Discussion
Whilst backing into the garage the other day, both radiator fans failed to come on leading to a bit of excitement and lost coolant.
As I understand it, the normal culprits are fan connectors, fuses, relays, sensor (in the block). Fuses and relays look ok, connectors are a bit crusty but not too bad, so combined with the fact neither fan came on I'm thinking the sensor has failed?
However, if I disconnect the sensor and turn on the ignition I get no voltage at either fan, which seems odd. It's running an Omex ECU so I guess there could be a difference there, anyone got any ideas?
As I understand it, the normal culprits are fan connectors, fuses, relays, sensor (in the block). Fuses and relays look ok, connectors are a bit crusty but not too bad, so combined with the fact neither fan came on I'm thinking the sensor has failed?
However, if I disconnect the sensor and turn on the ignition I get no voltage at either fan, which seems odd. It's running an Omex ECU so I guess there could be a difference there, anyone got any ideas?
Firstly, I'd open the fan power connectors and really get in there with a can of contact spray.WD40 and a toothbrush....they are notorious for getting cruddy...same connectors as the Chimaera...same location - and were a weak point on the Chim too.
Secondly, I'd contact garage/installer of the Omex (Racing Green?) and check the characteristics of that ecu. The MBE ecu would power ON the fans only with IGN and, on my car, with the engine running (so - ecu seeing running engine). With the MBE the check for the fan circuit was to fire up the engine and then disconnect the sensor (THIS is the one between and below the throttle bodies at cylinder 5 & 6, so airbox off to access.) the drivers side fan should run with the sensor disconnected.
I would have thought the Omex would follow same protocols.....basically, IF the ecu coolant sensor failed the fan would come on and run continuously to protect the engine.
Nick
Secondly, I'd contact garage/installer of the Omex (Racing Green?) and check the characteristics of that ecu. The MBE ecu would power ON the fans only with IGN and, on my car, with the engine running (so - ecu seeing running engine). With the MBE the check for the fan circuit was to fire up the engine and then disconnect the sensor (THIS is the one between and below the throttle bodies at cylinder 5 & 6, so airbox off to access.) the drivers side fan should run with the sensor disconnected.
I would have thought the Omex would follow same protocols.....basically, IF the ecu coolant sensor failed the fan would come on and run continuously to protect the engine.
Nick
Cheers Nick.
I think this is coming down to dodgy connectors as you say.
I read up on the Omex ECU and hooked the laptop up. The coolant sensor calibration requires a "Coolant Fail High" and "Coolant Fail Low" setting in °C. If the reading hits these values, it will fall back to "Coolant Temp Default" (in this case 100°C), and start the fans. The live reading when disconnecting the sensor is -25°C, and the "Coolant Fail Low" setting was also set to -25°C, so never got triggered. Why this wasn't correct in the first place I don't know, it's all explained in quite some detail in the manual, but never mind.
I upped the "Coolant Fail Low" by a degree and one fan came to life. A wiggle of the other fan's connector and that came to life too. I'll give them a proper clean up, but are there better replacements out there? They don't seem very weatherproof!
I think this is coming down to dodgy connectors as you say.
I read up on the Omex ECU and hooked the laptop up. The coolant sensor calibration requires a "Coolant Fail High" and "Coolant Fail Low" setting in °C. If the reading hits these values, it will fall back to "Coolant Temp Default" (in this case 100°C), and start the fans. The live reading when disconnecting the sensor is -25°C, and the "Coolant Fail Low" setting was also set to -25°C, so never got triggered. Why this wasn't correct in the first place I don't know, it's all explained in quite some detail in the manual, but never mind.
I upped the "Coolant Fail Low" by a degree and one fan came to life. A wiggle of the other fan's connector and that came to life too. I'll give them a proper clean up, but are there better replacements out there? They don't seem very weatherproof!
Just to complete the story on this. I sourced some new connectors (parts below if anyone is interested) and both fans are now working as they should.
Male connector body: 1-1418483-1
Female connector body: 1-1703841-1
Male pins: 1-968855-1
Female pins: 1-962915-1
Rubber grommets: 828904-1
Male connector body: 1-1418483-1
Female connector body: 1-1703841-1
Male pins: 1-968855-1
Female pins: 1-962915-1
Rubber grommets: 828904-1
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