Bleedin' Bleeding

Sun Jun 09, 2019 9:20 pm

Hi guys,

Bringing up the much loved topic of cooling system bleeding (sorry!). Got a 316 that has no bleed screws on radiator or engine block, and struggling to get what I think is an airlock out. Flushed the cooling system yesterday and my hot air started working again (although it wasn't super warm), but today I can't seem to get any hot air even after running for around 15 minutes.

When I squeeze the cooling pipes when the engine is off small bubbles do seem to come out of the radiator (cap off), but almost indefinitely! I was doing it for about 10 minutes and started to wonder wether I was sucking air back in.

Any advice on fully bleeding out all the air when there is no bleed screw?

Cheers

BristolE30

Mon Jun 10, 2019 9:24 am

Never worked on a 4-cyl but I remember from very distant memory the heater control had to be fully hot for it to bleed.

Mon Jun 10, 2019 7:04 pm

flybynite wrote: ↑
Mon Jun 10, 2019 9:24 am
Never worked on a 4-cyl but I remember from very distant memory the heater control had to be fully hot for it to bleed.

Thanks mate. Yes I did have the heater fully blasting whilst doing it. It's strange the heating seems to have come back on now, it just not all that powerful. Its hotter when idling, and cools down once you get going. Engine temp gauge sits just a tiny smidge past 1/2 - haven't noticed it go any higher (was just idling for about 20 minutes) but to be fair haven't had the chance to take it out for a long drive yet.

Someone said it could be the heater valve or the actual heater matrix being blocked... All the cooling pipes seem to be hot. All seems a bit delicate!

Cheers
Jo

Mon Jun 10, 2019 10:10 pm

Ive had exactly the same issue as you, the heater is hotter when idling but is not very good on the motorway. The engine temperature suggested no problems as it sat just slightly past the middle. Had my heater matrix changed and yes it was very blocked. Not an easy job to change though.

Mon Jun 10, 2019 11:50 pm

MyOtherCarIsAnE30 wrote: ↑
Mon Jun 10, 2019 10:10 pm
Ive had exactly the same issue as you, the heater is hotter when idling but is not very good on the motorway. The engine temperature suggested no problems as it sat just slightly past the middle. Had my heater matrix changed and yes it was very blocked. Not an easy job to change though.

Ah that’s interesting - so once you changed it it worked fine? Was it possible to refurb the old matrix or did you have to buy a brand new one?

Tue Jun 11, 2019 1:26 pm

If im honest, I havent had a chance to get the car out recently due to the horrible weather. I bought a new matrix, not too expensive, the old one looked terrible when removed as is to be expected with such an old part. In your case, I doubt it is the heater valve which is the problem, the way to check this would be to listen for the opening of the valves when you turn on the heater, if you can hear this then this is not the issue.

Tue Jun 11, 2019 11:48 pm

MyOtherCarIsAnE30 wrote: ↑
Tue Jun 11, 2019 1:26 pm
If im honest, I havent had a chance to get the car out recently due to the horrible weather. I bought a new matrix, not too expensive, the old one looked terrible when removed as is to be expected with such an old part. In your case, I doubt it is the heater valve which is the problem, the way to check this would be to listen for the opening of the valves when you turn on the heater, if you can hear this then this is not the issue.

Yes I think you are right, there is also a definite change in temperature when you switch between hot and cold, so think valve is okay.

Be interested to see how your heating is after the matrix change. Let me know! How much was the part roughly?

Thu Jun 20, 2019 11:58 pm

How long should it take for the engine to get to operating temperature?