Hi, I am getting summer maintenance done on my 2003 z4 e85 it currently has 106k miles. I have read on other forum posts that every 60k miles it is preventative maintenance to do a cooling system overhaul. This includes replacing: coolant expansion tank, radiator hoses, radiator, water pump, thermostat and thermostat housing. Does anyone know if this is correct or do you just replace parts as they go bad? Thanks
Cooling system preventative maintenance
- Thread starter Cprtt8
- Start date
North West Surrey
Welcome to the forum by the way. 
I bought a 12 year old E46 325ti in 2014 that had done 80k miles, and had the same M54 engine as the pre-facelift Z4 2.5i.
Within a couple of months it was losing coolant because the bottom of the radiator was bowed.
Rather than just replace the radiator my BMW Indy recommended a complete coolant system refresh rather than have one bit fail at a time, so IIRC it got a new radiator, expansion tank, thermostat, temperature sensor and auxiliary drive belt.
I'm not sure I'd replace all of that as preventative work, but if one bit failed I would do the lot while I was at it!
I don't think 60K is a hard and fast rule, it's more likely just an indication of when you might need to expect things to need attention.
I bought a 12 year old E46 325ti in 2014 that had done 80k miles, and had the same M54 engine as the pre-facelift Z4 2.5i.
Within a couple of months it was losing coolant because the bottom of the radiator was bowed.
Rather than just replace the radiator my BMW Indy recommended a complete coolant system refresh rather than have one bit fail at a time, so IIRC it got a new radiator, expansion tank, thermostat, temperature sensor and auxiliary drive belt.
I'm not sure I'd replace all of that as preventative work, but if one bit failed I would do the lot while I was at it!
I don't think 60K is a hard and fast rule, it's more likely just an indication of when you might need to expect things to need attention.
https://germanautosolutions.com/store/bmw-12bar-coolant-cap/
Only got my Z4 this February, 04, 3.0L, 53k.
Was searching for info on the web and found this site. Thought the propaganda on this item made sense, ordered one, along with their DISA upgrade kit. I put the cap on as soon as it showed up, holding on to the DISA kit for now.
It does make sense and not much money.
FWIW
Only got my Z4 this February, 04, 3.0L, 53k.
Was searching for info on the web and found this site. Thought the propaganda on this item made sense, ordered one, along with their DISA upgrade kit. I put the cap on as soon as it showed up, holding on to the DISA kit for now.
It does make sense and not much money.
FWIW
Awesome info, thank you all very much for your insight. Currently there is no leak or problem with the cooling system, so I will probably hold off on the cooling system overhaul for a while. I purchased the car last August and I have no service records from the past owners. There were some basic maintenance that had not been done to the car so I assume the previous owners were not into preventative maintenance. Below I will list all the repairs, modifications, and maintenance I have done since I purchased tge car. I will look into the DISA. I was un aware of that issue.
Replaced: intake/throttle boot, battery, spark plugs, all four shocks and struts, front upper and lower control arms.
Modifications: steel triangular front shock support (made handling so much better, highly recommend this), sprint booster (another great mod that makes the car feel very zippy.) and clutch delay valve. Replaced stock seats with Braum elite series racing seats.
Misc: ultimate cup holders, repaired the center storage door between the seat backs with a small screw. (The little plastic bit that triggers the switch to turn off the compartment light had broken off.)
Replaced: intake/throttle boot, battery, spark plugs, all four shocks and struts, front upper and lower control arms.
Modifications: steel triangular front shock support (made handling so much better, highly recommend this), sprint booster (another great mod that makes the car feel very zippy.) and clutch delay valve. Replaced stock seats with Braum elite series racing seats.
Misc: ultimate cup holders, repaired the center storage door between the seat backs with a small screw. (The little plastic bit that triggers the switch to turn off the compartment light had broken off.)
Attachments
1066 Country
Love the color as well, probably my favorite E85 color option. The seats are sweet. I did a web search and the price seems reasonable too...I'm just not ready to give up the heated/adjustable seats though...but they sure are nice.
Thank you all for the feedback. Here are some links to some of the parts.
Shock mount support
https://www.amazon.com/gp/aw/d/B01E6P7PAM?psc=1&ref=ppx_pop_mob_b_asin_title
Seats
https://www.braumracing.com/product/elite-x-series-racing-seats-black-stitching/
I do know the Braum Elite and Elite-X seats fit well, just don't forget the brackets.
I like to go on long road trips and the original seats were a bit hard and didn't have much support. The braum seats are super comfortable.
Cup holders
https://www.ultimatecupholders.com/
Sprint booster
https://www.amazon.com/Mini-Mania-Sprint-Booster-2003/dp/B01NA7ZQPQ
Thanks again!
Shock mount support
https://www.amazon.com/gp/aw/d/B01E6P7PAM?psc=1&ref=ppx_pop_mob_b_asin_title
Seats
https://www.braumracing.com/product/elite-x-series-racing-seats-black-stitching/
I do know the Braum Elite and Elite-X seats fit well, just don't forget the brackets.
I like to go on long road trips and the original seats were a bit hard and didn't have much support. The braum seats are super comfortable.
Cup holders
https://www.ultimatecupholders.com/
Sprint booster
https://www.amazon.com/Mini-Mania-Sprint-Booster-2003/dp/B01NA7ZQPQ
Thanks again!
Thanks. The seat swap was pretty straight forward. Braum has precision fit mounting brackets and a hardware kit. I recommend ordering everything through Vivid Racing via phone call (same price as ordering from Braum directly). The operators can help make sure you have everything you need. I actually paid my mechanic $80 (local full service Midas shop) to do it for me since I was having some other work done, and I have some significant back issues, but it is a very easy straight forward installation.
Be careful removing the old seats, they are very heavy.
It's pretty much taking out the 4 bolts that mount the seat to the floor and the bolt that attracts the seat belt buckle, put the new seat and brackets in and put the new bolts in and you are done.
Note: You will have an airbag light since there is no longer a connection to a pressure occupancy sensor. To fix this you need to take the car to a shop that has the BMW software and get a bypass programmed to the computer. This took me a while and a lot of research to figure out.
I will try to post more pics of the seats soon. I can't open the top at the moment, because I am replacing a power window regulator and the automatic top rolls down the windows before pulling the top back. Hopefully my new regulator will be here soon. (coming from Germany)
Be careful removing the old seats, they are very heavy.
It's pretty much taking out the 4 bolts that mount the seat to the floor and the bolt that attracts the seat belt buckle, put the new seat and brackets in and put the new bolts in and you are done.
Note: You will have an airbag light since there is no longer a connection to a pressure occupancy sensor. To fix this you need to take the car to a shop that has the BMW software and get a bypass programmed to the computer. This took me a while and a lot of research to figure out.
I will try to post more pics of the seats soon. I can't open the top at the moment, because I am replacing a power window regulator and the automatic top rolls down the windows before pulling the top back. Hopefully my new regulator will be here soon. (coming from Germany)
I forgot to mention, another modification I have done is a back box delete (removing the rear most muffler: stock setup=exhaust manifold to catalytic converter to resonator to muffler to tips)reuse the original tips, and keep the muffler aka back box incase you ever want it back on. It sounds mean like a race car (great tone and nice crackles) and passes emissions just fine. It cost $110 at the local Midas. Awesome mod for the money. I absolutely love the sound! 
Have read and watched videos on that...I think I’m too old for that anymore. I like the stock sound.Cprtt8 said:I forgot to mention, another modification I have done is a back box delete (removing the rear most muffler: stock setup=exhaust manifold to catalytic converter to resonator to muffler to tips)reuse the original tips, and keep the muffler aka back box incase you ever want it back on. It sounds mean like a race car (great tone and nice crackles) and passes emissions just fine. It cost $110 at the local Midas. Awesome mod for the money. I absolutely love the sound!
I have a 2006 Ducati S2R 1000 that has nearly straight pipes. I had a shop fabricate the cans and I eliminated the CAT upstream from the cans.
My mechanic said he was “embarrassed “ when test riding the bike. I had it at another shop and the service manager said, “I’ll pull out your loud ass bike for you.” I haven’t ridden much in the last 2 years (not because it’s loud, other reasons). But, I do wish the Monster was a bit less loud. Maybe it comes with age ?