2003 25i air intake question

Chanceschmerr

Chanceschmerr

Member
 Bristol, UK
Site Supporter
Hi everyone!

The first Z4 ive had a close look at has a tempting price, and even though it has a lack of maintenance info, it seems in decent shape (certainly for the price)

One item giving me pause is the aftermarket air intake. It looks slightly dodgy to me...
20260124_162725.jpg

20260124_162334.jpg

I'm certainly aware of cold air intakes (I almost put one in my Tiburon all those years ago), but I have no direct experience with them.

Should it look like this? It does look kind of gungy, do you often change out the filter housing?

In the end - would any of you go near a car with something like this?

Thanks all!
 
Sometimes a sign that other things may have been messed with too. Cheap adjustable suspension etc. or hammered but not maintained.
Also kind of shows the mentality of the owner that the air filter is held in place with a cut down section of the battery clamp, held with a couple of cable ties. So I'd be straight round to the boot to check the battery is still clamped down.

There should be a lid on that box. As it is right now it’s drawing in hotter air than standard.
Very easy to source the bits you need from a forum breaker.
Go back to standard, it is a decent design.
 
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Looking again at your photo, and it's hard to tell, but is the rubber cracked on the top mount? If so, that'll need changing and chances are when you do you'll find the shock is worn out, so you'd need to be budgeting for another £250+, assuming you can do the work yourself?

How much is the car up for? Would give us an idea if it's worth pursuing, as there are still plenty out there to choose from.
 
I agree with the above. Buy a second hand air box and revert to standard. The engine maybe unforgivably filthy but a couple of hours elbow grease will bring that back up to scratch.

More concerning for me is the accumulated crud on the undertray. That could be oil, or coolant or both; so you ought to reassure yourself where it is coming from. Oil filter housing gasket leaks are easy to fix, but sump gaskets less so. Coolant system leaks are common, particularly from split coolant reservoirs and connectors.

I don’t know how choosy you can afford to be in Canada, but in the UK there are a lot of very presentable 2.2/2.5 Z4s out there at very reasonable prices.
 
Thanks for the advice so far, everyone! Lots to consider here!

The car is up for £1400, with perhaps some negotiation down. 114k miles on the Odometer.

Current owner bought it 6 months ago but hasn't really used it, and told me that previous owner promised maintenance forms but ghosted him without providing them once sold. It was that previous owner that I guess did the intake and whatever else has been done to the car - current owner did a oil change on purchase and thats about it. He did mention that the previous owner had recently replaced the brake pads and lines, and on my inspection the brakes have plenty of pad on them, so that story checks out.
 
enuff_zed said:
Sometimes a sign that other things may have been messed with too. Cheap adjustable suspension etc. or hammered but not maintained.
Also kind of shows the mentality of the owner that the air filter is held in place with a cut down section of the battery clamp, held with a couple of cable ties. So I'd be straight round to the boot to check the battery is still clamped down.

There should be a lid on that box. As it is right now it’s drawing in hotter air than standard.
Very easy to source the bits you need from a forum breaker.
Go back to standard, it is a decent design.
Click to expand...
I didnt check the battery, but when he pulled up, the door lock button by the shifter started malfunctioning, and the passenger side lock kept cycling, so we couldnt open the passenger door. After a few mins and turning off and on, it worked again. I suspect an electrical short...

I think I'd probably just replace the intake with a standard air intake. Current owner has offered to replace the filter with a new one
 
Zedebee said:
More concerning for me is the accumulated crud on the undertray. That could be oil, or coolant or both; so you ought to reassure yourself where it is coming from. Oil filter housing gasket leaks are easy to fix, but sump gaskets less so. Coolant system leaks are common, particularly from split coolant reservoirs and connectors.

I don’t know how choosy you can afford to be in Canada, but in the UK there are a lot of very presentable 2.2/2.5 Z4s out there at very reasonable prices.
Click to expand...
Yeah, the engine itself didnt show any smoking gun as far as current leaks go, but I do have that question. Belts look in good condition from what I saw.

I'm in the UK for at least a few years. My ultimate plan is to find a good 2009-2011 i23 or i30 Manual Z4 that I'd baby and aim to import back to Canada when I eventually have to leave the UK, but in suspecting that it might take me a little bit to find the right i23/i30, I thought maybe I should buy an older Z4 just to have something in the meantime that drives, and maybe learn a few things first hand with these engines. I've never had a BMW before, but willing to get dirty and learn (as much as my wife and kids will allow haha!)
 
Chanceschmerr said:
I didnt check the battery, but when he pulled up, the door lock button by the shifter started malfunctioning, and the passenger side lock kept cycling, so we couldnt open the passenger door. After a few mins and turning off and on, it worked again. I suspect an electrical short...

I think I'd probably just replace the intake with a standard air intake. Current owner has offered to replace the filter with a new one
Click to expand...
I think I'd look for a different one tbh.
Door lock could be the GM5 module or more likely the lock actuator deadlock messing about.
 
This one still appears to be for sale but too very close to you
W

FOR SALE Thread '2004 2.5 SE Sterling Grey Manual'

Selling my Z4 2004 2.5 SE manual, as we're moving house in the not too distant future, and it's looking like a garage won't be on the cards with the downsize.

Currently on 103363 miles, MOT til 5th August 2025. Sterling grey. I acquired the car in August 2021, and have since done the following work to it, at a local BMW independent...

26/8/21 Both front wheel bearings replaced & roof motor relocated to boot (97547 miles)
28/1/22 Cam cover seal (98476 miles)
18/7/22 Oil & filter change (99654 miles)
22/7/22 New expansion tank and thermostat (no receipt)
11/4/23 Both front coil springs...
  • Like
 
enuff_zed said:
This one still appears to be for sale but too very close to you
W

FOR SALE Thread '2004 2.5 SE Sterling Grey Manual'

Selling my Z4 2004 2.5 SE manual, as we're moving house in the not too distant future, and it's looking like a garage won't be on the cards with the downsize.

Currently on 103363 miles, MOT til 5th August 2025. Sterling grey. I acquired the car in August 2021, and have since done the following work to it, at a local BMW independent...

26/8/21 Both front wheel bearings replaced & roof motor relocated to boot (97547 miles)
28/1/22 Cam cover seal (98476 miles)
18/7/22 Oil & filter change (99654 miles)
22/7/22 New expansion tank and thermostat (no receipt)
11/4/23 Both front coil springs...
  • Like
Click to expand...
I didnt know there was a buy/sell on here, I'll have to check it out, thank you!

Been just on Autotrader and FB Marketplace to be honest..
 
Chanceschmerr said:
I didnt know there was a buy/sell on here, I'll have to check it out, thank you!

Been just on Autotrader and FB Marketplace to be honest..
Click to expand...
Not such a selection on here but decent quality motors.
Definitely hold out for a 6-cylinder model, or maybe look straight into getting the E89 you mentioned.
 
enuff_zed said:
Not such a selection on here but decent quality motors.
Definitely hold out for a 6-cylinder model, or maybe look straight into getting the E89 you mentioned.
Click to expand...
Oh, I wouldnt buy anything but a 6-cylinder, N52 or M54 engine. Thats a hard line for me, its the engine I've wanted for sure.

Thanks the for assistance here! I just messaged the gentleman to decline purchasing this one. Looking at a few other ones out there. Theres a 2011 i23 Highline Spec Z4 in blackpool with only 49.5k miles on it that I'm checking now, for £4800. Cat S....I'd need to do my homework on what was done to it.
 
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