For the past week, the coolant temperature sensor on the Traverse has been intermittently failing so that the engine control module (ECM) had no idea what the engine’s temperature is whilst it’s running
Han Solo has a particularly appropriate take on that situation:
I’ve got a bad feeling about this!
Han Solo — Star Wars Episode IV (“A New Hope”)
The symptoms at first were pretty subtle when the air conditioning suddenly stopped unexpectedly and no amount of pushing the A/C button would bring it back to life.
Having proven conclusively the previous summer that my attempt at mending the air conditioning by trying to put more Freon into the system proved was a disaster because I missed a key step of bringing the system to a vacuum before loading the Freon through the manifold…having the A/C immediately disengage was bringing back very bad and potentially much more expensive memories than the emergency A/C recharge right before a quick trip to Savannah that showed I’d at least not blown the hoses and seals to hell.
After losing the transmission (twice!) recently and having to put on two tyres thanks to all of the nails dumped on the motorways round here, I really wasn’t looking forward to another massive repair bill when I’ve still made little headway against the last financial disaster!
That was when I noticed that the temperature gauge on the control panel was not showing a value at all.
Not good. Not good at all.
That was bringing back some very scary memories of when the Traverse dumped her coolant all over the I-87 flying overpass.
I was able to pull into a convenient petrol station and shut down the engine and then started her back up again.
All of a sudden, I’m reading coolant temperature again!
The next week would be watching the coolant sensor bottom out again and a restart would generally sort it but the problem was getting progressively worse.
I was pretty sure it was the engine coolant temperature sensor and a couple of YouTube videos made it look like mending it was relatively straight-forward with the right tools and a fair bit of luck given the very tight (and hot!) space it’s screwed into the engine block right next to a very inconveniently located dipstick.
OK, that looks much easier than the overly complicated procedure of mending a battery or replacing a headlamp on this Traverse which requires going through the wheel well and then blindly fumbling about with a moisture seal and connecting the wiring harness and replacement lamp.
Seriously, the GM engine designers must truly hate those of us who are reasonably mechanically inclined and have a modicum of intelligence about what’s going on under the bonnet.
So I get a new sensor for a whopping $30 from the auto parts store (which would have been far worse at the dealer!) and have Nicholas bring some of his tools home from his toolbox at Leith Toyota so that we can try to mend it before it fails utterly.
Unfortunately, we didn’t have a 1/2″ 19mm deep impact socket so off to Lowe’s in Garner I go to get one.
Mischief managed in finding one and that’s when all hell broke loose when the usual “wait a minute and restart” procedure not only wasn’t working, the engine was making supremely awful noises that seriously made me wonder if it was going to blow up right then and there and then finally dying. The third restart brought the sensor back to life and yelling at it near the jail on Hammond Road when it started doing the “bounce of death” was enough to convince the darned thing to keep it’s wits long enough to see me safely to my garage.
So much for that free chicken sandwich from Chick Fil-A for the Hurricanes dispatching the Islanders in Game 5 at PNC.
Now I don’t have a choice…we’ve got to try to mend the sensor or else I’m going to have to have the Traverse dragged to some garage and then I can toss another pile of money down the bog. 🙁
Enter the true hero of this story who was dead dog tired after a long day of mending Toyotas at his day job and got woken up for a bit of emergency surgery under the bonnet of the Traverse and without his smaller hands and much better automotive skills we’d probably still be trying to mend that stupid sensor.
Now the videos make it seem like it’s about a twenty minute job of moving a heat-resistant sleeve up the wiring harness, freeing the wiring harness, then using a socket wrench to replace the sensor and then plug the wiring harness back in and tidy everything back up.
Unfortunately, in a hot engine compartment where there are big wiring bundles and the dipstick holder completely in the way and a very tight space that you can’t see and is hard to illuminate which is where the sensor lives really sucks.
It turns out that the wiring harness is the truly vexing part of this process…it took about forty-five minutes to release the harness from the sensor. The old sensor was out five minutes later and it’s replacement torqued into the block just about as quickly. Then there was another thirty minutes and some serious luck along with some unlucky burns when Nicholas was able to finally make the harness connection to the back of the sensor so I could then tidy everything back up and replace the plastic cover that covers the engine block.
When we saw the state of the old sensor, the root cause of the intermittent failures became obvious with the crud encrusting most of the sensor that had built up over ten years.
Then there was the moment of truth and praying to whatever gods would listen when I turned the key and was rewarded with a valid temperature reading and a much smoother running engine.
One shakedown cruise to Cookout later and it appeared that we had successfully mended the sensor so that the Traverse could return to regular service in the morning.
Nicholas then headed off to some well-deserved sleep hopefully with good dreams of the heroic variety!
In a manner of confession, I did have a bit of a momentary freak out the afternoon after we’d mended the sensor when it was time to collect Alexander from school. Apparently I couldn’t be bothered to remember basic thermodynamics that in the hours that the Traverse had been sitting in the garage from the morning, the engine block had indeed cooled off.
So yeah, that bit of panic when it looked like the temperature gauge was dead again was self-inflicted.
Thankfully it was short-lived when I saw the first little wiggle of the needle and then it started moving up from the 160 degree low reading. 🙂
I think I’ve had enough automotive excitement to last me a while so can these mechanical problems take the following hint, please?
