HELP-Radiator fans don't turn off!! - LotusTalk

JUNGLISTluder · 08-15-2008, 10:58 AM

I noticed that when I turn my AC on, the radiator fans come on as normal. However, when I turn the AC off, the fans won't turn off until I turn the car off completely. This is regarless of engine temperature. After turning the AC OFF, the motor can be 185 and the fans will still run on high-speed until the car is turned off. I recall the fans turning off when the engine is normal operating temp (<200F).

The dealership is telling me that the fan is supposed to stay on, even after you turn the AC off (regardless of engine temp). Is the fan supposed to turn off after turning the AC off (assuming the motor is <200F)?

Thanks!

Pestodude · 08-15-2008, 11:18 AM

This is normal. In fact, I have overheating problems on the track so I turn the AC on when I grid then turn the AC off just before I head out on the track so the fans will be on and (hopefully) help keep the temps down.

Pengineer91 · 08-15-2008, 03:17 PM

Does this really make sense?

If I turn on the A/C for the first 5 minutes of a 4 hour drive, I'm gonna have them on the rest of the trip?

I find it difficult to believe that this is by design, even for Lotus.

TheViper · 08-15-2008, 04:42 PM

The fans always run at half speed while the compressor is operating, guess Lotus calculated that the additional air flow was needed because of the horizontal placement of the condensor..

Quote:

Originally Posted by Pengineer91

Does this really make sense?

If I turn on the A/C for the first 5 minutes of a 4 hour drive, I'm gonna have them on the rest of the trip?

I find it difficult to believe that this is by design, even for Lotus.

TimMullen · 08-16-2008, 05:56 PM

Quote:

Originally Posted by Pengineer91

Does this really make sense?

If I turn on the A/C for the first 5 minutes of a 4 hour drive, I'm gonna have them on the rest of the trip?

I find it difficult to believe that this is by design, even for Lotus.

It is rumored that they will in fact turn off after a period of time. I've tested it for about least a 25 minute drive home from work, and they didn't turn off. But they are supposed to at some point...

If it really bothers you, you could always shove in the clutch, turn the key off one click (not two unless you want to lock the steering wheel

) and then turn the key back on and restart the car...

azmurciev12 · 08-17-2008, 07:52 AM

wow! this is just what i was looking for. so you mean if i turn d A/C ON on my warm-up lap at the track then turn it off, the radiator fans will continue to run...at least for 25mins? this will surely help the radiator in cooling down.

i was going to have the workshop do an override switch so i can turn off the compressor and just have the fans running to help things keep cool when on track. i did this to my STi to help cool the radiator further. it seems the lotus will do it for me without doing anything.

i live where 95F ambient temp is common on the track so every assistance the radiator can get will be helpful in maintaining power. the exige has been reliable but i see temps reaching 200-203F at times and i feel there is some power loss.

Cinesnow · 08-17-2008, 10:45 AM

I pulled this up for your intensive learning purposes, hope it helps . . .

The two cooling fans are fitted beneath the radiator or (with a.c.) condensor/radiator package, and the coolant re-circulation pump is mounted below the header tank. Both fans and pump are controlled by the engine management ECU using data provided by the coolant temperature sensor mounted in the back of the cylender head.
The Cooling fans are switched on as a pair, and will operate at half speed (connected in series) when coolant temperature reaches 98°C/208°F on rise, and swich off at 94°C/201°F on fall. The fans will also operate at half speed irrespective of coolant temperature if the a.c. os switched on and the compressor is running. If the coolant temperature is rises to 103°C/217°F the fans will switch to full speed (connected in parallel), reverting to half spee at 98°C/208°F.
The Fans will also run at half speed, unless high coolant temperature dictates otherwise, when the a.c. is switched on and the compressor is running, or of the engine magement system detects a fault with the inlet air temperature or coolant temperature circuts.
At road speeds in excess of 85 mph (135 km/h), equating to fan stall speed, all fan functions are switched off.

Heat Soak
In order for the ECU to help control the engine temperature after switching off an engine whose temperature is over 88°C/190°F, the ECU will remain powered for a period of 20 minutes to allow heat soak management.
A coolant re-circulation electric pump is mounted below the coolant header tank and is plumbed into the heater supply line. When energized, the pump circulates coolant through the engine and heater system, drawing coolant back from the cylinder head, and pumping it through the heater matrix and into the heater return pipe and back into the thermostat housing. The pump functions only with the ignition off in conditions where the ECU remains live. The pump is the activated at coolant temperatures over 110°C/230°F, switching off at 100°C/212°F on fall.

Fan Control Module
The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted on top of the passenger side wheelarch liner.

08-15-2008, 10:58 AM	#1 (permalink)
JUNGLISTluder High Roller Join Date: Aug 2007 Location: Alexandria, VA Posts: 692 Images: 6	HELP-Radiator fans don't turn off!! I noticed that when I turn my AC on, the radiator fans come on as normal. However, when I turn the AC off, the fans won't turn off until I turn the car off completely. This is regarless of engine temperature. After turning the AC OFF, the motor can be 185 and the fans will still run on high-speed until the car is turned off. I recall the fans turning off when the engine is normal operating temp (<200F). The dealership is telling me that the fan is supposed to stay on, even after you turn the AC off (regardless of engine temp). Is the fan supposed to turn off after turning the AC off (assuming the motor is <200F)? Thanks! __________________ 06 Lotus Elise - AR/Blk, Touring, Premium, TC, HT, DRL Delete, X-Pel, TS Pro1 Exhaust, TS Pro1 Intake, BBmod, Saikou Michi OCC, 6000k HIDs, Stealth Bulbs, 07+ Letters, Re-grooved Bilsteins, LG Stone Guards, CR Engine Covers, S111 Folding Tow Hook, FF CF Spoiler, 17" PIAA FR-7s, CharlieX 06 ECU V2.0, Greddy/BOE Supercharger 88 BMW 528is - Blue/Llama Beige, M20 stroker motor, Alpina SW, 3.73 LSD, BavAuto Springs, Bilstein Sports, M3 SSK, 16x8 BBS, 225/245 tires, shadowline

08-15-2008, 11:18 AM	#2 (permalink)
Pestodude '07 Black Exige S Join Date: Oct 2007 Location: Los Angeles Posts: 474	This is normal. In fact, I have overheating problems on the track so I turn the AC on when I grid then turn the AC off just before I head out on the track so the fans will be on and (hopefully) help keep the temps down. __________________ Randy '07 Phntm Blk Exige S. Proalloy chargecooler, RLS IC tubes, Sector RTD brace, ForcedFed engine dampener, de-snorkle/ vel stack, cf side scoops/ mesh removed, algnmnt set up by Lucent in LA (machined control arms, etc), SS brake lines, 160 deg. thermo, Sector and "Stan's" shifter mod, "Stan's" clutch pedal mod, Voltphreaks 4.5lb battery, Stealth signal bulbs, blacked out turn side markers, 5 point harness

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08-15-2008, 03:17 PM	#3 (permalink)
Pengineer91 Registered User Join Date: Apr 2008 Posts: 34	Does this really make sense? If I turn on the A/C for the first 5 minutes of a 4 hour drive, I'm gonna have them on the rest of the trip? I find it difficult to believe that this is by design, even for Lotus.

08-17-2008, 07:52 AM	#6 (permalink)
azmurciev12 Registered User Join Date: Apr 2007 Posts: 55	wow! this is just what i was looking for. so you mean if i turn d A/C ON on my warm-up lap at the track then turn it off, the radiator fans will continue to run...at least for 25mins? this will surely help the radiator in cooling down. i was going to have the workshop do an override switch so i can turn off the compressor and just have the fans running to help things keep cool when on track. i did this to my STi to help cool the radiator further. it seems the lotus will do it for me without doing anything. i live where 95F ambient temp is common on the track so every assistance the radiator can get will be helpful in maintaining power. the exige has been reliable but i see temps reaching 200-203F at times and i feel there is some power loss.

08-17-2008, 10:45 AM	#7 (permalink)
Cinesnow Cinesnow Join Date: Jul 2007 Location: Lake Arrowhead, Ca / Sandpoint, Id Posts: 70	I pulled this up for your intensive learning purposes, hope it helps . . . The two cooling fans are fitted beneath the radiator or (with a.c.) condensor/radiator package, and the coolant re-circulation pump is mounted below the header tank. Both fans and pump are controlled by the engine management ECU using data provided by the coolant temperature sensor mounted in the back of the cylender head. The Cooling fans are switched on as a pair, and will operate at half speed (connected in series) when coolant temperature reaches 98°C/208°F on rise, and swich off at 94°C/201°F on fall. The fans will also operate at half speed irrespective of coolant temperature if the a.c. os switched on and the compressor is running. If the coolant temperature is rises to 103°C/217°F the fans will switch to full speed (connected in parallel), reverting to half spee at 98°C/208°F. The Fans will also run at half speed, unless high coolant temperature dictates otherwise, when the a.c. is switched on and the compressor is running, or of the engine magement system detects a fault with the inlet air temperature or coolant temperature circuts. At road speeds in excess of 85 mph (135 km/h), equating to fan stall speed, all fan functions are switched off. Heat Soak In order for the ECU to help control the engine temperature after switching off an engine whose temperature is over 88°C/190°F, the ECU will remain powered for a period of 20 minutes to allow heat soak management. A coolant re-circulation electric pump is mounted below the coolant header tank and is plumbed into the heater supply line. When energized, the pump circulates coolant through the engine and heater system, drawing coolant back from the cylinder head, and pumping it through the heater matrix and into the heater return pipe and back into the thermostat housing. The pump functions only with the ignition off in conditions where the ECU remains live. The pump is the activated at coolant temperatures over 110°C/230°F, switching off at 100°C/212°F on fall. Fan Control Module The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted on top of the passenger side wheelarch liner.

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