Engine fan wont turn off

[tsolson]

I have a CM870, in a KWT800. Demandated before i bought it, and then checked over by reputable people on this forum. Very good information available here, and if you care about the engine at all, get it looked at. My neighbor had his deleted by a reputable guy, ran good for several month, and then nothing but trouble. Turbos, head gasket, blown motors, stop engine light flashing every morning. Worst part is, he put brand new engine in, and used the same ECM, and on his third turbo again!!! sickening

As far as engine fan, i was having a weird issue with mine last fall. Weather was slightly below freezing, but not super cold. Engine fan would come on shortly after i started the engine, and stay on. And the air pressure in the air system would drop, compressor cut in, build up, and keep cycling like that, the engine fan on all the time. I figured i must have broken air line to fan clutch. Stopped after an hour driving, shut off engine, turned on the key to listen for leaks. Nothing. No leaks anywhere. Had another driver listen as well, but no noticeable leak. Restarted the truck and it worked perfectly the rest of the day.

Next day, same temp, same issue. Fan on, air pressure cycling. Shut off truck, and restarted,no more issues. Did it for the whole week i was hauling. Still don't know what was going on. Maybe the ambient temp sensor fouled up? IDK