Question about the engine.

[Sirmario]

Greetings all, I am in the market for a z4 2009+, i really find these cars attractive and need a fun cat to drive. I currently own a CLS550. Love it, but I want a two seater manual. The more I research the Z the more I am starting to love.

I would drive it alot, 300 miles per week probably.
I am set on the 6 cylinder engine. Which one is more reliable?
S30i? Or s35i?
If you have any other suggestions or tips please let me know. Looking forward to being a long time member.

Regards
M.

[Surfwooder]

No matter which one you choose, change all the fluids, engine oil, transmission oil, power steering fluid, and even brake fluid. Check the top, for noises opening and closing, also time 22 seconds each way. Look along the interior of the top for oil stains. The top goes up and down using hydraulics, and a leaking hose means lots of trouble, and money for a repair. Also, in the top there are a lot of either Hall sensors, or microswitches. I would also change the two salmon colored relays located on the hydraulic motor block located in the trunk, just to the rear of the battery. These relays control the direction of the top motor for up, or down movement. They handle the full load of current, if the contact burn out you're either stuck with top up, top down, or mid way between. If the top gets stuck in the trunk, there is no emergency "up" but a trip to the dealer. The top must be up to change the relays. Notice in the battery area if water has pooled in there, that means a leak in the trunk seals, or roof seals. Best to clean all the seals on the top, recondition with gummy fludge, and lube all the tops hinges with spray lube. Good luck on your purchase of a E89 Z4

[Sirmario]

Thank you very much for the input will definitely do this.

[BimmerBreaker]

The N52 (30i) naturally aspirated 6 cylinder will be more reliable than the turbocharged versions (35i/35is). The N52 was only used for 2009-2011 "30i" models. It makes less power than the turbocharged 35i but it is still a lot of fun and is easier on gas too. It is IMO the best option if looking to be a long term owner of an E89