Auxilliary fan

[jasonvan]

I have a 1998 528i. The other day, just before it got cold, my temp guage crossed into the red while sitting in a drive through. As soon as I took off the temp dropped. It only did it one other time later that night. I noticed that when the needle drifted into the red my auxiliary fan did not kick on. It has gotten rather cold here quickly and my needle has remained dead center. I have not, however, been able to get the aux. fan to kick on no matter what I do. Fuses are good and I cannot seem to find where, or which, relay it could be. I have also noticed a small amount of antifreeze on the garage floor recently. Appears to be coming from the area of where the radiator drain plug is located. Fluid level is fine. Any ideas would be appreciated.

Also, it appears as though my oil pan gasket is leaking. Anybody have a procedure guide to replacing it. Does the rack have to come out?

[Jeron]

If rev-ing the engine makes the needle drop quickly back to normal then likely it is air in the system. You need to bleed the air from the system.

The reason the aux fan is not coming on is because it is triggered by radiator temperature and the radiator is not getting over hot. The sensor for the engine temp is on the engine(head) and the aux fan sensor is on the radiator.

[Jeron]

You also need to fix the leak which is what is introducing air into the system.

[jasonvan]

Thanks Jeron. I will let you know what I come up with. Unfortunately it went to the shop today.