Member
1999 M coupe... replaced T-stat... I’ve done the car on ramps, heater on full bleed screw procedure, the shqueeze the hoses procedure, the pour coolant down the rad hose bit.... now Im just going to find some divining rods and see about that.
Bust seriously when I rebuilt my head i completly drained the block and had NO problems bleeding squeezing the upper and lower rad hoses. Now its a total flipping mystery. Im not loosing coolant anywhere but the heater only blows hot if the engine is at 1500rpm and above. Ive bled it a myriad of different ways over the course of a couple weeks....
One thing i did notice that seemed odd... when i filled the expansion tank with the bleed screw off, nothing came out the bleed screw untill the expansion tank was overflowing too. Weird or not?
Any insight into this? I have read a dozen or so threads befor wasting everyone’s time with yet another thread. TIA!
Last edited by Ring Rat; 02-20-2018 at 11:23 PM.
Member
I have nearly this exact problem. Car takes forever to blow hot and doesn't stay that way. I hadn't associated it with RPM but sounds similar. Tried bleeding to no avail. Been assuming t-stat stuck open. One other data point: the temp gauge on the dash cluster gets up to normal running temp always. The temp gauge in the center console only makes it about half way at best if it is cold out and I am experiencing this problem. Would love to hear from someone who solved it.
Member
Another point of interest, possibly... is when I squeeze the upper rad hose the squirt into the expansion tank is not a stream that shoots straight out, it is kind of deflected to the front of the tank... it is hard to tell if there is air comming out, but whenever i squeeze it there are small bubbles apearing on the surface of the coolant in the tank. Not sure if thats air comming out of the top of the radiator or of they are created by the cooland fallingninto the water. I squeezed both hoses with the car running for about 15 mins tonight and never got anywhere.
I did check the tstat in a pot of water before installing and it was working.
Last edited by Ring Rat; 02-21-2018 at 12:27 AM.
Ralph
Why did you rebuild your head?
Member
Rebuilt it a year and a half ago to do valves, guides and stem seals.
Last edited by Ring Rat; 02-21-2018 at 09:20 AM.
Sim Simma
Moderator
I would try the car on flat ground again, take upper rad hose off at radiator, pour coolant mix into hose until it comes out radiator opening. Re-attach hose, top up expansion tank.
Member
You're probably filling the tank too fast.Originally Posted by Ring Rat
The trick is to fill the expansion tank very slowly with the bleed screw out (ignore the red float for now). As soon as coolant comes out of the bleed screw without bubbles, you close the bleed screw and use a turkey baster to reduce the coolant level in the expansion tank to the correct level. That has worked for me. Operating temps are around 92°-99°C (M52TU) and I have full heat at idle.
Last edited by me77; 02-21-2018 at 04:36 PM.
Grumpy
BMW CCA Member
The bleed screw and the cap open the exact same passage. If the cap is off, the screw is redundant. Basically, leave the bleeder alone during the fill. It's only job is to allow you a final purge of the top on a hot pressurized system. This is after your done.
S52s don't have a red float. Nor do they have the super easy to fill high mounted tank of an M54. One of the biggest issues with these cooling systems is people giving and taking advice from a different car/engine combination.
Member
I tried that - doesn't work. Still was plenty of air trapped inside.
Member
What worked for me on m52 when heater didn't wanted to push heated air after radiator/hoses/thermostat replacing at idle for 30 minutes:
1) Make sure heater is on and on high speed.
2) Revs to 3-4k for about 5-10 minutes on warm engine to fill the heater core and push the air out of it (checking the engine temp) while squeezing hoses until the hot air is being pushed at idle.
3) During next 2-3 days driving around, still had to add 1-1,5 L of coolant.
Not sure about s52, but m52 engine requires around 11,5 - 12L of coolant, so knowing that you can measure how much you need to pour in...
Member
Yep still not bled! Ive %#*^ tried everything... holy crap. What the hell am I not doing!? Im guessing a dealer would be able to pull off this masters-level car maintenance project no sweat, yeh?. But really.. how would a dealership do it? Like it there an ACTUAL BMW approved procedure?
The upper radiator hos seems to always be empty when the car is off also... normal? Or at least id definitly always has air in it w/ the car off.
Anyway, the good news is I havent strangled anyone yet.
Last edited by Ring Rat; 02-25-2018 at 05:54 PM.
Ralph
Well, it's an S52, so, based on use of one on my S52, an Airlift 2 will work for you--Amazon Prime and it will be there by Monday. Don't discount the possibility that it's something else wrong and the system is bled just fine--heater valve, water pump, thermostat come to mind.
Member
Ordered... hopefully its the magic nail in the coffin of this. Thanks, I hope!
Sim Simma
Moderator
hmm, how much is in the expansion tank? level drops?
Member
Maybe I was just lucky, but I never had all of these issues with my cooling system. With my S54, I did the cooling system overhaul- new radiator, expansion tank, hoses. Put the components in, reinstalled the rest of the parts, filled the car with coolant. Drove the car up on ramps to put the front end up, then left the cap off, kept filling the expansion tank and burped the system. No issues since. Heat works fine, doesn't overheat, nothing.
Maybe try it again? I have an Airlift, but didn't use it.
Sim Simma
Moderator
S54's are self-bleeding
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Member
Well that explains it! How exactly does that work?
Ralph
Engineers pay attention and talk to each other.
Member
Lol, but seriously, how is a system “self bleeding?”
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Member
Perhaps a one-way check valve or something?
BB... Ive had the level at various points experimenting.... doesnt change much hot / cold / rpm, etc.
Member
Darn, here I keep hoping there is some trick I missed that would get the heater to put out hot air instead of merely warm!
Marty
Member
Ok so... everyone should get the Airlift tool. Was a snap, blistering hot air all the time now. Thanks for the tip! Even if you eventually succeed with the squeezing hoses / bleeder screw nonsense, that tool is definitly worth the price... And no guesswork. Not sure why I wasnt getting anywhere, but it took in a rather large ammount of coolant with no change to the level in the expansion tank.
Ralph
You're welcome--be sure to check the level after a couple of good drives to make final adjustment.
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