Interesting heat related problem

Hello!

We recently purchased a low mileage (55K) 2004 Z4 for my wife. The car has been working well, except for one puzzling thing.

Here in Kansas it gets pretty hot. The first time she had it out of the garage and sitting in the sun on a 105 degree day, she returned to find that despite the locks functioning fine, outside door handle would function. While on the phone with her I was able to find confirmation that this is an heat related issue with these cars, but remedy beyond the impracticable "wait until it cools off" advice. She was able to fiddle with it until one door opened, at which point the inside handle worked for the other door.

Additionally, she was unable to turn the key until the interior cooled off, and then experienced some mechanical resistance until the A/C had things cooled off.

Since then, I've noticed the passenger side outside door handle going inop when hot, but it comes back when it cools off.

I've had a similar problem with my 2001 330ci, but that was broken clips in the door. This really does come and go with the heat.

Does anyone have any advice before we head off to our independent BMW shop?

Thanks,

white

So to make sure I have everything straight. When hot outside both outside door handles will not open the doors? The locks all work normally though? The key when hot on the door will not turn correct? Does the inside door handle when hot open the vehicle with one or two pulls of the handle?

Thanks for your reply.

When hot, the outside door handles will not open the doors. Once in the car, the inside handles do function reliably.

The locks seem to function normally...that is that we get the normal audio queues of a 'beep' and the mechanical 'clunk,' and the locks pop up and down normally at the rear of the door.

Using the key in the door works normally. It turns and the lock comes up, but still no door handle actuation from the outside.

Regards,

~whitef

When hot and you unlock with the key does the lock rod move normally?

Yes. The lock rod pops up with either the button or the key.

Ok sounds like the lock actuators are giving you the issue and may need to be replaced. This can happen with either really hot or cold climates.

Thank you for the guidance.

Looking over the diagrams at RealOEM, I see a 512172024146 System Latch, right and a 512172024143 for the left side. Is that what you suggest be replaced?

Yes those are the actuators for both doors. Since this is a intermittent issue with the heat you may wanna have this checked out before you spend the money on those locks I know there kinda pricy. I have seen some very weird cases where the general module was causing the issue from bad relays.

We will do that. The parts are about $200 per side, plus probably about that in labor for our independent shop to put them in. Worst case, we could replace the driver's side and see if the symptom improves there, then do the other (or seek alternative medicine!).

Thank you again for your assistance.

~whitef