A few questions from a 6-Series newb

Hi, I hope your '6' gives you as much driving pleasure as the rest of usenjoy, and not too much aggro.

1) l run my 6 (same year as yours) on an API SG spec (or better) mineral oil. Since it must be changed by time as well as mileage my oil does not go beyond 4000 miles. This being the case there is no special advantage to synthetic oils IMHO unless you have tuned your 635 and the oil runs a lot hotter. In fact on an engine that has done a few miles it is a good idea to change the oil more regularly than the recommended interval.

2) Not standard equipment. If yours has it fitted it will be the first one in the UK I have seen (although it is not something I have been specially looking out for).

3) The 6 is very sensitive to wheel balance, much more so than lots of other cars I have owned. The vibration at speed is almost certainly due to this. Likewise new discs are not a lot of money and they only need to be thickness variant by 1/4 of a thou to cause a vibration. They go out on autos because the disc may be squashed by the brake pedal when it is really hot (eg pulling up sharp on the M25...). The E28/E24 steering is needlessly complex and any slop in the ball joints is a bad thing. In addition, front suspension bushings are a weak spot. A lot of people upgrade to a modified 750iL part which is stronger, or fit polyurethane bushes.

4) Could be a duff fuel pump or more likely fuel pump relay (or even the DME one). The latter are the ones added apparently as an afterthought on the fuse box just above the battery where they are subject to corrosion....Remove and clean as a first step.

5) Might just need a re-gas (leaks out thorugh the compressor seals if not used regularly), but if it is running on R12 refrigerant you will need to have it converted. This subject is worth a separate thread on its own, but a cheap option is apparently to use a combination gas, although it reduces efficiency. A full conversion to R134 is likely to be a lot more money as all the seals and the condenser/dryer need to be changed (I am told... any comments anyone?) 

cheers

1.  Vibration under braking can be a number of things as suggested however there are other classic culprits.  One is the control arm bushings which can be changed for milled down 750 bushes which are much wider.  Also the steering idler arm (links the main steering arm to the body on the inlet side) can cause your sympthoms as well.

2.  Cutting out - does your car have an electronic idle control valve (3 wires will go to it.  If it's two wires then it's a bi-metallic type).  If it does have the electronic control valve then this could be the problem.  Remove and spray with carb cleaner to lossen it up a bit as it is not responding when the Throttle Poistion switch shows closed throttle.  What speed does your car idle at.  Does it have a fast idle when stone cold?

I run mobil 1 in my rebuilt M635 engine - no issues yet!  Castrol GTX Magnatec should be fine.

Regards

Ian

Haynes used to do a manual for the E28 but the best one is the Bentley manual at £44.  Look on Amazon - I got mine (new) for £27.

I'm running 17" tyres at 34 psi all round which seems ok.

A good service from a specialist with knowledge of the E24 and/or M30 engine will be money well spent.

Expect to replace some if not all bushing in the front suspension at some point in the near future. Sixes eat bushes!!! fnah, fnah!

Which part of the country are you in?

AndyS wrote: Haynes used to do a manual for the E28 but the best one is the Bentley manual at £44.  Look on Amazon - I got mine (new) for £27. Which part of the country are you in?

Is this the Bentley manual you refer to? I suspect not as it seemed a bit more of a history of the 6 series than a manual....

http://www.bentleypublishers.com/product.htm?code=GBS6

....and, I'm based in the Midlands, well, at least the car is, I'm all over the place at the moment!!