E46 Fanatics Forum banner
21 - 35 of 35 Posts

· Registered
Joined
·
104 Posts
This made me wonder. Have you ruled out the fan being on (or on full speed) all the time? On the manual cars it should only come on when needed, commanded by the DME. If you have INPA there's a test you can do where you tell it to spin at 0%, 25%, 50%, 75% or 100%. If you step through those with the engine off you'll be able to hear when it's on (or you can get out and check) and the pitch will increase with speed. Or you could just start the car with the engine cold* and make sure it isn't spinning.

*question to fellow fanatics: would the AC need to be off too?
Ac would have to be off, with the AC on, the fan should spin almost all the time(but not at 100%), especially if you drive slow or are standing still.
 

· Premium Member
E30M3 Race F10 535 R1150Rt M Coupe
Joined
·
12,273 Posts
Good thoughts about a hyperactive fan, albeit if the thermostat is working correctly..... The engine stays up to proper temperature and the radiator is excessively cool.

The thermostats job is not to keep the engine cool, rather to hold it within a certain delta.

Waiting to hear back about the connection and if the thermostat is being driven open by the DME?
 

· Premium Member
Joined
·
11,517 Posts
This made me wonder. Have you ruled out the fan being on (or on full speed) all the time? On the manual cars it should only come on when needed, commanded by the DME. If you have INPA there's a test you can do where you tell it to spin at 0%, 25%, 50%, 75% or 100%. If you step through those with the engine off you'll be able to hear when it's on (or you can get out and check) and the pitch will increase with speed. Or you could just start the car with the engine cold* and make sure it isn't spinning.

*question to fellow fanatics: would the AC need to be off too?
If AC is on, then the front fan automatically turned on, so for the INPA test then I think the AC should be off.
 

· Registered
2003 330CI MT
Joined
·
10 Posts
Discussion Starter · #26 ·
Does not need to be cold, just remove it and go into the hidden menu on the cluster: BMW E46 - How to display coolant temperature digitally through the cars OBC - YouTube
If the car stays at 97C, the thermostat is good but the heating element is bad or the DME sends the wrong signal.
Hi all sorry for the confusion. Temp went over a 100 while test driving while I had the radiator fan out. I am assuming this is the reason. Been driving last day or two with fan back in and no overheating.

Still struggling to get to temp while moving. While stop and go or idiling I’m right at 12:00.

Will try removing the thermostat heater cable next time it’s cold.
Have been driving last two days with the tstat plugged in and unplugged, no discernable difference. Temp never gets up to 97, and only into 90s when idling/stop and go

I guess I'll be trying a new tstat
 

· Premium Member
E30M3 Race F10 535 R1150Rt M Coupe
Joined
·
12,273 Posts
INPA allows you to specify an electric fan speed for testing.
Let me be a little more clear.
In the GT-1 or ISTA there are "Test Plans" that take you through modules, step by step to arrive at a conclusion.

What Sapote and you describe is not a Test Plan, rather a command or activation.
 

· Premium Member
Joined
·
4,873 Posts
If it's not coming up to temperature, and unplugging the heater in the thermostat isn't changing anything, you need a new thermostat. There have been numerous threads here on exactly this. The BehrHella new ones even seem to do it out of the box. Which is poo.

t
 

· Premium Member
Joined
·
11,517 Posts
My concern is it’s taking too long to get up to temp and not all the way. No code yet, so maybe I’m wrong.
Too long to get up: how many miles from cold engine to what final temperature?
Did you do test drive with the Tstat heater wires disconnected?
The Tstat passed the boiling water test, and this is manual tranny so no failed auto tranny Tstat that causes slow coolant heating up. Maybe the elec fan turned on too soon due to bad lower hose sensor? To test, disconnect the fan connector (near upper right of radiator) and do a test drive to see if anything change.
 

· Registered
2003 330CI MT
Joined
·
10 Posts
Discussion Starter · #35 ·
Just want to close this out. I didn't drive much this summer, but did end up throwing another code about a month ago, and then when it finally got cold here the car would not get up to temp.

Replaced the Mahle T-Stat with Wahler and everything working great now!
 
21 - 35 of 35 Posts
Top