E90- Check Coolant light, hissing sound and water all over the engine

J

jncf

Active Member
Just want to check if any bro encounter such problem before...

Weather sunny, not hot. My E90 Check Coolant light suddenly came on.. Temperature looks ok, only a few KM from home, so decided to drive on.

Reach home in 10 mins, park car shut engine. Got off car and hear a hissing sound coming from under the hood.

Pop the hood and saw water all over the engine bay. Hissing sound detected to be gust of leaking air with some trace of water.

See picture attached.

View attachment 44761View attachment 44762View attachment 44763

Any idea what happen?
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

Obviously, there's a leak in your cooling system and it could be from any one from a number of spots (e.g. common areas to look for are: rubber hoses, radiator expansion tank, water pump, radiator cooling fin, etc) - left to right, cheap to more ex.

The location of your coolant spray appears to be a spot quite high up, so start looking from there. If it's a leaking rubber hose, it will be cheap to replace.

In my case, it had to be the more ex option :( I had a similar case many months back I saw some steam emitting from the front of my hood whilst i was driving. There was no coolant or electronic warning at all. I was only 5 min from one of the sponsor workshop in Sin Ming area so just drove there and get it diagnosed as i didn't want to have to pay more for repairs if the engine overheat.

Workshop tested the cooling pressure (by fitting a test gauge into the radiator expansion tank cap), and re-activate the hairline leak from the radiator fin. Apparently, this is a common problem in e90 as well, fix was simply to replace that whole part, coolant top-up to full level and problem solved.

Around $900 all-in, couple hours job.

Suggest you top up your radiator full with water (distilled if you can get, otherwise just pour in tap water), drive to nearest workshop to get this look into, and try not to let the car over-heat. Else, you may face more ex repairs down the road.
 
Last edited by a moderator:
Re: E90- Check Coolant light, hissing sound and water all over the engine

My guess is that your hose is leaking coolant ..... all that whitish residue ......
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

it seems to be pressurized even when the engine is shut off, maybe its the pressure from the boiling?

I can feel stream of the air and water as the source of hissing from here:

View attachment 44764
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

Seems like bro red-bean_bun is spot on.

Your rubber hose is leaking at the spot you highlighted, probably due to a hardened hose.

It is pressurised from the driving you did earlier from the engine heat, and will continue like this for a while more until it cools down.

As you do not know how much coolant you have lost, it's safer to wait till engine cools down sufficiently (i'd say around 2 hours) for you to open the radiator expansion tank cap and top-up with water. If you want it to cool faster, just leave your bonnet open.

Just drive to your nearest sponsors/workshop to get it changed, in the process, also check all other hoses and change if any hardened as well, for preventative measure.
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

This hose is attached to the Heat Exchange and there is a Vent Screw on it. Is the Vent Screw still intact?
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

The hose looks good. the leak seems to be from the adaptor (not sure of actual name for the component, might be the vent screw?) that the hose is connected to.

Already sent my car to the nearest workshop. Was told that the hose and the adaptor that needs to be replaced comes in a set as the radiator top hose, might not be able to order individually.

As it was too late when I sent in my car, have to wait till stockist open tomorrow then will know the cost.
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

Remember to use distilled water when filling up .......... And personally perhaps less coolant 75/25.

actually if possible just distilled water and 1 bottle of water wetter .....

jncf;931871 said:
The hose looks good. the leak seems to be from the adaptor (not sure of actual name for the component, might be the vent screw?) that the hose is connected to.

Already sent my car to the nearest workshop. Was told that the hose and the adaptor that needs to be replaced comes in a set as the radiator top hose, might not be able to order individually.

As it was too late when I sent in my car, have to wait till stockist open tomorrow then will know the cost.
Click to expand...
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

Just because of the pressure screw broke have to change the whole piping?

Not sure same symptom.

I also hv same hissing sound and water keep spray out from the screw too. I drive slowly and air con off to the workshop.
Went to "Boss". They help me change both side the plastic pressure screws. FOC. Really appreciate their value added service!!!
After that everything working fine till now. It is abt 1month ago.
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

I think it was previously "repaired". If you look at the pic carefully, got white sealing tape on the leaking one.
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

You bought used? Bandaid fix maybe by the dealer

jncf;932944 said:
I think it was previously "repaired". If you look at the pic carefully, got white sealing tape on the leaking one.
Click to expand...
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

yap, got this as a pre-own.

Cleaning up all the problems now for another good 4 year's drive. hopefully....
 
Re: E90- Check Coolant light, hissing sound and water all over the engine

Part and parcel of bmw ownership, esp e90 model

Keep her well maintained and she should serve you well for next few years ;)

jncf;933253 said:
yap, got this as a pre-own.

Cleaning up all the problems now for another good 4 year's drive. hopefully....
Click to expand...
 
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