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Looking to get an 01 vert in go9d shape, with only 30kmiles at a very attractive price BUT as soon as the key is turned, engine not run overnight, the temp gage pegs in the red zone. I suspect the coolant temp sensor at the bottom of the expansion tank, and it's relatively inexpensive.
however and to verify I'd like to chech the OBC hidden function for engine temp, but I think it gets its signal from the same, suspect CTS. Coolant level looks good, oil present, no way a car can go into the red zone without even starting... am I missing something?
Had a a 2002 325i for several years, several years ago, I need to get my E46 mojo back into shape. There are/were a couple dozen mostly older bimmers too., including 15 separate 2002s.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
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The temperature gauge uses the sensor located in the cylinder head between cylinders 5 and 6. That sensor is connected to the engine computer (DME in BMWspeak). The DME controls the temperature gauge. The sensor in the expansion tank is used to determine when the tank’s coolant level is low.
Google “BMW E46 hidden obc functions.” Run the test that exercises the gauge cluster. This will tell you if the temperature gauge is good or not. Please report back with the results.
Member
E46Fanatics is the site to go to. The OBC hidden stuff is documented well over there. The expansion tank only gives you a low level warning. Does it start?
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Runs just fine; I got the plug back onto the existing sensor by removing the cabin air filter tray, etc. Coolant full, I knew there should be no problem, went for a drive. Dash gage joined the party after some miles and read right in the middle where it should.
HOWEVER, to put it on is a real humbug b/c 1) you can't see the sensor 2) the connector only fits one way 3) the orientation is really skew 4) apparently you can't put it on with the wire bail on the connector. So today (Saturday) I took off the connector and let my wife (smaller hands) have a go. No dice. So I put it back together minus the filter tray, and we will take a drive of some miles this afternoon. I don't like doing this, but if the gage gets its sh*t back together I'll leave well enough alone, and add the connector clip to my stash-o-parts. Just in case I'm ever loony enough to remove the intake manifold.
FINAL ADVICE TO ANYONE WHO HAS THE INTAKE MANIFOLD OFF FOR WHATEVER REASON: Change the engine coolant temp sensor. If/when you old one craps, you'll be in a world of hurt. If you changed it, you'll have a known good sensor and likely no issues for as long as you own the car.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
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Got a new sensor, plugged it in, verified the old sensor is bad. I can fingertip touch the in-place sensor, but can't get a socket on it b/c there's some hose in the way. Looks like I'm in for doing it the hard way: intake manifold removal. Well not full removal, just enough to pull the back of the manifold off the cylinder head enough to get my fat fingers in there, plus a wrench.
Have see a few vids on manifold removal for the purpose of R&R the sensor, and will search further. Question is, do I have to remove the fuel rail and the enclosed wiring loom next to it, or can I leave them on the manifold? I think I can see the manifold bolts enough to remove them (and not drop them as they are M7 flange nuts and I have no spares).
I'll be baaaa-ck. Or maybe I'll be Beethoven. Time will tell. I'm not looking forward to this, but neither will I pay someone $100+/hour or more, for what is likely a 3-hour R&R.
Charlie
Your mission, should you decide to accept it, is to add value to these threads, either by pictures or by descriptions, so the next person with the same or similar problem stands on your shoulders.
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There is no need to remove the fuel rail. Disconnect the fuel line from the rail, and then leave it in place on the manifold. The bolts are easily accessible with an extension, and having a magnet handy can help a lot.Originally Posted by Honolulu
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You do not need to remove the manifold. Just remove the driver side wheel and work your hand from the bottom. That's what I did to reconnect the connector.
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