So more issues with the 2001 430... timing belt, water pump, serpentine belt pulleys, flushed the coolant. All done and buttoned up but on a drive today it overheated. First I noticed the temp gauge needle was half way between the 3rd and 4th mark. It's always on or very slightly above the 2nd mark so this was definitely abnormal behavior. It was stop and go traffic with more stop than go, with the AC on, outside temp around 88 or 90F (South Florida). When we would start rolling the needle would go down a tiny bit, but when we stopped it would go up a bit. It hovered in that area for a while but then I smelled coolant. After that it went up over the 4th mark and then I shut it off and rolled into a parking lot. Opened the hood to find the coolant in the overflow gurgling and either it or the radiator cap had spit out much of the coolant. We let the car cool for a while until the temp gauge was in the middle, started it back up and tried to keep going but within a minute and a half of getting back on the road the temp gauge was above the 4th mark, almost into the red but not touching it yet, I shut it off again and rolled into a gas station.

I can't seem to find any indication of what temperature these marks on the gauge correspond to. Some posts say there's "fuzzy logic" happening that gives the gauge its readout, others say it's a combination of sensors. Lots of discussions about what causes overheating. In this case the drivers side fan does not come on. The passenger side fan motor was replaced recently by the PO so this was not unexpected, just worrisome about the heat damaging the engine. I did not see any smoke behind the car and it ran smooth with no knocking before I shut it off.

Will these cars shut themselves off at some point to prevent engine damage like some Cadillacs do? Or will they commit suicide in an attempt to stay running in order to not cause an accident? My Cadillac would turn on the check engine light, then flash the light, then a loud buzzer would sound and if you kept ignoring that too then the engine would just shut off. Didn't see anything like that in the 430 though, the check engine light didn't even come on.


TLDR; The highest the needle ever got was just under the red mark at the H. It did not run for long at that temperature as the temperature was rapidly increasing and I shut it off immediately. It was there maybe less than 10 seconds. But it ran in that area above the 4th mark for maybe 30 seconds to a minute each of the two times it got hot. Is that hot enough to damage the engine?

 

Did this happen after water pump replacement and coolant flush? If so it is most likely air in the system or thermostat put in backwards. On my 2001 it took a while for me to get all the air out of the system.

 

Engine damage is a possibility but it probably didn't happen. Sounds like you have air pockets in the cooling system. The factory bleed procedure is to run the engine at 2500 rpms with the heater on in park for at least 5 minutes.

 

Yeah it was afterwards. I'll see about getting air out of the system, but the main cooling fan is indeed not working at all. It didn't come on even when the temp gauge was just below the red zone, only the passenger side fan was on at any time.

I let it idle for a while to let air out but I didn't know it's supposed to be held at that rpm for so long. I will definitely give it a better go after the new fan motor comes in. Drove it 10 miles back to the house today after refilling the radiator and it did fine until it sat idling in the driveway and then the temperature started to climb. Thanks for the tips about bleeding air out.