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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4317
Experience:  Mercedes Benz Qualified Diagnostic Technician
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I have recently driven down from Manchester to Reading in my

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I have recently driven down from Manchester to Reading in my 06 plate C-Class 220 CDI when I stopped at the services on the M40 at Warwick to clean my wind screen, due to the fact that the washer has not worked for some time. I proceeded to the petrol station to purchase some water which I tipped over the wind screen and then placed to wipers on.
Following leaving the services and continuing south on the M40 I became aware that I was loosing compression. I continued to travel steady all the way back to Reading and decided to check the engine. I've found no evidence of any oil leaks, or smoke whilst in transit, so would assume that it may be caused by a perished hose or something. I did notice that the temperature gauge was very low than what it normally is, normally registering just below the three quarter point when it was only just managing to reach the quarter point on the gauge.
Whilst identifying that there was no smoke whilst in transit would I be correct to assume that this could be down to a perished hose.
it must also be noted that the weathers pretty cold too, what do you think the problem could be?
Note; The mileage of the vehicles currently 175,000 and its been an excellent vehicle to date with only a new water pump and associated hoses as a result.

It sounds like the engine is going into limp mode - this happens when the engine ECU detects certain faults & will shut the turbo off to prevent any damage occuring.

There are many possibilities for the engine going into limp mode & would always recommend a check on a diagnostic tool to see what fault codes have been stored.

A leak in the intake system is a common problem & the rubber hose coming up from the intercooler to the intake manifold can often split & leak air. This is not always obvious as it only opens up when the turbo is producing boost. If you get another person to rev the engine as you feel & listen at the front of the engine around that hose you can usually feel or hear the air escaping if this is the cause.

Otherwise you will need the fault to be diagnosed correctly to identify the cause.

Best regards, Paul
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