# 1998 740iL Coolant leak



## Saiyan (Apr 13, 2006)

I did a search but the problem doesn't seem to manifest the same as everyone else's. Maybe the way the problem shows up will help tell what the problem is. My 1998 740iL has about 84,000 miles. When starting the car, the car seems fine, with no problems. But as soon as I pull out of the driveway, maybe after 500 ft of driving, the "check coolant level" warning comes up. So I come back home to check the coolant and the level is low. When the car is idle, no warning comes up. Then, I filled it with coolant & water until it is full (meaning the red dipstick is even with the top of the expansion tank). Then, I turn the heater on too and wait for the level to drop slightly and fill it again. I left the car idle for a long period of time and no leak seems to be showing or anything. But the problem shows up time and time again. Any help would be greatly appreciated!! Thanks in advance!!

About 1 year ago, I replaced the expansion tank when it cracked along with the sensor.


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## Solidjake (May 10, 2007)

Stop doubling post


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## Saiyan (Apr 13, 2006)

sorry, didn't realize it posted twice....i thought I edited the post twice.


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## Solidjake (May 10, 2007)

No leaks? Maybe from the radiator?


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## Saiyan (Apr 13, 2006)

no leaks are visible. I am planning on removing the bottom cover again to check but no warning comes up at idle and coolant level is fine.


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## Homebrew (Apr 20, 2009)

The same thing happen to my 98 740il 
been trying to find it for about a year or two
Guess what I found it 
it was leaking from the belly pan under the 
intake manifold
I saw a small trace of antifreeze coming out between
the transmission and the engine 
their are two drain holes on the back side of the motor
that will dump any fluid that gets under the intake 
So 
take the cover off the top of the motor 
get a flashlight 
and start looking under the manifold
Good Luck


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## Route 66 (Oct 5, 2009)

I had these same symptoms. The valley pan gasket was leaking. My indy shop replaced the gasket.


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## paullydoo1 (Dec 30, 2009)

I just bought my 740 two weeks ago, and have been adding coolant 500ml every few days. Finally took it to mech friend, pressure tested system to see a stream running out from tranny hole underneath. Are these drain holes you guys talk about in the bell housing area? no visible wetness from above and I'd hate to have to pull the engine just to see it's a valley pan gasket leak! Info much appreciated...:dunno:... and yes I have checked and confirmed no coolant is being blown out the pipes, or getting into the oil (thank heaven).


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## ronaldo123 (Dec 30, 2009)

nice post ... I left the car idle for a long period of time and no leak seems to be showing or anything. But the problem shows up time and time again. Any help would be greatly appreciated!!


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