Migh Mileage - Maintenance Advice requested
 

This is about my 2001 X5 with a 3.0L inline 6 cyl engine.

The truck has more than 200K miles and keeps running and running sweetly and reliably. Rock solid. It is my daily driver and takes a lot of abuse, I will say. I pile up my tools in it and do field work such as HVAC, Plumbing and other Handyman type of work.

But I worry about that other maintenance should I do considering the high miles.

Should I change / replace the Timing Chain guides? I know that is critical for the V8's but this is an inline 6. If yes, how difficult is it to do DIY on it.

Transmission - I will NOT replace the fluid. Should I top it up? What top up flid should I use.

You could just replace transmission filter, and drain and refill whatever you had in the pan, it's only about 1/3 or 1/4 of your total capacity.
What's the maintenance history?
I'd change fuel filter, air filter, cabin filter, braking fluid, engine oil, power steering, diff fluid.
Scan with INPA, stay on top of errors.
Look up after the cooling system.
The radiator will crack after 100k since last replacement.
Same for coolant expansion tank. Depending on your funds, I'd consider replacing all weak point in the cooling system. Thermostat, waterpump.
Best of luck!

Your transmission is a GM 5L40E. Uses regular Dexron ATF, and if it craps out, it's pretty easy to get parts for/have rebuilt.

Can also have it swapped to a ZF 5-speed manual if you encounter transmission problems. I swapped my 2006 3.0i to a ZF 6-speed manual out of a factory manual X5. Manual trans uses the same transfer case and driveshafts as the auto (just have to use a 5-speed for 2001-2003 and 6-speed for 2004-2006).

-Check your front axles; the boots are very often torn on E53s. Your engine (M54B30) isn't prone to timing chain guide problems.
-Change your crankcase vent valve (CCV) if you haven't. If it goes bad, crankcase pressure could cause the engine to have a bunch of leaking gaskets
-Oil filter housing gasket is prone to leaking (gasket costs a few bucks, couple hours of labor to replace though)
-Valve cover gasket often leaks onto the exhaust manifolds on high mileage examples, causing smoke
-If you get a strange vibration from the front suspension at certain speeds, it's likely your tension struts/front lower control arms/thrust arms (different terms for the same part)
-If your window regulators haven't been replaced, REPLACE THEM ASAP. Otherwise, you'll roll your windows down, and at the most inopportune time, the window regulators will give out and cause your windows not to roll up, such as before a rainstorm.

Also, hello from a fellow Tampa Bay resident!

Thanks @vbelsky - for your hello. ALl things you mention seem to be up to snuff. And I have changed the regulators a few times. Plus the drivers door handle carrier several times.

I asked about the chain guide particularly because it is an interference engine. I own a 1990 Mercedes 420SEL with a V8 engine. In that car, if you do not replace the guides at 100K miles, you are asking for trouble. But that is a V8. Our BMW E53 3.0i is an inline 6.

WHere is the CCV (Crankcase Vent Valve) located? I better check it out.

Under the intake manifold, but pull the vacuum hoses off the vacuum distributor manifold and if you have mayonnaise in them you need to change the CCV and all the hoses. Lots of tutorials around to help.

I suggest checking the two hard coolant pipes behind the oil filter.
When I did the head gasket, these were obviously in need of replacement and the cause of a slow coolant seeping situation. You have to have the intake off to do the job.

And if you're going to take the intake off, definitely replace the CCV. It's much easier with the intake off. If you live in cold country, you'll likely need to.