Let me throw my two cents worth in here. I work daily with a fleet of delivery trucks. I have been running the Cummins 4BT's since 1985 and the Cummins 6BT's since 1999. The "heater" on the 6BT's is for emission purposes ONLY. The 4BT's do not have nor have they ever had any type of heaters and yet they start in all types of weather. I have a couple of the 4BT's with well over 300,000 miles and they still start without aids.

The intake heaters will not improve starting performance on your Benz diesels. It will improve initial "cold running" emissions but that is all.

The 4BT's throw out an impressive cloud of smoke when first started cold (below 30 degrees F air temps) but when the engine reaches a minimum operating temperature it ceases.

If you disconnect the air heater on the 6BT (don't ask me why I do these kinds of things) it has exactly the same starting characteristics as the 4BT.

I can attest to the heavy draw. When I leave the house, if it is still dark, the after heat (after glow) dims the headlights enough to be noticeable. It is only for a second or 2 at a time, but can continue for a couple minutes if it is cold enough.

I found this on ebay:

http://cgi.ebay.com/ebaymotors/Mercedes-Grid-Heater-Intake-warmer-New_W0QQcmdZViewItemQQcategoryZ36474QQihZ013QQitemZ230234283122QQrdZ1QQsspagenameZWDVW

Thats for their semi-truck engines. Volvo uses an intake heater as well.

heres one from a 2003 cummins 5.9...

http://rbk3.com/mbz/CIH.JPG

Doesn't the heat at least allow the engine to start sooner than without heat?

When its below freezing.