My pickup (05 Dodge Dakota) has been virtually trouble free for the 10 years that I’ve owned it (bought it with 4k miles on it in 2006). No leaks, no issues other than routine maintenance. In particular, the coolant temperature gauge has consistently and faithfully read a little bit below the mid-point the entire time, once the engine’s warmed up. Maybe a hair higher in summer, and a hair lower in winter, but still pretty much in the same place.
I had the cooling system flushed and filled with long-life coolant in 2012. Haven’t seen any leaks, nor noticed any change in the behavior of the temp gauge.
So I take my pickup into the fast oil change place by the office to get the oil changed last Wednesday. Goons at the place change the oil, and tell me that I’m low on coolant, and that they’re adding some to top it off. I think “Ok… I haven’t checked it in a while, maybe the overflow tank was a bit low. No big deal.” They also tell me that I might have a slight coolant leak, but that they couldn’t tell if it was that, or some that may have spilled when they were adding coolant. Again, not a huge deal.
After driving out, I notice the temp gauge ABOVE the halfway mark. This hasn’t happened in 10 years of driving it. So I drive it a while at different speeds, etc… and notice that it is fine while at highway speeds, but gets hottest (without actually overheating) while driving at low speeds, especially stop and go type traffic. I google that, and find out that’s indicative of low coolant (?).
I think “Low coolant? Didn’t they say they just topped it off?” I topped off the overflow tank at lunch time, because it was really, really low.
So I let it cool off after driving home (it got hotter, but not overheating hot), and the following morning I checked, and the overflow tank was still low AND the radiator was low as well. Weird. So I filled up the tank and the radiator and put a bottle of that Bar’s Leaks stuff in as well. That did the trick- temp needle is back where it belongs, and the levels are staying steady.
So the big question is- what happened? Did the oil change knuckleheads turn the radiator petcock by mistake and let out a bunch of coolant? Did the temp sensor or thermostat or something stick and then release? Were the knuckleheads not telling me something?
I find it really perplexing that I’d have a vehicle that would read fine on the temp gauge until those guys fiddled with it, and then suddenly it starts threatening to overheat, and then doing exactly what they supposedly did remedied the problem.
Anyone have any ideas or theories?