Coolant Temps Keep Rising, Ideas?

As the title says I have noticed my coolant temps are slowly rising the last two or three weeks. I have noticed some weird things happening. First off my normal coolant temps are about 185 to 199 degrees as my ultra gauge says.

Unusual thing 1
3 weeks ago i started driving on a relatively cold engine and i noticed my coolant gauge going wild. Jumping from dead cold to operating temp and everything in between EXTREMELY fast. It would move up and down rapidly. The gauge would stop moving with right hand turns if i recall correctly. During a left hand turn the gauge would read the correct temperature. Basically this is really weird behavior and i have no explanation on why it happend and continues to happen on almost a daily basis now. **** side note -On past history every once in a while the temp gauge would read operating temperature until almost fully warm every once in a great while. Has happened im guessing 10 times or less since I have owned the truck

Unusual thing 2
My coolant temperature is slowly rising. I usually see temperature going up and down hills under load and coasting ranging between 190 and 199 as per my ultra gauge is displaying. Today on my way home on the hills my truck was running between 201 and 203 consistently and then on a long coasting period it would drop to 185 degrees coolant temp. This is unusual as the highest coolant temp i have had is 204 and i rarely go above 200 unless on a long hill under constant load for a long amount of time.

Unusual thing 3
When i was snow wheeling a day ago i got stuck. My truck was idiling for long periods of time as we were digging out for 4 hours. (never been that stuck before). When digging snow out from the underside of my truck i notice the dreaded green liquid on the snow. I crawled under for a peak and there was FRESH COOLANT on my catalytic converter. Not sure where the source is but this confirms that i have a leak of coolant somewhere unless there is an over flow. Keep in mind i was off camber when stuck which may change where the coolant could be coming from or have to do with it being on my cat at that time. I do not smell any coolant when i shut the truck off or its running.

Any help, ideas on what to check or any suggestions at all is much appreciated. I have had coolant problems in previous trucks and they are not fun to deal with. Im hoping to get a jump on this one early. Truck just turned 190k on the clock so parts might be wearing out about this time

 

A faulty coolant temp sensor can throw erratic readings to your gauge as well as loose wires/harness going to the sensor. I'd start by changing that since they're pretty inexpensive. Also your thermostat might not be opening up at the specific temperature it's supposed to, thats expensive too. Your mileage is climbing and things do go out over time.
The reason why your temp drops during long periods of coasting is because of the constant air flow blowing through the radiator, cooling it down! When my sport bike starts to climb in temp I pick up a bit of speed and the temp drops like you wouldn't imagine.

Also, flush the radiator fins clean to get all the bugs, dirt, mud and BS that might be in there as they restrict the amount of air flow and decrease the efficiency of the cooling system. Good luck and hope it helps!

 

Those Ultra Gauges sometimes need a short ground soldered right to the manifold fitting,,then that ground attached to a close nut or bolt. They can be waaay off and swing wildly sometimes if all the grounds are not proper. Nuked a small block chevy due to a bad ground using a Ultra gauge. Not so Ultra. Once I solderd a wire to the adapter for the sender fitting, then grounded that, It then read correct. Received 2 different Ultras and senders under warrantee thinking they were bad. They also like there own matched sender unit for the temp range of the gauge. Different temp ranges on those available gauges. Bought and mounted lots of those gauges over the years.

200° is up there,,not damaging and not over heating per say. Over heating is spitting water,,at around 220ish. Are you pushing water into the overflow?,,is it full and overflowing?

 

huh, my ultra never gets above 180 in 80 degree weather but my fan comes on all the time. I wonder if I should check my grounds now.... I don't have any over heating issues but you got me concerned about the Ultra being off.

 

That's what they will do. It will read up to a certain point then stop. Hot days or cold. It takes some pretty hot temps to cook a engine. I figure I was in the 260-290+ range when the small block dead locked on me.

A good candy thermometer is a accurate check of temps in the radiator. Or a metal spike BBQ thermometer. Just don't touch the ends of either against metal when checking. The first 1" of the hand held thermometer only touching flowing coolant taken thru the open radiator cap, vehice running of course.

Not saying this is Taco52's problem,,but a easy check to see. Usually, slowly climbing temps means a late Thermostat (opening late),or a plugged radiator, or a blown head gasket, late cooling fan,,,the list goes on. The gauge working, then not working during opposing turns leads me to believe a bad ground or wiring issue.

 

Can't speak to the gauges but I'd check the heater hoses running through the firewall for the coolant leak.

 

I checked my coolant this morning before i started it and it was plum full. Maybe i dont have a leak. But keep in mind that the dash gauge needle is off. The ultragauge seems to be reading the correct temperature. I think i might have a thermostat issue but im totally sure.

 

I havent checked the overflow but i have seen my ultraguage read 200° many times when going up over many mountain passes. I will check the overflow though. Could be why i saw coolant on the ground the other day when wheeling

 

Is the cold level staying consistent Trevor? Morning to morning?.

 

Years ago, I had this symptom (overheating while on a deep snow run). No problems with normal driving. After a lot of troubleshooting, I replaced my partially plugged-up radiator. Problem solved.

 

Considering you were stuck, and digging out your truck, I think the overheat and coolant loss was most likely a result of the radiator being blocked.

As for the gauge being erratic, and changing as you turned, I would be suspecting a bad connector/terminal/wire at the sensor itself, or between the sensor and the ECU.