Ultrarandom 3 Report post Posted November 13, 2013 (edited) After recently doing the head gasket I've been trying to bleed the cooling system as the lower radiator hose stays cold while the engine starts creeping towards the 3/4 mark on the gauge.So far what I have done is I've got the front end jacked up and have started the engine and had coolant come out the bleed hole as normal, then once (I'm guessing) the thermostat opens up the temperature of the coolant picks up drastically and splutters out, then if I close off the bleed screw for any period of time and re open it only steam comes out.Any suggestions as to what this could be before I just book it into SD European?Also the temperature gauge comes back down when I accelerate (when taking it for a quick run yesterday down the street and back).EDIT:To add, it's a motronic M20B25 so bleeding from the screw on top of the thermostat. Edited November 13, 2013 by Ultrarandom Quote Share this post Link to post Share on other sites
Kepes 231 Report post Posted November 13, 2013 (edited) What you're doing is fine but i think you're forgetting to turn the A/C on heat. Repeat what you do with the front jacked up (a sloped driveway works fine too + it's easier), start the car etc but make sure the A/C temp is set to hot. Keep the car running and open the bleed screw about every minute or 2 until no air comes out. Let your car get to operating temp, and bleed until steady stream of coolant comes outHope this helps! I have never tried it but did quite a lot of reading up on it. Edited November 13, 2013 by Kepes 1 Quote Share this post Link to post Share on other sites
Phil-540i 166 Report post Posted November 13, 2013 Ditto what he said ^^^^^^^^^ heater unit has got to be having flow through it too........... All the fans are working ok?? Just asking in terms of 'why did it originally blow the head gasket??' sorta thing........ Quote Share this post Link to post Share on other sites
Allanw 1071 Report post Posted November 13, 2013 Just asking in terms of 'why did it originally blow the head gasket??' sorta thing........ ^^^This. WHY did it blow the headgasket? I've never had any difficulty bleeding Dads E30 on the flat. What other work did you do with the head gasket? You could have a faulty waterpump or a clogged radiator. Quote Share this post Link to post Share on other sites
Ultrarandom 3 Report post Posted November 13, 2013 Forgot to mention I did already have the heater going.It hadn't so much blown the head gasket as it just had a slow seep out from the coolant out the side so I took the head off, new head gasket, got the head machined and properly tested, also got the valves lapped and a proper clean up, replaced timing belt and all.Only thing I didn't do was the water pump, radiator was flowing easy when I was flushing it and the water pump had been working fine beforehand, never had any overheating problems even with the leak in the head gasket. Is also sort of hopeful thinking that it'd be neither of those.Has an electric fan on a switch which was also keeping it at temperature beforehand.Will give another go tomorrow but have a try on the flat again since some people say that they're somewhat designed to be bled that way.Problem is if I leave it running for a minute or 2 the engine will completely cook, I feel bad enough having it get as high as it does. Quote Share this post Link to post Share on other sites
Ultrarandom 3 Report post Posted November 13, 2013 (edited) An additional update to how I'm going with this. After reading through the bentley I got an idea and with the engine still dead cold I've been holding the expansion tank up higher than the bleed screw with the cap off and opening it up, this has been getting a decent amount of air bubbles out and seems to be working, will do more work on this in the morning but hopefully will have it sorted tomorrow =D (today now)EDIT: After doing this and running it through after 5 minutes of idling after reaching operating temp this was the site I hadStill a bit of air in there which Im slowly working out but progress is progress =D.Letting it cool down now and coming back to it again to check the expansion tank once it's cold. Edited November 13, 2013 by Ultrarandom Quote Share this post Link to post Share on other sites
Eagle 1662 Report post Posted November 14, 2013 The way i always bleed if i dont have a compressed air source\fittings available: Remove the the expansion tank cap, draw breath & put your mouth over it and blow whilst having a finger blocking the expansion tank vent hose and the other hand opening the bleed screw, its like bleeding brakes as you need to close the screw before releasing pressure and repeat. It usually takes me <30s to get all the air out then i will recheck once its a operating temp just to be sure. So much easier and faster than open\close bleed screw, tilt car etc method and it works well on E30's due to the expansion tank location Quote Share this post Link to post Share on other sites
Kepes 231 Report post Posted November 14, 2013 The way i always bleed if i dont have a compressed air source\fittings available: Remove the the expansion tank cap, draw breath & put your mouth over it and blow whilst having a finger blocking the expansion tank vent hose and the other hand opening the bleed screw, its like bleeding brakes as you need to close the screw before releasing pressure and repeat. It usually takes me <30s to get all the air out then i will recheck once its a operating temp just to be sure. So much easier and faster than open\close bleed screw, tilt car etc method and it works well on E30's due to the expansion tank location Sounds like a great way. Is this with the engine running or not? And A/C set to heat am I right? Quote Share this post Link to post Share on other sites
Ultrarandom 3 Report post Posted November 14, 2013 The way i always bleed if i dont have a compressed air source\fittings available: Remove the the expansion tank cap, draw breath & put your mouth over it and blow whilst having a finger blocking the expansion tank vent hose and the other hand opening the bleed screw, its like bleeding brakes as you need to close the screw before releasing pressure and repeat. It usually takes me <30s to get all the air out then i will recheck once its a operating temp just to be sure. So much easier and faster than open\close bleed screw, tilt car etc method and it works well on E30's due to the expansion tank location That's actually a real good way haha, don't know why I didn't think of it. I used a similar method on my old Skyline too. Quote Share this post Link to post Share on other sites
Eagle 1662 Report post Posted November 14, 2013 Sounds like a great way. Is this with the engine running or not? And A/C set to heat am I right? Yeah. You can it either way but i do it from dead cold as ive usually just refilled the cooling system. Quote Share this post Link to post Share on other sites