Over heating Pleeese help

[confused60]

Hi I am new to this so please be patient with me. I have a 1997 BMW E39 540i. It started to over heat was told it was a Radiator problem replaced. Same problem replaced thermostat, Told then cylinder head gasket had the gas test done by Silverton. Found no problem with that. Then replaced water pump still over heating. The thing is that if you drive slowly revs below 1500 does not over heat. If I drive normally over heats (I have not let it over heat past 3/4) If it starts to get hot just slow down and it drops back down to normal. There are no water leaks. The system does build up a lot of pressure. Could the gas reading been a false positive. Any help PLEASE.::blueCry:

 

[b3rg]

Hi

Please ensure that your mech is doing the proper bleed procedure. If the coolant is not bled through properly, there will still be air in the system.

What coolant are you using as well?

 

[Veteran]

Has it perhaps been tuned and is running very lean ?

 

[confused60]

Hi

Please ensure that your mech is doing the proper bleed procedure. If the coolant is not bled through properly, there will still be air in the system.

What coolant are you using as well?

Hi yes I printed out a bleed procedure "meeknet.co.uk" Heaters to 32 degrees C. Fan Low, car on incline bleed screw etc.
I used the Green coolant not sure of the name got it from Midas.
There is no water leaks during the day. However at night when the caar stands the next morning there is a pool of water under the car. About 2Lt not sure where it has come from as it has run off from the "guard" under the engine.
I am thinking of having the cylinder head gasket re tested.
Question on the small return pipe that runs along the top of the radiator into the Fill bottle. There is only a very small trickle of water coming out when the car is idling is this correct even if the car is at 2000rpm. Should it not be a spray?
Thank for the feedback thus far I really do appreciate the help.
One other thing when I am driving and engine starts to over heat (I Never let it get past 3/4) why if I drop the revs down to 1500rpm does the temperature go back to normal?

 

[naickers]

Had a similar issue, there is a solenoid on the left hand side firewall that is leaking the coolant, it will also suck air via this leak, before we found this leak we had changed the radiator , all the pipes the water pump and pressure tested it a couple of times, just follow the water pipes ti that solenoid,

 

[confused60]

Had a similar issue, there is a solenoid on the left hand side firewall that is leaking the coolant, it will also suck air via this leak, before we found this leak we had changed the radiator , all the pipes the water pump and pressure tested it a couple of times, just follow the water pipes ti that solenoid,

Thanks will try that Is it the left hand side looking at the engine from the front or sitting inside the car? sorry to ask such a stupid question but I am a total novice. You don't by any chance have a part number. or a diagram as to where it is.

 

[naickers]

Left hand side from inside the the car, will take a pic later and post it later,

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[confused60]

Left hand side from inside the the car, will take a pic later and post it later,

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Thank you so much will really appreciate it

 

[confused60]

Left hand side from inside the the car, will take a pic later and post it later,

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Hi I am attaching a diagram of what I think you are saying is the solenoid is it correct part. BMW don't have stock where did you get yours from please thank

 

[naickers]

This is the one I was talking about, got a second hand one from BMW Spares in Edenvale,

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[confused60]

This is the one I was talking about, got a second hand one from BMW Spares in Edenvale,

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Thank you so much. Before I go and buy a new one They are expensive it is the heater valve. How did you find the leak was it visible ? Mine only looses water when standing overnight. During the day no water leak visible even if parked for 5 hours.
Take it when you had your pressure test done did not show a problem.
Thank you again for all your help.

 

[naickers]

Yes, mine as well could not see or find the leak, my mechanic disconnected the radiator sealed off the hoses and pressurized the system to over it's normal threshold, but I think he was very lucky to spot it,

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