mtnman82

So it's happenned a couple times now over the past 3 months of summer, and only when in line at a drive thru. While driving everything seems normal, and most other times even when in a line. My daughter drives the car, mainly around town (with A/C on). Yetserday was the 2nd time it started to overheat in a line. she said she was watching the temp needle creep up until it almost hit the red, then she turned off the car and only started it to move forward. After she got on the road it cooled down again. I have the hydraulic radiator fan. I did some quick searching yesterday and this morning but didn't find much. Any simple procedures to check out the hydraulic fan system? Thanks in advance!!!

Edit: also wondering where the thermostat is located? Thanks!

CUMan

Check the power steering pump. There is a wiring harness which MUST be plugged into the pump. This harness sends a signal from the cooling fan control unit (inside the car under the glove compartment) to the power steering pump when more fan cooling is needed. The power steering pump then increases its output and the cooling fan speed increases.

For some reason, this harness often gets unplugged when work is done on the car and does not get replaced. The cooling fan hydraulic operation is rather unusual, and it appears that many mechanics do not realize how important this connector is. If it is unplugged, the engine cooling will likely be adequate when the car is moving at good speed; however, when the car is idling (drive through lane, perhaps) or moving slowly in hot weather, the fan speed must increase to provide enough air flow.

mtnman82

I'll check that out! The fan speed does increase, after a few seconds, when I turn the A/C on.