Engine runs very cold on working temp and heater dosen't blow hot air

[Slow325i]

Since i bought this 89 325i month ago ,needle almost never pass blue on temp gauge,and heater dosen't blow hot air just warm
I was wandering what could be wrong

[tyro2001]

your thermostat could be stuck open?

[Slow325i]

Today i check temp on every collant hoses and on thermostat housing with laser thermometer and all i got was 135-142F

BTW i checked headers (exhaust manifold) too, 450-500F

[Majin]

Check your thermostat, When I bought mine it didnt heat up all the way. I went ahead and bought a new thermostat thinking that was probably it. Mine was somehow broken and was partially open. They are cheap and easy to change.

[mysticguy04]

My cabrio did the same thing.
I bought the car from down south. I live in New England. I found out that the thermostat that was in the car was for higher southern temps and it ran cool. I replaced it with a new themostat and voila - the temp gauge is now right in the middle!

[Slow325i]

Whats stock thermostat 176,180 or 191F on 89 325i

[Slow325i]

Got new one today from Advance Auto Parts 176F (80C),and my old was stuck open,looks like it was BMW OEM part (meybe stock one who knows)
New one works fine and needle now almost reach half

Here is a few pics of old thermostat

[Smitty325e]

You will know the thermostat is working if the lower rad hose [ goes from lower-rad to thermostat housing on a 6 cyl ] stays cold until the engine warms up, at which point it will get warm (when the thermostat opens)