Overheating returned recently after several repairs. The reservoir keeps filling up, but doesn’t always go
back to its original half fill. I kept the reservoir tank at half full only.
In the mornings, the temp guage on a downhills is low, the temp guage would float very low as if the engine was just starting up. I also don’t put pressure on the gas pedal and just let car drive on momentum. Don’t know if that’s related or TMI.
Replaced the water pump last year.
AC compressor doesn’t run anymore. Didn’t checked that system yet. I don’t know if it’s related here, but warm air through the air vents work.
Another overheating problem I had before this was that the catalytic converter was plugged up. Slowed down to 30 to 40 mi/hr on freeways and uphills. I checked with compression test, no problems. Replaced the cat eventually. New O2 sensors, too. The original problem was “engine misfire,” because of bad sparkplug coil wires. I should’ve replaced the wires quickly, but I tried to drive it home, so the soot clogged up the cat.
Replaced the thermostat sensor last week, because of an error code.
Replaced the thermostat housing (plastic), too, because it warped.
I think I should have replaced the cap, but I haven’t yet.
Before I replaced the above items, the top radiator hose was hot, bottom was less or nearly cold sometimes, but this changed yesterday to both hot. The temperature gauge would also climb past middle at stop signs or at idle. Goes down when I’m running on the freeways. To compensate, I would rev the engine at idle/neutral (2,500 RPM for about 10 to 20 secondcs) to bring the temp back down.
No leaks, except the top cap of the reservoir tank gets wet around the cap.
The fans work when the temperature is at middle or above middle on the temp guage. I don’t know if these should work at one line before the middle.
Relay switch and fuse box under the hood, http://www.sebringclub.net/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=62698&g2_serialNumber=2
I used a DMM. Relay switch (fan lo, #34) is 74.3 across 86 and 85. Meanwhile, an equivalent relay switch on #35 (fan hi) is 73.9 on OHM or resistance test. Sorry, I haven’t done automotive electronics since I took the class years ago, so I’m not so familiar with these anymore. Actual part numbers on the relay switches: 56006709, 50732, and 1714A3.
Off topic: I keep reading about this crankshaft sensor on how it gives you rough idle. I wonder if this contributes to overheating. I’m getting that rough idling too and the engine would even die sometimes at idle/stop. Don’t know if it’s heat or the crankshaft sensor. Car is now 200K+ mi now. I’m discounting the vacuum lines now since I also replaced the check valve and the tubing lines before and after the check valve.
Any ideas would be appreciated. Thanks!