Coolant pressure issues

[fparada]

Hi All,

I have a 2001 325i sedan, I haven't drive the car in a while because after changing the cooling system I notice that the coolant was leaking from the expansion tank cap. I change the cap and same problem. something that I notice is that car had a lot of pressure when was parked overnight.

Please let me know if you had this problem and how to fix it or what could be the cause.

Thanks

Fernando

[Shaunturner82]

It could b 1 of 3 thing either a new water pump the thermostat or it is not bled tidy when you bleed the system as your looking at the car from the front jack the right hand side right up as far as u can so u get the bottle higher than the engine cause it sound like its not bled tidy

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[hoon4life]

Mine didn't leak but the problem sounds similar when I changed my coolant my car would run hotter and tons of pressure in the system... the problem was there was air bubbles in the system and it took a week for all the air to work its way out and me adding tons of coolant on the system

[Dave1027]

Maybe you have the coolant over filled. The top of the level indicator stick should just be poking out the neck of the ET. No higher.

[MIKYZZ4]

If cooling system was replaced due to overheating, then damage may have been done to the headgasket.
Perform a cylinder leakdown test, while observing coolant for telltale air bubbles.

[riley111]

I've had the exact same to me, turned out to be a thermostat.

[Eaglesail]

Thanks for being here.....You have a greatly better mechanical observation and help offering...than many here.

[legoman67]

over pressure cooling system is almost always headgasket.

[Eaglesail]

Interrupt once the cooling system....Check back all procedures as if all cooling system parts were replaced.....Just as if as a pilot take off procedure...upon the next flight! Remember..the BMW cooling system needs to be 'burpped'...a 'burp' screw...is attop ..a mechanic will know.