No heat from the bottom hose.

[Vince70]

Today while I had a spare morning I decided to drain the coolant on my fathers E36 Bmw 4 pot and did the normal procedure of putting the heater on full blast etc to make sure it was air lock free.

 

I decided to leave it running for 30 minutes to see it the car was behaving itself and it got up to temperature slap bang in the centre of the gauge nice and quick as normal and it won't go past that and the heater is nice and warm.

 

But the problem is I don't seem to be able to get the bottom hose on the rad to heat up which I was wondering was due to an airlock or maybe the stat doesn't kick till maybe it gets to a higher temp which the car doesn't seem to get to.

 

So I wondered if there's anything I could do but to be honest I've never checked the lower hose for heat before on this car and wondered if it was normal.

[vulgalour]

Remove the thermostat and run it up to temperature, see if the hose is warm then.  If not you may have a blockage/air lock elsewhere in the system.

[PiperCub]

Do E36's suffer from the same waterpump & thermostat issues that the later E46's do? If so, could this be at least part of your trouble along with an airlock?

 

After 30 mins running, the bottom hose should at least be warm IMO.

[Station]

Drive it rapidly on a private road (industrial estate), slam on the brakes, swerve violently side to side, reverse and slam on brakes. Just repeat that until you feel hot air through heater/pipes.

It saves faffing round with squeezing pipes/waiting five hours with the cap off to get air bubbles out (zzzzzz).

[Split_Pin]

^^Don't forget driving through the pile of cardboard boxes!

 

Id agree though, just drive it, that's what I do after a coolant change.

[dollywobbler]

Leaving a car just ticking over at this time of year isn't very good for it anyway. I'd always take a car for a short run after coolant replacement - not too far in case something's up, but enough to get it nicely warm and to get the heater going nicely. Always fun on cars with no sodding temperature gauge!

[twosmoke300]

Depending on cooling system layout a cool bottom hose used to mean that the radiator is working well . But BMW being from the fatherland probably has an upside down system.

[Vince70]

Cheers Two smoke that's put my mind at ease, especially as it's not my car but my fathers and I'm away again tomorrow so I wouldn't want to get an irate phone call about his car broken down on the side of the road with a cloud of stream coming from the bonnet.