What is the Hose Diagram for 2008 BMW 335 xi Coupe

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.
If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.
The hose goes in to the engine to a crossover and comes out the other side close to the thermostat housing,the blockage may be there.
If you still wish to replace the stat...
The thermostat in the northstar engine is located at the bottom radiator hose (unlike most conventional cooling systems), the hose connects into the housing where you will also find the water pump.

You will need to remove the air filter housing and air duct to gain easy access to the thermostat.

Remove the hose from the housing,then remove the two bolts on the flange,the thermostat can then be pulled out.

Take note of the orientation of the thermostat as you remove it.

The thermostat in the Northstar engine is a dual action device.
One end of the stem is the Thermostat(obviously) and at the other end is a spring loaded pressure valve(the thinner end).
Make sure the thermostat end is nearest the rubber hose and the pressure valve end is in towards the engine.

ON THE 2000 323I IT'S IN THE TOP RADIATOR HOSE IT'S ONE PIECE,THERMOSTAT,HOSE AND HOUSING

There are two hoses that come from the radiator. The very bottom hose is conneted to the thermostat housing. Looking at the car from the front under the hood just below the first hose is another one same in diameter and there it is two bolts and you done.

the thermostat is in a small bellshaped housing which is attached to the engine block. the housing has a hose stuck on it which goes to the radiator. generally the hose which attaches near the top of the engine as opposed to the hose which attaches at the bottom. seldom does a thermostat simply plug up, but it is generally the easiest part to replace.

The normal operating temperature for the Northstar engine is around 210 degrees.
The fans will not come on until the temp hits 225 degrees.

The thermostat in the northstar engine is located at the bottom radiator hose (unlike most conventional cooling systems).

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.The hose goes in to the engine to a crossover and comes out the other side to near the thermostat housing,the blockage may be there.

If the other end of your purge line is not connected to anything then that is the problem......it must be reconnected otherwise the cooling system is not pressurized.

The thermostat is located at the upper radiator hose end of the engine. The hose will connect to a housing that will have to be removed in order to change the thermostat.
While you have the thermostat housing removed, make sure you flush the old coolant out and replace with new.
Good luck.

for the 2.2L engine follow the lower radiator hose it will take you to the thermostat housing. the 2.3L 2.4L follow the coolant inlet pipe it will take you to thermostat hosing.you have to remove exhaust manifold heat shield to remove thermostat housing.

Follow the top radiator hose to where it connects to the engine it will be connected to your thermostat housing. Disconnect the radiator hose and unbolt the housing your thermostat will be behind the housing.

The thermostat in the northstar engine is located at the bottom radiator hose (unlike most conventional cooling systems), the hose connects into the housing where you will also find the water pump.

You will need to remove the air filter housing and air duct to gain easy access to the thermostat.

Remove the hose from the housing,then remove the two bolts on the flange,the thermostat can then be pulled out.

Take note of the orientation of the thermostat as you remove it.

The thermostat in the Northstar engine is a duel action device.
One end of the stem is the Thermostat(obviously) and at the other end is a spring loaded pressure valve(the thinner end).
Make sure the thermostat end is nearest the rubber hose and the pressure valve end is in towards the engine.

Don't forget the new gasket when you install your new stat, you may have to order this separately.


Overheating........

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.
If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.
The hose goes in to the engine to a crossover and comes out the other side close to the thermostat housing,the blockage may be there.

Also note that the cooling fans don't come on until the coolant temperature hits around 225 degrees.
During normal highway driving the fans will very rarely come on(if at all) due to constant air flow through the radiator.They will only usually come on in heavy traffic conditions on a hot day.
But......if you have the Air Con switched on, the fans will run all of the time.

The thermostat is found at the end of the top radiator hose . Find the top radiator hose and follow it to the engine .There you will find a thermostat housing with the end of the hose attached . There will be 2 bolts holding down the housing to the engine. Undo the bolts and pull the housing off and the thermostat will be there.