Maintanence question

[5tre5i]

Hi there, I'm in the midst of getting an oil change, I finally gathered up money for the oil, which is black...anyways...the temperature in my car is starting to go up a bit past the halfway point, can it be from the oil being so dirty, or something really bad? Also after replacing the battery I saw a decrease in mpg, I was getting roughly 30 mpg, now it's barely getting 15-20, I was told the spark plugs were changed, which is about 4-5k miles ago.

I have a few things I need to do for the car: change the oil/oil filter, transmission fluid/filter, diff. fluid, and possibly spark plugs depending on condition, power steering hose needs to be replaced, and the front right corner needs to be checked out because something sounds very loose, could possibly be the tie rod.

Sorry and one more thing, my brakes sometimes lock up, if I press down hard enough (not going fast, this is from pulling out of my driveway), I read that the master cylinder could be the culprit, and ideas?

Much obliged for the help, Thanks a bunch.

[Binjammin]

You weren't getting 30mpg in a 535.

[5tre5i]

I was getting close to it, at least according to the mpg monitor, and the 450 tank range I was getting (assuming I was actually going the speed limit....), but regardless, the car is eating gas up now, way more quickly then before

[SpeedsterBek]

You answered your own question, dragging brakes cause decrease in MPG. Rebuild your calipers and lube the bushings.
Temperature going up past 12- check water pump, replace T-stat, flush the system, check the operation of the Fan clutch and aux fan.
The best advice I can give you is this: diagnose, diagnose, diagnose first before throwing new parts at the car. This is very important no matter if you're rich or barely afford to buy some engine oil. Bentley manual should be your bible and common sense should be your Jesus haha.

[michaele30]

Check the DIY section if you need the bentley for reference

[5tre5i]

You answered your own question, dragging brakes cause decrease in MPG. Rebuild your calipers and lube the bushings.
Temperature going up past 12- check water pump, replace T-stat, flush the system, check the operation of the Fan clutch and aux fan.
The best advice I can give you is this: diagnose, diagnose, diagnose first before throwing new parts at the car. This is very important no matter if you're rich or barely afford to buy some engine oil. Bentley manual should be your bible and common sense should be your Jesus haha.

My brakes don't drag though, they work perfectly fine unless I press a bit harder than normal. I had an issue on my old car, when you press the brakes (when the abs light was off) it would lock up and you couldn't brake, but when the abs light was on it worked much better, the issue was that the hub was apparently cracked. I read on here that the Master cylinder design is crap, and that causes the breaks to do what they do. This problem has been going on even before the drop in mpg.

I don't plan on buying new parts except for the power steering pump, which is leaking, I'm cheap (have to be when you're a rich college student like myself) lol, if it's broken, fix it, if it's still broken then replace it.

Might need a flush, the car sits for a couple of hours and the it's still hot afterward...also a recent thing.


Check the DIY section if you need the bentley for reference

Thanks will definitely check it out, I know next to nothing about the E34, or BMW in general, so the book will definitely help thanks.

Just 2 questions, what oil do you guys recommend, it's an 89 with 215k, dino oil seems to have been used for most of its life, so I want to stick with that instead of synthetic so it doesn't leak. I figured 20w-50 will help clean the gunk inside it because it was sitting for quite sometime, but not sure what to use, suggestions?

Also, what kind of spark plugs should I use, I'm sticking to Bosche, but not sure if the copperheads are effective, or if I should save my pennies and opt for the upgrade, I know the platinum are better, but is it worth the extra $?

Thanks big time for helping this newbie.