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coolant leak anyone advice? thank you soo much. I'm still a rookie with this car.

9K views 4 replies 4 participants last post by  Pinecone 
#1 ·
Hey. So I have a 99 bmw m3 e36 that seems to be leaking coolant. I've been told it's the not so smartest thing right now to be even remotely driving my car. I was wondering if I could get an opinion on how i can fix this myself. I'm taking it in Monday to japanese auto tech to get it checked out. Thanks again!!
 
#2 ·
It all depends where it is leaking. If it is the water pump you better not be driving it too far as it may seize and if it does your engine will immediately overheat and you stand an excellent chance of warping the head and then you will be out about 1500 bucks.

If it is leaking from the radiator you will most likely need to get it replaced which is not a hard thing to do (is your car an auto). Autos are slightly harder.

Go to pelicanparts for a good write up on most cooling system items that are closely related to your car.

I have done maybe 10-12 of these cooling systems overhauls on E30's/e36's/e46's and they are mostly the same.

If you pull the radiator (most likely place it will leak is the plastic top hose attachment point) them also replace the thermostat and the water pump unless you know for sure they have been replaced.

Be careful with driving this car if the water pump is weaping as you may kill your cooling system if it stops.

Feel free to let us know what your tech tells you as you should be able to replace the radiator, water pump, thermostat for not a huge cost.
I can tell you how to do this but if you don't have the skills and tools let someone who does do it. Your car is too expensive to make a cooling system mistake.
 
#3 ·
Hi fun2drive,

On my E46 2001 318i (manual) I can see some leak under top hose pipe (near radiator cap) I couldn't see any obvious reason (like loose / incorrect fit or cut in pipe) all seems to be okay except I have to top up coolant every 2 months. Leak is very less like few drops but requires a fix. Is this an easy DIY or I have to seek help of a garage?

Thanks for your time.

Regards,
Afsar
 
#4 ·
Since you have an E46 it is a real possibility that your expansion tank has a split in it. This is very common for your car. To check look under the cap area, most splits are along the tank radius that is closest to the middle of the car. Updated expansion tanks have cured this problem for most E46 owners.
Look at this site
http://www.realoem.com/bmw/showparts.do?model=BL32&mospid=47610&btnr=17_0140&hg=17&fg=05

And item 3 is the expansion tank. If it is that tank that has split or leaking then it is not hard to replace but I would suggest having someone do this that had done it before as it takes a lot of force to remove the tank.

If the tank is not the issue then I don't know what else could be the problem except the radiator itself. Don't replace anything until you can physically see where the leak is coming from.

Last E46 I did the only leak was the temperature sensor sitting in the radiator plastic lower hose. It was just the O ring but we had to buy the whole sensor unit since BMW and no one else seemed to have the O ring...
 
#5 ·
How many miles?

Water pump and thermostat housing are good for about 70 - 80K miles. Radiator about 100 - 110K miles. Check the sticky at the top of the forum.
 
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