BMW: convertible e30, valve lifter, bmw day

Question
Hi Josh,

I purchased a 1988 e30 convertible 2 years ago, very nice car i love the drive. A few questions i have for you, hope you can help

1-should i put a valve lifter cleaner before i flush my oil?
2-my roof leaks where do i go without getting ripped, i went to my local shop they want 1800 for after market?
3-should i keep my battery on a charger during winter storage?
4-my clutch makes a rattling noise, when i depress the pedal noise goes, is this the bearing?
5-the differential makes a slight zingy noise, should i change the oil or put an additive?
6-it has a slight rough idle, but doesnt every old car do? any tricks on smoothening idle?

thank you for you time and have a great BMW day

lucas

Answer
Lucas,
 I will answer your questions in the order you gave them to me.

"1-should i put a valve lifter cleaner before i flush my oil?"  
 Well this one is kind of up to preference.  First off, BMW's (especially these engines) do not have lifters.  Lifters are typically found in American V8's, where the camshaft is down inside the engine instead of running above the head.  Lifter's ride on the camshaft and transfer that energy through a pushrod to open the valves.  So if you put this in your engine hoping to help a sticking lifter... it's not going to do much.  It's completely up to you if you want to do this, however I have never heard of ANY of these products actually working.  Most of the time it's just some petroleum product that "says" it will help this or that... but just ends up taking your money.  It's completely up to you!

"2-my roof leaks where do i go without getting ripped, i went to my local shop they want 1800 for after market?"
 To be honest, I dont know where you live, so I cannot recommend anyone.  Also I own an 87' convertible, and I put the top on myself.  If you set aside a day, and take your time you can do a really good job, it will just take you longer to do.  There are tons of internet sights showing how to remove/replace convertible tops.  Your leak might not be from the top, check the rubber seals where the top touches... these are known spots for leaks.

"3-should i keep my battery on a charger during winter storage?"  
 I dont think that's a good idea.  The best possible thing to do would be to go out and start the car once ever couple weeks.  The engine needs to be started anyways, so go out, let the car idle for 10-15 minutes, this will keep sludge from building, and it will allow the alternator to charge the battery.  I definately would not leave a charger hooked up all winter, that's just asking for a fire.

"4-my clutch makes a rattling noise, when i depress the pedal noise goes, is this the bearing?"
 More than likely this is the "throw-out" bearing.  When you press the clutch, this bearing is pressed onto the pressure plate.  Like many bearings, they also wear out over time.  You will have to drop the transmission to do this, and if it's been several years since the clutch was replaced, I would do it at the same time.  

"5-the differential makes a slight zingy noise, should i change the oil or put an additive?"  Are you sure it's the differential?  Alot of times this noise is from wheel bearings getting worn.  It usually makes a "whine" in the rear of the car.  So all you have to do is replace the wheel bearings.

"6-it has a slight rough idle, but doesnt every old car do? any tricks on smoothening idle?"
 Well, these engines weren't as "silky-smooth" as the later one from the 90's through today, but they should still be as good as most engines.  I would check the O2 sensor, and if it's been along time since it's been replaced, I would go ahead and do that.  The main thing is VALVES... these engines need a valve adjustment about every 20,000 miles.  If the valves are out of adjustment then the valves open a fraction to late/early.  A rough idle is usually from valves that are too tight.  If you adjust the valves, there should be 0.010" clearance between the rocker arm and the valve spring on a COLD engine.  If its less than this idle will be rough, and if it's more the valves will be loud and can affect the idle.

 hope this helps,
 Josh