i own a 1996 1.8 diesel mondeo, about 6 weeks ago, when i was in a traffic jam, i was creeping along when suddenly the engine speed soared, redlined, then settled back down, i was told this could be due to the turbo being nackered as there was oil in the intercooler, so i changed it, 4 weeks later it did the same.....stuck in traffic, engine speed goes through the roof, but i was ready so i stalled it - (wording changed - DD). there was oil in the intercooler again! so i went back to the scrap yard, and got another turbo............2 days later and its done it again!!!!
is it really the turbo's that are nackered? or is there another way for the oil to enter the intercooler?? or could there be a fault on my car which causes the turbos to fail? or is it the turbos themselve that are crap because theyre from the scrap yard????
please help!
|
|
Who is giving you this Technical Analysis? Reading your post carefully it appears that you got both your replacement turbos from a scrapyard; why not change your mechanic instead of your turbos? You are already well on the way to spending more on this car than it is worth IMHO!
|
|
|
missfruitcake
There's always a fair bit of oil in the pipework, so that isn't proof of an - incredibly rare on these - turbo failure. If the turbo fails, [usually at speed on the over-run] you'll produce a cloud of blue smoke the size of Wales; did this happen? If it did, is the sump-oil level correct; [do you have the right dipstick] and are the engine breather hoses clear. A blocked breather is far more likely than a failed turbo.
If you didn't get the cloud of blue smoke, a fuelling fault is more likely. Any air getting into the fuel can cause this and the diaphragms in both the primer on the filter-head and the aneroid unit [on the front of the pump] are very prone to leaking.
|
i have another "friend" at the moment telling me to check the compression as he thinks the head gasket is blown........ i personally doubt it as there is no loss of power at all, just these occasional surges when stuck in traffic, is it worth doing a compression test or will this be a waste of time?
thankyou!
|
When you say redlined in your original post, is that *exactly* what you mean?
Two possibilities spring to mind (although I'm sure there are more!),
If a diesel begins to run off its lubricating oil, or from some flammable vapour in its ingested air, then it will rev beyond the normal maximum governed speed of the engine - it can rev so hard it will self-destruct.
Or, did the revs rise to the normal maximum governed engine speed and *no further*?
If the latter, then you are more than likely looking at a fault inside the injector pump, if the former, you need to find and trace the source of the extra "fuel"
I hope that is helpful,
Number_Cruncher
|
the engine appears to run off its own lubricating oil, as when the intercooler was removed immediatly afterwards it had oil in it,so the theory behind the "nackered" turbo,was that the seals had gone, it was throwing oil into the intercooler, then when it builds enough up it throws it into the engine therefore causing the excessive rev's,
believing this to sound feasible the turbo's been replaced twice and it still does it.it only seems to happen when its been stuck in traffic for 5-10 minuites, so i wondered if there was another way for the oil to be getting into the into the intercooler, or is the only way was through the seals on the turbo? if this is the case, are the turbo's all nackered, or could there be a fault with the pipework/oil pressure for my engine to "break" every turbo that goes on it???????
|
|
|
|
missfruitcake
A blown headgasket it a possibility: never seen one cause this effect on one of these, but L/Rover TDi's do it regularly - usually to total engine destruction. What about the smoke question? NC puts a good point about "redlining;" most "diesel runaways" result in bits of red-hot metal scattering in all directions; being able to stall one is rare.
|
|
If it was sucking oil in via the headgasket, then there would be no signs of it in the intercooler.
|
|
|
|
|
|
missfruitcake
Nothing revealed so far should justify changing the turbo; [they're oil flooded and don't have pressure-retaining seals in the conventional sense.] Still awaiting that crucial smoke information [and the mileage would help too.] Even if oil were pooling in the [high-mounted] intercooler, why should it be sucked in at idle; it's far more likely to happen under hard acceleration. Were any of these turbos found to have failed or showing excessive shaft play when removed?
A breather fault [just possibly abetted by a H/G gas leak from combustion chamber to crankcase] is by far the most likely.
|
A split boost diaphragm can cause surging although it's usually accompanied by poor economy and poor performance.
Idle tends to be generally ropey as well.
Any other symptoms apart from the surging?
Cheers
DP
|
i have never noticed any smoke from the exhaust when this has happened, but thats not to say there hasnt been any as my concentration is usually on avoiding hitting the car in front and stalling the car!!
other symptoms are that it sometimes goes on its own when in high gear, ie: you dont need to press the pedal as much to keep a constant speed, this only happens intermittently and is hardly noticeable unless youre expecting it.
the turbo's all appear fine when they have been fitted, with no major play, the car i own is regularly serviced and has 125000 on the clock.
|
missfruitcake
When a engine starts consuming it's own oil, it cannot burn it efficiently and the smoke is unmissable. Even when you'd got it stalled, the cloud would catch up and you'd probably not be able to see the end of the bonnet; the whole street would be brought to a standstill for several minutes until it dispersed. I think you can forget the turbo for now, this is sounding more and more like a fuelling issue; have you ever noticed any of the symptoms DP listed above? Does it produce a harsh, hammering clatter when it surges?
|
|
i noticed the last time it did it, that when i tried to stall it in 2nd then 3rd, it clattered like a can of marbles then was ok, but if the smoke would have been as suggested (ie:street comeing to a standstill) then im sure that did not happen!
|
Hmmm! Just read your last post and hope this isn't too late to help.
My present 'L' reg TD did this and eventually snapped the cambelt. Cause is belt drive sprockets on end of crank coming loose due to a pin shearing - not nut coming loose btw. These symptoms are exactly as happened on my car, the clatter would disappear only to start again in a while. Love your description of 'can of marbles;' its exactly right. This could well have been caused by the gross over-revving you described but is probably not related otherwise.
|
|
|
|
this is caused by a fault in the fuel pump. It happened to an acquaintance of mine a few years ago. this too was a 96 model. I forget the exact cause but it IS in the pump. How could it be in the turbo - makes no sense :((
As someone else said it is probably not worth getting it fixed. You can pick up these cars at British car Auctions for peanuts.
|
|
Uneven running and surging on these engines can be caused by air getting into the pump.
|
|
|
|
