coolant water at the reservoir always nearly empty

[markus_74]

Hello,

I have try to fix this problem since last year, change my radiator, check all hose and also change radiator cap and water pump.

after all fixing the loss of water is reduced a lot, but after I fill it about half of the reservoir about next 2 week the water coolant level will be stay at the nearly bottom may be about 1 inch from the bottom.

temperature is still normal.

where the water go? and is it normally?

thank you my car is 318i M40

[Brianmoooore]

A lot of E30s will stabalise their coolant levels at about half an inch lower than the official correct level, but yours does sound extreme.
As long as the level is above the top of the outlet pipe at the bottom of the reservoir there is enough there, but an inch will barely be enough for this.
The best way to check where the coolant is going is to do a pressure test by using compressed air to keep the cooling system under pressure while the engine is cold.
A DIY way is to remove a heater hose at the bulkhead, connect a spare bit oh heater hose in its place, and then connect a copper tee between the two ends. Connect the branch of the tee to a compressed air source at about 20 PSI, and wait to see where the water is going.
Don't try to start the engine without turning it over by hand first, or with the spark plugs out, in case water has partly filled one of the bores.

[markus_74]

A lot of E30s will stabalise their coolant levels at about half an inch lower than the official correct level, but yours does sound extreme.
As long as the level is above the top of the outlet pipe at the bottom of the reservoir there is enough there, but an inch will barely be enough for this.
The best way to check where the coolant is going is to do a pressure test by using compressed air to keep the cooling system under pressure while the engine is cold.
A DIY way is to remove a heater hose at the bulkhead, connect a spare bit oh heater hose in its place, and then connect a copper tee between the two ends. Connect the branch of the tee to a compressed air source at about 20 PSI, and wait to see where the water is going.
Don't try to start the engine without turning it over by hand first, or with the spark plugs out, in case water has partly filled one of the bores.

thank you Brian for your advice

I have remove the heater matrix from my coolant route, I made some short pipe just to connect hose to heater matrix and join the other pipe to the hose from heater matrix.

There is some water in the coolant reservoir it is very shallow but still above the small pipe with hole in the very bottom of the coolant reservoir

does is is OK?