That was a fun attempt at getting to work. LONG story short, 97 Honda accord SE 4 Cylinder Non Vtech, 235,000 miles. I got about 5 miles into my 50 mile commute and I realized the temp needle was very high. Not in the red but close. I pulled over and checked for coolant gushing out but there was nothing. It was dark so I turned the heat up and nursed it to the walmart parking lot waiting for the auto store to open. Upon initial inspection there was a small amount of coolant that appeared to be splashed from the radiator cap area but no obvious leaks. The overflow tank was half full. I went inside to let it cool down. 30 minutes later I inspected further and found the coolant to be at the top by the cap so I didn't lose any fluid really. I checked coolant fan fuse and it's fine. I dont know how to check relay fuse to see if it's good. I didnt see the drivers side fan on but being so cold, would it even come on? I turned the AC switch on and the passenger side fan came on but sounded like it was rattling a bit, kind of struggling along. I checked the connection to the fan motor and it was snug. So I decided to drive the 8 miles to O'Riellys auto and wait till they opened. The car drove fine, didnt' overheat, temp gauge stayed at the slightly under halfway spot like it always has.

Now a little history. This is the original thermostat. I suspect thats the issue but the fan thing has be a bit unsure. I bought one at the auto store anyways just to be done with that. I had to get the radiator replaced a year and a half ago so it's pretty new. top hose was replaced as well. The two things I suspect are 1) Thermostat and 2) radiator cap. It's surprising the radiator cap would be shot after less then 2 years but it's not a Honda radiator so maybe thats common?

I did a search and found the DIY link but am not quite sure about how to check the fans by jumping wires? It sounds simple but I'm no mechanic; it'll take me 4 hours to change the thermostat if I can even find it. lol

Any feedback is appreciated. I'm waiting for the sun to come out and warm things up a bit before starting work.

 

thermostat is probably failed, especially if it's original. fans probably didn't come on due to lack of coolant circulation triggering the temp sensor. nickels worth of free advice.

 

Another thing to check is the coolant itself; if the water to ethylene glycol ratio is too high the coolant can easily freeze on an eleven degree day.

 

Thank you for the reply. The coolant doesnt appear to be frozen, runny just like collant Ive always seen. Thank you for the reply and for helping me diagnose.

 

I don't know if this is good or bad, I finally removed the thermostat. It took ME forever just to gain access. I'm having to do this outside and I can hardly feel my stinking hands. lol I need a garage! OK, so the thermostat doesn't look in bad shape at all. The gasket is in quite good shape too. I am going to look up how to test the thermostat, if memory serves you boil it?

It needed to be replaced due to age alone so I'm glad it's getting done. I just wish it had waited until march. I hope this does the trick. Thank you for the help with my diagnosis.

 

Is there anyway to tell if this thermostat is the original? I don't recell it being changed but memory can fade. The part number stamped on the thermostat is "78C RTN 4/97".
It's in such good condition I am wondering I did have it replaced years ago and just forgot. My service records don't indicate anything. My local honda parts guys had no idea. Thank you.

 

So I boiledso mew ater, just before boiling I dropped the old thermostat in and it slowly opened up. It seems to be working. While it does need to be replaaced due to age alone, I wonder if this was the curplrit of my overheating issue this morning. I will install the new one and drive and see if that works.

If anyone has any instructions on what to check next that would be great. I am referring back to the DIY section for the troubleshooting of overheating issues, but am getting a bit confused.

 

Hmmm, I'm starting to lean back toward frozen/slushy coolant. When you look through the pressure cap into the radiator it is impossible to see the condition of the coolant in the cooling tubes between the tanks; that's where the frozen mixture (if any) will most likely reside.

 

ok, ive not run into anything other then regular runny coolant, but i guess from your description i woulndt see any slushy stuff right? I have the thermostat replaced but the hose from the airbox to the throttle body is ripped on the ridges along the body so now I have to get that replaced. My local auto parts places dont' carry it and I want to avoid the dealer. Once I get that replaced then I can test drive it and see if that works. At least Ive replaced a VERY old part. Thank you again.

 

There may be a problem with the cooling fans. If your car was overheating, both cooling fans should turn on, doesn't matter what temp. it is outside the car. In addition, if you turn on the A/C, both cooling fans should have turned on. The fans should run strongly, not one fan struggling along.

Another check you can do is, follow the lower radiator hose to the engine. The lower radiator hose is attached to the thermostat housing on the engine block. There is a fan switch (thermo-switch A) there. Disconnect the electrical connector (usually a green connector) from the switch. With a small paper clip or wire, jump the terminals on the electrical connector and turn the ignition to ON. Does both fans run?