engine overcooling

[kimumu]

Hi, people

I have posted aboit this issue I am having on other forums but unfortunate the engine overcooling issue remains.

I have already replaced thermostat twice(new wahler ones), engine coolant temperature sensor under the intake manifold, flushed the coolant, bled it 5 times and replaced electric fan switch sensor.

Still it takes a very long time to get to operating temperature(needle bang in the middle) and even when the needle gets to the center it would drop toward the first dot but never pass it. I haven't noticed any coolant leaks and I can still get hot air from the vent. And I get similar mileage compare to before.

I first noticed it about a year ago when I was driving on the high way.

What do you guys think? Am I not.doing enough bleeding? Or something serious is happening to my car. It kind of drives me crazy at this point.

Anything will be greatly appreciated. Thank you.

[BMWfanz]

Have you tried dashboard digital tests? or laptop with INPA or other diagnostic software

[Flow]

Oil temperature is always a bit to the left of the center, if that is what you are talking about ?
Water temperature is in the middle usually.

This is when driving normally, not hard.

This is pretty much the normal needle position :

[kimumu]

Have you tried dashboard digital tests? or laptop with INPA or other diagnostic software

I have never tried it. Do you know how? I got inpa.

[kimumu]

Oil temperature is always a bit to the left of the center, if that is what you are talking about ?
Water temperature is in the middle usually.

This is when driving normally, not hard.

This is pretty much the normal needle position :

I meant water temperature. My oil temperature looks just like in the photo.

[jayjaya29]

Your car is fine. The coolant temperature is fine as long as the needle is between the 2 dots, it does not have to be right in the middle.

[bigjae46]

I think there are different temp thermostats floating around. So you might have a thermostat that opens at a slightly lower temperature. This will slightly increase fuel consumption. You do want to get the oil temps up to 212f or 100c frequently since that helps keep the moisture out of the oil.

Or could have the bypass in the oil filter housing blocked. Common thing for an E46 which sees track time to have.

[samthejam]

If you aren't getting the 105 DTC for temp implausibility. I absolutely wouldn't worry about it. Maybe you just have a very good fan clutch

[sapote]

Use INPA to monitor both the radiator outlet and engine coolant temperature sensors while driving, pay attention to when the radiator outlet temperature STARTS going up at what engine temperature. This should only happen when engine temperature is 85c or above.

[Stilt]

I think there are different temp thermostats floating around. So you might have a thermostat that opens at a slightly lower temperature. This will slightly increase fuel consumption. You do want to get the oil temps up to 212f or 100c frequently since that helps keep the moisture out of the oil.

Or could have the bypass in the oil filter housing blocked. Common thing for an E46 which sees track time to have.

There is a motorsport thermostat that opens at a diff temp, which to my understand opens up at 55c vs the oem which opens up at 80 degrees celsius (if I'm not mistaken).

[BL92]

The thermostat is set at 80 degress C and can be viewed in INPA to check correct operation. The E46 M3 has a coolant temperature gauge that displays in real time!

You may be getting confused with a car that has a dummy temperature gauge installed

"dummy" gauge in the sense that its center weighted.

What’s the point of a dummy gauge? For automakers, they’re a way of keeping novice owners from misinterpreting or getting worked up about the actual performance of their vehicle. Simply put, car companies don’t trust drivers not to freak out when they’re exposed to the temperatures that come with regular engine operation.


Source

AI Overview

Many car manufacturers use a "dummy" or "needle-in-the-middle" coolant temperature gauge, where the needle stays in a normal range once the engine warms up, to reduce driver anxiety. Instead of showing the exact temperature, it only moves from a cold position to the middle, staying there until there is a real overheating problem. These gauges simplify the dashboard and rely on a warning light to alert drivers to serious overheating, although some drivers prefer gauges that show more specific temperature data, as these can provide early warnings of other issues.

[6speedS54]

Oil temperature is always a bit to the left of the center, if that is what you are talking about ?
Water temperature is in the middle usually.

This is when driving normally, not hard.

This is pretty much the normal needle position :

Can you show the default needle position when car is off?

[kimumu]

Thank all of your tips. I just bled the coolant again and haven't driven it yet. When I bled the coolant I accidentally bumped into the car and I saw bubble came out of bleeder screw. So I yanked it couple more times and saw bubble came out again. I kept yanking it until there was no bubble coming out. Was I forcing air trapped in the system out or is happens wheneverthe car is being shaked?

[BL92]

S54 do not require bleeding as per TIS

Re-read my post above

[kimumu]

S54 do not require bleeding as per TIS

Re-read my post above

ok. Thanks. Now can a bad battery cause the needle to fluctuate? I replaced my alternator a year ago. Since then my battery only reads around 12.2 volts when car is off. I have no idea how old the battery is. I bought my car 2 years ago. Since then I have fitted angel eyes and a backup camera(which only works sometimes).