Thanks a lot I see the difference now.
They seem to be working fine now as before the new solenoid I was getting about 28mpg and now up to 36mpg.
For long term reliability is it advisable to leave the upper flaps as they are or would removing them be a worthwhile thing to do?
Regardless of popular opinion removal is a personal choice.
However slight, the flaps are engineered for a purpose, ford spent millions designing, prototyping and testing them.. So they clearly serve a purpose.
Ford aren't in the habbit of chucking money developing useless components.
However there are lots of people who say removed with no issues.
What it boils down to is, do you trust ford engineers and all of their testing and development data, static dyno testing; flow bench testing which we aren't privvy to.
Or do you trust somebody on the Internet who thinks they know better than the car manufacturer posting saying they removed them without causing any problems, without any testing carried out or data to support their claims?
As above all down to personal choice
What my own independent findings have been is that they fail when the piston rings allow excessive blow by into the sump, it causes oil to spit into the oil separator and despite the separators purpose being to separate the oil, once the blow by gets too much it overwhelms the oil separator and oil ends up in the inlet manifold.
That was one reason why ford modified the oil separator and increased the size of the PCv hose, the modified separator had extra baffles and the PCv hose was to allow for a lower crankcase pressure, if you can evacuate the gases / vapour quicker it will be at a lower pressure... Lower pressure should in theory mean less oil spitting as less pressure to force the oil out.
Probably one reason why later cars tend to be a bit more reliable on flaps, although I have seen them fail on mk2 focus just the same. But less common at the moment...
Maybe as the engines get older it will become more common.
But the link between oil and failure is, the oil is not clean oil, it has carbon in suspension from the exhaust blow by, this coupled to heat leads to a gumming up effect on the flap bearing surfaces and it gradually wears it away as a result.
Ford didn't help the cost cutting measures either, manifold is designed to take 3 bearings between the ports, on mk3 mondeo they was originally only fitting 2 and on mk4 mondeo they removed them completely. Leaving it inadequately supported.
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