97 Accord Overheating Issues
 

Hey guys,

Just wanted to start by saying sorry if anyone else has posted about this, but I haven't been able to find anything that's helped me in the forum so far unfortunately. I have 97 Accord lx with an f22b2, and I'm having overheating issues.

What used to happen was that I would come to a stop and my engine would idle, then drop to about 500 rpms and my temperature would go to about 3/4 of the way up. I could cool it down by revving it up to between 1,250-1,500 rpms, and the gauge never went past 1/3 of the way up when I was in motion.
Over time the issue has gotten worse. My gauge now goes all the way to full hot at a standstill and it tries to while I'm in motion also. The only thing that stops it from getting hot is applying a very small and specific amount of throttle.

I know of several things that may be causing/contributing to the problem:

1.) Seal of radiator overflow bottle is melted- My brother crashed this car previously, and it caused some problems with the heating system. I got the car fixed, but it is clear they didn't replace the radiator overflow bottle, as it still has a melted seal. When I pop the hood after I've been driving, I can see that the overflow bottle has been leaking small amounts of fluid. However, my overflow tank is full- which I'm not sure if it's supposed to be or not...

2.) One fan doesn't come on until after I turn the car off- I also had a fan replaced because one of the blades was broken. The new fan doesn't seem to come on when it's supposed to when the car is on, and it runs for about 5 minutes after I turn the car off every time.

3.) I used cheap radiator fluid- I know this is probably not really likely to be causing too much trouble, but when I first got the car back, I was having overheating problems that got very bad very fast so I had to flush my radiator when I was low on money. I picked up fluid from the gas station, flushed my radiator, and replaced the fluid. This alleviated my problems instantly for about a month. I don't know if it's the quality of the coolant I used or the fact that I've been losing coolant drop by drop but hey, I figure it's useful information somehow.

4.) Exhaust leak- I know the radiator/fan issues are the most likely culprits, but again, I figure information can only help. I'm pretty sure I've got a bad gasket or something because my exhaust was replaced only about a year ago. No smoke coming from the tail pipe. I don't know if this would affect anything with my engine temperature.


I have really basic knowledge so I wanted to consult you guys before I started spending money and poking around in my engine bay. What do you recommend I fix first/how do I fix it and what do I need?

Thanks in advance for any help I get!

First, check the radiator fans. Follow the LOWER radiator hose back to the thermostat housing. Kinda below the throttle body. In that housing is a 2-wire "sensor" which is actually the fan switch. Unplug that & jumper the wire with a paperclip or little wire. Key ON, that should make BOTH fans run. Does it? If not, then something's wrong with that circuit or the motors. Tell us what happens & go from there.

If that DOES make both fans run, then likely that sensor isn't good.

Hondas don't like to have air pockets in the cooling system, and that's what the cap and reservoir are supposed to do. First, bleed out any air from the little bleeder screw at the thermostat. Then at the radiator cap.

How did the reservoir "lose it's seal"? It's not supposed to be airtight. The hose from the radiator cap has to be airtight and has to go down to the bottom of the reservoir. If that's leaking, the radiator can't suck fluid back in when it cools down. Just like drinking through a straw with holes in it.

How it's SUPPOSED to work:
As the engine heats up, the antifreeze expands and pressurized the radiator. With further expansion, the radiator cap lets it out to the reservoir.
When the engine cools down, the small inner disk of the radiator cap opens inwards letting it suck back in. That only works if the very outermost gasket of the cap can properly seal against the very outermost rim of the radiator neck.

So how can it break?
That seal at the outermost rim of the radiator neck can have an air leak. The hose over to the reservoir can leak. Either way, when the radiator wants to suck fluid back in, it gets air instead. The result is the reservoir gets overfilled & spills out, while the radiator itself gets more air inside.

A weak or incorrect radiator cap which allows coolant to escape under low/no pressure can also cause reservoir to overfill. If radiator cap is old, try a replacement.

good luck

Thanks for the quick replies guys.

I'm at work right now but I will test these things when I get home and update you on the results.

Figured I would just close this thread by stating that it was my radiator overflow seal that was causing it. The bad seal was causing small amounts of coolant loss when the radiator would take coolant in, so over time my overheating issues obviously worsened. I did use the advice you guys provided, and I appreciate it!

Thank you for coming back with the "end of the story" :)