Engine Temp and Heater

[aleebee156]

Two separate things that may or may not be connected, im unsure but both symptoms appeared same time.

1- My engine temp gauge has been fluctuating. recently it has been low around 160F, but then will take about 3-4 seconds and move up to around 220F. Then will drop back down... its acting funny. concerns me. Could just be the gauge but I'm not sure. This is not normal for the truck, normal it would sit I would say about 190F and be steady and not fluctuate at all.

2- My heater has also been working intermittently. sometimes works great, others it doesn't work and blows cold.

Related symptoms????

Both symptoms seem to be there when outside temps are very cold, like id say under 15 degreesF. Neither symptom appears to be a problem when outside temps are above freezing 32F. Truck is from California, is going through its first cold winter in Colorado.

Truck runs fine with both symptoms.
Truck also through a P0171 code around the same time when it got cold. SES light has been on most of the time the last few weeks, but sometimes not there, like today the light was not on. Driving last night SES light was on. Not too concerned about that code at this point but thought I would add in all the things going on.

Also don't recall what rating the thermostat i installed years ago is.

Sorry for the long post, and the multidimensional nature of it...

 

[4L80]

How is your antifreeze strength? Symptoms sound similar to what happens when your fluid in your rad, motor and lines is at the temperature where it's turning to slush.

 

[aleebee156]

Good question, ill have to get a strength tester and check it. I should just change it anyways, its been about 45,000 miles since its been changed. Its always the simple things... I tend to overlook them!

 

[aleebee156]

Picked up a tester, now just waiting for engine to cool to test the antifreeze...

 

[aleebee156]

How is your antifreeze strength? Symptoms sound similar to what happens when your fluid in your rad, motor and lines is at the temperature where it's turning to slush.

Thanks for the antifreeze reminder. couldn't check the strength cause levels are too low I couldn't get any fluid out. I hate that i've let it go that far. From what I could see the coolant looked very rusty in color. Time for a change. This will likely fix my problems, if something else comes up ill keep you posted.

 

[Bob L]

If you are draining the system why not change the questionable stat while at it?

 

[90halfton]

Definitely change the tstat, it's like 10 bucks. Good maintenance if draining coolant. Sounds like a lazy tstat with the fluctuation in temp anyways.

 

[aleebee156]

Definitely a good call, stat will get changed.

I've always diluted my own antifreeze with distilled water to make a 50/50 mixture. Do you guys have any experience with the stuff like from Prestone thats a 50/50 mixture ready to use? i've never used it, but it seems really easy to just buy that and pour it in. might cost me more money tho. experience with it?

 

[Bob L]

I havn't used the premix as I have a couple of gallons in my shop all the time and when one is empty I just pour half of the new gallon in and fill both with water. For the average driver that just wants to add some coolant it is easier to use premix even if it costs a little more. I have never used distilled water and have been fixing cars for over 45 years. I never heard of using distilled water for coolant only for topping off batteries. Before solid state regulators adding water to a battery was a regular part of service.

 

[beardeddummy]

Wouldn't hurt to flush the system while your at it water hose and a little effort