E36 318is heating issue

[GazC]

Hi fellas, brand new to the forum and BMW's. Bought myself a fairly clean and tidy e36 318is just over a week ago. I've done a google search and know this question has been asked a million times before but I'm not getting any hot air in the cabin. The water pump badly needed replacing so did that yesterday and flushed the system and filled it up again and bled it so it's all good. Temperature gauge is working fine, fan is working also but the air is stone cold. Not totally up on my beemer's so is there anything small I could be missing. Didn't bother changing the thermostat as it's working fine from what I can tell...any other areas to check?

Thanks in advance.
Gary

Sent from my GT-I9300 using Tapatalk

[Paddy]

Sounds like your thermostat is stuck open, did you have that replaced while the water pump was getting done?

Hi fellas, brand new to the forum and BMW's. Bought myself a fairly clean and tidy e36 318is just over a week ago. I've done a google search and know this question has been asked a million times before but I'm not getting any hot air in the cabin. The water pump badly needed replacing so did that yesterday and flushed the system and filled it up again and bled it so it's all good. Temperature gauge is working fine, fan is working also but the air is stone cold. Not totally up on my beemer's so is there anything small I could be missing. Didn't bother changing the thermostat as it's working fine from what I can tell...any other areas to check?

Thanks in advance.
Gary

Sent from my GT-I9300 using Tapatalk

Edit: Just re-read and you mention the stat is working, did you remove it and throw it in hot water to see it actually move? If your engine is m42 the stat can be removed from the housing and it's cheap enough to replace, if the engine is m44 I think the entire housing has to be relplaced as the stat is formed into the housing.

[hamish262001]

Sounds like an air lock
Was the heater working before cooling system work?

Sent from my HTC Desire X using Tapatalk

[GazC]

It sort of worked but only luke warm air but the water pump was basically goosed so thought replacing that and a system flush would do the trick. Didn't change the Thermostat as thought it would be ok...would it be stuck open?

Edit:it's an M44 engine and I didn't physically remove the thermo to test it no. Could that be the fault. Checked the coolant levels again this morning and it barely moved so don't think there is any more air trapped.

Sent from my GT-I9300 using Tapatalk

[Venom]

Put the front of the car up on stands, open the rad cap, start the car, let it get up to temp, get a large pipe and some water, place the pipe in the rad where you would normally put in the water, and then pur in the water down the pipe to get it up over the level the rad can hold and turn the bleed screw slowly. Once all the air has escaped then bring it for a spin. See if this helps.

It's also worth while making sure that the Heater control valve (under the battery tray, at the fire wall is working). Also do you have digital air con or the non digital? If digital I think the motor or resistor can be an issue.

Let us know how you get on.

[Paddy]

It sort of worked but only luke warm air but the water pump was basically goosed so thought replacing that and a system flush would do the trick. Didn't change the Thermostat as thought it would be ok...would it be stuck open?

Edit:it's an M44 engine and I didn't physically remove the thermo to test it no. Could that be the fault. Checked the coolant levels again this morning and it barely moved so don't think there is any more air trapped.

Sent from my GT-I9300 using Tapatalk

It sounds like either an airlock or the stat is stuck open. If you can take out the housing with the stat, you could try drop it in boiling water to see if the bi-metal strip causes it to move, if it's broken it will stick open as that's the design, they fail open. If it were to fail closed as in stuck shut, the engine would overheat fairly quick and blow the head-gasket. It fails open to allow the coolant to circulate. However the engine will eventually overheat this way too.

If there is an airlock, one side of the hosing at the rad would be hard; as in pressure in it, and the hose on the other side of rad, you will be able to squeeze the hose together; as there is nothing passing through so no pressure.

[GazC]

Well the car heats up and drives completely normally as in the temp gauge rises when car is fully warm and cools normally also. It is digital aircon so maybe that has something to do with it. The guy I bought it off mentioned some loose wire or connection under dash in passenger footwell but he hadn't a clue. Is there anything in that area to check maybe?

Sent from my GT-I9300 using Tapatalk

[armando]

Well the car heats up and drives completely normally as in the temp gauge rises when car is fully warm and cools normally also. It is digital aircon so maybe that has something to do with it. The guy I bought it off mentioned some loose wire or connection under dash in passenger footwell but he hadn't a clue. Is there anything in that area to check maybe?

Sent from my GT-I9300 using Tapatalk

had hou heater switched to max hot and max flow when you was bleading it?
i would chech does the wheater valves move at all

[gn3dr]

You said you are not getting hot air into the cabin. Is the fan blowing cold air? My pollen filter was filthy and it made a big difference to heater temperature once I changed it.
Curiously it seemed to highlight a stuck open stat also. Before I changed my Pollen filter, my car always head up to about the middle of the temp gauge. Once I changed my pollen filter I noticed it took longer for the temp gauge to reach midway - highlighting a stuck open stat. I changed the stat and now it heats up to middle of guage within 5 mins driving.
The 2 things shouldn't really be related. I can only assume that lack of air flow through pollen filter took away the cooling effect of air flow through the heater matrix.

[GazC]

Yeah I had the fan switched to max heat while the system was being bled.

The fan blows just cold air into the cabin do possibly needs a new pollen filter...that couldn't be the whole cause though could it? From what I'm reading and what I've described everything is kind of pointing towards and failed thermo.

Sent from my GT-I9300 using Tapatalk