1994 325i heater problems

[iveson2]

My daughter's 1994 325i heater blows only room temperature air. I would like to change the thermostat, hoping the current one is stuck. Where is the thermostat and what tips might there be in replacing it?

[MPWR]

The thermostat is on the front of the engine. This is how to replace it. (Incidentally, if you're going to work on your BMW, I strongly recommend Wayne Dempsey's book, along with a maintainence guide like Bentley's).

But I'm not sure this will change the heater performance. A stuck thermostat may prevent the heater from blowing hot air, but it usually creates other more obvious problems also (and it's not hard to tell if the thermostat needs to be changed).

Does the engine overheat? Or does it not get to operating temperature quickly, or at all? These are signs of thermostat problems.

How's the coolant level?

[iveson2]

Originally Posted by MPWR

The thermostat is on the front of the engine. This is how to replace it. (Incidentally, if you're going to work on your BMW, I strongly recommend Wayne Dempsey's book, along with a maintainence guide like Bentley's).

But I'm not sure this will change the heater performance. A stuck thermostat may prevent the heater from blowing hot air, but it usually creates other more obvious problems also (and it's not hard to tell if the thermostat needs to be changed).

Does the engine overheat? Or does it not get to operating temperature quickly, or at all? These are signs of thermostat problems.

How's the coolant level?

The engine is not overheating. The temp needle stays in the middle. Seems to warm up on average pace. I flushed the collant last week and filled anew. The coolant resevoir is maintaining at proper level. Fuses are OK. Blower fan fine. A/C operates normally. The thermostat idea was just an idea of an expensive possible solution. I would be open to other possible solutions. Back to the thermostat, where exactly in the front of the engine should I find it?

[Scrapper]

the top hose from radiator leads you to where the thremostat on the moter.

[Broken-wrench]

Some of these cars REQUIRE that you bleed air from the systems to get them to function correctly. On my '94 318IS, there is a button on the top of the radiator that has an X shaped slot for a large screw driver. That is the bleeder valve on the coolant system. If the heater worked prior to changing the coolant, it needs bled. If that's not it, then the heater control valve mounted on the firewall is to blame. This valve is how the cabin has 2 temperature controls as the heater core has 2 sides, one for the driver & the other side for the passenger. You have 1 feed hose from the cylinder head to this valve and 2 leaving it to the heater core/s. There is then 1 return hose from the heater core back to the engine.

Let us know what you find!

One more thing... Does she have the dash vent temperature control wheel set on "blue" for ambient , outside air or is it set to "red" to run air thru the heater core into the car via the dash vents?

[Bear]

Son-in-law has a1990 325ic abnd he put a 180 degree thermostat in her and she blew warm air, replaced that stat with a 195 one and now it works fine. Should be a bleed screw right on or next to the thermostat housing for bleeding air.

[Bear]

I mis-spoke, the thermostat we put in was a 191 F. I believe the factory standard is 80 degree C or 176 degrees F.