H22A1 overheating
'TL : DR' Car overheated (not all the way to H, but about 3/4), no leaks, no water in oil, thermostat opens, fans work, fan switch works, fan timer works.
Let's start with specs... I have a 1996 H22A1 (converted to OBD1) with about 50k on the rebuild. When I had my last overheating issue (due to a hole in the upper radiator hose) I replaced the upper hose and found a few other leaks while I was testing. I replaced the water pump (and timing belt) and installed a new Koyo Race aluminum radiator with dual 12" Mishimoto fans wired to the original fan plugs. Since then the temp gauge sits at about 1/3 and doesn't move.
Last Thursday afternoon I was driving about 10 miles home from work on surface streets (25-40 mph, signals and stop signs) with the A/C on as it was over 100 degrees out and noticed about 2 miles from home that the temp gauge was creeping up. I tried to keep moving as best I could and it seemed to slow the climb. When I got home it was at about 2/3 to 3/4 to H. I shut off the car and checked for leaks/steam and there were none. I took a different car to work on Friday.
Saturday I went to troubleshoot the issue. Tested the fans (both worked), checked the oil (a quart or so low, but no water in it). Turned on the A/C with the ignition on but not running and both fans came on. Checked coolant level and rad was full, overflow tank was just above the min line. I started the car and let it warm up. Using my IR thermometer I was watching the hose temps and the thermostat housing temps (on both sides of the thermostat to see when it opened). The thermostat seemed to open when it should and both fans came on at about the correct temp. So according to all of my troubleshooting, the car should not have overheated, yet the gauge was definitely climbing.
I'm at a loss and I'm afraid to drive the car. Any ideas??
Let's start with specs... I have a 1996 H22A1 (converted to OBD1) with about 50k on the rebuild. When I had my last overheating issue (due to a hole in the upper radiator hose) I replaced the upper hose and found a few other leaks while I was testing. I replaced the water pump (and timing belt) and installed a new Koyo Race aluminum radiator with dual 12" Mishimoto fans wired to the original fan plugs. Since then the temp gauge sits at about 1/3 and doesn't move.
Last Thursday afternoon I was driving about 10 miles home from work on surface streets (25-40 mph, signals and stop signs) with the A/C on as it was over 100 degrees out and noticed about 2 miles from home that the temp gauge was creeping up. I tried to keep moving as best I could and it seemed to slow the climb. When I got home it was at about 2/3 to 3/4 to H. I shut off the car and checked for leaks/steam and there were none. I took a different car to work on Friday.
Saturday I went to troubleshoot the issue. Tested the fans (both worked), checked the oil (a quart or so low, but no water in it). Turned on the A/C with the ignition on but not running and both fans came on. Checked coolant level and rad was full, overflow tank was just above the min line. I started the car and let it warm up. Using my IR thermometer I was watching the hose temps and the thermostat housing temps (on both sides of the thermostat to see when it opened). The thermostat seemed to open when it should and both fans came on at about the correct temp. So according to all of my troubleshooting, the car should not have overheated, yet the gauge was definitely climbing.
I'm at a loss and I'm afraid to drive the car. Any ideas??
Comment