Jump to content
Sign in to follow this  
aimlesslee44

Cooling System Air Lock?

Recommended Posts

1997 323i E36. I drained the coolant from the radiator via blue plug and top and bottom hoses, flushed radiator (not the engine block) and refilled via the reservoir with new coolant (50/50). It didn't appear to take as much as drained out howver have monitored temp gauge and its fine and reservoir level and its fine. Could I have an air lock? Would the temp gauge show this or is the sensor at the radiator only?

Thanks

Share this post


Link to post
Share on other sites

You have to bleed the system. On e30's there is a bleed valve on top of the thermostat housing. Yuo loosen the bolt (don't need to undo it totally) and pour coolant in while the engine is running, when water comes out the valve, tighten it and you're done. I image e36 have something similar.

Edited by bravomikewhiskey

Share this post


Link to post
Share on other sites

Thanks Bravo, I loosened the bleed valve but not until most of the coolant had been replaced, massaged the hoses and got quite a few bubbles out. Does the temp gauge read from the block or just the radiator?

Share this post


Link to post
Share on other sites

When bleeding the system, make sure the car is up to operating temp, so as the thermostat is open, and yes if you have an air block you will get a rapid overheating of the engine as the water isn't there to cool it, been there myself. Another way to check is to look in the radiator with the engine running, being very careful, and you should see movement in the water level, without any bubbling or chucking, this shows that the water is flowing. With my E30, I ended up having to put the garden hose up the small bottom return hose and forced water thru to get rid of my air block. If you don't have overheating after 10 or 15 mins of running I would doubt you had a blockage.

Share this post


Link to post
Share on other sites

sorry this is another E30 answer.

when we installed the link and fired the car up it, it was fine at idle. after about 5 mins driving it was very hot. i put the heater on to vent some excess heat and noticed it was cold :blink:

when we gt it back home and after about an hour of trying to bleed it, a friend told me to jack the front of the car up and bleed it.

this allowed the air that was trapped in the heater set up to push through.

something else to try anyway

hope it helps

Share this post


Link to post
Share on other sites

Thanks Bravo, I loosened the bleed valve but not until most of the coolant had been replaced, massaged the hoses and got quite a few bubbles out. Does the temp gauge read from the block or just the radiator?

Temp gauge sender reads off the engine - usually near the thermostat, to bleed I normally only 3/4 fill the system then run until up to temp - thermostat opens (bleed screw open if there is one) by this time air will have risen to the top & released, then just a matter of filling to correct level. Recheck when cold.

N.B. Cant always rely on temp guage to show high with an airlock even if engine overheats - if there is air sitting behind the sender it will not read correctly - just like a temp guage will not read high if the engine has lost all it's coolant - no coolant to measure temp of.

Cheers Grant

Share this post


Link to post
Share on other sites

Thanks guys, it doesn't appear as if theres an airlock BUT whats happened now, only since I flushed the radiator (which I'm fast starting to wish I'd never touched) is that the heater cuts in and out at random regardless of whether its on auto or manual, the whole display goes out then lights up and goes hard out etc etc. Could this be just a coincidental electrical fault or have I muffed something with the radiator flush etc????

Share this post


Link to post
Share on other sites

Thanks guys, it doesn't appear as if theres an airlock BUT whats happened now, only since I flushed the radiator (which I'm fast starting to wish I'd never touched) is that the heater cuts in and out at random regardless of whether its on auto or manual, the whole display goes out then lights up and goes hard out etc etc. Could this be just a coincidental electrical fault or have I muffed something with the radiator flush etc????

Hi, Can't imagine it being cooling system related - did you disturb any wiring (earths etc) when servicing the cooling system?

Otherwise I would suspect it being coincidental.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...