Nandasmo

I did drain the cooling system for a timing belt change. And when I did refill the system the radiator fan doesn't come on, and the cooling is blowing coolant from the cap. But the gauge of the panel doesn't move from the middle. And the only thing that I can think of is the system need to be bleed and I don't know how to do it. And the fan works only when I turn the A/C on. Can somebody help me to find the bleeder. Thanks.

PhilStubbs

If my memory is correct there isn't a bleeder. The radiator cap should be the highest point in the system. I have a funnel that mounts in place of the radiator cap, I fill that start the engine and turn on the heat. Keep an eye on the gauge and let it run till the cooling fan cycles twice. Shut it off and let it sit for 5-10min while the rest of the bubbles work their way out.

Sticker Bomb

No there is no bleeder on them. I notice a lot with integras, civic, and crv's, the fan will not turn on for ever just letting it idle. I've always gone for a drive to get the fan to turn on faster, it also normally will get the air out of the system a little bit to if there still is some.

Nandasmo

Thanks guys for the help. I'll give it a try and post the results. One more thing I don't understand the idea of the funnel, how do you prevent coolant not coming out from the cap and the nozzle of the funnel. Unless the funnel is an special one and penetrates tight in the cap.

PhilStubbs

It has a fitting that connects to the radiator just like the cap.

Nandasmo

Ok. I got it, and thanks.

Nandasmo

I manage to built a plastic bushing between the hole of the radiator and the funnel, which worked good. Then I followed all the instructions, now both fans are turning on, and no more coolant is coming out of the cap. But, I am confused, because I thought that only when you turn the A/C both fans kick in or is this correct. Thanks.

PhilStubbs

I'm a little rusty on the details of the system, but I'm pretty sure one fan should come on for cooling, then the second one if the temp still increases and both fans with the a/c.

vrc123

I wasn't able to get my Gen 2 CRV to the point the fan would kick on by idling or even running it at 1500 rpm. I had to take it for a drive around the neighborhood. I was gentle with it because I knew there was air in the system and didn't want to overheat it due to lack of water flow.

I was thinking about buying one of those funnels designed to attach to the radiator (saw it on the Eric the Car Guy Video). One thing I will mention is that these radiators can burp big time. I had the engine off and it was still not warmed up at all by feeling the radiator and hoses. I took the cap off slowly and there wasn't any escaping pressure. I left the cap off and was checking some other stuff under the hood. About 30 seconds later the radiator burped/erupted. Luckily I was wearing glasses but it blew new coolant all over me, the underside of the hood, the engine and on to the passenger quarter panel. It was mega. I have never experienced this on all of the cars I have worked on. Usually it just burbles up a bit. It would have been just as ugly if I had been using the funnel so that is why I mention it.

Nandasmo

Thanks for the info, so that next time I will be more careful.

Nandasmo

Hey guys, sorry for being a pain on the neck, but I am still having troubles with the “cooling fan not working”. Here is what I’ve done so far:
1. Checked fuses under dash and under hood, working good.
2. Tested relay, by removing it and checking for continuity on terminal #1 and #2, while applying battery power to terminal #3 and ground to terminal #4, working good.
3. Jumped the two wires going to the fan switch, and fan turned on.
4. Measured voltage between the #1terminal of the radiator fan relay and body ground, 11 volts.
5. With ignition on II checked the voltage between the #3 terminal of the radiator fan relay and body ground = 11 volts.
6. Checked for continuity between the #2 terminal of the radiator fan relay and the #2 terminal of the radiator fan motor – 2 pins connector, got continuity.
7. Checked for continuity between the #1 terminal of the radiator fan motor – 2 pins connector – and body ground, got continuity.
8. Measured the voltage between the #2 terminal of the radiator fan switch – 2 pins connector – and body ground = 11 volts.
9. Removed the yel/grn wires connector from the “coolant temperature sending unit” and turned ignition to II position and grounded it, the needle on the dash moved up to the hot position. And when I am driving the car it stay in the middle range, never got to the high range.
10. Tested the “radiator fan switch” with hot water and I got continuity from the 2 pins terminals.
11. I run the engine at 1500 rpm and again both fans came on.
Finally, last year a changed the thermostat and the engine coolant temperature sensor –ETC. And last month and changed the radiator cap. And one more thing that I want to mention is that I am using after market parts. Now and running the car with A/C on, because it is how I get both fan running.

Nandasmo

Hey guys is me again, today I did change the "radiator fan switch" and nothing new happened. I am still running the car with the A/C on. And tomorrow I will try to change the thermostat and the ECT engine coolant temp sensor". Any help would be appreciated.

tech8

How the cooling fans work:
With the ignition to ON or START, if the coolant temperature is above 199 degrees F (93 degrees C) at the radiator fan switch, then the switch will close, which should turn on both the radiator fan and A/C condenser fan.

With the car running, if the A/C is turned on, both cooling fans should run, regardless of the coolant temperature at the radiator fan switch.


You may not have a problem with the cooling fans. The fans won't come on until the coolant temperature is above 199 degrees F (93 degrees C). The fans are not supposed to stay on all the time when your car is running. Are you overheating? Doesn’t sound like you’re overheating, as you stated the temperature gauge shows the needle around the middle. If it was going to H, then you may start to overheat.

Nandasmo

Hey guys I did check the timing with a timing light and I found out that the mark is about one inch behind, I tried to adjust it by rotating the distributor forward but even though I got it to the maximum that its allowed and the mark is still close to a quarter inch behind. Can you guys tell me if it is Ok. or do I have to uninstall and reinstall the belt and make sure that the timing is correct. One more thing, I saw a video on You Tube that is necessary to jump a connector that is located under the glove compartment. This way any change made will be recorded on the computer. And Thank you again for all the help.

Nandasmo

Now I am wondering if the timing belt is out of time, can this condition be the reason of getting both fan running at the same time?

Nandasmo

Hi guys, it is me again with the same problem. But I think that I found what is causing it. I followed the troubleshooting from the honda manual and I got to the point that it is telling me this "Repair open in the GRN wire between the radiator fan relay and the PCM/ECM" because I got battery voltage from the No 4 terminal of the radiator fan relay 4P socket and the body ground. Also, I get the same answer for the condenser fan. Can you guys give me an idea of the procedure how to do that. And please help me out,because I am totally frustrated. Sorry one more question what the GRN stand for, It is ground or a green wire.

Nandasmo

Hey guys, I am in the need of a wiring diagram for the "underhood fuses/relays box to the PCM. And please don't give up on me, please.

tech8

Your posts are a little confusing. Clarify what exactly is happening; so, I can understand what the issue may be, if there is even any issue.

1. GRN means a green wire.

If both fans run with the A/C on, that means the PCM is sending the ground signal through the green wire to both the condenser fan relay and radiator fan relay. It would also mean there isn't an "open" in the green wire coming from the PCM to the two separate relays. In addition, that means the relays are working.

2. You've indicate you jumped the two wires going to the fan switch, and fan turned on. Is that one or both fans turning on?

But, then you indicated when you ran the engine at 1500 rpm and both fans came on. I am not sure I am reading a problem here.

tech8

Are you overheating?

The fans don't run constantly, unless you turn on the A/C. If the coolant temperature at the radiator switch is below 199 degrees F, the fans do not run unless the A/C is turned on.

ARMED

so, what is the problem? i dont get it

Nandasmo

Hey Tech8, when I jumped the 2 connectors of the radiator fan switch only the radiator fan turn on. And when I said that running the engine at 1500 rpm. I don't know if I am correct, but I think when the engine exceeds 96 C, it is when the radiator fan kick in but not along with the condenser fan (A/C). And this is what I am getting. It doesn't matter how long I keep the engine running I never get the radiator fan working by itself, both fan kick in. One more thing that I would to add is: without the relay I did measure the socket #2 on the relay box (with out the ignition switch on) and body ground I don't get battery voltage, and according to the circuit diagram socket #2 get voltage all the time from the battery. But on the other hand, I do get voltage on socket #1, which is supposedly to get voltage only when the ignition is on. And all this is telling me that probably there is something wrong with the "Relay box" but I am not sure, that is what I need a pro opinion. And thanks for replaying. And my car is not overheating.

tech8

Radiator and condenser fan operation is controlled by the PCM/ECM and the radiator fan switch.

The PCM/ECM turns on the condenser fan and radiator fan for engine and refrigerant cooling whenever the A/C is on. If the engine coolant temperature at the radiator fan switch is above 199 degrees F (93 degrees C), both fans should also run.

Looking at the circuit diagram:

Radiator fan relay (normally open type relay):
Terminal pin 2 gets power from Fuse 57 and is hot at all times.
Terminal pin 4 gets power from Fuse 17 (when the ignition is ON).
When terminal pin 3 is grounded from either the radiator fan switch or PCM (via the green wire), this energizes the relay (the ground source from pin 3 and power from pin 4 energizes the relay) and closes the relay. When the relay is closed, power comes from terminal pin 2 through the closed “contact” to terminal pin 1 to the Blk/Red wire to feed the radiator fan motor. Think of the relay like a raised draw bridge (open). When the draw bridge is lowered (closed), then the bridge can be crossed.

When the relay is open, no power is allowed through to terminal pin 1.

A/C condenser fan relay (normally open type relay):
Terminal pin 2 gets power from Fuse 56 and is hot at all times.
Terminal pin 4 gets power from Fuse 17 (when the ignition is ON).
When terminal pin 3 is grounded from either the radiator fan switch or PCM (via the green wire), this energizes the relay and closes the relay. When the relay is closed, power comes from terminal pin 2 through the closed “contact” to terminal pin 1 to the White wire to feed the A/C condenser fan motor.
When the relay is open, no power is allowed through to terminal pin 1.


When you jumped the 2P harness connector for the radiator fan switch (with the ignition turned on), this should energize both the radiator fan relay and A/C condenser fan relay to close the relays and allow power to come through the relays to turn on both fans.

The only part that doesn’t sound normal is only the radiator fan running when you jumped (grounded) the harness connector for the radiator fan switch. Normally, both fans should run when the connector for the fan switch is jumped. However, since you're not overheating and both fans sounds like they run when they should (i.e., coolant temp. above 93 degrees C or A/C on), this may not be a big issue. If both fans run, it means power and ground are coming through both relays.

tech8

Sounds like you may be mixing up the relay terminal numbering.

Nandasmo

Hey Tech8, today I did change the relay box but I got the same result. I kept the engine running for 30 min (with the A/C off) with the control of the temperature at the high selection and again both fan turned on. And for the numbers of the relay 4 pins sockets I am using the following circuit diagram, which is telling me that socket #2 of the radiator fan relay and the condenser fan relay both are hot all the time from the battery, and socket #1 get power when the relay close. Also, I am including a copy of the troubleshooting circuit. And I am sorry when I said that I jumped the radiator fan switch connectors, what I meant was the #1 and #2 sockets of the radiator fan relay.

tech8

Honda sometimes numbers the relay terminals for different Hondas in the circuit diagrams.

I'll edit my above post to match the one you're using first.