Greetings ! Great forum you have here !
Got a lot of much needed info already through the search function.
I am really enjoying my 1st Bimmer.
1991 525i M50 5 Sp.. It is the metallic biege with sunroof.
(I have had many of the the 2 wheeled ones. My current ride is a '87 K100RS MotorSport.)
It has the Pioneer Super tuner III W/remote and a Pionneer disc changer in trunk (was this OE for this car ?)
The quality of this car at 156K is amazing ,it drives and handles like a new car. No rattles, squeaks or slop in the handling. Just a rock solid car. and everything works. $2800 sounded like a fair price to pay.
I am thrilled with this car !
The PO was a US military guy, who picked it up new in Germany and had it sent back home with him. He always had it properly serviced. So it was takin well care of.
It was sold to another family member a couple years before i bought it. So it did not receive quite the level of attention the 1st owner gave it.
It did get all new brakes and rotors, new Cat and O2 sensor and tune-up with all new filters (minus the cabin filter) before i bought it.

Things that need attention now is a new muffler. If i cannot find a good used one through a local wrecker.
(We have many in my area. I live half way between Sacramento and San Francisco, CA)
I was going to see about getting a 70 series Flowmaster (quieter one) or a Magnaflow to replace currrent one.
I am also open to any recommendations on the exhaust . This needs to be done soon. Has a VERY annoying exhaust note as it is. And I'm on a budget. ( I know, if you need to ask, you can't afford it.
I have other hobbies too. I cannot sink all my funds into just one

I also need to repair the AC . I'll just convert it to R134, since it has the correct compressor.
I pressurized the system an found leaking Orings. Receiver driers are cheap on eBay. I will flush system and replace all the O-rings on all the fittings.

I need to flush the PS fluid and coolant with fresh as well.
And put synthetic lube in the Diff. and trans.

One thing i wanted to ask the group. I am doing an oil change next weekend.
I have a case of 5 quart jugs, of the old the old red cap Mobil-1 15-50.
Do you guys think i sould use this oil , or go with Dino oil ?
The car has no leaks ,and I'd like to keep it that way.
From looking at the car's records for the last 4-5 oil changes, they have been using Castrol GTX. The guys who did the services are from a very respected independant Euro-car repair shop.
I was wondering if there was a reason for this.
I would hate to have to car spring a leak with the slippery stuff.

Anyway, I'm sure to have more questions.

Thanks much, and happy motoring !!

Chris
N.California