Overheating

C

Chippychandler

Member
Hi to all,

Had my Z4 2007 2.5 sport 87k on the clock for two years now. No issues whatsover, but recently once the engine temp needle gets to middle temperature, normal every day temperature, its never gone higher than the middle of the temp gauge even when pushing the car. Now it goes slowly to the right and into the red. Filled radiator to ensure sufficient water that was ok. But this happens after driving circa two miles and reaching normal operating temperature. Question: is this a thermostat problem, or water pump, is there anything I can do to identify what the problem is? I'm not leaking water at all. Any assistance much appreciated and any suggestion of a mechanic near Stratford Upon Avon most welcome.
 
Hello and welcome.

Sorry to read of you issue, you may get a better response if you post this in the e85 problem forum
 
raymond.harper said:
The N52 engine has an electric water pump and it could be showing signs of failure https://www.youtube.com/watch?v=huBRlldlajw
Click to expand...
Agreed.
Take the cap off the expansion tank and start the engine. You should see a thin stream of water entering the top of the tank, if not then your pump is dead. Do NOT continue to use the car as it will overnherat very quickly.
 
Thanks for your response, when I take the filler lid off, the needle is floating and the water starts to fill and will overflow with the engine running. I assume this is a sign that the water pump is indeed working? Also i note that the heater does not blow hot air anymore?
 
Chippychandler said:
Thanks for your response, when I take the filler lid off, the needle is floating and the water starts to fill and will overflow with the engine running. I assume this is a sign that the water pump is indeed working? Also i note that the heater does not blow hot air anymore?
Click to expand...
You have an airlock somewhere then!
Raise the front of the car on ramps or similar.
Connect a trickle charger as the bleed process takes a while.
Ignition on but do not start the engine.
Set heater to maximum, activate the 'Automatic' button then reduce the fan to its lowest setting.
Press accelerator pedal to the floor for at least 10 seconds, then release.
You should hear the electric pump start to run through a bleed cycle. It is quite quiet so you may better hear the water flowing round the pipes.
The process takes about 12 minutes.
Check and top up the expansion tank.
You may have to repeat this a few times to get all the air out.
If it needs a few goes then after every second bleed remove the ignition key for about 3 minutes to let the DME drop off line, then repeat the procedure.
 
Thanks for your input and advice.. does the car need to be raised at the front? I guess this is to allow any trapped air to make its way to the expansion tank is this a correct assumption. Do I need to take the radiator/expansion cap off or do I leave it on during this bleed process. The engine runs normal until reaching the centre of the temperature gauge where it normally sits in the middle perfectly never moving. I can drive a mile , two sometimes three then the needle starts to climb towards the RED. If i let it cool down I can drive off again for a mile or two. Also, there is no heat whatsoever anymore. I squeezed the water pipes, which is easier than I thought almost as if they feel empty, the two black pipes heading towards the dash board, one black tube with a blue arrow on it facing the dashboard connected to a cast metal pipe... Apologies but you will realise I have very little experience with engines, have just really enjoyed the excitement of driving my Z4. Closed I get to flying i guess.
 
Thanks for your input and advice.. does the car need to be raised at the front? I guess this is to allow any trapped air to make its way to the expansion tank is this a correct assumption. Do I need to take the radiator/expansion cap off or do I leave it on during this bleed process. The engine runs normal until reaching the centre of the temperature gauge where it normally sits in the middle perfectly never moving. I can drive a mile , two sometimes three then the needle starts to climb towards the RED. If i let it cool down I can drive off again for a mile or two. Also, there is no heat whatsoever anymore. I squeezed the water pipes, which is easier than I thought almost as if they feel empty, the two black pipes heading towards the dash board, one black tube with a blue arrow on it facing the dashboard connected to a cast metal pipe... Apologies but you will realise I have very little experience with engines, have just really enjoyed the excitement of driving my Z4. Closed I get to flying i guess.
 
It is best raised at the front but technically not essential. Simply putting it up on a kerb or driven onto a couple of planks will help.
What I would do is start with the cap off so you can see what is happening. Be ready to top up if the level drops. The water level may rise and fall a few times during the process, but when the 12 minutes is up and the bleed stops it will leave you with a true level. If this is low then top up and repeat.
 
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