Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
Squeaky Dashboard
I own a 2011, 335i E93 with the M Sport Package.
At 15 years old and 59,500 miles on the clock, it has developed a squeak in the dashboard. I hardly hear it driving with the top down and the music playing; however, with the top up, it is annoying.
I bought the car 12 years ago with 30,000 miles. The car has been garage kept since I’ve owned it. I like the car and would like to keep it. Do you have any suggestions?
Bruce
I’m sorry to say that the convertible is never ever going to be quiet. If a noise has developed, there are a few things you can do to isolate it but I have no guarantee that you can eliminate it.
- Consistently duplicate the noise and identify the area it is coming from.
- If the noise occurs when going over bumps, you will need to duplicate the noise and then apply pressure, with your hand, to the area it is coming from and see if the noise changes. Repeat this until you are able to get a consistent change.
- If you can hear it and there is no change in whatever you try doing to suppress it, you will need to start removing dash components. Remove components and then drive the car, keep doing this until the noise stops or changes.
- Worst case scenario is the dash needs to come out and be reinstalled.
- Pro tip: Check areas that are on the engine bay side and make sure any support braces are tight. Sometimes dash noises can be coming from the engine bay and reverberate through the car. I know the E93 has at least two braces that connect to a bolt on the base of the windshield by the cabin filter housing. Worth a check.
- Turn the radio up.
M240i A/C Hot Flashes
“The A/C is working perfectly. Poor A/C is a brand feature” was the answer I got from a dealer on my second visit two months after having bought my brand-new M240i coupe in 2018.
The issue that caused the dealer visits is still the same issue that happens today, eight years and 57,000 miles later. It can best be described as an ice freeze ball, which I have been told at some point or another does not exist. I have never had the A/C in the car serviced.
The issue is that, under the right conditions, the system gradually starts losing air volume while both the fan and compressor gradually increase in speed, and at theend, there is no air flow at all and, I feel very confident, that if I do not shut off the system, the fan and/or compressor would self-destroy. You live and learn, and over the years, I have found out that if I let the car sit for a few hours, the problem goes away and the A/C works fine.
Below 80 F, life is good with the A/C. Between ~85-95 F, you notice a drop in performance, but it still sort of works. At ~97+ F with the Texas sun hitting directly driving on I-10 West, I can consistently kiss the A/C goodbye. Next morning it’ll be fine. I do have a 10-year-old, 150,000 miles Subaru Outback with an A/C that is impervious, almost defiant of the Texas heat. I can churn ice cream while the asphalt melts, so I just leave the Bimmer in the garage.
s this truly a characteristic of the brand, as the original dealer claimed? Can it be fixed, and what might be causing it? If it is a leak, I am amazed that the original refrigerant has not been fully depleted after eight years. By now, fixing any major A/C problem probably would cost more than the residual value of the car, and before I do anything I would like to know your opinion.
Ivan Lozada
Sugar Land, Texas
There are a couple of factors at work here. The first is that the system uses 1234yf refrigerant which does not perform as well as the previous style of refrigerant, R-134. BMW made this change back in 2015 (give or take) because the EPA mandated the 1234yf stuff is better for the environment. But when the A/C complaints started coming in, the “no problem found” answers were coming back to the customer with no repair to perform. The answer ended up being the refrigerant just isn’t as good.
Secondly, the conventional A/C condenser (air cooled, just like an engine radiator) was phased out and converted to a water-cooled system that eliminated the conventional heat exchanger. This is often what a secondary fan was used for on older vehicles. But that water-cooled system uses engine coolant, the engine radiator (with aux coolers), and the engine fan to perform the duties of the A/C condenser for a 1234yf system.
A/C works best with the car rolling down the road, to ram air over the front bumper. When at idle, it will kick up the (engine) fan speed in order to keep air flow over the radiator, to keep the condenser working. A drop in air flow (over the radiator) can cause a hiccup in which you might notice a drop in A/C performance. The car does its best to compensate based on whatever A/C settings you have at the moment.
As someone who used to live in Mckinney, Texas, I know what you’re dealing with in terms of weather. Texas is, for lack for a better word, disrespectful to its population when it comes to extremes in weather. Due to the heat and humidity, your A/C evaporator is working hard to keep cool. There ought to be a solid stream of water coming out from under the car while the A/C is running. Because it’s working so hard, I wonder if it’s freezing over and the evaporator temperature sensor tells the A/C control unit to pause A/C operation until it unfreezes. Which is why it works fine after sitting for a few hours.
While in operation, the A/C is going to do what it can to keep you cool. So do not be afraid of the fan speed picking up so you shut the whole system off. It’s supposed to do that. Will it hurt anything? No, there are pressure sensors in the A/C system that shuts itself off in over/under pressure situations. Your vehicle make and model did not have a high failure rate of A/C issues since my days at the dealer. Does not mean you could use a refrigerant top off, it wouldn’t hurt, but I doubt you have a lack-of-refrigerant issue based off your description.
