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Discussion Starter · #1 ·
Hello to all M owners, I've got a e39 2000 540i and have a few issues that I have no idea of what it can be from. As I started up the car on a cool morning it seemed as if the engine kept wanting to stall or cut out I thought it would be the fuel pump or spark plugs, but later on I thought to myself it might be misfiring. I've also been filling a whole Arrowhead water bottle filled with antifreeze/water almost every 2-4 days. So I searched up the symptoms together and found out one of the cylinder heads could possibly have cracked therefore this is happening. Any help from previous experience of this type of problem? Thanks.
 

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Blacktop540 , i would remove all coils & spark plugs , let sit overnite , put cardboard over each cylinder head , crank it over & see what comes out. If you have an internal coolant leak more than likely you will see antifreeze blow out of the cylinder or cylinders it is leaking into. That is to say that there are no visable signs of an external leak.


Good luck!
 

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Discussion Starter · #5 ·
Thanks guys, the car right now is at the body shop polishing up but as soon as it comes back it's going straight to my mechanic and if anything major does occur, maybe bore out to a 4.6 liter from a 4.4.? :)
 

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Wow, that's a lot of coolant to be losing. And it is definitely not leaking externally? No puddles on the drive or wetness under the hood?
Check the dipstick for higher than normal oil level or white foamy emulsion to see if it leaking into the crankcase.
Are you getting any sweet smelling white smoke when you start it up cold?
A good way to check for leakage into a cylinder is to remove the spark plugs and look for any that are abnormally clean.
You can buy coolant system pressure testers quite cheaply. They use a hand pump to pressurize the whole system to the normal pressure or higher, then you can watch for pressure drop and look for leaks. A lot safer than checking around a running engine. I don't know if M5's need a a special adapter for the pressure cap.
 

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A code reader (peake or autozone visit) would help with the first problem. A professional who can find the leak is probably required for the second problem.


Chowdah has a good point as far as the code reader. It can also help to determine the cylinder or cylinders the coolant is getting into. If coolant is getting into the cylinders after sitting a bit it will foul the spark plugs in those cylinders until it is cleared out with running the engine.
 

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Discussion Starter · #8 ·
Yes definitely not having any external leaks and the car runs fine while driving and right after it is warmed up. I think the code reader will let us know which banks are having misfires for sure, and I will try to check my spark plugs for sure I think that will give it away the most.
 

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Discussion Starter · #9 ·
I also had the check engine light go on a while ago along with the leaking coolant but before I took it to my mechanic it went off so I thought nothing would be wrong, but we followed up with this issue now so let's hope to see it's not the block.
 

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we cant really tell you the problem until you run live data and checked error codes from your control unit. probably its just your plastic water tank that leaks very slowly, (very common on M62 E39) and some problem with gaskets leaking air and/or you got water leaking near the intake manifold. i have a hard time describe this problem for you... as my english really sucks :p

so I let these pictures do the work: http://tech.bentleypublishers.com/servlet/JiveServlet/download/71-33911-328939-5761/valley%20pan.jpg
Gasket near #1 on this picture: http://bmwfans.info/parts/catalog/E39/Sedan/Europe/540i-M62/LHD/A/2001/october/browse/engine/engine_block_mounting_parts/

however... good luck!
 

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Your English is better than many on here ;)
 

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Fastest way to look for an internal leak in the head, is start the car cold and squeeze a hose. If the hose starts getting firm before the car is warm.... not a good thing means that compression is leaking into the cooling system. Look for air bubbles in the coolant bottle when running. If this is slow it may only leak on the vacuum stroke but will pressurize on the compression stroke. If it is a crack or head gasket failure I have had great success with a product called irontite by kwik-way.com
 

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M5 guys dont' have this problem; but, check your valley pan!!!!



they often ooze/leak and because of the location, the coolant steams off before any leak is seen on the ground. Not to mention, the belly pan can hold a fair amount of fluid.


things to check on these cars that love to eat cooling systems:

Valley Pan
Radiator
Water Pump
Expansion tank
Heater hoses

All of the above should be replaced around 60-80k, otherwise they will most likely fail shortly after - the reason is the 540s run coolant temps of 105-114*C for highway efficiency. To do this, you need to raise the maximum system pressure to >20psi. That extra pressure and extra heat tends to really stress the entire system; thus, they fail like clockwork.





EDIT: the misfiring could have many causes:

- MAFS
- Vac leak
- old fuel filter
- plugs
- coils
- leaky valve covers (leaks oil into the spark plug holes
- cam angle sensor(s)
- crank position sensor
 
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