On the topic of microfilters and clogged vents, etc...

[Jon K]

I've my 1992 525i with 160k on it. I bought it like... 3 years or so ago with 100k on it. Throughout my owning it, I've never replaced the microfilter and needless to say my ac vent (and heat for that matter) flow is crap! My sister has a 1995 530i (not sure when the filters been changed) and it pours heat out so much that if I have it on max heat on the feet (alas im a poet) it actually becomes irritatingly hot! So essentially, am I dealing with a clogged microfilter (of which I just ordered from BMA) alone or is there potentially some other reason why my vents don't blow very much???

Oh yeah, and my blower is fully functional -- it really screams at 4 but theres very little displacement... Duey or someone mentioned cleaning up the heater core... how would/where would I access that?

[Tcdoe]

Do cars without air conditioning have microfilters too? If not then my heater core must be clogged up too, because I'm not getting enough heat at all.

[JonE]

I would definately try that microfilter replacement first as getting to the heater core probably requires taking much of the dash apart. Many have reported much better flow after changing that filter, you must've seen some of the comparison pics?

[Jon K]

I would definately try that microfilter replacement first as getting to the heater core probably requires taking much of the dash apart. Many have reported much better flow after changing that filter, you must've seen some of the comparison pics?


I've seen the pics but I was more or less trying to see how much more work would be involved to get directly to the heater core, so as to not put the car back together and then have to take it apart should the filter not fix the issue

[JonE]

I haven't done the heater core removal on the E34, but did on my E30 and it was significantly more work to get to the core. I don't have the microfilter but, from what I understand it is like getting to the "sword" which was some work, but easy compared to getting to the core. If I were in your position I would switch the filter, then try the airflow before putting everything back together. Then, if needed, you'll save some time if you need to do more.

[mikemaster]

The microfilter really doesn't take that long to get to. It's mainly just taking the glove box out, and then a few other items. I'd say an hour to replace it and clean it out. BTW, I've found it helpful to have the car on ramps while working under the dash. Less strain on the back.

The heater core takes a good while longer to get to, (taking the center console out) and it's kind of unlikely that that would be clogged unless you don't have a microfilter. I was also able to clean some more leaves and junk out of the airways by removing the large access cover on the firewall, but that's only because I was in there for another project. :)