Weak heater...car also takes a LONG time to warm up.

[Denton]

Hey boys and girls,

My 525i that I've had since the beginning of fall takes forever to warm up. I'm talking 25 minutes for the water temp to reach the middle, driving on surface streets.

Once warm, the heater is very weak. Not only is there not much air being blown, but the heat doesn't feel, well, HOT. I know that I do have the controls adjusted correctly. :) The "4" setting on the blower feels like what "2" should blow, but is very loud.

I'm thinking that the microfilters need to be changed, but surely there is another problem with the car.

Thanks for any and all advice.

[stilljester]

Have you replaced the thermostat?
If the blower speed isn't proper have tested the resistor?

[Denton]

Have you replaced the thermostat?
If the blower speed isn't proper have tested the resistor?

The thermostat was replaced by a new OE one by the PO at around 75k miles.

The blower speed increases like it should, but when it's on "1" you can hardly feel a thing through the vents.

Have not tested the resistor...so these symptoms are similar to a bad resistor?

[stilljester]

The thermostat was replaced by a new OE one by the PO at around 75k miles.

The blower speed increases like it should, but when it's on "1" you can hardly feel a thing through the vents.

Have not tested the resistor...so these symptoms are similar to a bad resistor?

Yeah mine was just like that - setting on "1" felt like nothing a "4" was basically "2-3"

It take longer to order the part then to install it.
http://www.bmwe34.net/e34main/maintenance/electrical/Data/Sword3.jpg

[colo525i]

fan may be part of the problem but the car shouldn't take that long to heat up. I might need a few miles to get full temp even on a really cold night. I'd try a new thermostat while you're at it. They like to pop apart, that's how mine was when i got it out.

[Denton]

Hmmm...thanks for the responses.

So maybe my thermostat just takes a long time to open up? (Not really sure how it works).

It NEVER gets hot, and the water temp will be dead in the middle, but it just takes 20 minutes to get there, and the heat isn't really hot.

Thanks again, and those PNs are very helpful.

[Derek A.]

I have the same problem.

I know my car doesn't have the microfilter and I just cleaned up the heater core.

My thoughts tend to drift toward the blend doors. As I have decent heat but nothing coming out of my feet.

[gtopaul]

Hmmm...thanks for the responses.

So maybe my thermostat just takes a long time to open up? (Not really sure how it works).

It NEVER gets hot, and the water temp will be dead in the middle, but it just takes 20 minutes to get there, and the heat isn't really hot.

Thanks again, and those PNs are very helpful.

You can tell for sure if it's the thermostat by CAREFULLY touching the lower radiator hose after about 10 minutes of warming up. That hose should be damn hot and if you can grab it and hold on (not hot) you've either got a bad thermostat or water pump impeller has come apart.

Paul

[Denton]

Thanks.

Paul: I promise I won't sue you if I burn myself. :)

[gtopaul]

Thanks.

Paul: I promise I won't sue you if I burn myself. :)

I appreciate that.;) I do this test almost everyday on the service isle at work (Bimmer place).

Paul

[shrike071]

IMHO - I place very little stock in anything the PO said he/she did to the car before I owned it. To me, it sounds like a classically failed thermostat.

[Denton]

IMHO - I place very little stock in anything the PO said he/she did to the car before I owned it. To me, it sounds like a classically failed thermostat.

Gotcha. My car was a CPO car, so everything was done at Global Imports. I've got an Excel file of all of the service, but it's in Atlanta.

[BillionPa]

replaced thermostat 30000 miles ago... sounds like its due for a new one.

[brick8]

Mine takes about ten minutes to reach the middle line when it is really cold out (0-10 degrees F). Seems like forever when it is that cold. My volvo warms out in about 2 minutes. Plan on doing the thermostat asap.

[Denton]

Thanks for the advice guys.

What thermostat to order (how cold)? Do I order a TStat gasket as well?

[Alexlind123]

Thanks for the advice guys.

What thermostat to order (how cold)? Do I order a TStat gasket as well?

Whoever answer this question, could you answer it for the 535i engine as well?

[bigtisas]

Had the same problem. Car took a long time to warm up. Replaced the thermostat last month and solved the problem. :) I bought the t-stat from autohausaz.com and it came with a gasket.

The weak air blown problem could be the microfilter. If you haven't changed it for many years, do it.

[zhandax]

The 540i and (it looks like) the 535i have an O ring instead of a gasket for the thermostat Thermostat goes in the water pump, O ring goes on top of that, housing goes on top of that. O ring seals the housing. The 525i is a different design, but it appears to use an O ring also. Yes, replace the O ring. They are much cheaper than doing it twice. Biggest pain is draining some of the coolant. Here are the parts for a 525i: http://www.realoem.com/bmw/showparts.do?model=HD63&mospid=47404&btnr=11_1503&hg=11&fg=35

[Dash01]

Bingo on the 535i O-ring placement.

Before you install the new T-stat, drill a ~1/8" hole near its lip, and place it at the 12 O'clock position when back in its housing. This allows air to move past, and makes bleeding the cooling system much easier. Also, open the heater controls to max heat when bleeding, and park the car nose high.

[AutoXr]

My fan problem was similar when I got the car. Dug down in there and found the microfilter. It was clogged with snow! Cleaned it all out and airflow increased a bunch!

[MikeM5]

Hmm...I actually have been having a similar issue with my M5. After replacing my radiator/cooling hoses, it seems to take a lot longer to get to the middle...

and the temp gauge again drops on the highway esp when not sustaining revs. t-stat definitely?


Hey boys and girls,

My 525i that I've had since the beginning of fall takes forever to warm up. I'm talking 25 minutes for the water temp to reach the middle, driving on surface streets.

Once warm, the heater is very weak. Not only is there not much air being blown, but the heat doesn't feel, well, HOT. I know that I do have the controls adjusted correctly. :) The "4" setting on the blower feels like what "2" should blow, but is very loud.

I'm thinking that the microfilters need to be changed, but surely there is another problem with the car.

Thanks for any and all advice.

[Vanguard]

Sounds like the thermostat is stuck open.

[grave77]

it happens even with new t-stats. they might jam. if they jammed open it will take time to heat the car and you will not feel hot air with the heater.

usually u wont feel the air flow like the cool air do, as it's kind of protection to ur health or you will get sick every time u leave the car. but you can still change the microfilter to get better flow. ur best place to check is that windshield and ur feet. there will be enough flow to know how its performing.

better you fix ur t-stat soon cuz it's not good for the engine.