E46 325i, Coolant indicator and steaming engine , help please

BarryM

New member
Hi, could anybody guide me please, I'm really not technical. My Coolant indicator came on yesterday, but before I got home I noticed steaming from the engine. When I opened up, there's a round valve that was steaming like a pressure cooker. I filled with water and coolant, the dipstick rose, which I thought was ok. Went for a short drive, same problem. I'll try again this morning, maybe needs more water? Any advice?
 

Ratslaaf

///Member
Your coolant system has a leak and simply filling it with water won't help as you need to bleed the system (using the small screw at the radiator). You have to find the leak though as the problem will plague you forever.

It can be something as simple as a leaky radiator or cracked water reservoir, or can be a crack in the head. I suggest that you get the coolant system tested at a radiator shop firstly and eliminate from there. This was a common problem on E46's
 

BarryM

New member
Thanks, I'll get it checked out. Appreciate your help


Can you recommend a quick fix so that I can get the car safely to an expert?
 

samman325

///Member
I suspect its your bleed screw thats broken and thats where the steam is coming from, i.e. where the leak is. But as Ratslaaf said, the cooling system in general on the e46's are problem prone so better to get the whole thing checked.

I would suggest getting it towed. These engines heat up very quickly and the last thing you want is to cause more damage.
 

Ratslaaf

///Member
The quick fix would be to add water into the reservoir and to open the bleed screw till you can see a solid flow of water back into the water reservoir. You monitor this by looking into the reservoir opening while the car is at temperature.

But as Sammeer said, this might be a pretty severe problem and can lead to further failures if you don't manage it straight away. If you not feeling confident about any of this, get the car towed.
 
I agree it sounds like the bleed screw, a well known point of failure, buy two so you have one spare.

Then you'll have look at doing a complete cooling system overhaul, otherwise you'll be in for an engine overhaul with the cooling overhaul.
 

Ratslaaf

///Member
^^^ this.

I ended up with a cracked head as at the time didn't know enough about the danger of these cars overheating.
 

obbzie

New member
very comon problem, usually a cracked expansion tank.

suggest you get it sorted ASAP, these engines dont like being overheated, you could crack your head.
 

JayDrft

Member
Hi Barry,

Just want to add my 2cents, Have you noticed any dis-colouring in the water? Alternatively, have you checked your oil.

It may be likely that you popped a head gasket due to over heating, so the conclusion obtained from the oil or water colour will indicate the severity of the incident.

If you are not finding any dis-coloured fluids in the engine or radiator - then its quite possibly what the other guys have mentioned.

I had a cooloing system issue on my e34 525, it turned out the hoses feeding hot water to the heater on the firewall side - were just loose, and I mean a little loose and it tended to bring the temperature up quite a bit. I checked this after a drive or the car picking temp up to half way point, and just as it started picking up above the usual point on the temp. guage, i shut the motor off and listened very nicely as to where I would hear a hissing noise from.

Not being a technical person - perhaps if you give us a location of where you are - someone a bit more technical could come through and confirm the issue. The Fanatics on this forum are great like that!!!
 

Blue Shirt

Well-known member
BarryM said:
Hi, could anybody guide me please, I'm really not technical. My Coolant indicator came on yesterday, but before I got home I noticed steaming from the engine. When I opened up, there's a round valve that was steaming like a pressure cooker. I filled with water and coolant, the dipstick rose, which I thought was ok. Went for a short drive, same problem. I'll try again this morning, maybe needs more water? Any advice?

The radiator cap on the expansion tank is designed to release pressure exceeding 2 bar (typical for M54 motor). The steam that you saw escaping was the result of the engine overheating because the coolant level was too low as indicated by the little light on the instrument cluster.

Next time the coolant level light comes on, stop the car immediately, wait for the engine to cool down then add coolant and bleed the system before driving further. The bleeding screw is right next to the radiator cap in the top radiator pipe that runs from the thermostat housing. If you don't bleed the system, trapped air in the cooling system will just let the engine overheat again.

Then, find & fix the leak that allowed the coolant to escape, this is usually a cracked expansion tank (where the radiator cap screws into), a cracked thermostat housing or the temp sensor in the radiator outlet (bottom pipe).
 

BarryM

New member
Thanks for your input. I took it to a local service cried, turns out the water pump is gone, so the radiator hosing etc needs replacement. You guys are really helpful, it's a pleasure being a part of this forum
 
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