318ti.org forum - View Single Post - IMPORTANT: Two plastic cooling system parts that WILL break.

SSpeedracer · 03-13-2013, 07:17 PM

I swapped the block plastic on a '95 M42 with 150K miles and the piece broke apart in my hands.
I swapped the block and head plastic pieces on a '98 M44 with 330K miles and both were in great condition (other than o-rings being stiff).

The M42's use a higher temperature fan switch 91/99C vs the M44's 80/88. And in my case I found the M42's low speed fan circuit was not working. It was only cooling at 99C trigger point. 176F versus 210F.

In late '95 early '96 BMW decided to lower the fan switch for the 318Ti. Why? A lower temperature is less efficient, reduces fuel mileage, and increases wear/load on the alternator. There is no reason to reduce temp unless they found a pre-ignition problem and i doubt that was reason.

Perhaps BMW recognized the 318's cooling system weakness and tried to band aid it with a lower fan temperature.

Also, refurbishing the M42 cooling system is a little easier than the M44.

03-13-2013, 07:17 PM	#141
SSpeedracer Senior Member Join Date: Sep 2010 Location: Southern California Posts: 107 iTrader: (0) Photo Gallery	I swapped the block plastic on a '95 M42 with 150K miles and the piece broke apart in my hands. I swapped the block and head plastic pieces on a '98 M44 with 330K miles and both were in great condition (other than o-rings being stiff). The M42's use a higher temperature fan switch 91/99C vs the M44's 80/88. And in my case I found the M42's low speed fan circuit was not working. It was only cooling at 99C trigger point. 176F versus 210F. In late '95 early '96 BMW decided to lower the fan switch for the 318Ti. Why? A lower temperature is less efficient, reduces fuel mileage, and increases wear/load on the alternator. There is no reason to reduce temp unless they found a pre-ignition problem and i doubt that was reason. Perhaps BMW recognized the 318's cooling system weakness and tried to band aid it with a lower fan temperature. Also, refurbishing the M42 cooling system is a little easier than the M44. Last edited by SSpeedracer; 03-13-2013 at 07:20 PM.