The Daily Wail

I have a two-year-old, 2003/53 Mercedes E320 CDi Avantgarde that has now completed 87,000 miles. The car has been serviced by Mercedes from new and, apart from one or two electronic niggles, has been essentially problem-free.

Some months ago an engine speed related faint whine/howl developed. The sound is most obvious at low speeds around town and at tickover is more of a 'whir'. I am an engineer by training and my gut feeling is that it could be timing chain related or, more worryingly, something associated with the automatic gearbox.

I am not imagining this and am mindful of the problems highlighted in your column about twelve months ago where engine coolant had seeped into the automatic gearbox via the transmission oil-cooler, with expensive results. I would be interested to hear your observations?

Asked on 22 April 2011 by JB, Nottingham

Answered by Honest John
The big problem with these cars when fitted with 'Valeo' radiators is that the joints for the automatic transmission heat exchanger inside the engine radiator fail, admitting engine coolant to the transmission. So, first thing, check for contamination of the ATF.
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