Temp gauge question

Before anyone tells me to search, I already did and couldn't find a definitive answer. I apologize in advance for my long-windedness.

So, last Saturday, I replaced my water pump, thermostat, upper and lower radiator hoses, expansion tank and WP pulley. Before I did this, I had a P0128 code and figured I would do the complete overhaul instead of just replacing the thermostat. When the CEL was on, the temp gauge would sit slightly to the right of the center line. When I checked the actual coolant temp in the hidden OBC menu, it ran around 84-90 degrees. A little low due to stuck open thermostat. When the CEL would go off, the gauge would sit dead in the middle. After the overhaul the CEL was still lit but went out and the temp gauge was still slightly to the right of center. The actual temp hovered around 95 degrees C., which is normal. The CEL went out on it's own after a few run cycles but the gauge is still sitting to the right of center. I tried resetting it by performing the gauge cluster test. At first it didn't change anything but when I did the cluster test yesterday after work, the gauge went to center. Then, this morning, after the car got to operating temp, the gauge is sitting just to the right of the center line. I don't think I need to worry about this, but it bugs me because I know it's supposed to be dead center. Does anyone have any answers / solutions?

The temp hovering around 95 seems about right...but it could be a few degrees high depending on what you're doing at the time. I'll really only see 95-7 when I'm idling a bit or driving very slowly after reaching op temp.

Thus, my questions would be what components did you use? Did you replace temp sensor, check belts/pulleys, use OE coolant mixed with distilled?

My random guess is that the thermostat is, I hope, aftermarket, maybe an aluminum housing with crappy electronics. If you used such a therm, that'd be my guess.

Also have to ask...you said you thought your therm was stuck open before, but that the needle was 'right' of center...meaning overheating. If therm was stuck open, the needle would be to the left of dead center. Please clarify.

Keep monitoring temp using cluster...monitor coolant level, because it will drop after major work, even if you bled properly.

HTH...last thing I'd think is a gauge problem, unless you had cluster off to do some silly mod...in which case, check the cluster connections.

GL!

"The temp hovering around 95 seems about right...but it could be a few degrees high depending on what you're doing at the time. I'll really only see 95-7 when I'm idling a bit or driving very slowly after reaching op temp."

Thus, my questions would be what components did you use? I bought the cooling system overhaul kit from Tischer. Did you replace temp sensor, yes check belts/pulleys, yes use OE coolant mixed with distilled? yes


My random guess is that the thermostat is, I hope, aftermarket, maybe an aluminum housing with crappy electronics. If you used such a therm, that'd be my guess. No. OE BMW, part of kit from Tischer which includes:

OEM BMW E46 3 Series Cooling System Repair Kit
OEM BMW E46 3 Series (non M) Cooling System Repair Kit. New E46 M3 Cooling Kits now available!

Kit includes genuine BMW:

Thermostat w/ housing/gasket (11537509227)
Waterpump (11517527910)
Upper radiator hose (17127510952)
Lower radiator hose (11531436408)
Expansion Tank (17117573781)
Radiator Cap (17111742231)
Engine drain plug crush ring (07119963200)
Lower hose temp sensor (13621433077)
1 gallon BMW antifreeze (82141467704)

Also have to ask...you said you thought your therm was stuck open before, but that the needle was 'right' of center...meaning overheating. If therm was stuck open, the needle would be to the left of dead center. Please clarify.
Actual temp was 82 to 86 degrees C. according the the hidden OBC function.

Keep monitoring temp using cluster...monitor coolant level, because it will drop after major work, even if you bled properly. Checked 3 days in a row after replacing averything.

HTH...last thing I'd think is a gauge problem, unless you had cluster off to do some silly mod...in which case, check the cluster connections. I'm going to unplug and plug the cluster back in this weekend. Everything else seems normal except for the fact that when I get on the gas more and rev higher, the temp starts to drop into the 80's. I thought it should go up. Maybe my cooling system is too efficient. Lol

I'm thinking it's a gauge issue as I've read quite a few posts in my search process where people have mentioned that their gauges don't read dead-center.

Originally Posted by jerseyrider

Before anyone tells me to search, I already did and couldn't find a definitive answer. I apologize in advance for my long-windedness.

So, last Saturday, I replaced my water pump, thermostat, upper and lower radiator hoses, expansion tank and WP pulley. Before I did this, I had a P0128 code and figured I would do the complete overhaul instead of just replacing the thermostat. When the CEL was on, the temp gauge would sit slightly to the right of the center line. When I checked the actual coolant temp in the hidden OBC menu, it ran around 84-90 degrees. A little low due to stuck open thermostat. When the CEL would go off, the gauge would sit dead in the middle. After the overhaul the CEL was still lit but went out and the temp gauge was still slightly to the right of center. The actual temp hovered around 95 degrees C., which is normal. The CEL went out on it's own after a few run cycles but the gauge is still sitting to the right of center. I tried resetting it by performing the gauge cluster test. At first it didn't change anything but when I did the cluster test yesterday after work, the gauge went to center. Then, this morning, after the car got to operating temp, the gauge is sitting just to the right of the center line. I don't think I need to worry about this, but it bugs me because I know it's supposed to be dead center. Does anyone have any answers / solutions?

HOW FAR TO THE RIGHT?

If you are obsessing over the thickness of the needle, get over it. The needle can easily be off center by its own thickness, or double, without alarm.

I was under the impression that the cluster needle was basically an "idiot light" and would read dead-center for a wide range of temperatures?

yes shanneba confirmed that the needle is calibrated to read dead center with something like a range of 85-115 range. (something like that)

OP, if your gauge is cocked to one side during normal driving (basically all day) then the needle was possible messed with (repositioned) at some point. It should read dead center under normal operating temps (assuming your cooling system is healthy and bled correctly)

gl

Originally Posted by jerseyrider

...
Also have to ask...you said you thought your therm was stuck open before, but that the needle was 'right' of center...meaning overheating. If therm was stuck open, the needle would be to the left of dead center. Please clarify.
Actual temp was 82 to 86 degrees C. according the the hidden OBC function....

What was the needle "showing" at these times? Also slightly off-centre?

Originally Posted by jdstrickland

HOW FAR TO THE RIGHT? 1 mm

If you are obsessing over the thickness of the needle, get over it. The needle can easily be off center by its own thickness, or double, without alarm.

Not obsessing but just concerned because at one point in my ownership of the car, it was at dead center.

By the way, this was a pretty simple DIY for anyone who's concerned about the skill level needed for this. The worst parts were coolant getting all over the place and getting the old expansion tank off. What a b!tch!

Originally Posted by daki_bmw

What was the needle "showing" at these times? Also slightly off-centre?

Yes, about 1 mm to the right of center. I believe it's something with the servo for the gauges because when I shut the car off, the needle comes to rest between the white line and the blue section. Also, during the cluster test the needle goes past the white line on the red side the same amount that it's off-center. Before I did the overhaul, the needle would sporadically fluctuate between dead center and where it's sitting now for days at a time. I've decided not to worry about it because I have no leaks and the actual temp is in the normal range.