This sounds like a cliche, but please bear with me.
I've had this Mondeo for 14 months now and put 21,000 miles on it. For all my satisfaction with it in most respects, even I will admit it has always struggled to even move its own weight below 1,800 RPM. The turbo then comes in with a surge between here and 2,000 RPM. As other Mondeo TD's I've tried have all been much the same, it was a lot of car for what I paid for it, I can drive around it easily enough, and I like the car in other respects so it's never bothered me too much.
And so it has been until last weekend when I did the routine oil and filter change. I normally use the cheapest 10W/40 semi synthetic diesel oil I can find as long as it has a half recognisable brand. This time however, I got a good deal on some fully synthetic 5W/40 stuff from Halfords (which I posted in the General board to let others know). I put this into the engine on Saturday of last week, installed a new oil filter (Motorcraft as always) and changed the diesel filter (second time since I've had the car). Everything else was just the usual check over / top up. No other parts or fluids were replaced. No hoses, cables or wires were disturbed
All I can say is that from this moment on, the gargantuan flat spot at the bottom end has gone. I can now accelerate from pretty much idle in third or fourth, and the car actually responds to the accelerator. Of course there's no boost this low down, but it will actually pick up enough to keep up with town traffic which it wouldn't before. The turbo now starts to wake at 1,500 RPM, and builds progressively up towards 2,000 instead of coming in with a surge just past 1,800 with absolutely zip below it. The car feels no faster outright, but is just so much nicer to drive.
Doubting myself, and as a test, I kept quiet about it in front of SWMBO who rarely drives the car (she hates its sluggishness), and generally doesn't know or care about cars particularly. She took the Mondeo today on a 40 mile round trip to a mate's house, the first time she'd used it since this recent service. On her return, the conversation went something like:
SWMBO walking in the door: "what have you done to the Mondeo?"
Me (seeming uninterested): "Nothing. Serviced it last weekend but that's about it. Why, what's wrong with it?"
SWMBO: "It's still horrible, but it feels like a sports car compared to before. That horrible laggy / flat bit at low revs has gone and the throttle actually does something at low revs now. Much nicer to drive"
So, not my imagination.
Any ideas? Anyone seen this before?
Cheers
DP
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Could be down to the oil 5W/40 being thinner than the 10W/40 and the oil lubs well so less friction. I experienced a similar noticable change to a Ford petrol engine a few years ago using the same oil.
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You could have inadvertantly refitted a displaced O ring on the fuel filter or something? Moved the throttle cable perhaps?
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groups.msn.com/honestjohn - Pictures say a thousand words.....
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My Mondeo was exhibiting pretty much the same sympthoms as DP's till I took it in for it's MoT a month ago. I mentioned it to the garage who traced it to air getting past the seal on the filter, replaced it and cured the problem.
I would suggest it was this rather than better quality oil which did the same for DP.
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Robin Reliant, formerly known as Tom Shaw
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Sorry, misread the original post and thought DP had replaced the fuel filter!
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Robin Reliant, formerly known as Tom Shaw
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Sorry, misread the original post and thought DP had replaced the fuel filter!
He did change the fuel filter.
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>>He did change the fuel filter.
And the performance change reported is many many times more likely to be because of this than the oil change! I agree with DL's post above and a change in the fuel filter sealing is the most probable cause of this performance enhancement.
Put in a more scientific way, the OP changed two things at once - which is not a good thing if you want to understand cause. Therefore, we cannot be 100% sure which of them was responsible for the change in behaviour of the vehicle.
Number_Cruncher
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Could be down to the oil 5W/40 being thinner than the 10W/40 and the oil lubs well so less friction.
Only true when cold. Exactly the same viscocity when hot.
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Fuel filter ! Most definite.
if the oil had made that much difference it would be an engine on borrowed time ?
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Thanks for your comments all.
Interesting idea re: the fuel filter. However, I have changed this before and noticed no difference before / after.
Cheers
DP
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Try changing the oil to mineral, and that may prove something... ;o)
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