or how.

I think I am off with my oil consumption and its more like a litre in 5-6000 miles. Car was parked for several weeks and I have not kept good records. I have not had the impression that the engine "uses oil" excessively. It only runs lumpy when its putting out lots of blue smoke. The rest of the time its smooth and the exhaust is clear unless I go below 1800 rpm going up a hill (gone off the turbo) when it puts out a bit of black smoke.

The fuel pump has been tampered with ...by me and adjustments have all been small (1/8th of a turn)and monitored. They can be reversed with no problems.

Before I installed this engine I replaced the timing belt. The keyway was damaged and been bodged a bit. I painstakingly worked on it myself and inserted another thinner key to take up the side play in the shaft groove so I dont think there is any movement at the front pulley. I torqued up the shaft bolt very well and used loctite. Its worth checking though.

I do go down a steep hill in first when its first started up, using the engine as a brake so it probably does suck quite hard during that time. Smokes like crazy at the bottom pulling away.

Someone suggested to me me that when the head was replaced (following an overheated engine) that they just took the valves out of the old head and put them into the replacement head and the valve stems could be worn.

Are there really people out there that do that !!??

Whats the best way to check the turbo for oil loss?

Thanks, Steve

[cackshifter]

TBH the symptoms do sound really like valve stem seals; I had one or two blow off the top of the guides and let oil in, resulting in a big gust of smoke at the bottom of my hill first thing then nothing after that; thought the guides were knackered when in actual fact they were well lubricated. It's happened to me on 2 300tdis. If you've just done them, probably unlikely but might be worth a quick look under the rocker cover before you start stripping other stuff.

Nigel

[piper109]

TBH the symptoms do sound really like valve stem seals; I had one or two blow off the top of the guides and let oil in, resulting in a big gust of smoke at the bottom of my hill first thing then nothing after that; thought the guides were knackered when in actual fact they were well lubricated. It's happened to me on 2 300tdis. If you've just done them, probably unlikely but might be worth a quick look under the rocker cover before you start stripping other stuff.

Nigel

I pushed all the new seals in place with a deep well socket that was a nice fit. They all offered reasonable resistance.

I would be surprised if they had come out but I will certainly look. Its kind of surprising that enough oil can collect somewhere along the top edge of the seals to make significant smoke when it gets sucked into the intake, or run down onto the valves when the engine is stopped, not to mention cause lumpy running. I cant deny its happening though.

Do 300tdi valve stems typical accumulate heavy wear? If some bandit did fit old valves into new guides is there likely to be a lot of stem wear at 150k which is when the head was replaced? Had I taken the head off of course I would have checked for excessive play but I did the seals with the head all torqued down. I have no signs that a new head gasket is needed so I didn't to want to take it off for the heck of it. I'm wondering if I should take the head off and replace all the valves and guides with new.

I would like to check out the other possibilities, turbo leaks etc. Oil is definitely getting into the combustion chamber to make it run lumpy.

If an injector was leaking some drips when the engine was stopped, what would the symptoms be on startup?

Thanks, Steve

[cackshifter]

Just a thought - if you took the intercooler hose off the manifold (Ok it might sound odd), and then started it next morning like that you'd eliminate oil from the turbo as a possibility, as it simply couldn't be feeding it in. Equally if it's blowing out an oil mist it might point to it. A turbo is a bit expensive to swap on the off chance it fixes it.

Nigel

[Range Rover Blues]

If there was a lot of fuel in the cylinder on startup you'd hear excessive dieseling on the first few revs, a heavy cracking sound if you like. You'd get some smoke and it might take more cranking. If the fuel was there for any time though it would drain past the rings, you'd see that in the oil eventually.

I'm not convinced you generate enough vacuum in a TDi to draw oil up past the rings, it might pull a little down past worn valve stems but if the selas fit then again not convinced entirely. Possible the turbo leaks, pressure whilst it's workiing would stop oil leaking as much, however oil leaks often get worse once the engine oil warms up.

I've come accross things as simple as oil that puddles in air filters until the car negotiates a hill that causes symptoms like you describe, perhaps oil is puddling in the engine breather hose?

I'd be interested if you get to the bottom of it.

[piper109]

Just a thought - if you took the intercooler hose off the manifold (Ok it might sound odd), and then started it next morning like that you'd eliminate oil from the turbo as a possibility, as it simply couldn't be feeding it in. Equally if it's blowing out an oil mist it might point to it. A turbo is a bit expensive to swap on the off chance it fixes it.

Nigel

Thats an idea worth trying :-) I seem to recall that the top inter-cooler hose runs a bit downhill to the intake manifold.

Thanks, Steve

[piper109]

Thats an idea worth trying :-) I seem to recall that the top inter-cooler hose runs a bit downhill to the intake manifold.

Thanks, Steve

Well I was wrong, the inter-cooler runs uphill to the intake manifold. I ran it with the Inter-cooler hose disconnected. It was still smoky and what came out of the turbo pipe was pretty oil free though there was a small oil accumulation where the hose becomes bigger than the inter-cooler nipple and therefore drops down a bit.

I guess its still the valve stem seals at fault....or perhaps the valve guides to valve stem clearances. I guess I will have to pull the head off and fix those. How hard a job is it to replace the valve guides?

Steve