Was it the hole in the rad hose?

[55Test]

My 98 Civic had had a hole in the upper radiator hose for an unknown length which I only found a few days back when I noticed a little wetness on the hose itself. The hole is almost un-noticeable but it will spray a fair stream at times. I've noticed that lately my car has been running a bit hot. Around 204-214 Fahrenheit with the heat off just cruising along at 45-50 MPH. I replaced that upper hose and the thermostat today, and after bleeding the cooling system then taking it for a little test drive, it doesn't get hot like it used to. It's running about 188-194 Fahrenheit now. I boiled the old thermostat and it didn't seem bad, it was still opening fully and closing smoothly, but I still put the new one in all the same. With the old hose and thermostat, I could bleed the cooling system for like an hour and it still seemed like there was some trapped air in there. Would the hole in the upper radiator hose have allowed air to enter the cooling system and caused my car to run hot?

 

[Colt45ws]

Yup yup and yup. Not so much allow air in, but the system can't pressurize so you end up running hot. I had a Cavalier that one day started to run real hot. 230-240F if I let it. It was just a bad cap leaking pressure.

 

[Tegger]

Originally Posted By: 55
I've noticed that lately my car has been running a bit hot. Around 204-214 Fahrenheit with the heat off just cruising along at 45-50 MPH. I replaced that upper hose and the thermostat today, and after bleeding the cooling system then taking it for a little test drive, it doesn't get hot like it used to. It's running about 188-194 Fahrenheit now.

How--and exactly where-- are you measuring those temperatures?

Were both thermostats of the same rating?