Hey all, I just got finished replacing a radiator and thermostat on my 1994 Accord Ex manual transmission and I am facing two problems. After I poured in coolant and bled the the system....

1) The radiator cap I got that is for my car and supposed to be for the radiators that fit my car doesn't fit. Its like it wont push down far enough to catch on the plastic guard to lock in place, I need a deeper radiator cap or something and the guy at autozone says "sorry man, don't know what to tell you". It is a new toyo radiator.

2) After I bled the coolant system I started to car with the radiator cap off (of course) and first thing is, in the whole 10 minutes the fans haven't come on once and I checked all the plug ins for the electronics, and also their is this high pitched squealing noise that sounds like a boiling tea kettle, I cant pinpoint what it is... Any help is appreciated.

 

Does the old Rad cap fit? If so get a new one from Honda. The noise is pretty much like a tea kettle as you have a coolant void(air pocket) and the thermostat hasn’t open yet. I would open the bleeder screw on the thermostat housing and keep an eye on the temp reading as you let it warm up. When you have a nice flow of coolant out of the bleeder you should have the air out. The fans will take some time to turn on but make sure it doesn’t overheat. The rad level will go down as it warms up. I would keep adding, but when the fans come on some coolant will overflow the rad.

 

so i let the cooling system bleed more, opened up the valve, but the stream coming out the bleeder valve when the car is on and warming up is not very strong. When I turn the car off though and open the bleeder valve it gushes out.. I decided to cap the radiator and drive it around the block and back to see what happens. I came back and both the upper and lower radiator hoses were hot and I could see steam coming up from under the radiator cap it looked like and the fans still had not come on.

 

I would just let it idle until the thermostat opens and keep an eye on the temp gauge. You are going to see steam. It may take a long time for the fans to come one. If you have air in the system the fans will not come on from Temperature. Please tell me you got a Honda Thermostat. Make sure you have the fan turned off that cools the Interior as that will slow down the cooling system reaching the Temp to start the rad fans.

 

Hey, first off I really appreciate your input, thank you so much for help. I didn't see your most recent post until now and I have since run some more tests and I think I isolated a problem, tell me if you think it makes since because I haven't bought the new part that I think I need just yet (will in the morning).

I decided to test all the electronics of the fans so I took some speaker wire and jimmy rigged together a jumper wire to test all the motors and continuity of circuits. the fan motors both whirred to life when I connected them on one end of the wire with the other on the battery. (so I know the motors of both the condensor and radiator fans work for sure). Next I decided to check both the engine coolant temperature (ECT) switches A & B (One above the thermostat housing and the other on the water pump housing). I don't know if I did the test right but my results were accurate so I am confident that I did. I disconnected both switches and turned the car on, let it run for a minute. I then hooked up the speaker wire on one end to ohmmeter to measure continuity if I closed the circuits on the switches. ECT Switch B (located on the water housing) gave me a reading, it jumped around a lot so I don.t have a measure of ohms, but it showed me signs of life. I moved the wire up to the thermostate housing to test ECT switch A and the ohmmeter didn't give me any reading at all, it stayed still.

The conclusion that I have drawn is that I need an Engine Coolant Temperature (ECT) switch A to be replaced and I plan on picking one up at NAPA in the morning to see if its the problem, if not Ill take it back. You think that this is plausible?? I am also in the morning going to take the switch i am replacing and run the test in water at the 192 - 204 degree temp or whatever it is and run it through the ohmmeter that way just to make sure..

 

...and no I didn't buy a Honda thermostat, I know I know I should have but I didn't. I was on a tight budget this summer so I bought the cheapest thermostat I could find at Baxter Auto Parts for $7.49. It is an OE style temp thermostat, I hope this isn't a problem for the time being. on my next drain, flush, and refill... which I will probably do much sooner than the recommended 30,000. I will probably do it in a month or two just to clean it out after all the new parts put in and I will purchase a better thermostat for when I get to that point.

 

As long as the temperature gauge in the car reads normal, you should be all set. You never told us details about the temp.

 

the temperature gauge on the dash in the car, the one on the far left (either oil or water temp gauge) I think, if thats what your talking about, it reads just fine as of now as Ive been letting it run in the garage, but it still doesn't ease my mind that the fans aren't running, period. So I'm pretty sure I need to replace that ECT Switch A above the thermo housing. Also the squealing tea kettle noise I heard the first night finishing the project has subsided once i bled the coolant system more thoroughly and now is only a faint squealing, nothing like before. So.. ya the temp reads fine, I think I did the install all correct and everything should be running good, but the fans haven't come one once and the ohmmeter didn't give me any reading on the one switch when I tested it with the car on.

I just bought this car about two months ago and I actually have a theory as to how the original crack got in my radiator to begin with to warrant this whole project. Every time I would turn the car off, the fans (radiator and condenser) would run for about 20 sec or so.. which is normal I think, but I never heard them come on while the car was ever running, at a stop light or what have you (I also couldn't have been paying attention to that though). I think that the fans didn't cool the radiator enough to where pressure built up and cracked the radiator because that one switch on the thermo housing wasn't operational. But again, this is just a theory that I conjured up to warrant this project and make me feel better about the conclusion I have drawn and to make me feel smarter as an amateur mechanic = P I just kinda teach myself as I go with a Honda factory service manual and a Hayne's manual. I think I do alright... As of 72 hours ago I had know idea what a thermostat did or what an ECT switch was, now I feel I have confidence in how the cooling system in my car works. As frustrating as it can become (VERY frustrating and tedious) I absolutely love this learning process, and all of you guys are HUGE help, thank you so much again.

 

Early on working at a Honda dealership I got fooled with changing the temp sensor for the fans only to find out the vehicle needed a thermostat. The fans will not come on until water/coolant is flowing through the thermostat. The coolant bypasses the route of the thermostat until it opens, so you have no coolant contacting the sensor.

I doubt you need the sensor. If you have air in the system the fan may not come on either from temp. My 95 when it blew the head gasket one of the few symptoms was the fans only came on after shutting it off. It took close to an hour for it to overheat surprisingly at an idle. You are going to get an education in Honda Cooling systems. Do the fans work with the AC on? Both should come on with the cycle of the compressor. The tea kettle noise is usually when the block is drained of coolant like installing a water pump and the engine heats up with no coolant while waiting for the thermostat to open and when it does it is like pouring cold water into a hot pan on the stove. I am wondering if the lower hose is filled with coolant at the engine. I have had cars where the thermostat would never open and had to fill one of the Rad hoses. Generaly these where vehicles that had the thermostat at the bottom but your tea kettle noise has a cause.

I would let it run until either the fan comes on or the gauge goes over the middle which means it is overheating.

 

The 2 fan switches are not supposed to give resistance readings. Only open & closed, just like a switch.

Sounds like the one in the thermostat housing is OK so far. It's responsible for switching the fans while the engine is running. So unplug that one & jumper it's wire with a paperclip. Key on, that should make both fans run. If not, then your problem is in the car's wiring. (Or a bad motor but you've already ruled that out)

The fan switch in the nozzle for the UPPER radiator hose is responsible for switching ONE fan after you turn off the engine. It's also a switch, so it should be open/closed. NOT supposed to give a fluctuating reading. But that one isn't supposed to have any authority over the fans while the enigne is running.

The water temperature sensors for ECU and for temperature gauge are screwed into the end of the head. Sorta below the distributor.
Sender for the gauge has ONE wire.
Water-temperature sensor for EFI has a 2-wire plug.