SOS - coolant change gone bad!

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Hi Guys,

I just tried to do a coolant change on my 2001 740. I couldn't find any drain screws on the engine or the radiator, so my friend and I dropped off 3 hoses that were attached to the radiator. The large one on the right that goes to the engine, the smaller one that goes to the expansion tank and a small one at the other side that goes up and over the (transmission cooler  - I think?). In total, I think I drained about 7 or 8 litres of coolant out. I understand that the system holds 12.5 litres.

I then reconnected all the hoses, and filled up the expansion tank to max with a 50/50 water-coolant mix. Then, leaving the radiator cap and bleed screws open, started the engine with the heaters set to max. The coolant level did nothing for w few mins, then dropped a lot. I topped it up to max again, and continued to watch. Air bubbles came out of the bleed valve for about 5-10 mins, and we waited for the coolant temparature to rise to normal (on the temp gauge). Steam then started coming out of the bleed valve, and the coolant level rose a lot and overflowed out of the radiator cap. We decided to put the cap on and leave the bleed valve open, and we saw more steam come out of the bleed valve. We then put the valve on, and decided to go for a drive to see what the temparature did. It was initially find (vertical needle), but intermittently it would jump up to just below the top quarter mark.

I decided to leave it overnight to let is completely cool, then check the level. When I looked this morning, removing the cap, the level indicator stick was low, but rose up slowly to above max in 10-15 seconds.

Does anyone have any ideas about what is happening? Do I have an airlock somewhere? How can I fix this?

I posted on this forum a couple of times asking how to do the change, and just got "It's straight forward" responses, but no links to instructions. If anyone has any E38 specific instructions, I'd really appreciate it.

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Volvo240GLT Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Groupie Joined: 26-June-2005 Location: Aylesbury Status: Offline Points: 66	Topic: SOS - coolant change gone bad! Posted: 03-October-2005 at 06:50
	Hi Guys, I just tried to do a coolant change on my 2001 740. I couldn't find any drain screws on the engine or the radiator, so my friend and I dropped off 3 hoses that were attached to the radiator. The large one on the right that goes to the engine, the smaller one that goes to the expansion tank and a small one at the other side that goes up and over the (transmission cooler - I think?). In total, I think I drained about 7 or 8 litres of coolant out. I understand that the system holds 12.5 litres. I then reconnected all the hoses, and filled up the expansion tank to max with a 50/50 water-coolant mix. Then, leaving the radiator cap and bleed screws open, started the engine with the heaters set to max. The coolant level did nothing for w few mins, then dropped a lot. I topped it up to max again, and continued to watch. Air bubbles came out of the bleed valve for about 5-10 mins, and we waited for the coolant temparature to rise to normal (on the temp gauge). Steam then started coming out of the bleed valve, and the coolant level rose a lot and overflowed out of the radiator cap. We decided to put the cap on and leave the bleed valve open, and we saw more steam come out of the bleed valve. We then put the valve on, and decided to go for a drive to see what the temparature did. It was initially find (vertical needle), but intermittently it would jump up to just below the top quarter mark. I decided to leave it overnight to let is completely cool, then check the level. When I looked this morning, removing the cap, the level indicator stick was low, but rose up slowly to above max in 10-15 seconds. Does anyone have any ideas about what is happening? Do I have an airlock somewhere? How can I fix this? I posted on this forum a couple of times asking how to do the change, and just got "It's straight forward" responses, but no links to instructions. If anyone has any E38 specific instructions, I'd really appreciate it.
	Cheers Henrik Morsing '89 Volvo 240GLT B230E/AW70 '89 BMW 635CSi Highline Motorsport '70 Chevrolet Chevelle (Malibu) 350/350 Previous cars ----- '76 Volvo 244GL B21E/M40 '87 Chevrolet El Camino 305/200r4

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M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 03-October-2005 at 07:45
	not lookig to pass over this, but try this site someone may be able to help. definatley sounds like an air lock in the system somewhere, how comes you only got about 2/3rds of the coolant out if there is 12 litres in there? Edited by M3AG
	we're the Sweeney son, and we ain't had our dinner.....

sleeper Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II Original and STILL best Joined: 26-March-2004 Location: East Sussex/Kent border Status: Offline Points: 2098	Posted: 03-October-2005 at 08:01
	I think the 7 has a 'storage heater' type device on it, could this tank hold the missing litres? anyone know of a circuit diagram on the TIS?


Volvo240GLT Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Groupie Joined: 26-June-2005 Location: Aylesbury Status: Offline Points: 66	Posted: 05-October-2005 at 02:11
	Thanks for this. Parking the car uphill and opening the bleed screw 'til collant came out sorted it. We added 4 liters of coolant after that so it must have been very low.
	Cheers Henrik Morsing '89 Volvo 240GLT B230E/AW70 '89 BMW 635CSi Highline Motorsport '70 Chevrolet Chevelle (Malibu) 350/350 Previous cars ----- '76 Volvo 244GL B21E/M40 '87 Chevrolet El Camino 305/200r4

M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 05-October-2005 at 04:17
	glad the link could be of use.
	we're the Sweeney son, and we ain't had our dinner.....