98 Accord LX 2.3 Fans & Temp Gauge
 

Ok guys I'm back with another question. I just replaced the motor in my car and now the fans won't kick on and I think the temp gauge is messed up as well.

New parts are thermostat, fan switch, temp sensor and temp sender. I have let the car idle for 20 min and the fans never kicked on. The upper radiator hose was hot to the touch but the lower hose was cool.

I bought a temp gauge at Autozone but it didn't have the right adapter to screw into the block. Does anyone know of one that will fit for sure?

Do you have a IFR reader?

When the car ran for 20 Min, what or where was the temp gauge? Did it "peg" or was it just below half?

IFR reader?

Gauge was just below half.

Sounds like either there is still air in the cooling system or there is an issue with the thermostat. The temperature gauge may or may not be an issue depending on what it is showing. -- My guess would be air still in the system. Most of the air purging comes after the thermostat has opened.

The Engine Coolant Temperature (fan) switch is located at the thermostat housing and measures coolant temperature coming back from the radiator through the lower radiator hose. The thermostat is on the other side of the thermostat housing and opens/closes based on the temperature of recirculating coolant coming from the cylinder head and with coolant returning from the radiator.

If the lower radiator hose is cool, the thermostat probably hasn't opened yet.

Is there another place besides on the thermostat housing that I need to bleed the line? I had it open yesterday but may have been doing something wrong. Working on cars is still a pretty new thing for me.

The 2 places for air to collect (in your engine) is the radiator cap and the thermostat housing. When it's cold, squeeze the radiator hoses. If there's air pockets, you'll hear/feel the liquid sloshing around in there. It just feels different when it's all liquid with no air.

You should also hear the faint sound of that little vent pin in the thermostat when you squeeze the hose. If you don't hear that, then maybe think whether you have the thermostat installed the wrong way.

If the gauge stayed just below half, that's good. And I wouldn't expect the fans to come on until the gauge goes somewhat above half.

IFR = infrared temperature reader?

The fan switch is on the thermostat housing. You can unplug it & use a wire to short between the 2 wires. Key on, that should make both fans run. Unless it's really hot out, I sometimes have a hard time getting the fans to run.

I will try that with the fan switch tonight. I am also going to pick up a infrared temp sensor after work. I will post the temps from various places at different run times. Might even hold the throttle open so the motor stays around 2000rpm

Places I am going to check the temp:
Radiator Cap
Upper Radiator hose ( in about the center of it)
Lower Radiator hose ( in about the center of it)
Thermostat Housing
Block around the Temp Sender

Is there anything I am missing?

Don't go buy a reader....sorry should have been clear, just wanted to know if you had one already.

Turn the key to on/pos II and set the heat to MAX heat, turn the blower motor off, turn the car off. Bleed the air using the coolant bleeder. Car cold/cool, open the bleeder. Remove the rad cap and SLOWLY add coolant until there is a steady stream of coolant coming out of the bleeder. Close the bleeder.

Top off the rad and the overflow. Install the cap to the "FIRST" click - not all the way. Start the car and let is run. Watch the temp gauge and if at any time the gauge gets close to 3/4 shut the car off. Let the car run, until the fans cylcle at least once. This could take close to 30 min sitting still...do the fans cycle, does the temp gauge spike?

If the fans run, shut the car off. Let it sit a few minutes (~5 ?). Remove the cap....WARNING, you only did ONE click so it would not build pressure - hot coolant will burn skin.

Top off rad and over flow if needed. Install cap ALL the way. Drive the car and let us know what the temp gauge does/acts.

I bought a temp gun because it's something that I can always use. And Sears had a cheaper one than Harbor Freight.

Here are the readings I got.

Cold without starting the car:
Radiator Cap - 63°
Upper Radiator Hose - 66°
Lower Radiator Hose - 64°
Hose at Thermostat Housing - 66°
Block bt Temp Sender - 65°

After running 5min:
Radiator Cap - 78°
Upper Radiator Hose - 115°
Lower Radiator Hose - 78°
Hose at Thermostat Housing - 94°
Block bt Temp Sender - 131°

After running 10min:
Radiator Cap - 81°
Upper Radiator Hose - 159°
Lower Radiator Hose - 82°
Hose at Thermostat Housing - 98°
Block bt Temp Sender - 148°

After running 20min:
Radiator Cap - 88°
Upper Radiator Hose - 175°
Lower Radiator Hose - 120°
Hose at Thermostat Housing - 160°
Block bt Temp Sender - 168°

After running 30min:
Radiator Cap - 96°
Upper Radiator Hose - 177°
Lower Radiator Hose - 160°
Hose at Thermostat Housing - 170°
Block bt Temp Sender - 170°
gauge went to about 3/4 and the fans kicked on for about 30 seconds and gauge went down to under 1/2

After running 45min:
Radiator Cap - 95°
Upper Radiator Hose - 170°
Lower Radiator Hose - 172°
Hose at Thermostat Housing - 165°
Block bt Temp Sender - 184°
gauge went to about 3/4 and the fans kicked on for about 30 seconds and gauge went down to under 1/2

Then decided to take the car for a drive. About 10 min in I checked everything
Radiator Cap - 90°
Upper Radiator Hose - 163°
Lower Radiator Hose - 140°
Hose at Thermostat Housing - 140°
Block bt Temp Sender - 180°

Gauge never moved above half while driving.

That all looks good to me.