I have an 85 735i with some minor problems.
Has anyone experienced:
1. Chatter in a relay activating the heat as the car is coming up to temperature. Sometimes it clatters with the turnsignal on,other times all by itself. If the air volume wheel is left at 0 until the car is warm it will not do it.
2. I noticed some play in the clutch fan, perhaps 3-5 mm at the outer fan blade, not including blade flex. Is this excessive or be a reason for concern?
3. Regular spark plugs vs. platinum. I put in a set of platinum plugs and gapped them the same as the regular plugs. The car ran better but only for a short time. Did I make a mistake?
Kudos to all you out there who are willing to share your knowledge and expertise with those of us a litte more green.

If you hear the solenoid under the right side of the panel (under the glove box area) don't worry about it. This is the pnumatic switch for the hot water valve. Sometimes it cycles back and forth until it reaches setpoint.

Flex fan. This could be a sign of things to come. Your fluid coupling/bearing could be wearing out causing the play. For now I would keep checking it. If it gets worse then you will have to replace the fan clutch. Are you sure the bolt or nut that holds the fan to the pump is secure?

Plugs. I don't think you made a mistake as long as you gapped the correctly. But why did the performance drop off. What did the old plugs look like when you removed them? Why don't you remove a couple of the new ones and compare them to the old ones that you replaced. Is there oil on them? There must be a reason why the performace fell off. Something must have coated or covered the plugs. What else did you do when you replaced the plugs? There may be another reason why the engine is not running as good as before.