Hi All - I am based in the UK and bought a BMW Z1 last year - one of my dreams since I was a kid and quite an enjoyable car so far.
What is the normal needle position on the temp gauge in your cars? Is it bang on the mark on the middle all the time, left of it or right of it?
My Z1's needle constantly moves between the second mark and the mark in the middle and I wonder if that is normal behaviour or there should be no movement at all like modern cars.
For example, going down hill the temp drops and the opposite happens when going up hill. Having good air intake at the front keeps the needle just left of the mark in the middle. Leaving the car idle for a while moves the needle right on the middle without overheating though.
Thank you for your comments.
BMW Z1 Engine Temp and Needle Position on Gauge
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- Joined: Sat 11 Jan, 2025 21:00
- Posts: 5
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Congratulations and welcome.
Was it like that when you bought it? In my case, normal fluctuates between 11 and 12 o'clock position, and does not move much beyond that. Is it possible to compare the temperature of the engine block to the reading on the gauge, using a meter of some sort? If its running normally and not actually overheating, could it be a connection issue with the gauge, the earth connection, or the temperature sensor itself?
Was it like that when you bought it? In my case, normal fluctuates between 11 and 12 o'clock position, and does not move much beyond that. Is it possible to compare the temperature of the engine block to the reading on the gauge, using a meter of some sort? If its running normally and not actually overheating, could it be a connection issue with the gauge, the earth connection, or the temperature sensor itself?
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Your temp gauge readings are ok. In summer months the needle on mine stays at 12 o'clock when warm and in use. It moved to the right once (one o'clock) when being used hard uphill in the mountains.
Do you have service history with the car ? I replace the coolant every 5 years (BMW suggest every 2 years); drain the system via the bottom radiator hose and flush the radiator from the top with a running hosepipe until the water runs clear. Refill with 100% water and use the car for half an hour (the front under tray will be off) and drain again before refilling with a mix of deionised water (from a dehumidifier if you have one) and a good quality anti freeze / corrosion inhibitor at 60/40 ratio. When you refill leave the cap off the header tank and let the car come up to working temperature until the thermostat opens so that the system bleeds any trapped air, top up with the fresh coolant mix if required.
I would avoid snake oil type "waterless coolants" they are expensive, cannot be topped up with water if need be and the engine will run hotter than the normal operating temperature.
I also replace the water pump, fan belt and thermostat every time based second cam belt change, (approx every 10 years), sooner if you cover many miles. They are not expensive and take 20 minutes to fit while also replacing the cam belt.
Do you have service history with the car ? I replace the coolant every 5 years (BMW suggest every 2 years); drain the system via the bottom radiator hose and flush the radiator from the top with a running hosepipe until the water runs clear. Refill with 100% water and use the car for half an hour (the front under tray will be off) and drain again before refilling with a mix of deionised water (from a dehumidifier if you have one) and a good quality anti freeze / corrosion inhibitor at 60/40 ratio. When you refill leave the cap off the header tank and let the car come up to working temperature until the thermostat opens so that the system bleeds any trapped air, top up with the fresh coolant mix if required.
I would avoid snake oil type "waterless coolants" they are expensive, cannot be topped up with water if need be and the engine will run hotter than the normal operating temperature.
I also replace the water pump, fan belt and thermostat every time based second cam belt change, (approx every 10 years), sooner if you cover many miles. They are not expensive and take 20 minutes to fit while also replacing the cam belt.
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Mine seems to get to operating temperature very quickly from cold, is that a sign of a less than efficient thermostat?
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Given most of us use the car in the summer months, when the top can come down, the engine should get up to operating temperature pretty quickly with the standard 80 degrees c thermostat when driving away from cold, there is no need to let the car idle to warm up.
You can get aftermarket 71c and 88c opening units which may be appropriate for very cold or very hot environments.
You can get aftermarket 71c and 88c opening units which may be appropriate for very cold or very hot environments.
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- Joined: Sat 11 Jan, 2025 21:00
- Posts: 5
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Hi TJS and Jet - sorry for late reply and thank you for sharing your experience!
Mine operates exactly as you describe - between 11 and 12 o'clock so that kind of reassures me! Car has a lot of service history and has been in storage for 10 years approx. I did a mini over-haul after buying the car and that included changing the thermostat, new head gasket, viscous coupling, checking the cam belt and flushing the whole system prior to adding the right coolant.
I was just a bit paranoid as I wasn't sure what the normal operating behaviour was supposed to be
Thank you and hope to see you soon at some BMW meet up!
Mine operates exactly as you describe - between 11 and 12 o'clock so that kind of reassures me! Car has a lot of service history and has been in storage for 10 years approx. I did a mini over-haul after buying the car and that included changing the thermostat, new head gasket, viscous coupling, checking the cam belt and flushing the whole system prior to adding the right coolant.
I was just a bit paranoid as I wasn't sure what the normal operating behaviour was supposed to be

Thank you and hope to see you soon at some BMW meet up!
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- Joined: Sat 11 Jan, 2025 21:00
- Posts: 5
Re: BMW Z1 Engine Temp and Needle Position on Gauge
Hi TJS and Jet - sorry for late reply and thank you for sharing your experience!
Mine operates exactly as you describe - between 11 and 12 o'clock so that kind of reassures me! Car has a lot of service history and has been in storage for 10 years approx. I did a mini over-haul after buying the car and that included changing the thermostat, new head gasket, viscous coupling, checking the cam belt and flushing the whole system prior to adding the right coolant.
I was just a bit paranoid as I wasn't sure what the normal operating behaviour was supposed to be
Thank you and hope to see you soon at some BMW meet up!
Mine operates exactly as you describe - between 11 and 12 o'clock so that kind of reassures me! Car has a lot of service history and has been in storage for 10 years approx. I did a mini over-haul after buying the car and that included changing the thermostat, new head gasket, viscous coupling, checking the cam belt and flushing the whole system prior to adding the right coolant.
I was just a bit paranoid as I wasn't sure what the normal operating behaviour was supposed to be

Thank you and hope to see you soon at some BMW meet up!