Overheating?

Mott Power · 31st December 2012, 00:30

Lately I've had an "overheating" issue when driving for a longer period of time, mostly city driving and long idles. It'll gradually increase in temperature and then at some point the needle will go all the way to the red instantly and oil temp increases to about 200. However, if I shut the car off and turn it back on while it does this the temp shows well below the half way mark and oil temp is around 150. I had replaced the coolant temp sensor a while ago when it was doing this before and that seemed to stop it for a while until I took the car out of a 3 month storage and it began doing it again.

I'm starting to think its an electrical issue of some sort since the temp doesn't stay the same when I turn the car off and on again. Radiator runs hot, clutch fan seems ok, and the engine seems fairly cold when its doing this (just judging by touch). Anyone have insight on this or experienced this phantom problem before? I have a new clutch fan and thermostat going in this week and my daily commute to work doesn't cause the issue since its a brief drive.

roverguy10 · 31st December 2012, 01:52

Get yourself a good IR thermometer and start measuring the engine temps to see if it is a sender issue or something else. You need to figure out what direction to continue diagnostics first

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jack eiler · 31st December 2012, 03:24

I had the same problem- make sure you replace the seal in the bottom of the tstat housing. I'd vote stat and seal.

Check the temps on both the rad hoses to see if their about the same temp; when it's in the overheat mode. ps. they'll be hot. If one is really different find the cause, and it'll solve your problem.

Mott Power · 31st December 2012, 04:33

Thanks for the tip, will definitely check that. Just did it again and popped up some codes:

Engine coolant temp. Plausibility
Engine system flow too low
Exhaust gas temp. Sensor
Misfire cylinder 3

Hopefully the thermostat is the culprit; makes sense and I kind of figure it is. I'll check back once replaced.

caspian65 · 31st December 2012, 04:56

Another thing to consider is the radiator being plugged up with debris, this can cause the engine to run hot. Bad t-stat usually means engine running too cool.

Of course, sensors are easiest thing to check first.

Mott Power · 31st December 2012, 05:36

I'll most likely do a full flush of the system then. But to add to what happened tonight, after I turned the car off and on again and began driving back from my errand the car actually ran cool and didn't get to a normal temperature. Coolant and oil temps seemed pretty low.

Thanks for all the help so far, guys.

Sailor24 · 31st December 2012, 09:56

That is a check gauge warning. If you read the codes I would bet that you will have code 69.

Mott Power · 31st December 2012, 17:02

Quote:

Originally Posted by Sailor24

That is a check gauge warning. If you read the codes I would bet that you will have code 69.

Yup, it was 69. The Peake codes were 4F, AA, 18, and 69 if I remembered correctly. Seems like the thermostat, engine isn't getting up to normal temperature and only running moderately warm.

I'm thinking of just replacing the T-Stat tomorrow and then replacing the seal and o-rings next weekend for which I am still waiting on shipping confirmations (didn't do enough research before ordering the T-stat and realized I should do all those items as well). I don't mind having to pull it twice in a week as long as it can possibly prevent this scenario again.

Sailor24 · 31st December 2012, 17:57

First thing you might want to do is go get the software updated for your car. The 4F should not be there. It was deleted by BMW with a software update and the actual part is not available. Should be a free update, it was a voluntary recall. I hope the 18 was actually the table definition if it was listed first or you needa coil.

68FB · 31st December 2012, 18:04

Quote:

Originally Posted by Sailor24

That is a check gauge warning. If you read the codes I would bet that you will have code 69.

Sailor, what do you mean by gauge check warning? Temps go high and the DME pushes the gauges way over to make it obvious? So this happen before overheating warning messages come in?