Check engine light and thermostat

[talljames]

My check engine light (same as service engine soon) came on a week or so ago. Pretty sure it is an open cooling thermostat from what I have read. Temp needle at 12 o’clock and doesn’t drop down to 11 o’clock. Engine appears to still run fine. Need to hook up my foxwell.

Anyway, does anyone have any experience on how long you can drive with a fault open cooling thermostat?

I have a service in early February coming up. Maximum drives are around 45min. I haven’t lost any major coolant. Before the check engine light came on I was loosing little coolant over a long period and forgot to check for a while and suspect I caused the issue then.

[andrewwynn]

On e53 the temp indicator isn't a m thermometer, it's effectively a 3 position indicator. Cold engine warm engine overheated engine.

Get the temp running on foxwell and monitor or use the hidden menu.

I had a stuck open tstat for about four months due to the non thermometer dial.

[talljames]

Apparently, from past member comments, the engine runs cooler and the fuel economy goes down under this scenario. Did you travel any large distances in your case?

[andrewwynn]

Fuel economy is shit and it's prob not great for the engine.

[talljames]

Well, maybe I have had this thing wrong all along. Need to get the foxwell on it as to why the check engine (SES) light is on. The temp gauge gets quickly up to 12 O’Clock and does not move. Did the cluster check after travelling 25min and it read 105 deg celsius which is telling me the t-sat is working I think. Will post more after the foxwell read for errors.

[andrewwynn]

I never got ses from low temp you of course need to scan for errors not guess.


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[talljames]

Too much reading xoutpost I’m afraid. But, it was a valid contender before I did the test. Will check before I post next time if possible.

[workingonit]

Originally Posted by talljames

1)My check engine light (same as service engine soon) came on a week or so ago. Pretty sure it is an open cooling thermostat from what I have read. Temp needle at 12 o’clock and doesn’t drop down to 11 o’clock. Engine appears to still run fine. Need to hook up my foxwell.

Anyway, does anyone have any experience on how long you can drive with a fault open cooling thermostat? ...

2)Well, maybe I have had this thing wrong all along. Need to get the foxwell on it as to why the check engine (SES) light is on. The temp gauge gets quickly up to 12 O’Clock and does not move. Did the cluster check after travelling 25min and it read 105 deg celsius which is telling me the t-sat is working I think. Will post more after the foxwell read for errors.]

I had a SES/CEL on my '09 HHR Panel following a low coolant incident, while running the A/C. The A/C shut off , which drew my attention to the rapidly rising engine temperature, but no SES was displayed, until later. Luckily, this happened just as I was turning into my driveway at home (on 11-27-2020).

The code was set later, I presume, because the coolant was really hot at the time, and showed up after the coolant was refilled. I cleared it, and it never came back; maybe the T-stat stuck open when the incident occured, and I refilled it before I checked for codes?

Originally Posted by Kelly Blue Book

Error code P0128 indicates that your engine coolant temperature is below the thermostat regulating temperature. This means that your Engine Control Module (ECM) or Powertrain Control Module (PCM) has recognized that your engine is running cooler than it's supposed to.

After the coolant was refilled (neglected for several years, as the overflow reservoir is impossible to see tucked-in behind the radiator), and the engine checked for possible head gasket leakage (none), the van was driveable again (sans A/C, which wouldn't work).

Long story short(er): After many discussions on another forum, and going on wild goose chases due to misleading advice from others, I tried out my Foxwell NT510 Elite scantool for the first time ever (I bought it with General Motors software in January, but hadn't tried it out until 5-15-21 (exactly one week before I got my X5, the reason I bought the scantool in the first place...I bought the BMW software just prior to that day). I used the bi-directional tool to activate/reset the thermal (pressure?) sensor on the A/C, so it would work again. To me, that was worth the price of admission alone, every other following use of the Foxwell was/is a bonus).

Anyway, the SES was triggered by low coolant on my HHR, and showed up as being set by P0128 (as scanned by my Innova 3100i scantool, bought in 2016...prior to my purchase of the Foxwell); perhaps your SES light was set similarly? I don't know what code the Foxwell would've shown, as it wasn't on hand until after the code was deleted.

[talljames]

Thanks for the post workingonit. I will see if I can clear the code with my foxwell and see if it comes back. I was out in the dark last night with my foxwell trying to make sense of all the errors that were coming up. I have had a few electrical issues after I changed the battery just the other day as I have a bad Becker BM53 radio module which I think has stopped the full reset of the system and caused communication issues on the ibus. For example, indicators on cluster not showing in the car but working outside. I am waiting on a repaired BM53 to arrive then I will disconnect the battery and replace the BM53 and then see if the system resets everything and brings my indicators back to life.

[talljames]

All codes clear and it hasn't come back. Also, all indicators inside now working again. Great little tool my Foxwell 520 pro.