Z4 Maintenance?

[vietfobulust]

Hello everyone, I recently inherited a Z4 2.5si from my older brother. The car had 68k miles on it and I have put on 10k miles since then(78k now). He purchased the car used at 65k miles. He lowered it with H&R springs and put some Linea Corse 19"s on it.

Anyways, the car has been not been performing like when I first got it. I can start hearing the engine noise more. The car seems to respond slower as well. I have been doing oil changes myself w/ BMW Synthetic but other than that I have not done anything else. So my question is what kind of major maintenance work should I perform on this car so that it would drive just as new?

Being a college student, I cannot afford to bring it to the dealership or a mechanic. I was thinking of ordering parts and ask my uncle(who is a mechanic) to help me.

I love this car to death and I do not want it to break down... I could not find any maintenance guide except for a checklist. Please help me find out what typical maintenance work(mostly engine/transmission) should be done so that I can continue to enjoy this wonderful car, also any other suggestions would be fine too. Thanks!

[KN0XVILLE]

I'd say find a local euro tuner/repair shop; usually they can do the same maintenance work as dealerships but for a fraction of the cost.

[pokeybritches]

Ignore the BMW maintenance schedule for the most part. They consider transmission and differential "lifetime" fluid. They recommend 15k miles between oil changes. Many on this forum do 7500 mile oil changes and change the transmission and differential fluids every 30-60k miles (at least do it every 100k miles). Try a google search as well as a forum search, as there are many technically-minded individuals with quite a bit of experience with these cars that have their own maintenance schedules. Dealership maintenance is less than the minimum IMHO.

[vietfobulust]

Oh that also reminds me the car is an SMG and the shifts have been sluggish. Thanks for the tip, I will definitely get the transmission fluid and diff fluid switched out asap.

[pokeybritches]

I doubt that will make any noticeable difference in your performance though. Honestly, the best thing you can do for your performance is swap those 19's for lightweight 17's. The fluid changes are more upkeep, and will reduce deterioration over time.

[ZZZZ]

being as I just picked up a second hand Z4 on Friday and did a bunch of maintenance on it (since I don't know what was done previously on it).

- cleaned throttle body
- changed spark plugs
- changed air filter
- seafoam engine + gasoline
- changed transmission/differential AND SMG fluid
- oil change (lubromoly synthetic)
- clear drain hoses for soft-top (on my to-do list now)
- check/change brake pads (changed the two fronts)
- changed all engine/drive belts
- changed control arm bushings
- lubed all latches/mechanicals that I could think of

the car is driving better (most responsive) than when I purchased it... but I also downgraded from 18" summers to 17" winters which of course helps as well. But I still find it's thirsty for fuel compared to my 330i which has the same engine + is heavier. I still have to investigate and find out why. I do know that I need a new DISA valve, which may be the culprit.

I also haven't changed my fuel filter or cabin filters yet, but those are on the to-do as well.

[mhughett]

Don't owners of M54-engined Z4's do proactive replacement of key cooling system components (water pump, thermostat, belts, tensioners) every 60-90k miles? When I was on the E39 board, it was like a religious mandate that these be done on a regular basis and on newly purchased used cars that did not have this work done in their service records.

[ZZZZ]

water pump should already have the metal impellers instead of the plastic ones in 2003+. thermostat I usually do when I notice the car not warming up quickly, staying cold, or not much heat coming out of the HVAC. tensioners/pullys and belts should be done though. I also replaced my radiator as preventive since the old one got bent at the bottom of the car... (must've hit a speed bump or something similar). Sooner or later the reservoir usually cracks near the sensor too.

[mhughett]

Originally Posted by ZZZZ

water pump should already have the metal impellers instead of the plastic ones in 2003+. thermostat I usually do when I notice the car not warming up quickly, staying cold, or not much heat coming out of the HVAC. tensioners/pullys and belts should be done though. I also replaced my radiator as preventive since the old one got bent at the bottom of the car... (must've hit a speed bump or something similar). Sooner or later the reservoir usually cracks near the sensor too.

BMW went back to composite impellers and is currently NOT using metal in its water pumps for these cars. It's impossible to know whether your car has metal or not. Nevertheless, the bearings on these water pumps fail as much as the impeller and it's a good idea to change out the pump at 60k miles regardless of which type of impeller it has.