Fan issue - can't seem to figure what's going on
05-15-2017, 04:59 PM
#1
Thread Starter
Fan issue - can't seem to figure out what's going on
Posted a thread few days ago my concern with the temps being around 200-215 while in stop and go traffic but today I noticed I hit 225 for about a minute or so.
Later, I checked and noticed while the ac was on, both my fans would cycle off and on. They would turn on for about 20-30 seconds and then turn off for about 30 seconds- 1 minute. This happens with or without the ac.
I swapped relays and this didn't fix the issue. If I remember correctly, when the ac is on, both fans should run. Also when my car was at 215-225, the fans shouldn't cycle off and on even if the ac is off.
When I jump both relays for the condenser and rad fan, the fans work and stay on.
Is there something else I should check other than the relay as to why they keep on cycling off and on with the ac on or off and hitting over 215?
Later, I checked and noticed while the ac was on, both my fans would cycle off and on. They would turn on for about 20-30 seconds and then turn off for about 30 seconds- 1 minute. This happens with or without the ac.
I swapped relays and this didn't fix the issue. If I remember correctly, when the ac is on, both fans should run. Also when my car was at 215-225, the fans shouldn't cycle off and on even if the ac is off.
When I jump both relays for the condenser and rad fan, the fans work and stay on.
Is there something else I should check other than the relay as to why they keep on cycling off and on with the ac on or off and hitting over 215?
05-15-2017, 07:01 PM
#2
Fan thermal switch?
05-15-2017, 07:16 PM
#3
Thread Starter
I replaced the radiator fan switch this past weekend. Is there another switch I should look for?
I thought it might be defective but if it was, wouldn't that not matter if the ac is on. Shouldn't both fans run at any temp when the ac is ok?
I thought it might be defective but if it was, wouldn't that not matter if the ac is on. Shouldn't both fans run at any temp when the ac is ok?
05-16-2017, 02:48 AM
#4
Personally I never run the ac just cause its "hard" on the car and it wastes gas but coolant temps dont look too bad but they are a touch higher than normal. Higher coolant/engine temps are actually good. The hotter you run the car the more efficiently it runs. But its normal for the fans to come on and off in that period of time.
But back to your question have you check your thermostat? You can get a j's thermostat and it will keep the car a ton cooler. From what I've read on forums people with ap1's, their coolant gauge goes down too two bars in stop and go traffic. I believe their thermostat opens fully at 65 degrees C. (instead of the 93C the stock one opens at) You can also get an aftermarket fan switch from j's or mugen that correlates to the thermostat you bought.
But are you 100% sure the coolant in the radiator is getting above 200 degrees F? If its not then it will never tell the fan to turn on, how are you getting these temps if you dont mind me asking. If everything is working properly then thin out your coolant. Water transfers heat a lot better than a 50/50 mix, coolant is just there so the water doesnt freeze so you really dont have to have such a even ratio. If your in Florida, try a 70/30 ratio and your car will cool down a lot quicker while keeping the water from boiling
But back to your question have you check your thermostat? You can get a j's thermostat and it will keep the car a ton cooler. From what I've read on forums people with ap1's, their coolant gauge goes down too two bars in stop and go traffic. I believe their thermostat opens fully at 65 degrees C. (instead of the 93C the stock one opens at) You can also get an aftermarket fan switch from j's or mugen that correlates to the thermostat you bought.
But are you 100% sure the coolant in the radiator is getting above 200 degrees F? If its not then it will never tell the fan to turn on, how are you getting these temps if you dont mind me asking. If everything is working properly then thin out your coolant. Water transfers heat a lot better than a 50/50 mix, coolant is just there so the water doesnt freeze so you really dont have to have such a even ratio. If your in Florida, try a 70/30 ratio and your car will cool down a lot quicker while keeping the water from boiling
05-16-2017, 03:09 AM
#5
Both radiator fans should run when (1) the ignition is On, (2) the AC is On (green light) and (3) the interior fan is On (one or more green lights). Note this happens with the engine running or not-running and regardless of engine temperature. (Just confirmed this a minute ago in my garage.)
Radiator fans will cycle On and Off when the AC is Off based on radiator temperature. They come on a bit before radiator temperature is 190°F (someone can confirm my memory here). That's about 7-bars on my AP2 engine.
-- Chuck
Radiator fans will cycle On and Off when the AC is Off based on radiator temperature. They come on a bit before radiator temperature is 190°F (someone can confirm my memory here). That's about 7-bars on my AP2 engine.
-- Chuck
05-16-2017, 03:52 AM
#6
Thread Starter
Thanks for the replies.
Im using the modifry ect now with the default setting. I swapped out the rad fan switch this past weekend since I thought that was the issue. I use the funnel system after on the radiator to eliminate any air in the system.
I know when the car's ac isn't on, that the rad fan will cycle on and off but it's strange how it cycles. My car, it using this method will overheat if I'm idle. I saw my readings go from 4 bars to 5 which is over 225 with the rad fans still cycling. Once I start to drive, the temps start going down.
With the ac on, the ac light comes on and blows cold air but the fans still cycle off and on. Is there a relay which controls both fans kicking on at the same time? I know there is a relay for the rad fan and another for the ac fan but wasn't sure what controlled both of them.
For now, I just took both relays out and plugged it with the ignition so once the car turns on, both fans kick on which for the most part keeps the car at 3 bars (190-205).
Ill keep looking to see if I notice anything but it's strange how when the car is over 215, the fans aren't staying on and continue to cycle with or without the ac.
Im using the modifry ect now with the default setting. I swapped out the rad fan switch this past weekend since I thought that was the issue. I use the funnel system after on the radiator to eliminate any air in the system.
I know when the car's ac isn't on, that the rad fan will cycle on and off but it's strange how it cycles. My car, it using this method will overheat if I'm idle. I saw my readings go from 4 bars to 5 which is over 225 with the rad fans still cycling. Once I start to drive, the temps start going down.
With the ac on, the ac light comes on and blows cold air but the fans still cycle off and on. Is there a relay which controls both fans kicking on at the same time? I know there is a relay for the rad fan and another for the ac fan but wasn't sure what controlled both of them.
For now, I just took both relays out and plugged it with the ignition so once the car turns on, both fans kick on which for the most part keeps the car at 3 bars (190-205).
Ill keep looking to see if I notice anything but it's strange how when the car is over 215, the fans aren't staying on and continue to cycle with or without the ac.
05-16-2017, 06:05 AM
#7
The stock thermostat starts opening at 176-180° and is fully open at 194° which is what sets the minimum operating temperature of the engine. Having the fans turn on before 190 seems like it would be counter-productive. My manual says the fan switch in the radiator closes at 199°F but doesn't say when it opens and there's usually 5-10° or more of hysteresis in mechanical switches. I also looked up my old data and when I measured an '04 AP2 the 7th bar on the gauge came on at 168° according to the ECM OBD output. That sounds way low for the fans to be coming on.
Things to note - The coils of both fan relays are wired in parallel so both fans ALWAYS run at the same time. Either the radiator switch OR the ECM can turn the fans on, but both must agree in order for the fans to turn off. Assuming the radiator switch is open, the ECM can turn the fans on and off based on it's own logic. What that logic is I don't know but I would be surprised if the ECM doesn't take the ECT reading into consideration, or maybe even speed. I know there is a high-rpm cut-out for the AC compressor which I believe is above 6,000 rpm but I don't remember the exact set points.
It sounds like your only way of measuring coolant temperature is the ECT module. I suggest you do 2 things - monitor the ECT voltage and/or the OBD ECT signal. Compare the ECT sensor voltage to the chart in the ECT Module manual to see if the ECT module is working correctly. I bet it is, which means your sensor voltage is lower than it should be. Is that because the engine is running hot or is there some electrical problem artificially causing the sensor voltage to be low? If you're monitoring the sensor voltage and watching the gauge, remember the gauge itself has a 10-second delay on each segment, so it will take at least 30 seconds for 3 more segments to light up.
And whatever happened to basic trouble-shooting? If the car is overheating, wouldn't you suspect the thermostat might be bad? If it doesn't open fully or opens at too high a temperature that could cause the symptoms you are seeing. The thermostat is a pain to change - measure your sensor voltages first.
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Things to note - The coils of both fan relays are wired in parallel so both fans ALWAYS run at the same time. Either the radiator switch OR the ECM can turn the fans on, but both must agree in order for the fans to turn off. Assuming the radiator switch is open, the ECM can turn the fans on and off based on it's own logic. What that logic is I don't know but I would be surprised if the ECM doesn't take the ECT reading into consideration, or maybe even speed. I know there is a high-rpm cut-out for the AC compressor which I believe is above 6,000 rpm but I don't remember the exact set points.
It sounds like your only way of measuring coolant temperature is the ECT module. I suggest you do 2 things - monitor the ECT voltage and/or the OBD ECT signal. Compare the ECT sensor voltage to the chart in the ECT Module manual to see if the ECT module is working correctly. I bet it is, which means your sensor voltage is lower than it should be. Is that because the engine is running hot or is there some electrical problem artificially causing the sensor voltage to be low? If you're monitoring the sensor voltage and watching the gauge, remember the gauge itself has a 10-second delay on each segment, so it will take at least 30 seconds for 3 more segments to light up.
And whatever happened to basic trouble-shooting? If the car is overheating, wouldn't you suspect the thermostat might be bad? If it doesn't open fully or opens at too high a temperature that could cause the symptoms you are seeing. The thermostat is a pain to change - measure your sensor voltages first.
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05-16-2017, 06:28 AM
#8
Personally I never run the ac just cause its "hard" on the car and it wastes gas but coolant temps dont look too bad but they are a touch higher than normal. Higher coolant/engine temps are actually good. The hotter you run the car the more efficiently it runs. But its normal for the fans to come on and off in that period of time.
But back to your question have you check your thermostat? You can get a j's thermostat and it will keep the car a ton cooler. From what I've read on forums people with ap1's, their coolant gauge goes down too two bars in stop and go traffic. I believe their thermostat opens fully at 65 degrees C. (instead of the 93C the stock one opens at) You can also get an aftermarket fan switch from j's or mugen that correlates to the thermostat you bought.
But are you 100% sure the coolant in the radiator is getting above 200 degrees F? If its not then it will never tell the fan to turn on, how are you getting these temps if you dont mind me asking. If everything is working properly then thin out your coolant. Water transfers heat a lot better than a 50/50 mix, coolant is just there so the water doesnt freeze so you really dont have to have such a even ratio. If your in Florida, try a 70/30 ratio and your car will cool down a lot quicker while keeping the water from boiling
But back to your question have you check your thermostat? You can get a j's thermostat and it will keep the car a ton cooler. From what I've read on forums people with ap1's, their coolant gauge goes down too two bars in stop and go traffic. I believe their thermostat opens fully at 65 degrees C. (instead of the 93C the stock one opens at) You can also get an aftermarket fan switch from j's or mugen that correlates to the thermostat you bought.
But are you 100% sure the coolant in the radiator is getting above 200 degrees F? If its not then it will never tell the fan to turn on, how are you getting these temps if you dont mind me asking. If everything is working properly then thin out your coolant. Water transfers heat a lot better than a 50/50 mix, coolant is just there so the water doesnt freeze so you really dont have to have such a even ratio. If your in Florida, try a 70/30 ratio and your car will cool down a lot quicker while keeping the water from boiling
I don't think we're talking about a fully race-built engine that needs every ounce of cooling capacity possible, so if it's really overheating then something is wrong and that something needs to be identified and fixed. I ran a Comptech SC on my first S and did many track days in 90-95° temperatures and never saw the engine overheat. I had 199° intake air temps (yikes!), but the coolant never had a problem.
Despite what "everybody knows", changing the thermostat and/or the radiator fan switch does NOT increase the cooling capacity of the system. All it does is delay engine warm-up (BAD) and when under light loads force the engine to operate at too low a temperature (WORSE). It does nothing to improve cooling under high load conditions.
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05-16-2017, 06:51 AM
#9
Thread Starter
Not sure where the comment about wanting to run the car under 180 came from. Never stated that. My concern is the rad/condenser fan cycling off and on while the car continues to increase in temp.
In regard to the thermostat, I don't believe its bad. When checking to make sure there wasn't any air in the line, the top rad hose heats up, bottom is cool until the temp gauge hits 3 bars. Then you can feel the heat on the bottom hose of the thermostat opening up.
Now with both fans running, the car hits 190-205 fine and will stay like this unless I'm idle. On idle, it will hit 4 bars but once I start driving, it goes back down to three. So I'm assuming on idle with both fans running, its around 205-210 which is perfectly fine. I just want to determine what other things I can check to see why the fans cycle and don't remain on with the ac set to on or when the temp is hitting 205-210 and the ac off.
Before I did the jump of the fans last night, just to clarify, the car would on idle hit 4 bars and then hit 5 bars without the car moving. During this time, both radiator/condenser fans cycle off and on even if the ac was on. Even though this still falls in line with the stock temp range for 3 bars(Under 235), something isn't right.
In regard to the thermostat, I don't believe its bad. When checking to make sure there wasn't any air in the line, the top rad hose heats up, bottom is cool until the temp gauge hits 3 bars. Then you can feel the heat on the bottom hose of the thermostat opening up.
Now with both fans running, the car hits 190-205 fine and will stay like this unless I'm idle. On idle, it will hit 4 bars but once I start driving, it goes back down to three. So I'm assuming on idle with both fans running, its around 205-210 which is perfectly fine. I just want to determine what other things I can check to see why the fans cycle and don't remain on with the ac set to on or when the temp is hitting 205-210 and the ac off.
Before I did the jump of the fans last night, just to clarify, the car would on idle hit 4 bars and then hit 5 bars without the car moving. During this time, both radiator/condenser fans cycle off and on even if the ac was on. Even though this still falls in line with the stock temp range for 3 bars(Under 235), something isn't right.
05-16-2017, 09:42 AM
#10
What year is your car? I wonder if the algorithm for the ECM controlling the fans is the same for every year? If we're not sure that all years are the same, how do we know that your fan cycling is abnormal?
For now, let's set aside the issue of the fans cycling on and off. Suppose the temperature gauge indicated you never went above 205° (stayed at 3 bars) would you even be concerned about the fans? My point is that if the gauge is wrong and the coolant temps are actually normal does it matter that the fans cycle on and off? If not, then the real issue is whether or not the coolant temps are getting higher than normal or if something else is causing the gauge to read high.
Your "feel the hose" test is good and does indicate the thermostat is opening, but is it opening at the right temperature and is it opening fully? If we assume the thermostat is the cause of higher temps then the radiator fan switch should be forcing the fans to run. It might be time to see what is making the fans cycle - the ECM or the radiator switch? You'd have to unplug the wires from the switch to know for sure, and I suggest you put a continuity tester on the radiator switch to make sure that it is turning on. If the gauge is correct and the temps go over 200° then the fan switch should close. I know it's a new switch but is it the right switch?
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For now, let's set aside the issue of the fans cycling on and off. Suppose the temperature gauge indicated you never went above 205° (stayed at 3 bars) would you even be concerned about the fans? My point is that if the gauge is wrong and the coolant temps are actually normal does it matter that the fans cycle on and off? If not, then the real issue is whether or not the coolant temps are getting higher than normal or if something else is causing the gauge to read high.
Your "feel the hose" test is good and does indicate the thermostat is opening, but is it opening at the right temperature and is it opening fully? If we assume the thermostat is the cause of higher temps then the radiator fan switch should be forcing the fans to run. It might be time to see what is making the fans cycle - the ECM or the radiator switch? You'd have to unplug the wires from the switch to know for sure, and I suggest you put a continuity tester on the radiator switch to make sure that it is turning on. If the gauge is correct and the temps go over 200° then the fan switch should close. I know it's a new switch but is it the right switch?
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