NZ BMW 368 Report post Posted September 23, 2012 (edited) Hi Team, I was of the impression that I'd done the recommended cooling system overhaul of my E39. I ask this because I started the car after work the other day and the dreaded "CHECK COOLANT LEVEL" flashed up as soon as I started. Luckily I live in a constant state of paranoia and have been carrying around about 3L of premixed BMW coolant in my boot for about six months, so I was able to simply fill the expansion tank to the required level and return home. The expansion tank still had coolant in it so it was just triggering the sensor by the looks of it. The last work I had done on the cooling system was back in July and I've done just over 1000km's of mainly city driving since then. Here's what I've replaced: Radiator Upper radiator hose Lower radiator hose Water pump Expansion tank Bleeder screw(s) Radiator cap Thermostat & housing Is there anything I'm missing? Heater hoses? etc? I will have my mechanic pressure test the system when it's next in for a service which is soon. Thanks in advance, Nathan. Edited September 23, 2012 by NZ BMW Quote Share this post Link to post Share on other sites
speedyg 16 Report post Posted September 23, 2012 It could have just had a small air lock/bubble somewhere in the system that has worked it's way out. I know that state of paranoia I have done a full re con of my 530i too, still checking the fluid every week! Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted September 23, 2012 could be the heater matrix circuit? could also be a minor crack in the head gasket (just age, nothing to worry about) thats letting water into the combustion chamber. my Mercedes did that. Quote Share this post Link to post Share on other sites
NZ BMW 368 Report post Posted September 23, 2012 I'd be suprised if the head gasket was damaged on a car that has just clicked over to 130k km What's the heater matrix circut? Quote Share this post Link to post Share on other sites
BM WORLD 1265 Report post Posted September 23, 2012 I'd be suprised if the head gasket was damaged on a car that has just clicked over to 130k km What's the heater matrix circut? inside heater core .have seen cars with 68k have the head gasket go. can be due to one ot 2 overheating issues which can weaken it , or corrsion with age etc Quote Share this post Link to post Share on other sites
NZ BMW 368 Report post Posted September 23, 2012 inside heater core . have seen cars with 68k have the head gasket go. can be due to one ot 2 overheating issues which can weaken it , or corrsion with age etc I know what you're saying but I don't see any mixing of oil and coolant, nor do I smell any coolant burning whilst driving or after parking. I also don't have any white smoke from the exhaust or engine. I guess the only way for sure is to have the system tested - isn't there a test for combustion gases entering the cooling system? My mechanic's invoice states they pressure tested the system after the work in July which I think would indicate a leak too. Quote Share this post Link to post Share on other sites
BM WORLD 1265 Report post Posted September 23, 2012 I know what you're saying but I don't see any mixing of oil and coolant, nor do I smell any coolant burning whilst driving or after parking. I also don't have any white smoke from the exhaust or engine. I guess the only way for sure is to have the system tested - isn't there a test for combustion gases entering the cooling system? My mechanic's invoice states they pressure tested the system after the work in July which I think would indicate a leak too. hi i wasn't saying yours has a leaky head gasket.yes you should get a tk test done to see if any gases getting into the coolant system. all plastic coolant pipes and any plastic parts in the coolant system should be changed about every 100,000km or 10years etc, also check viscous fan clutch coupling , water pump , thermostat and radiator. also check the operation of the 2 speed aux fan. electric water valve/tap for the heater system?? Quote Share this post Link to post Share on other sites
NZ BMW 368 Report post Posted September 23, 2012 hi i wasn't saying yours has a leaky head gasket. yes you should get a tk test done to see if any gases getting into the coolant system. all plastic coolant pipes and any plastic parts in the coolant system should be changed about every 100,000km or 10years etc, also check viscous fan clutch coupling , water pump , thermostat and radiator. also check the operation of the 2 speed aux fan. electric water valve/tap for the heater system?? Yup, like I've said I'm pretty sure I've replaced all the plastic parts per my first post. But from what I understand the other place suggested is the valve/tap for the heater system? I'm not sure how the aux fans and the fan clutch can leak coolant but for what it's worth I have replaced the whole aux fan unit on this car already and the operation of the new unit has been tested and okay-ed back in 2011. Recently I also did my own old school "hand test" on the viscous fan clutch. With the car off it is smooth to move but feels like it's in molasses. If it's excessively "free wheeling" or sticky it usually indicates a problem. So working on the assumption that none of the new parts are defective again already my loss of coolant could be: Air bubble Heater valve Heater core Head gasket Quote Share this post Link to post Share on other sites
