I'm having 2 problems as we speak, nothing major at all
The temperature gauge for some reason is sat to far below the blue box when the car is off and even when it starts so it saying the max temperature is right in the quarter line somewhere hmm, I did take the dash apart and the needle is moving freely so I haven't a clue
The radiator makes a slight whine once started, does get louder or any quieter when I drive so I don't know, it's never effected the way the car drives though and the heating works perfectly can get cold and hot air which also relates to the above question
Any ideas? New e30, nothing major as far as I'm aware
Moderator: martauto
Have you checked the thermostat? May have failed open giving slow warmup and low temp gauge reading.
Re: radiator noise, any coolant loss? Is it a hissing air kind of noise?
I'd suggest checking all hoses, flushing cooling system and re-filling with new coolant then bleeding. Which engine do you have? My 325i thermostat failed soon after buying it (over 10 years ago now!) and once I changed it has always been fine since but has had a few coolant changes since too for good measure.
Re: radiator noise, any coolant loss? Is it a hissing air kind of noise?
I'd suggest checking all hoses, flushing cooling system and re-filling with new coolant then bleeding. Which engine do you have? My 325i thermostat failed soon after buying it (over 10 years ago now!) and once I changed it has always been fine since but has had a few coolant changes since too for good measure.
Just to make you aware that the m20b25 (325i) engine is known for reading low on the temperature gauge.
A quarter line reading is nothing to worry about.
Take a look at the second to last paragraph of the following link.
http://www.e30zone.net/e30zonewiki/index.php/Cooling
A quarter line reading is nothing to worry about.
Take a look at the second to last paragraph of the following link.
http://www.e30zone.net/e30zonewiki/index.php/Cooling
- TriggerFish
- E30 Zone Regular

- Posts: 507
- Joined: Sat Jun 30, 2012 11:00 pm
- Location: Aylesbury, Bucks
Mine does what you say. Sits below blue when off, and then moves to the first white line out of the blue section once warm. In traffic, it will creep to the midpoint mark. That's with a new 80c thermostat fitted, and a new radiator.
To test the gauge works for the full sweep under its own power, unplug the brown sensor on the thermostat, and connect the plug to a length of wire, and connect this to a ground on the car - it should complete the circuit and move the gauge fully into the red.
To test the gauge works for the full sweep under its own power, unplug the brown sensor on the thermostat, and connect the plug to a length of wire, and connect this to a ground on the car - it should complete the circuit and move the gauge fully into the red.
- Brianmoooore
- E30 Zone Team Member

- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
If you look at the OP's other post, you will see that the engine in this car is a M40B18, so all this talk about a M20B25 is irrelevant. The temp. gauge on a car with this engine should sit right in the middle, so either there's a wiring fault, or the car has a faulty or no thermostat.
Needs checking fairly quickly, because if it's running at too low a temp., it will be over fueling, and petrol will be contaminating the oil.
Needs checking fairly quickly, because if it's running at too low a temp., it will be over fueling, and petrol will be contaminating the oil.
- Cyant1fical
- E30 Zone Newbie

- Posts: 44
- Joined: Fri Jan 27, 2017 11:00 pm
- Location: Newcastle
Thanks for the replies people, I'm going to have a look tomorrow when I get some free time, I'll keep an update and let everyone know what's happening, I have a vague idea of what could be the problem so it can't be that hard to fix in imaging
As for the fan noise, I can't hear any kind of air coming out of any pipes anywhere and they all feel solid, can't find any corrosion, like I say I'll keep updating thanks everyone!
As for the fan noise, I can't hear any kind of air coming out of any pipes anywhere and they all feel solid, can't find any corrosion, like I say I'll keep updating thanks everyone!
- Cyant1fical
- E30 Zone Newbie

- Posts: 44
- Joined: Fri Jan 27, 2017 11:00 pm
- Location: Newcastle
Second reply, the car engine doesn't feel cold in certain places, the heating works perfectly in the car cold and hot, also unless I'm dumb, how do you check the thermostat? 
Remove it and heat in a pan on the stove to check it opens around correct temp and closes as it cools. Depending where it's mounted on your engine you can feel pipes either side during warmup to gauge when it's opening but I prefer visual inspection hence removal and pan.Cyant1fical wrote:Second reply, the car engine doesn't feel cold in certain places, the heating works perfectly in the car cold and hot, also unless I'm dumb, how do you check the thermostat?

