ezeiset

Hey i have a 93 honda hartchback stock d15b with intake and 2 1/2 inch exaust.last week it got pretty worm out and i popped my hood to check my oil and fluids,u know the normal stuff. i realized that the over flow tank was full and the rad was almost empty but my temp gage was fine.then it got cold out again and its fine now what the hell is wrong with my car it seems like on worm days it pushes anti freeze into the over flow but not on cold days i dont understand it what should i look for? Thanks for ur help!

Cuda70

You probably need a new radiator cap. If you are not leaking or burning coolant, then it sounds to me like the spring in your cap is FUBAR.

seaphin

several potential problems, but I would more likely guess that the thermostat is sticking at times. This is one of the cheapest fixes to try, besides the radiator cap that is. Dont trust the temp gauge. If the radiator is low at times then the engine is also low. There is a bleeder valve on the cylinder head next to the thermostat housing. This is approx where the engine temp sensor gets its readings. If the engine is low on fluid, then you get air pockets at the top of the cylinder head, and hot air doesn't affect the temp sensor as well, giving you a false low temp reading, when the temp is potentially very high, causing fluid to force into the over flow. after you replace the thermostat, fill the system back up with approp. H2O/antfreeze mix, and then have a buddy give the engine a little gas while you open the bleeder screw next to the thermostat housing. It looks just like your brake bleeder screws. You could also rev the engine rev yourself with the throttle body in front of you, anyway when you give it the gas, fluid will squirt out of the bleeder valve, and burp out any air pockets that were trapped. While it is squirting out, close the valve. when finished pop off the radiator cap and top things off, if needed.
Something else I just thought about. In the bottom of the radiator is a part called a thermosensor. On your Honda (all Honda's, Acura's) the radiator fan is electrical, not mechanical like many American made cars. Anyway this thermosensor reads the temp in the radiator, and when it gets hot enough, it turns the radiator fan on. This is an independent system, and this is why when the engine is hot, and you turn off the ignition key, the fan will sometimes continue to run. If you have air conditioning on your car, and the A/C is turned on, then both fans should run all the time, but with the A/C turned off, the one fan operates independently of everything else, or at least it should. If you have an over heating problem, and I think that you do (radiator low on fluid, and overflow bottle full), then this fan may not be turning on when the engine is hot. You can diagnose this fairly easily. Run the motor until it is warmed up. Usually only five minutes will do (with the A/C turned off), and the fan should kick in. If it doesn't then you might suspect the thermosensor, or the fan motor itself. Pull the rubber cap off of the thermosensor. Its a black rubber cap with electrical wires at the bottom of the radiator. After you pull the cap off you will see the thermosensor at the bottom of the radiator, it looks like the male end of a plug that you would plug into the wall. Think plug on the end of a lamp, or portable radio. The two prongs that stick out are round instead of flat and square. Back to the rubber cap that covers the thermosensor, take a piece of speaker wire, and bend it into a "U" shape, strip both ends and pulg it into the holes in the rubber cap. This completes the circuit, and should cause the fan to come on (ignition key in the on position maybe). If this bypass does not cause the fans to come on, then it looks like the fan motor might be bad. If it does come on, then the thermosensor is not sending the signal that things are hot in the motor, and you should replace the thermosensor. IF these are both OK, and the fans appear to be operating properly, then the problem is in the radiator cap, or the thermostat. These other two things are fairly easy to replace, and less expensive to replace also. The thermostat is a little bit of a pain to replace. The bottom bolt on the thermostat housing is a little hard to get to, but a 10 - 12 inch extension on a 10 Metric socket will ease this process. Also before you remove the bottom thermostat housing bolt, put a little grease in the end of your 10 socket. This bolt is easy to drop, and it will fall down, and bounce off of the the starter, and forward on the transmission housing, to an area that you can't see, and can't get your hand into. The grease helps the socket hold the bolt, and keep it from getting away. I usually buy an extra bolt from my Honda dealer when I'm doing this job, as it's easy to lose them to this situation. If you happen to lose the bolt this way, and don't have a spare, then get your garden hose out and point it into the area where the bolt disappeared, turn the water on high, and then search the ground under the car to see where it came out. When you go to put the new thermostat in, put more grease on the head of the bolt to stop you from dropping it again. I hope this is helpful.

Modified by seaphin at 3:35 PM 3/15/2006


Modified by seaphin at 3:42 PM 3/15/2006

ezeiset

Thanks for ur help i will be doing this this weekend!