Heater not working and its cold out here...

[Killacortes]

So i have a 1990 325i with an m50. My heater works when im at a stop or if im going at slow speeds. but if im on the highway/freeway going high speed it only blows cold air. Also when i turn the fan on it doesnt work all the time, sometimes if i hit smack it a little bit i can hear the fan start lol

Anybody got any ideas on what to check first????

[mamzak]

Thermostat?
Coolant level?
Heater core?

[87e30]

Does it work initially when you turn it on then stop working?

If so check your heater bypass valve and make sure the hoses are oriented properly going into the heater core.

[Killacortes]

no it turns on sometimes but not all the time
hoses are good
thermostat is like 4 months old

so heater core or valve??
what makes the blower stop turning on or off

[glucklich21]

How cold is the engine running? As for the fan, I have the same issue, I think it's just the fan as my old one didn't do it.

[Danny]

Your hoses going into the firewall are routed backwards.

[e30trooper]

Your hoses going into the firewall are routed backwards.

could this really happen? my heater sucks ass, never gets hot. last owner rebuilt the engine.

[Danny]

If its hot at idle and cold at high rpms, yes.

[e30trooper]

If its hot at idle and cold at high rpms, yes.

hmm. its sorta hot when first turned on then cold since. Your not fuckin with me danny are you? If your right i will buy you a paid of boxers with ur name on it :)

[Danny]

No I'm not fucking with you.

[e30trooper]

No I'm not fucking with you.

ok good. i might just take your work and tomorrow swap them around. i figured it might be the thermostat.

[Killacortes]

How cold is the engine running? As for the fan, I have the same issue, I think it's just the fan as my old one didn't do it.

engine temp stays right in the middle.

Your hoses going into the firewall are routed backwards.

the hoses are not backwards

its hot at low speed and cold at high speed
i can be at 5k in 1st and feel the heat but at 2.5k going like 40 or something it gets cold again

[Danny]

Oh okay, well that sounds like a bad blower motor.

[ethrtyiS]

ive actually got the same issue. it sucks because its only going to be getting colder.
i need to have someone take a look at mine.

[Killacortes]

Oh okay, well that sounds like a bad blower motor.

would that be the same reason why it only turns on sometimes?