Cooling fans

[morepowerjoe]

Hey guys I think that I have an issue. My engine cooling has always been right where I want it to be around 203-210 and I have the factory t-stat. I have my fans set to come on at the appropriate times for that temp. But the other day my engine overheated. When I got home I let it cool off and checked the radiator and there was very low coolant in there, so I filled it up and took a drive. When I got back home I noticed coolant leaking from the reservoir. So then I thought it was leaking from the side so I replaced it. After another drive it was still leaking so I checked it and it was over full so I assumed it was coming from the overflow hole. I thought maybe radiator cap and replaced that. Now after another drive I noticed my temp was higher than usual like at 218 at idle and it never goes over say 210 so I popped the hood and noticed that my fans were running really slow. So I was wondering if there is a high and low relay for the fans and maybe the high one is out? Any help is appreciated.

[SaReNi]

have yo noticed if there is a difference of the fans coming on when the a/c is off vs when it is on? I've noticed on mine, that, like most vehicles I have seen, the fans come on automatically when the air is on. I've also notice on mine, that the fans don't come on until somewhere around 215 or 220 when the a/c is off, but when the a/c is on, the temp gauge never makes it that high.

[morepowerjoe]

Hey buddy thanks a lot for the info. That's exactly the type of answer I was looking for. I'm gonna pay attention to the fans next time I take a drive. Thanks again.

[0stones0]

Originally Posted by 1JEWLDSSRS

I just got through going through a similar situation, engine was getting pretty hot (212) sitting still, when we got moving it would cool down some, but not like it should have. So when I got home and was sitting in my carport letting it idle like I do to cool it down before I shut her off, it was sitting at 212 and never got down to 192, which is where I shut things down. So I popped the hood and noticed my cooling fan on the passenger side was NOT running, it is the high speed fan according to my mech, and the drivers side fan is the low speed fan, and it WAS running. So the next day I took her up to the shop to check out what was going on, when we popped the hood, as before the passenger fan was NOT running again, he bumped the fan motor with his hand and it came on! Yea, but when we shut it off and re-started it, that same fan did NOT come back on, but the driver side was still working, low speed. He said that the brushes in the fan motor were bad is why it would not start up, but when you bump it, they make contact and start up until you shut it down again. So since I had 125k on them, and in Florida I replaced BOTH fan motors and has been great ever since!! Thank God! Also on the coolant leak thing, at the same time we found that my radiator tank had cracked up under the top left part of the tank on the driver side and coolant was running down the side, looked like it had been leaking for a while by the looks of it, so we installed a new OEM radiator as well. Was quite an expensive repair for it all, but now she is running cooler than ever. Hopefully this is good info for you and your issue. Apologize for the long novel.. lol.

Great info sir! Didn’t know about the low and high speed on the fans and the fact that they are are independent of each other. Good to know!

[NOT A 45]

Originally Posted by 1JEWLDSSRS

Yea, I didn't know that either until I had the fan problem. I was also under the assumption BOTH had a low and high setting to come on at the same time, but nah, that isn't how it is. lol. Learn something new everyday with these Camaros..

I hate to contradict your mechanic because I know you trust him, but that is NOT how they operate! Here's how it works:

The engine cooling fan system consists of 2 electric cooling fans and 3 fan relays. The relays are arranged in a series/parallel (S/P) configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block.

In low speed operation, the ECM applies ground to the coil side of the cooling fan low speed relay. This energizes the coil and applies voltage directly to the right cooling fan through the switch side of the low speed relay. The right cooling fan is connected in series to the left cooling fan through the de-energized series/parallel (S/P) cooling fan speed control relay. The series circuit operates both fans at low speed.

In high speed operation, the ECM applies a ground to the coil side of the cooling fan low speed relay, the S/P cooling fan speed control relay, and the cooling fan high speed relay. When energized, the high speed fan relay applies voltage directly to the left cooling fan through the switch side of the relay. Simultaneously, the low speed fan relay and the S/P speed control relay provide ignition voltage and a direct path to ground for the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

[morepowerjoe]

Originally Posted by NOT A 45

I hate to contradict your mechanic because I know you trust him, but that is NOT how they operate! Here's how it works:

The engine cooling fan system consists of 2 electric cooling fans and 3 fan relays. The relays are arranged in a series/parallel (S/P) configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block.

In low speed operation, the ECM applies ground to the coil side of the cooling fan low speed relay. This energizes the coil and applies voltage directly to the right cooling fan through the switch side of the low speed relay. The right cooling fan is connected in series to the left cooling fan through the de-energized series/parallel (S/P) cooling fan speed control relay. The series circuit operates both fans at low speed.

In high speed operation, the ECM applies a ground to the coil side of the cooling fan low speed relay, the S/P cooling fan speed control relay, and the cooling fan high speed relay. When energized, the high speed fan relay applies voltage directly to the left cooling fan through the switch side of the relay. Simultaneously, the low speed fan relay and the S/P speed control relay provide ignition voltage and a direct path to ground for the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

So in my situation I could have the high speed relay out?

[gtstorey]

Originally Posted by morepowerjoe

So in my situation I could have the high speed relay out?

I'll try and post the wiring diagram this evening when I get home. Without it in front of me, it's hard to remember exactly, but I think it's possible that it could be one of the other relays that could still cause problems with the high speed fan operation.

[NOT A 45]

Originally Posted by morepowerjoe

So in my situation I could have the high speed relay out?

Cooling Fan Relay 1 operates both fans at a low speed
Cooling Fan Relay 2 and 3 operates the left fan at a high speed
Cooling Fan Relay 1, 2 and 3 operates both fans at a high speed
KR20 cooling fan relay identification:
The KR20C cooling fan low speed relay is COOL FAN LOW Relay K613
The KR20E cooling fan speed control relay is COOL FAN CNTRL Relay K614
The KR20D cooling fan high speed relay is COOL FAN HI Relay K612

Yes, I'd look at the high speed relay and circuit

[13_SS_RS]

Originally Posted by 1JEWLDSSRS

I just got through going through a similar situation, engine was getting pretty hot (212) sitting still, when we got moving it would cool down some, but not like it should have. So when I got home and was sitting in my carport letting it idle like I do to cool it down before I shut her off, it was sitting at 212 and never got down to 192, which is where I shut things down. So I popped the hood and noticed my cooling fan on the passenger side was NOT running, it is the high speed fan according to my mech, and the drivers side fan is the low speed fan, and it WAS running. So the next day I took her up to the shop to check out what was going on, when we popped the hood, as before the passenger fan was NOT running again, he bumped the fan motor with his hand and it came on! Yea, but when we shut it off and re-started it, that same fan did NOT come back on, but the driver side was still working, low speed. He said that the brushes in the fan motor were bad is why it would not start up, but when you bump it, they make contact and start up until you shut it down again. So since I had 125k on them, and in Florida I replaced BOTH fan motors and has been great ever since!! Thank God! Also on the coolant leak thing, at the same time we found that my radiator tank had cracked up under the top left part of the tank on the driver side and coolant was running down the side, looked like it had been leaking for a while by the looks of it, so we installed a new OEM radiator as well. Was quite an expensive repair for it all, but now she is running cooler than ever. Hopefully this is good info for you and your issue. Apologize for the long novel.. lol.

sorry to thread jack, but what is the reason you let your car idle to cool down when you are done driving it? wondering if its something I should be doing since I'm cammed now and its also pretty hot in GA

[SaReNi]

Great info Not a 45!!! thanks for posting that.

[1JEWLDSSRS]

Originally Posted by 13_SS_RS

sorry to thread jack, but what is the reason you let your car idle to cool down when you are done driving it? wondering if its something I should be doing since I'm cammed now and its also pretty hot in GA

Hey there, just one of my quirks I have. I don't like shutting down a hot engine. When I back her into the carport and the temp is up around 199-203 from driving thru town, I will let her idle for a few minutes and cool down to around 192 before I turn it off. I figure this way all the coolant and oil has a chance to circulate throughout the engine and "settle down" so to speak and cool things down. No reason, just me...

[13_SS_RS]

Originally Posted by 1JEWLDSSRS

Hey there, just one of my quirks I have. I don't like shutting down a hot engine. When I back her into the carport and the temp is up around 199-203 from driving thru town, I will let her idle for a few minutes and cool down to around 192 before I turn it off. I figure this way all the coolant and oil has a chance to circulate throughout the engine and "settle down" so to speak and cool things down. No reason, just me...

Well that makes sense to me

[CamaroCracka]

The last time I took my radiator out, I noticed one of the hot connectors on the plug was burnt. I ended up replacing it with a couple metri-pack connectors since I could not find both sides of the connector. You might want to look at that and make sure the connection is good.

I also had a relay or fuse go out on the vert that stopped the fans from working altogether, but I let a shop fix that due to time constraint.

[morepowerjoe]

Well guys I think I got her fixed. Alls I did was replace the high speed relay and now it's going up to 100% speed now. But here's the thing, when I turn on the ac the fans don't go to a 100% right away. I know the as the ac raises in kpa pressure the fans are a % based on that pressure. But I thought they came on at a 100% when the ac was turned on but looking at the tune I know that's not the case. I have the factory t-stat in it which I think is at 187*. So I have my fans set like this.
203* 65%
206* 75%
210* 85%
213* 95%
The highest my temp has gone to so far with these settings is 212* in 97* weather here in Texas. So just shy of 95%. Am I asking to much of these fans or do you think I'm ok since I'm staying at 85%?