Driving in extreme heat & engine light

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garyb1st

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Got two alarms driving in extreme heat yesterday.

We left the campground early to avoid the forecasted high of 123º in Needles CA. It was only in the mid-90º's when we drove past the Needles exit at 6 AM. For those not familiar with the grade on I-40 heading west toward Barstow, it's long and steady. Not much more than 3 - 4% but the elevation gain is about 2300 feet. Needles is about 350 feet.

I had never heard this particular alarm before. I thought it might have been my wifes cell phone. The second time I heard it I also saw the light on the dash. A water can that illuminated. We were running hot but my dash gauge had not moved. Still sitting exactly in the middle. I turned off the AC and had my wife check her phone which had the Torque ODB app. It was up to 225º at one point. Usually the motorhome runs in the mid 190º's to maybe 218º on a long pull.

Turning off the AC helped and we managed to get to a rest area where I checked the coolant. Everything seemed to be OK. No leaks, no smell of coolant.

Not sure what's wrong with the dash gauges. They were replaced prior to our purchase. Since we managed the remaining 200 miles back to our home in heat hovering around 100º, I'm hoping there is nothing wrong with the cooling system. In the 4 years we've owned the Pace we've driven maybe 20,000 miles and the ODO is currently around 53,000. Not sure what service was performed prior to our ownership but I'm thinking at least a thorough check of the radiator/cooling system is in order.

Anyone with the Workhorse 8.1 Vortec have similar experience?
 

SpencerPJ

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The guys on the Ford truck forums swear that if they increase the octane (as Ford recommends), their trucks run cooler when towing. Just a thought. I have no issues, but the condition you explained yesterday, who wouldn't get slightly overheated ;).
 

Gary RV_Wizard

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May be nothing wrong with the gauges. It's possible the temp sensor that feeds the gauge is in a different part of the cooling system than whatever triggers the alarm, so reporting a different temperature. Also, analog dash gauges aren't necessarily real analog gauges - sometimes they are just simulated based on digital data from somewhere.
 

JayArr

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Modern instrument clusters use stepper motors to move the needles and they are prone to failure. The motors are very cheap, you can buy them on eBay for a couple of dollars. The sensor isn't connected directly to the gauge anymore either, the computer reads the sensor and then commands the stepper motor to display a certain position of the needle.

Mine went in my Envoy last year on a long trip it. It would give a normal reading when I started to drive but then it wouldn't move after that, just like you describe, so you think the coolant temp is OK but it's overheating.

I bought a set of replacement motors on eBay for about $20 and replaced the coolant stepper motor myself in about 20 minutes. 4 months later the oil gauge did the same thing so I pulled it again changed them all (speedo, tach, battery voltage, fuel) While I had it out I changed all the lights in the cluster to LED as well.


There are lots of you tube videos showing how to do this.
 
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garyb1st

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The guys on the Ford truck forums swear that if they increase the octane (as Ford recommends), their trucks run cooler when towing. Just a thought. I have no issues, but the condition you explained yesterday, who wouldn't get slightly overheated ;).
Good point on the gas octane. I usually run 87. One time the station only had 86 octane so that's what I got. I didn't notice any issues. Of course it was 15º cooler and we were coming out of the mountains so mostly down hill.

Gary,
 

garyb1st

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May be nothing wrong with the gauges. It's possible the temp sensor that feeds the gauge is in a different part of the cooling system than whatever triggers the alarm, so reporting a different temperature. Also, analog dash gauges aren't necessarily real analog gauges - sometimes they are just simulated based on digital data from somewhere.
Good to know. Hopefully that's all it was.
 

garyb1st

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Modern instrument clusters use stepper motors to move the needles and they are prone to failure. The motors are very cheap, you can buy them on eBay for a couple of dollars. The sensor isn't connected directly to the gauge anymore either, the computer reads the sensor and then commands the stepper motor to display a certain position of the needle.
Thanks for the info. I'd love to have some better gauges. Hopefully the Torque OBD app is working properly.
 

TheBar

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The guys on the Ford truck forums swear that if they increase the octane (as Ford recommends), their trucks run cooler when towing.
That is true. Lower octane forces the computer to retard timing to eliminate knocking. Retarded timing causes an engine to run hotter because it has to work harder to produce the same horsepower. Which is amplified when going up a grade. Timing is also why higher compression engines make better gas mileage on higher octane. Using E85 instead of E10 gasohol can increase octane but is a wash because alcohol is less 25% less combustible than gasoline and makes the engine work harder. Which also lowers gas mileage by about the same percentage.
 

Skookum

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225 or so is the higher end of normal, still OK.

On a lot of GM chassis, cars and trucks, the ECU tunes out normal temperature fluctuations as seen on the instrument cluster gauge. For example, if you have a 195 degree thermostat and the ECU allows the coolant temp to reach 225 before kicking on high-speed fans or before the mech fan fully engages, you may not see any fluctuation on the dash gauge at all. If you've ever driven an older car with a truly analog/mechanical gauge, just idling, the temp gauge will creep up into that 220 range before the fans kick on and brings it back down. Rinse/repeat.

If coolant levels - both the radiator, and overflow, are topped off, no leaks, I might suspect a ventilation issue. Radiators and condensers can load up with bug carcasses which restricts airflow. A lot of bugs shred as they go through the AC condenser and get stuck between the condenser and radiator. If it has a mechanical fan (I think 8.1's do?) it could be a fan clutch issue where the clutch isn't engaging fully and you're not getting enough airflow.

It's all worth checking into, and good on you for having and OBD app that gives you actual data from the sensors themselves!
 

Skookum

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Actually, would be helpful if you posted a picture of the warning light that you saw.

A "water can" isn't something that rings a bell. GM coolant warnings usually look like a thermometer in water. I wonder if you had a really high oil temperature instead.
 

garyb1st

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Actually, would be helpful if you posted a picture of the warning light that you saw.

A "water can" isn't something that rings a bell. GM coolant warnings usually look like a thermometer in water. I wonder if you had a really high oil temperature instead.
download.jpg
It only lit for a moment so not positive but it looked something like this and it was in the upper right hand corner of the dash. I see it is more likely the oil light. I had checked the oil level both before and after the light illuminated and it was probably a quart low. Other than being a quart low on oil, what might cause the light to illuminate? At the time, I was pushing the Vortec pretty hard. I was driving between 60 and 70 trying to beat the heat and maintain engine RPM's while going up the grades.
 

HueyPilotVN

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Gary,

I have a suggestion that I got from an old Trucker.

I used to drive on I-40 when I traveled across the country on many trips that would pass thru Needles.

He told me about an easy detour that would bypass the mountains west of needles.

Heading west out of Needles, about 10 miles turn north on Hwy 95. You will go about 5 miles and you will come to the railroad crossing. Turn left on a good paved road, (west) and you will follow the train track over to Goff which is where it meets up with I-40.

This is the route that the trains use to avoid the grade.

It is not that much longer and it will very much help to keep from overheating your engine.

You can also use it going east but the grades on I-40 are not as long as heading west.

Try it next time.

It wont fix your gauges but it will keep your engine cooler.

Say "Hi" to Maria for me.
 
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JayArr

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Ummm... I think I think you're right, that's a low oil pressure light, it's an oil can not a watering can.

Being down a quart will make it light, especially on an incline when all the oil sloshes to the rear of the pan, your oil pump may have momentarily been sucking air.

You may want to familiarize yourself with how to read oil pressure on the Torque app in case it lights again.
 
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Skookum

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View attachment 147010
It only lit for a moment so not positive but it looked something like this and it was in the upper right hand corner of the dash. I see it is more likely the oil light. I had checked the oil level both before and after the light illuminated and it was probably a quart low. Other than being a quart low on oil, what might cause the light to illuminate? At the time, I was pushing the Vortec pretty hard. I was driving between 60 and 70 trying to beat the heat and maintain engine RPM's while going up the grades.


Yep...That concerns oil, not coolant. Either a pressure or temperature issue.
 

garyb1st

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Gary,

I have a suggestion that I got from an old Trucker.

I used to drive on I-40 when I traveled across the country on many trips that would pass thru Needles.

He told me about an easy detour that would bypass the mountains west of needles.

Heading west out of Needles, about 10 miles turn north on Hwy 95. You will go about 5 miles and you will come to the railroad crossing. Turn left on a good paved road, (west) and you will follow the train track over to Goff which is where it meets up with I-40.

This is the route that the trains use to avoid the grade.

It is not that much longer and it will very much help to keep from overheating your engine.

You can also use it going east but the grades on I-40 are not as long as heading west.

Try it next time.

It wont fix your gauges but it will keep your engine cooler.

Say "Hi" to Maria for me.
Thanks Bill. I've been on Hwy 95 a number of times and recall passing that road. Always wondered where it went. Will definitely take it next time we're heading home on the I-40.
 

garyb1st

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Ummm... I think I think you're right, that's a low oil pressure light, it's an oil can not a watering can.

Being down a quart will make it light, especially on an incline when all the oil sloshes to the rear of the pan, your oil pump may have momentarily been sucking air.

You may want to familiarize yourself with how to read oil pressure on the Torque app in case it lights again.
Thanks Jay. Don't recall seeing oil pressure on the Torque app. As I recall, it was a free download so maybe it's only available on the upgraded version. I'll take a look next time we're out.
 

Edd505

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Mar 22, 2021
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Elephant Butte, NM
Modern instrument clusters use stepper motors to move the needles and they are prone to failure. The motors are very cheap, you can buy them on eBay for a couple of dollars. The sensor isn't connected directly to the gauge anymore either, the computer reads the sensor and then commands the stepper motor to display a certain position of the needle.

Mine went in my Envoy last year on a long trip it. It would give a normal reading when I started to drive but then it wouldn't move after that, just like you describe, so you think the coolant temp is OK but it's overheating.

I bought a set of replacement motors on eBay for about $20 and replaced the coolant stepper motor myself in about 20 minutes. 4 months later the oil gauge did the same thing so I pulled it again changed them all (speedo, tach, battery voltage, fuel) While I had it out I changed all the lights in the cluster to LED as well.


There are lots of you tube videos showing how to do this.
Towing with a Ford Mustang, that's the issue.
 

TheBar

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MS
Other than being a quart low on oil, what might cause the light to illuminate? At the time, I was pushing the Vortec pretty hard. I was driving between 60 and 70 trying to beat the heat and maintain engine RPM's while going up the grades.
If it has been a while since your oil was changed the oil may have been foaming causing low oil pressure and the warning light. This will destroy an engine fast. The combination of high heat, high rpm, and low oil level can create air bubbles in the oil causing it to foam. Quality engine oil has anti-foaming additives in it that get depleted over time. Add oil when it is low or better yet change it. I change oil every 5,000 miles or once a year, whichever comes first. It is way cheaper than a new engine.
 

Mark_K5LXP

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Albuquerque, NM
I just looked and did not see oil pressure on my phone with Torque Lite, but it is there on my paid version on the tablet I use with the RV. Making a trip today so I'll try logging it and see what the pressures are like over the course of my run.

In my experience with hot/thin oil I've seen some oil pressure lights flicker only at idle, under way pressures were always normal. Have never seen the oil light come on with my 8.1 Vortec at any time. It will be interesting to see the data log after the trip today.

Mark B.
Albuquerque, NM
 

Gary RV_Wizard

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I had checked the oil level both before and after the light illuminated and it was probably a quart low. Other than being a quart low on oil, what might cause the light to illuminate?
That oil indicator is driven by oil pressure status, not actual oil volume. If the oil is low enough, pressure may drop because either flow is reduced or the oil pump starts churning foam. Higher temperature can also exacerbate the low oil pressure condition.
 
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