Engine Temperature Slightly High

Originally Posted by Bim3Por911

I too have the shifted coolant gauge syndrome. It seems to manifest itself if the car sits outside in temperatures below 25°F. I'll do the "Easter Egg" gauge reset when the temperatures warm and the gauge will go back to normal. I bought a new battery last spring, reset the gauges and I was 12 o'clock high with the gauge until the car saw 25°F overnight, and then it shifted again. The telltale is the zero position of the gauge when it's dead cold. It's about 1 mm clockwise from normal. The center reading is similarly offset.

When I first encountered the shifte gauge syndrome I reset the gauges multiple times and it just wouldn't stay permanently "fixed". The battery I had was nine years old so installed a new DuraLast battery and then the reset took semi-permanently.

I used the "Easter Egg" gauge cluster info to read the actual coolant temp - it's a consistent 93 - 94°C. When I got the car in 2011 it had the original coolant pump in it so I replaced it with the high zoot EMP Stewart pump which has a 25% higher flow rate than stock.

SterlingArcher - For what you've spent on cooling system components you could have installed a complete Zionsville All Aluminum retrofit including the $400 metal thermostat housing. Go to Zionsville.com to have a look at what they make for the e46. If you go that route you'll never worry about your cooling system anymore regardless of the silly gauge antics - unless you've got parts from a disintegrated pump lodged somewhere.

As I said before - I'm convinced that the cooling gauge offset is an electrical issue and has nothing to do with the health of your cooling system - unless you're actually seeing gauge EXCURSIONS as you drive and that's a different matter. For more peace of mind try getting a DVM with a thermocouple adapter (I've got a Fluke that I use) and actually read the surface temperature of the expansion tank. See if it fluctuates or is different from what the #21 test reading tells you.

Yes, always in retrospect is it easy to see how much better the money could have been spent. It's difficult however, when it's one thing at a time over the course of a year.

I never would have spent so much troubleshooting just a needle issue if it had not always been accompanied by the SES - P0128 code. Up until last week when I replaced the radiator again I had never seen the two as separate issues. Prior to the P0128 code I had never seen the needle being off-center and due to P0128 occurring the first time with an over-heat, and almost an over-heat on the second; I certainly wasn't going to "leave it alone".

And of course troubleshooting P0128, everyone I talked to said that 99.9% of the time its a coolant thermostat issue. Hence, the 3 thermostat's I went through before considering other parts as the issue.

As it turned out, if you've been following my posts, it ended up being a low-flow issue with a Behr replacement radiator I had used just after installing the first of my three thermostat's. I don't think anyone would have guessed that given an overheat P0128, it certainly was not my first guess as the culprit.

Since replacing the Behr radiator with a BMW radiator, all my P0128 issues are resolved. The car no longer has a coolant temp that fluctuates to the hot side or threatens to over-heat. What has however, identified itself to be a separate issue is the needle being shifted, under normal conditions, just a couple mms to the right of it's previous normal resting spot.

BUT, with no SES code present and the ability to watch the coolant temp remain steady with Test7 on the digital display; I am certainly not going to spend my time worrying about just the normal needle position being slightly shifted.

And as it turns out, I gather this needle issue is not uncommon from all the other posts about it. It seems to be an issue with cold temps and old needle position motors that is resettable in the short term using Test21 OBC reset once the car/gauge is at a warm enough temp. This will only last though, until the next time the gauge is out in the cold below approx 25F for some amount of time.

I would bet a new instrument cluster (with new gauge/ needle position motor) would solve this problem but, I won't be spending the money right now to find out!

- Sterling

Originally Posted by RayPooley

The guage is just a guide. The best way to check coolant and oil temperatures is through a scanner. These values are monitored and stored in DME. I don't think you can really draw any conclusions from the fact that the needle is 1 mm to the right of the middle mark. I certainly would not go spending **** loads of money on anything until I had run time values from the DME.

My guess is cxvarol only had the issue because of an aging instrument cluster/ shifted needle position in cold ambient temps; no coolant temp issues, he didn't mention any fluctuating temp or overheats, nor any SES codes.

He never posted again once being told how to verify his coolant temp right from the digital display.

- Sterling