How do I bring a 1989 325i back to its prime?

A couple weeks ago I bought my first 325i. It's an '89 with over 250,000 miles on it. I'd like to bring it up to tip top shape and would appreciate advice.

The first matter of business was to replace the timing belt. I did that, an oil change, a cold air intake, and some cosmetic repairs. What else do I need to do for this well driven machine? Are there hose and gasket kits I should know about? The car runs great and currently has no serious issues. There is an occasional check engine light that pops up (stomp test gives code 1222 (oxygen sensor issue of some sort)), but other than that the car is apparently fine.

Did you replace the water pump when you replaced the timing belt? Go through the Ign system how old are the wires? pull your plugs and see if you can see what your O2 sensor is talking about (rich/lean), Check Out your Cap and Rotor. Look for corrosion at connectors and clean up your crank sensor if its dirty or dusty. That was what was keeping my 89 from sparking and burning all the fuel properly. look for leaks and replace as necessary. replace your fuel filter. you could clean up your throttle body and put some seafoam through it if you would like and it should run like a champ :]

Thanks a bunch. No I didn't replace the water pump, just the timing belt and crank and cam seals. I'll look into the water pump. It looks like my valve gasket is leaking as well, is that an easy fix? Just take the head covers and rockers off and get to it?

valve cover gasket isnt hard. just remove the bolts take the cover off and just replace the gasket. clean all mating surfaces and replace. would be a good time to adjust valves if you have the skills. start with a cold motor. your gonna have to turn the crank to TDC on cylinder 1 and loosen the lock nut and with a feeler gauge and measure between tip of valve stem and rocker arm. spec is .010 of an inch. continue rotating the engine through all the cylinders doing this for every intake and exhaust valve. it wouldnt hurt to go through and check after you adjust the valves and do some fine adjustments. the full procedure is online. a place to check would be pelican parts. they have alot of procedures on there

locknut torque 8 ft lbs

Check radiator hoses and drive belts. Consider gaerbox and rear axle oil changes. Suspension bushes will need checking. Wheel alignment should be considered. Change fuel flexibles and vaccum hoses.

Gaskets are all passed there prime. Hard driving will prove that. I would take care of the ox sensor. If its bad its hurting you gas mileage. Take a look at your brakes, wouldn't hurt to do a over haul. Pleading, pad, and rotors.

Complete fluid flush and all filters is always a good idea. I think that you should put new rotors and rebuilt calipers on your car. having them rebuilt is very cheap. and they are great!

inspect your tierods, your control arm balljoints. and your swaybar links. look for play in the joints.

those are also not to expensive to replace. and if you do replace them, you can use the opportunity to sawp to solid control arm bushings for added feedback.

after that is done, Review your suspension,

The sad question is: 'How prime do you want to spend?'

Originally Posted by HicksLJames

Did you replace the water pump when you replaced the timing belt? Go through the Ign system how old are the wires? pull your plugs and see if you can see what your O2 sensor is talking about (rich/lean), Check Out your Cap and Rotor. Look for corrosion at connectors and clean up your crank sensor if its dirty or dusty. That was what was keeping my 89 from sparking and burning all the fuel properly. look for leaks and replace as necessary. replace your fuel filter. you could clean up your throttle body and put some seafoam through it if you would like and it should run like a champ :]

I replaced the spark plugs, because the others had clearly been in there too long. I'm no pro at diagnosing how lean/rich or whatever else the spark plugs can tell. Here's a picture, can you see the plug well enough to take a shot at perhaps what that O2 sensor may be talking about?

Originally Posted by BMWFatherFigure

The sad question is: 'How prime do you want to spend?'

You're right. That is the sad truth. Unfortunately I'm forced to keep it pretty budget.

Your plug tells me you are running junk fuel for a start...
So you must be running it in the USA or Angola

If you want to take a plug-chop, you must look into the front of the plug with a loupe

Yeah those plugs look fried... and for the A/F ratio. I just went out and bought a wideband and a guage and welded a bung in my exhaust and installed it. took alot of guess work out but its not something that someone inexperienced should try and do but it does help alot