srose111

OK RonJ, valve moves. Check

Ran the car in garage after returning home.

1. AC blows ice cold, no problem there.
2. Temp Gauge climbed to about 70% up from mid way point. Some people are saying it shouldn't move no matter.
3. The cooling fan is automatically coming on. Ive been trying to get someone to tell me exactly where to place a temp probe (exactly) as I do not know, that way I can monitor when the ECT sends message to ECU and fan comes on? If you can advise, thank you.
4. If I rev the rpms, the temp does come down just a fraction, but it certainly doesn't go up. All good so far.

Former User

Temp should never rise above half way. My Civics never reach above about a third of the way to Hot. Maybe you still have some air trapped in the cooling system.

The fan switch, not the ECU, is the primary mechanism to turn on the fan.

chrysler kid

The computer does not control any aspect of the cooling system. The primary role of the computer is to be a calculator for air fuel mixture.

mk378

You're chasing chicken vs. egg here. Put the paper clip in so the fan runs all the time (this will not damage anything). Test drive and/or run in the driveway and see if it overheats. If it still overheats with the fan always on, the problem is not fan related.

The fan circuit is connected to the ECU but I think this is an input only-- so the ECU detects when the fan comes on and can bump up the idle to compensate for increased electrical load. I don't think the ECU is able to turn the fan on.

srose111

@mk378: Youre right and I agree. I called uncle and took it to auto electrician yesterday, just to verify what I have troubleshooted. He had an IR temp gun and we lazed the thermo cover and head at idle after a 20 min drive. The fan didn't come on tis 240F. Both upper and lower rad hoses same temp, so the thermostat is opening and operational. IT should be its, brand new OEM.

So, I ordered OEM ECT sensor and Fan Switch. Im 100% certain the problem will be solved with the fan coming on as it should at 180F vs 240F which is super late. Again , I knew the last Thermo switch put in was crap $26 aftermarket,but now I know sometimes you have to go with OEM and its very worth it.

Im in Texas and it gets hotter than hell here , esp in traffic, so this is a fix I need to dial in before next summer.

Ill put in a final report after I get those installed. Should be the end to all Honda Civic LX overheating troubleshooting. Lots of good gouge in this thread, so I hope it helps a lot of people.

srose111

At some point this will come up again and Im sure it will help y'all. I had a bitch of a time finding this, but wanted to make sure Im posting correct info.

For the following vehicle: 2000 Honda Civic LX, AT :

• If you are replacing the thermoswitch (A93) # 12 in diagram the bolt size 15/16" or 24mm. Yes its really that big.

37760P00003 - SWITCH ASSY., THERMO (A-93) (NIPPON THERMOSTAT) - 2000 HONDA CIVIC SEDAN - GENUINE HONDA OEM PARTS

• If you do replace this it is strongly recommended to change out the ECT sensor too. # 13 on the diagram. This bolt is 3/4" or 19mm. This is how part is listed: 37870PJ7003 - SENSOR ASSY., WATER TEMPERATURE (TW5) (MATSUSHITA) - 2000 HONDA CIVIC SEDAN - GENUINE HONDA OEM PARTS

You need a deep socket for both. I imagine a crescent wrench can get in there, but much easier with a deep socket. Something like pic attached.

*Also note if you have cheap aftermarket installed, the bolt sizes could be different. When I pulled my AM part off Ill edit this post. I have a shitty Thermo switch.

Finally if you don't have a ton of tools and would have to buy this and are wondering...."so is it cheaper to just pay to get it done?" Answer is: its going to be a MIN of $65 to get those installed, so buying the socket will still save you money and you get to keep it.

94EG8

I saw your PM but I didn't know what the size was offhand and I never had a chance to look.

Hasan Khurshid

What are the 2 connection on thermostat housing? For what purpose these 2 coolant connection are used?