Engine temp after replacing thermostat and sensor to 106 C on highway?

[TonyT]

I had the water pump, thermostat and coolant sensor replaced and got a cigarette lighter adapter for my laptop. Went for a highway drive at 30 F and I see the temps are right around 100 C when doing 62 mph. However when I do 120 kmph or 74 mph then the engine temp moves up to about 106 C. I see the "Ma and Pa Kettle" gauge moving three ticks to the right but I'm running some OBD2 software on my laptop. (I'm sure used to linear gauges rather than gauges which are very "sensitive" in the middle.)

I have noticed in a bit of city stop and go driving a while ago that it would also warm up a bit almost to the 3/4 way when idling at a stop light. Then I could hear the fan kick in and things would cool down. And as soon as I revved the engine it cooled down within ten seconds to the middle.

So it seems a bit warm at times but maybe that's nothing to be concerned about.

The engine temps were at 98 C after 12 minutes of highway driving while idling in a parking lot as I was figuring out the software a bit more.

 

[Chickenhawk]

Something is not right. The gauge needle should be pretty rock solid all the time except the very warmest days driving in traffic.

Once warmed up, mine never wavers from one-half tick to the right. Ever.

Is it possible there is still air in the cooling system?

 

[TonyT]

Something is not right. The gauge needle should be pretty rock solid all the time except the very warmest days driving in traffic.

Once warmed up, mine never wavers from one-half tick to the right. Ever.

Is it possible there is still air in the cooling system?

And before the replacement it was almost always a tick to the left unless in heavy stop and go traffic on a hot day. (Hot day in Alberta is 85 F).

Sure, there could be air. A highly recommended mechanic did the work for me but who knows ...

 

[Chickenhawk]

At least you corrected the underheating. That can cook your cat converter pretty quickly.

(Watch for a decrease in performance, especially when accelerating on the highway or climbing hills. Those are the early symptoms of a clogged cat. Keep in mind a clogged cat will rarely throw any trouble codes because it can be almost completely clogged and still clean what little exhaust gets through.)

The gauge itself is designed to smooth out small fluctuations so you don't get Ma and Pa upset, as you know. Reading directly from the OBDII port, a 195 degree thermostat begins opening close to 195 (90 C) and should normally run between 200 to 210. That's why I think your 106 C is a bit high. I run 120 in similar weather as you, and my gauge never wavers much, and unless I am in really slow traffic on a really hot day, my fan has never come on.

Do you run lots of gravel roads? Maybe take the top of the rad shroud off and check the space between the rad and the air conditioner for leaves or other debris. This is one of the most common causes of slight overheating problems on vehicles with correctly-functioning cooling system components.

 

[TonyT]

Do you run lots of gravel roads? Maybe take the top of the rad shroud off and check the space between the rad and the air conditioner for leaves or other debris. This is one of the most common causes of slight overheating problems on vehicles with correctly-functioning cooling system components.

No, I don't run a lot of gravel roads and neither did the previous owner. I'll pull the rad shroud off though and take a look.

 

[Mooseman]

Fadyasha had the same problem. He pressure washed the condenser and rad and mud just came out. He does live in the desert though. Other than that, maybe there's some internal blockage. Could take the rad to a shop and have it cleaned internally or get a new rad if it's really bad.

Another thing is to make sure your coolant mix isn't too strong, max 70% Dexcool, 30% distilled water or use premixed. Best is 50/50 if you're not in a really cold climate. Water has better heat dispersing properties than coolant. You could add some Water Wetter. Usually helps in lowering temps.

Edit: Just saw you're in AB . You're probably gonna have to run 70/30 because it does get cold out there

 

[TonyT]

Given that this is Alberta and it's winter I haven't been too worried about this problem. But I just took a highway trip and it seems to be worse. Sure enough the external computer indicates the temps are now about 110C when going up slight grades. So I'm thinking maybe it's a sensor problem. Bought one of those infrared thermometers, found a good spot to measure which is just on top of the engine block on the metal tube just before it enters the rubber hose to the rad and sure enough that metal is 110C or 248F

I can also hear the fluid bubbling into the recovery chamber.

Now this only happens if I'm driving on the highway. And today this was at 110 kmph with outside temps of +3. Or 65 mph and 35F. Within a few minutes of arriving at town/city speeds of 50/60 kmph it's back down to, say, 102 or 103C.

So now I'm thinking it's one of three things. The thermostat is mostly blocked, the water pump isn't moving much or the rad is quite blocked. Now when I stated in my original posting I had replaced the water pump, thermostat, and sensor that wasn't quite accurate. I had replaced the water pump back in May along with the coolant. At that time I was not having over heating problems. Instead it was reporting underheating but the new thermostat and sensor fixed that.

The over heating problems started right after the sensor and the thermostat was replaced in October. So I'm really, really suspecting the thermostat as hardly opening when it gets warm.

Side note. I didn't pay much attention but the Android Torque program stated the load factor was at 100%. Other than when idling. But I didn't pay much attention to that number so I could be wrong.

Finally I haven't inspected the rad. It's been too frigging cold out since October. Snow fell and it hasn't been warm since.

Tony

 

[Ryda55555]

Make sure theres no air in the coolant, it'll cause it to flucuate like that.
Run the truck and check the coolant resevoir, i dont know the exact steps to figure it out but im pretty sure someone will add to this

 

[TonyT]

Make sure theres no air in the coolant, it'll cause it to flucuate like that.
Run the truck and check the coolant resevoir, i dont know the exact steps to figure it out but im pretty sure someone will add to this

There's lots of fluid in the reservoir but I suspect that's not what you mean. Hopefully someone will jump in maybe with a link to a thread. I couldn't see anything relevant with a few minutes search.

 

[Ryda55555]

There's lots of fluid in the reservoir but I suspect that's not what you mean. Hopefully someone will jump in maybe with a link to a thread. I couldn't see anything relevant with a few minutes search.

I just did some searching for you and you have to make sure you have dex-cool coolant in there and no air in the rad or it'll cause fluctuations in the tempurature, it could also be a faulty fan not coming on at the right time

Heres how fix the air in the rad problem,
Open the rad cap and run the engine till its up to tempurature and fill it up with dex cool until it wont take anymore and then fill the overflow tank to the line.
This should eliminate all the air (hopefully this works for you)

 

[TonyT]

I just did some searching for you and you have to make sure you have dex-cool coolant in there and no air in the rad or it'll cause fluctuations in the tempurature, it could also be a faulty fan not coming on at the right time

Heres how fix the air in the rad problem,
Open the rad cap and run the engine till its up to tempurature and fill it up with dex cool until it wont take anymore and then fill the overflow tank to the line.
This should eliminate all the air (hopefully this works for you)

Yes, I have Dexcool in there.

I have not previously done the rad cap until it's warm and filled it up myself. However I did pull the rad cap several times over the past six months when it was cold and the level was just fine. I'll double check the reservoir level but I think it was about half full earlier today.

As far as the fan goes it turns on when the temps hit about 105C or 106C. Insert commentary about jet engine taking off. And only when going up a hill and after 10 or 20 seconds after I start going up the hill. So that fan behavior seems reasonable to me.

But when idling around town the temps only drop to 102C or 103C after a highway run. That seems quite high to me when driving around town at +3C temps.

 

[signalnc]

Tony--so before you took it in to the shop to get the coolant, water pump, and thermostat changed the truck was fine. Then you get it back and it is running hot. ....I would take it back to the guy who did the work. I'm thinking you got a bad thermostat. I would also ask if he put in a new water pump or a refurbished one. Nothing wrong with a refurb, but generally they don't last as long and for all the work involved it's not worth saving the $15 or $20 on the cheaper part. Unfortunately the mechanic might be good, but he is probably putting in cheaper parts. I learned that lesson last month.