Replaced Radiator/Thermostat -- Loud Squealing
 

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.

ok Kris.. I'm going to take your advice. So heres how I will proceed from where I am at now, tell me if you think otherwise...
...I just got done successfully jumping the plug (Male piece) over the ECT switch A with a paperclip and fans turned on (relays and fuses...OK)

1) I am going to refill the drained coolant system and bleed the air out with the car off.
2) Turn the car on, open bleeder valve again and allow vehicle to run for 5 to 10 minutes with bleeder valve open, adding coolant as necessary to radiator, or until I see if its gushing out the bleeder valve as it does when car is off. (Is this because the thermostat is open when the car is off and seals up when the car is on until a certain temperature?? I'm a little confused by that)
3) Turn A/C on with car on to see if fans work.
4) Leave car on until I am confident air is out of system
5) Leave car on until either overheating signals on temp guage or fans come on.
--> If fans come on then everything should conclude
--> If fans don't come on...
6) Drain cooling system and take the radiator, lower hose, and thermostat apart again
7) replace new thermostat with original Honda thermostat (I believe) that was in their to begin with.
8) Cut about an inch or two off lower radiator hose (I think it may be a little longer than it needs to be, it's bent SLIGHTLY more than needed in one spot near the radiator)
9) Put it all back together and refill cooling system with old thermostat
10) Repeat steps 1 - 5
--> If everything seems to work OK, go take the new thermostat back and purchase a higher quality thermostat from Honda this time around and then take it all apart and put together one more time.. phewwww

---> Does this seem like a good plan.... in accordance with your suspicions Kris? I hope so, if not let me know if you have other suggestions..
-----> One more question I have... is it alright to keep draining and refilling without flushing the system like this while trying to diagnose? I mean I haven't driven it anywhere I think it would be but wanted an opinion.. I also am not draining the block, I was never able to find that bolt from any of the diagrams or tutorials I came across.

Also, just for my own satisfaction in know exactly what is working and not, now that I know the fan motors are ok and that all the wiring, relays and fuses are ok.. Is their anyway to test the two switches and the water temp sensor just so I know for sure. In the Honda service manual their is a test they show for the switches where you heat up water with the end of the switch in the water until it heats up to the degree where the switch will turn on, how do I know if the switch is on or off, what are the indicators that I am looking for?

If you have a volt meter, you need to switch it to either resistance or open/short.

With the sensor unplugged, there should be infinite resistance (open circuit) when the engine is cold across the two pins of temp sensor a. When the engine coolant gets above 199F is when the circuit should read ~0 resistance (closed circuit) on the temp sensor a.

My volt meter has a temperature setting, but not sure about yours. There is an IR device that can read temperatures. It may be easier to drain the coolant into a clean container. Remove the sensor, put just the sensor part into boiling water (212F) and see if the sensor reads closed.

thank you PaHonda, I will try that and I will check the voltmeter for its options... I have to get ready for work so I couldn't really go to far into the car just yet but I have some partial results of what I just did....

I refilled the coolant and bled the system, then I turned on the car with radiator cap off and the bleeder valve open. I let it run at idle that way for about 15 to 20 minutes. the coolant at the radiator cap area started to boil over the top so i threw a funnel their to catch some and a rag over the top of it. I saw that more started coming out the bleeder valve when the coolant started to boil but not a steady stream, just squirts, and then a low pressure tinkle off the side of the valve, so i closed it and shut off the engine, fans never came on.

I then threw the radiator cap on again because its boiling over all over the place and decided to run the engine until either the fans came on or it overheated that way. Well... the fans never came on and the temp gauge read directly in the center (normal) but a good amount of steam was coming up from under the radiator cap for a good 5 minutes, so I shut it off and have to get ready for work.. I'm stumped. I am almost convinced I need to disassemble and redo it with the old thermostat, or.. that it is that ECT switch possibly.

From you description it sounds like you never gave it time for thermostat to open. You still have air in the system also, nothing abnormal after replacing Cooling system component.

If you can't get the air out of the system you may have blown the head gasket but it is hard to tell so far.

how much time am I supposed to give it? And should the radiator cap be off the whole time?? because the coolant is boiling all over and out the radiator opening after a good 15 minutes. I was sitting out their for a good 30 min. all in all waiting for those fans to come on and they never did. And as far as the air, what else besides leaving the bleeder valve open can I do? and how long am I supposed to leave that open while the engine is at idle. It sounds like what I have to do is leave the car sitting their for like 2 hours steaming waiting for fans that don't seem like they will ever turn on. Should I go drive it around the block again? this time for longer, if I did that the valve should open FOR SURE because the temps WOULD reach what they needed to be at.

The way I bleed any air out of the system is to have the coolant drained, open the bleeder valve, fill the radiator and watch bleeder valve. Once air stops spitting out and a steady stream of coolant comes out, shut the valve and top off the radiator. Do this with the engine NOT running and cold.

The coolant may be pouring out, because liquids expand when they heat up. That is what the overflow bottle is for.

The temperature gauge should be between 1/4 and 1/3 of the way up with the honda thermostat in there. Your aftermarket may open up at a different temperature.

You will know if air is in the system, because the idle rpm will be all over the place.

As for testing, it is not simple to determine the coolant temperature unless you have an IR temperature reading.

Temp sensor B turns on the fans when the car is turned off, and it sounds like it is working from your description. Temp sensor A turns on the fans when the car is running.

Temp sensor B circuit closes at a temperature is higher than Temp sensor A. So, if Temp sensor B reads closed, then temp sensor A should read closed. If A does not read closed, then you should replace it.

well it doesn't idle all over the place and I have bled the system while the car was off an cold and waited for a steady stream, but then I also bled the system with the car running and it wasn't as steady of a stream. So.. maybe what I will do is drive it on over the Honda or an auto parts store, and see if they can test the two switches for me to see if they open, because I think the fans not turning on seem to be my only problem that I am confused about

I am sure the dealership can test it for you.

Really, you just need to find the open/short setting on a digital volt meter. It may be under the diode test.

If the volt meter leads are not touching, the meter should read open. When you touch the leads, the meter should read closed and the meter usually beeps.

Those sensors read closed when the coolant temperature rises above the set temperature on each sensor. 200F for sensor A and 223F for sensor B.

That is why when sensor B is closed, sensor A should read closed.

here is a good link to do some reading and diagnose

http://www.techautorepairs.com/overheating.html

thank you for that deserthonda it looks very helpful, I am going to read through all of that before I hit the sheets for some shut eye. I am also going to hit up the dealership or oil can Henry's or something in the morning to test those switches and see what other information I can find. I should be able to make it over their fine. I took a little test drive tonight, longer than my other one. I drove around for 10 - 15 min and revved it up a little bit, tried to heat up the engine and the gauge showed normal temperatures, wasn't overheating, but the fans still failed to turn on with engine on or off. A/C turned them on though. The differences I have noted from my test drive are that the A/C gets the car cooler much faster and the heater heats up much quicker after this repair it seems. Also, the engine or performance seems much better as well, runs smoother and acceleration is more responsive. I stopped at a stop sign and got out to see if I could hear fans and I did hear a faint squealing noise though I will have to keep checking in on.