Diagnosis Please...

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stevieb
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Diagnosis Please...

Post by stevieb »

Pug 405 1.9td with 152,000 on the clock doing 1,000 miles per week for the last five months without a hiccup. Head gasket changed by main dealer at 133,000 miles to remedy a minor oil leak on the front corner of the block/head.
The turbo is KKK, with a Bosch fuel pump.
Here's the symptoms...
Slight jolt and loss of power on uphill stretch of M1 earlier today, followed by puffs of black smoke. Loss of power nothing dramatic - very much like a gusty headwind. I slow the car down and the smoke turns blue. Slow down to stop on hard shoulder and the smoke turns white and resembles a steam train whilst ticking over on the hard shoulder.
Engine cools and get a tow home courtesy of RAC.
Car started at home - no smoke, and seems to rev okay. Engine warms to normal operating temperature, and random puffs of smoke seen from exhaust. Blipping the throttle causes plumes of smoke, but a gradual increase in revs does not. The engine is making no untoward noises, and the coolant, although bubbling a tiny bit immediately after the thermostat opens, looks reasonably clean, and has not dropped as far as I can tell. The oil has not emulsified, though the pressure warning light has come on (and stayed on) since the car has been home, and the level has dropped dramatically since being checked just last week.
The exhaust is also spewing out large quantities of unburned oil when the engine has warmed - more so when blipped.
Is this likely to be an "oil getting in combustion chamber" problem - i.e. piston rings or the air inlet part of the turbo? Or could it be the head gasket? The were no tell-tale signs in the coolant last year when the oil was weeping out, so I guess the coolant test isn't conclusive. The rad cap doesn't appear to be holding in any excess pressure when cold.
Alternatively, could it be the turbo on its way out? The oil out of the exhaust looks and smells like it's come straight from the crankcase - not a combustion chamber.
I seem to have symptoms from a number of different possible causes, but nothing to point a definite finger. Can anybody throw any light on the matter?
beezer
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Post by beezer »

Are you sure it is oil being burned? Could be slack in the timing gear.
stevieb
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Post by stevieb »

Hmmm, hadn't thought of that Beezer. Cheers for the idea.
I was suspicious about the timing belt tensioner last year - I suppose if that has given up the ghost the belt may have slipped. But at 95mph (and accelerating) on the M1 wouldn't that have been more catastrophic?
Definitely something else to investigate. Doesn't explain the oil in the exhaust gases though...
Hmmm, I'm off for another think.
Dave Burns
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Post by Dave Burns »

A diesel engine will burn any oil getting in to the cylinders in quantity, this will deffinately have side affects like knocking and an erattic idle or rough running, you don't seem to think there is any of that going on so I would go for the turbo, especially with the white smoke, and raw engine oil is unlikely to make it to the exhaust from the cylinders.
Take the intake pipe off at the compressor end and feel for radial play in the bearings, if its gone down good style it will rob the engine of oil pressure at low speed.
Dave
stevieb
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Post by stevieb »

Makes sense Dave, cheers. I suppose a leaky head gasket may well cause startup problems (a bit like a dodgy glowplug), whether it be leaking in OR out.
I'm definitely with you about the oil pressure - it seemed to drop right off when tested earlier, but at revs it picked right up again (tested using the old hand over dipstick hole trick).
Anybody got any suggestions on turbo repairs, or replacements, if this proves to be the culprit? Anywhere I can get it reconditioned asap? Preferably near Sheffield.
stevieb
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Post by stevieb »

It's too dark to go removing hoses et al at the moment so I've tried another little test.
A while ago I checked my boost pressure using a tyre pressure gauge rigged into the take-off from the intercooler to the diaphragm on the fuel pump. Revving the engine, even without load produced a slight movement (though very little). Revving to about 2000rpm in first with one foot creating some resistance on the brakes caused a definite movement.
Tonight there is nothing. No pressure whatsoever.
I've also noticed an unpleasant noise - which wasn't there before - I can only describe it as sounding like a Dinky toy car being run along asphalt. It only appears when the throttle is pressed hard and released (over-run? run-on? not sure of the term), and appears to come from the right area to be turbo related - though this is also close to the head gasket leak from last year, I doubt a gasket leak would be making that kind of noise, especially without any other signs of leakage.
Like Dave says, the oil pressure is low at low revs, but the warning light goes off at anything above tickover - but when this noise appears, the warning light flickers at me. Definitely related.
Now to get the thing sorted - or scrapped.
beezer
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Post by beezer »

Sounds very much like turbo problems. Reason I thought it might be slack timing is IO had similar symptoms which were tracked down to loose crank pulley bolt. Smoke on blip none at constant revs and erratic during journeys. The noise sounds like turbo (bearings?).
Scrapyard looks likely. I have had some success with the following online service. You tell them what you want and you get phone calls half an hour later.
http://www.all-carparts.co.uk
stevieb
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Post by stevieb »

Cheers Beezer - I'll give 'em a try tomorrow. I might just get time to try a few local breakers in the afternoon - fingers crossed an' all that.
You may be closer to the truth than you think though, with the timing gear idea, because it's definitely a "chattering" kind of sound (valves JUST touching pistons? Maybe?), though I don't think the engine would rev so freely without some other tell-tale sign. In fact if anything, the engine is revving more freely than ever - something I once noticed td's do when the turbo is disconnected...
stevieb
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Post by stevieb »

Right, I gave into temptation and removed the inlet pipe to the turbo. The shaft (tip) deflects off centre about 0.5mm each way. It rotates reasonably well, but feels like it has a few tight spots as it turns, though this may just be the restricted access playing tricks on me.
Any more thoughts?
EDIT - is it worth me checking the shaft from the exhaust side? I don't know whether it can be reached once the front section of the exhaust is off. It might add more weight to the above theories.
I should also add that the inlet side of the turbo wasn't excessively oily - at least no more so than it was last year, when the main dealer informed me that just a little oil in the inlet tract is normal. I suppose the best way to tell is to remove the turbo completely. Oil on both manifold AND exhaust sides means engine oil leak, oil on just the exhaust side means turbo leak. Hmmm...
beezer
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Post by beezer »

There shouldn't be any tight spots. Right enough, oil leaks should be obvious. Expect some free play. If you can get the whole thing out you can check it out more easily.
stevieb
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Post by stevieb »

Yeah, I think that's my job for tomorrow night. Pull out the turbo and do some investigating.
I'm just hoping I can get a good run home from Bradford now... I dread to think what hire car I'm gonna get...[?]
I'll post back with my findings. This nice new keyboard will have even more black fingerprints all over it...[B)]
stevieb
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Post by stevieb »

Okay, part of the job is done. All hoses and the inlet manifold are off. Just the turbo bolts to get off after the DWF does its business.
I've only looked at the inlet side so far, but the opening on the the air filter side is only slightly oily - mainly sticky - so this is likely the little bit that gets dragged in from the engine breather in the air filter housing. However, the opening to the intercooler is well and truly oiled up - and fresh wet oil at that. So it look as though the seals this side are gone at least.
Now to get the whole unit off and see what the exhaust side is like.
beezer
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Post by beezer »

Looks like you will be looking for a turbo unit!
stevieb
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Post by stevieb »

Cheers for the help guys, it was definitely the turbo. I finally got the thing off and the exhaust manifold side was dry (and sooty), but the exhaust front-pipe side was dripping in raw oil.
Second-hand turbo now installed. A LOT less play in the shaft than in the original so I'd say that's where the problem was. I'll dismantle it tomorrow, and see what's occurring inside it.
New one so far seems to be a lot better - plenty of boost pressure when revved too - considerably more than before. Just need to recalibrate my fuel settings and all will be hunky-dorey.
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