Oil & Antifreeze Worries – Mercedes-Benz CLS 320 CDi

Car Mechanics Help!

Q   I have recently bought an 07-plate Mercedes-Benz CLS 320 CDi with the seven-speed autobox and the V6 3.0-litre engine. It has FSH from a Merc dealer. The last service was done 5000 miles ago and the car has 95,000 miles on the clock.

I would like to give the car a full service. I have bought all the kit: oil 5w30, MB 229.31/51 oil, air and fuel filters and so on. I also bought red antifreeze which was MB certified. However, on checking the antifreeze in the car, it is blue. Will I be able to put the red antifreeze in the car instead of the blue? Or will it cause problems? Having looked online, the red antifreeze is said to be superior to the blue.

Mercedes-Benz-CLS
Powerful V6 turbodiesel CLS is about to get a DIY service

I have noticed that it’s very oily around the air intake pipe collar to the turbo inlet. I have seen reports that oil dripping down from here damages the swirl motor underneath. Do you know if Mercedes has a modified part for this? Or is it just a case of cleaning it and applying some gasket sealant?

Also, I am looking to change the transmission fluid. Do you know what type of fluid goes in and how many litres I will need? I have looked online and they say it needs 12 litres of fluid in total – draining the sump pan oil gives four litres and changing the filter and disconnecting the oil cooler line at the front removes a further seven litres of old fluid; you then top up with new to complete the job. Do you know if this model has a separate transmission fluid dipstick or not? And do you know what type of fluid goes into the final drive?  Could you also tell me where the pollen filter goes on this car? And finally, where I can get a service repair manual?
Steve McCreery

A   Starting with your antifreeze question, the red and blue should not be mixed; they are both a different type of antifreeze. The red is OAT (Organic Additive Technology) and the blue is Monoethylene Glycol. This is not to say that the blue is inferior, just that it’s different. Admittedly, the red antifreeze has a longer life, but it is not suitable for all metals, whereas the blue antifreeze has a shorter life but is suitable for all engines. If you wish to use the red antifreeze in your vehicle, you should first flush through the cooling system to remove all of the blue coolant.

The oil you are seeing is most likely coming through the turbo. You cannot seal this off and no gasket seal should be used. Whether it is likely to cause a problem in the future will depend on how bad it is. There are reports of the dripping oil damaging the swirl motor and it may be worth ensuring that the leakage is not excessive. The problem is not as widespread as that of the Chrysler 300C with the MB engine as the manifold system is slightly different.

The auto gearbox fluid is MB 236.7 Comma MVATF or an equivalent grade and the filter located in the gearbox sump pan should also be replaced along with the sump pan gasket. The torque convertor can be drained by removing the bung at the base of the bellhousing to access the drain plug. There is a very comprehensive post on the MB world forum which covers the gearbox oil change: http://bit.ly/1jDoSoN 

The oil in the final drive should be 85w90, while the pollen filter can be found under the bonnet, beneath a plastic housing between the strut top and the bulkhead.

Finally, as with most modern vehicles, data is no longer available in book form and is now all on CD. These can be purchased on eBay, but be sure that your computer meets the necessary requirements noted in the listing.

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