[RaySE46]

Hi, hoping someone can shed some light.

Around a year ago my beloved 00' E46 316i se ran into a few overheating issues.
Its a 1.9l Inline 4 from factory and from what I can gather these engines were created for the 318i e36's.
The car was bought on 54k and was absolutely mint, around 6 months later we sit on 79k after being put through its paces regularly.
Nothing has ever gone wrong on the vehicle with an immaculate MOT history. The only problem's I've had being brake pads and tyres... lol

Around 6 months in the car very slowly started getting through coolant to where around 3 months later it was needing to be filled at least 1/2 every 4-5 days.
The car eventually overheated on a short journey and a pin-prick sized hole where the radiator joins the expansion tank was shooting steam out.

Being barely drive-able, the radiator was replaced.
The garage it was staying at suggested it may be the thermostat or water pump.
He found the thermostat wouldn't appear to open in boiling water, so I bought a new thermostat.
With this not having much effect, I replaced the water pump.

The problem seem to be fixed for around 1-2 weeks, excellent I thought. Problem Solved.

How wrong was I...?
Two weeks of regular use later I took the car for a short drive and parked up outside of a friends garage with the engine idling, after around 10 mins of sitting there, bang, the expansion tank blew the back out of itself and dumped its coolant everywhere.
Having come from ECP, I replaced this with an OEM expansion tank.
It has sat looking very confused ever since.

Now, the car produces a small amount of white smoke when cold, which it never used to, which point towards a HG failure.
On two occasions I have also found milky residue in the expansion tank. NEVER in the block or on the dipstick, which I find very odd.
The car last had an oil change when it visited its main dealership early into my ownership and the oil is still very very clear.

Clearly the car is building too much pressure, the leak into the expansion tank is of course worrying, but possibly not damming??
Some have suggested it being the oil cooler, or possibly the heater matrix. Is this possible?

Personally, I pride myself on being a capable/competent driver, but mechanically I have zero knowledge.
Any advice would be greatly appreciated.
Thank you in advance.

 

[Bimmer3er]

Maybe it needs a cooling system overhaul but it seems very odd... Any other signs of head gasket failure?

 

[RayPooley]

Hi, hoping someone can shed some light.

Around a year ago my beloved 00' E46 316i se ran into a few overheating issues.
Its a 1.9l Inline 4 from factory and from what I can gather these engines were created for the 318i e36's.
The car was bought on 54k and was absolutely mint, around 6 months later we sit on 79k after being put through its paces regularly.
Nothing has ever gone wrong on the vehicle with an immaculate MOT history. The only problem's I've had being brake pads and tyres... lol

Around 6 months in the car very slowly started getting through coolant to where around 3 months later it was needing to be filled at least 1/2 every 4-5 days.
The car eventually overheated on a short journey and a pin-prick sized hole where the radiator joins the expansion tank was shooting steam out.

Being barely drive-able, the radiator was replaced.
The garage it was staying at suggested it may be the thermostat or water pump.
He found the thermostat wouldn't appear to open in boiling water, so I bought a new thermostat.
With this not having much effect, I replaced the water pump.

The problem seem to be fixed for around 1-2 weeks, excellent I thought. Problem Solved.

How wrong was I...?
Two weeks of regular use later I took the car for a short drive and parked up outside of a friends garage with the engine idling, after around 10 mins of sitting there, bang, the expansion tank blew the back out of itself and dumped its coolant everywhere.
Having come from ECP, I replaced this with an OEM expansion tank.
It has sat looking very confused ever since.

Now, the car produces a small amount of white smoke when cold, which it never used to, which point towards a HG failure.
On two occasions I have also found milky residue in the expansion tank. NEVER in the block or on the dipstick, which I find very odd.
The car last had an oil change when it visited its main dealership early into my ownership and the oil is still very very clear.

Clearly the car is building too much pressure, the leak into the expansion tank is of course worrying, but possibly not damming??
Some have suggested it being the oil cooler, or possibly the heater matrix. Is this possible?

Personally, I pride myself on being a capable/competent driver, but mechanically I have zero knowledge.
Any advice would be greatly appreciated.
Thank you in advance.

Questions.
Is it still overheating?
Is the heater putting out heat?
Is it still losing coolant?

You could test the expansion tank for the presence of exhaust gases. That would rule the HG in or out.
I assume there's no coolant in the oil. Right?

You could pop some fluorescent dye in the coolant and use an ultraviolet lamp to detect any leaks.

If the heater isn't throwing out heat you may have an air lock. Bleeding the coolant system properly is essential.
You need to run the engine up to normal temperature (98C) so that the thermostat opens and coolant passes
through the radiator. Otherwise you can end up with too little coolant in the system. This can lead to overheating
and lack of heat from the heater. You should feel the bottom radiator hose to make sure it's hot and you should
set the heater controls to fully on while bleeding.

 

[RaySE46]

Maybe it needs a cooling system overhaul but it seems very odd... Any other signs of head gasket failure?

For an overhaul what else could be replaced apart from hoses? I feel like I've replaced most of it already but wouldn't be 100% sure.

Only signs I've noticed is
the small amount of smoke,
every time it runs im losing water.
odd occasions of milky residue in the expansion tank.

Someone on another forum recommended a sniff test so ive just ordered one and will let you know the result

 

[RaySE46]

Questions.
Is it still overheating?
Is the heater putting out heat?
Is it still losing coolant?

You could test the expansion tank for the presence of exhaust gases. That would rule the HG in or out.
I assume there's no coolant in the oil. Right?

You could pop some fluorescent dye in the coolant and use an ultraviolet lamp to detect any leaks.

If the heater isn't throwing out heat you may have an air lock. Bleeding the coolant system properly is essential.
You need to run the engine up to normal temperature (98C) so that the thermostat opens and coolant passes
through the radiator. Otherwise you can end up with too little coolant in the system. This can lead to overheating
and lack of heat from the heater. You should feel the bottom radiator hose to make sure it's hot and you should
set the heater controls to fully on while bleeding.

Hi Ray,

Yes its still overheating but only when the coolant has depleted which is to be expected.
Thats a good question, I havent tried the heater, I know the mechanic had problems with the heater when the new radiator was installed and bled.
It is still losing coolant.

Ive just ordered a sniff test kit and will let you know the results when it arrives, if the test comes back clear, is that a definite thumbs up for the HG or could it still be gone?
Before the test I'll let it run for a good while and try the heaters.

Thank you for your help,
Ray

 

[RayPooley]

For an overhaul what else could be replaced apart from hoses? I feel like I've replaced most of it already but wouldn't be 100% sure.

Only signs I've noticed is
the small amount of smoke,
every time it runs im losing water.
odd occasions of milky residue in the expansion tank.

Someone on another forum recommended a sniff test so ive just ordered one and will let you know the result

Diagnose. Don't just throw money at it.

If it passes the

Hi Ray,

Yes its still overheating but only when the coolant has depleted which is to be expected.
Thats a good question, I havent tried the heater, I know the mechanic had problems with the heater when the new radiator was installed and bled.
It is still losing coolant.

Ive just ordered a sniff test kit and will let you know the results when it arrives, if the test comes back clear, is that a definite thumbs up for the HG or could it still be gone?
Before the test I'll let it run for a good while and try the heaters.

Thank you for your help,
Ray

If it passes the sniff test next should be ....

UV Dye & UV Torch Kit Leak Detection Fluid For Car Cooling Antifreeze System RLD2 : Amazon.co.uk: Automotive

Buy UV Dye & UV Torch Kit Leak Detection Fluid For Car Cooling Antifreeze System RLD2 at Amazon UK. Free delivery on eligible orders.

www.amazon.co.uk

 

[Bimmer3er]

For an overhaul what else could be replaced apart from hoses? I feel like I've replaced most of it already but wouldn't be 100% sure.

You could get kits from places such as FCP Euro, though it will be pricey if you don't do the work yourself, otherwise you can order the parts separately... Make sure you're buying OEM where it's needed or quality aftermarket if it's the superior product as you're going to replace cheap parts all of the time...