Marshall, or someone else, posited that they defective #14 heads have all failed and been replaced by now. While not absolute, and overheating will still crack good heads, I think there might be some merit to that statement. The '87 SDL I had still had the original head at 200,000 miles and showed no signs of being cracked. A hard upper radiator hose on a cold engine is one possible indication of a crackede head, though not the only one. Bottom line, if I didn't see signs of a cracked head, I would not be afraid of the car. On Sat, Jul 30, 2011 at 7:16 PM, Peter Frederick <psf...@earthlink.net>wrote:
> In the middle of the part number on the head is a two digit code -- the > original is -14-. the first improved head is -17- and the best version is > the -22- one. > > They crack through from the combustion chamber to the coolant and or oil > passages, causing the usual results -- overheating, coolant use, etc. > > The head gaskets also fail pretty often, between cylinders and from cooling > passages or oil return to the outside, resulting in leaks. Worst failure is > between the oil passage across the front of the block -- failure here allows > oil to enter the #1 cylinder under pressure. If enough gets in there, the > #1 rod gets bent. > > All the bits from the -14- head will fit the -22-, with the proviso that it > may be necessary to machine the pre-chambers to clear the bottom of the > large hole in the heads. The correct ones, with inclined injectors, are a > bit shorter at the shoulder, and if they don't fit correctly the pre-chamber > will leak compression at the upper seal, usually badly enough that the > engine will not run. > > Always use all new head bolts, they often fail when re-used, as I > discovered on my old 300D. > > > Peter > -- OK Don 2001 ML320 1992 300D 2.5T 1990 300D 2.5T 1997 Plymouth Grand Voyager _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
