Ford - Focus :: 2000 Temp Gauge On Dash Maxes-out And Overheat Warning Light Comes On

This past Saturday afternoon I'm out driving on the highway when the temperature gauge on dash maxes-out and the overheat warning light comes on. I get off at the next exit and stop at the nearest repair shop. (Which happened to be not too far from the exit.) During these moments of driving the car is not behaving as if it were overheating. No steam/vapor coming from the engine, it's performing okay, A/C runs cold, running heater on full-blast seems to do nothing to ease the gauge and the temperature in the engine bay feels about "normal."

So, since this is a Saturday at almost 5PM most of the repair shops are closing (it's a known fact cars don't break down past 5 o'clock on Saturdays.) So they say the'll look at it on Sunday.

I get a call on Sunday and I'm told that as near as they can tell the car is not overheating, the overheat light or check-engine lights weren't coming on and the car is behaving normally. The thermostat is "gunked up" and they recommend new coolant or a coolant flush." I just opt for new coolant, forgoing the flush, as I didn't really have the funds for it, an additional $100 or so. They say there are no codes in the system.

They do it and end up having to keep the car overnight so that the... air bubbles will work out of it? (?!)

I pick it up this past Monday evening and on the drive home the temp-gauge does as it was doing when this process began. It started creeping "hotter and hotter" meanwhile the car is behaving otherwise fine. (No overheat light this time.) Get home, open the hood, no vapor, no excess heat. Nothing.

They spend quite a bit of time running it, hooking it up to a diagnostic machine, etc. While the temp-gauge is sort of "floating around" between normal and "hot" it doesn't reach an "overheat" and the diagnostic machine registers normal temperatures. This time they find a code in the system, though the check-engine light has never come on. They recommend, again, the coolant flush so I go ahead and do it (they give me a discount), and drive the car home, again the temp-gauge "floats" around the dial, never quite getting to "overheating."

I drive to work just fine Thursday (today) morning with no real trouble with the gauge. (Though, FWIW, I had to tap on the dash to get the dash-light on that side of the console to come on.) This brings us to Thursday afternoon.

I make a couple of errands and as I'm stopped at a pharmacy drive-thru the temp-gauge is "floating." Driving home on the highway it reaches "overheating", turning the light on (again, car is not behaving in an overheating manner. A/C still cold, running heat doesn't ease gauge, no vapor from engine compartment.) When I pull in my parking spot the A/C and the car starts to "stall" some and NOW the check-engine light comes on. I shut the car off and I see vapors coming from under the hood.

I open the hood and the engine is covered in the anti-freeze/coolant and the coolant reservoir is empty. The various hoses and such that are clipped on to parts of the front engine cowling are loose (the plastic screw/"snaps" came out of their holes) and pushing on the upper-radiator some and it seems awfully loose. (Like the upper mounts aren't properly seated or something.)

Call the shop ask them what they are doing to me, they say they'll have another look at it and pay for the tow to get the car back to their shop. Awaiting word on what is going on, likely sometime tomorrow.

All of this strikes me as very, very odd and all seems to pile up quickly from taking it to this shop. With a replaced thermostat and flushed coolant I have a hard time understanding how the engine could genuinely overheat. All of the hoses and such seemed fine, and running the engine for a while at the shop the other day generated no problems to the techs working on the car. Yet, they're the only ones who have messed with it. Assumptions on their part Tuesday afternoon were something to do with the water pump (replaced at 100,000 miles with timing belt. Car is now at 145,000 miles.) Or a faulty temperature sensor (or what passes for it on the car) sending false readings to the gauge.

Car is a 2000 Ford Focus ZTS with a 4-Cyl, 16V, 2.0 Liter engine. It has 145,000 miles on it, timing belt and water-pump were replaced at 100,000 miles have had regular oil-changes on (more or less) every 5,000 miles or so. I will admit to not getting coolant changes/flushes as often as one should but the car never really had an overheating issues or problems starting in the winter.