Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[24_Valve]

I've been keeping a close eye on my coolant temp and fan operation following prolonged fast idle test at MOT.

My rad fan only cuts in when coolant temp gauge is showing 97.5 degrees. It usually cuts out about 93 degrees and this process repeats itself... temp rises high, fan cuts in, temp drops & so on. There is no steady temperature unless I'm on a run (wind assistance). When the rad fan does cut in, both a/c fans cut in too. So I have either no cooling or max cooling? Is this normal or should I replace rad thermo-switch etc.. Also should rad fan cut in low speed before temp rises to 97.5 degrees?

Any Ideas.. ?

[Marks DTM Calib]

Seem to recall we have a guide to allow you to check this out so worth having a look in the FAQ's and maintenance guides.

Sounds like arelay not working possibly

[24_Valve]

Did have a good look before posting (always do) but only found FAQ on coolant temp gauge display & the disparity between FL & PFL models... will go and trawl back through 'em :-/

[24_Valve]

Nope, 'just dave aw' & my own posts (same thread)... http://www.omegaowners.com/forum/YaBB.pl?num=1276355362/15 nothing else 

[Kevin Wood]

Do the fans go straight to full speed or half speed first?

Could be that the half speed stage is defective for some reason.
Might be worth grounding the pins indicated on the fan test connector (from the thread you linked to) and see what happens in each case.

"Quite hot" should give you the air con fans on slow and the rear rad. fan on slow.

"Very hot" should give you these on high speed.

Kevin

[24_Valve]

Thanks KW... they seem to go straight to high speed when temp hits 97.5... I think half speed stage might be defective but didn't want to ground the pins without being certain that I've understood dave-aw's description of the pin order correctly.. The pic that I posted is to the best of my knowledge what dave is describing? but wouldn't mind a second opinion 

[Abiton]

As far as I can see, the only pin which mustn't be grounded is pin 3, the 12V one.  So use your multimeter on dc volts, black probe on battery negative, red probe to each pin in turn 'til you find pin 3.  Mask this off with a bit of gaffer tape to prevent accidents while you then go round the others shorting them in turn to chassis ground and seeing what happens.  The pin numbering should become apparent (by what happens) if it hasn't already by establishing which is pin 3.

Hope this helps, and do take some good piccies as this could make a really useful "How to" guide.

Edit: actually this might be nonsense, as other pins than 3 may show 12V... :-/

[RobG]

This might help http://i863.photobucket.com/albums/ab197/philrich1064/Fan_test.jpg

[Kevin Wood]

As far as I can see, the only pin which mustn't be grounded is pin 3, the 12V one. 

Yes, and this is fed by a solid black wire.

Kevin

[bigdods]

I had this problem a while back. The low speed fan fuse was blown so it was either no fans or full on high speed when the temp got high. IIRC it was a big green fuse. Under the bonnet there are a set of fuses under a cover by the battery. Take a look under there, pull all the fuses and check if one has blown.

[24_Valve]

Posted by RobG Yesterday at 10:46
This might help http://i863.photobucket.com/albums/ab197/philrich1064/Fan_test.jpg

Thanks RobG this is the missing link  this confirms the pin layout exactly the way I thought. Also expected results for the PFL when testing... I can do a decent 'how to' with photo's if admin approve (would mean nicking 'dave aw's diagram and test results for FL models though) 

p.s. looks like I am missing relay K67 in on my mig  http://www.omegaowners.com/forum/YaBB.pl?num=1276355362/15 anyone got a spare 

[TestOmega]

Posted by RobG Yesterday at 10:46
This might help http://i863.photobucket.com/albums/ab197/philrich1064/Fan_test.jpg

Thanks RobG this is the missing link  this confirms the pin layout exactly the way I thought. Also expected results for the PFL when testing... I can do a decent 'how to' with photo's if admin approve (would mean nicking 'dave aw's diagram and test results for FL models though) 

p.s. looks like I am missing relay K67 in on my mig  http://www.omegaowners.com/forum/YaBB.pl?num=1276355362/15 anyone got a spare 

The following for my Catera 2001 which is equivalent to 2000 vintage facelift Omegas,

Auxiliary Fans Low Speed, Electric Cooling Fan Low Speed :
Battery voltage is supplied to heater water auxiliary pump whenever ignition switch is on. When engine temperature reaches 212°F (100°C), primary cooling fan temperature switch stage 1 will close, enabling fan control relay K26 to energize. When fan control relay K26 energizes, battery voltage from fuse 52 is applied to auxiliary coolant fan 1 (auxiliary engine coolant fan 1 is wired in series with auxiliary engine fan 2, through normally closed contacts of fan control relay K52. This will cause auxiliary coolant fans 1 and 2 to operate at low speed. Fan control relay K26 will also supply battery voltage to engine coolant fan resistor, voltage passes through resistor to electric coolant fan. Engine coolant fan resistor will cause engine coolant fan to operate at low speed. Primary cooling fan temperature switch stage 1 contacts will open when coolant temperature reaches 203°F (95°C). This will turn all 3 fans off, unless air conditioning system is on.

Auxiliary Fans High Speed:
 When engine temperature reaches 221°F (105°C), secondary cooling fan temperature switch contacts will close and energize fan control relays K52 and K28. When fan control relay K52 energizes, it will ground terminal "B" of auxiliary engine coolant fan 1. Terminal "A" of auxiliary engine fan 1 still receives battery voltage from fan control relay K26. Auxiliary coolant fan 1 is no longer in series with auxiliary engine coolant fan 2 and will now operate at full speed. When fan control relay K28 is energized, battery voltage from fuse 40 will be applied to terminal "A" of auxiliary engine coolant fan 2. Auxiliary coolant fan 2 is no longer in series with auxiliary engine coolant fan 1 and operates at full speed. Terminal "B" of auxiliary coolant fan 2 is permanently grounded. With stage 1 contacts of primary cooling fan temperature switch closed, electric cooling fan will continue to operate. Secondary cooling fan temperature switch contacts will open when coolant temperature reaches 212°F (100°C). This will cause auxiliary engine coolant fans 1 and 2 to operate at low speed.

Electric Coolant Fan High Speed:
 When engine coolant temperature reaches 230°F (110°C), primary cooling fan temperature switch stage 2 will close energizing fan control relay K67. When fan control relay K67 energizes, battery voltage from fuse 42 will be applied directly to terminal "A" of engine coolant fan (bypassing engine coolant fan resistor ) and engine coolant fan will operate at full speed. All other operations that were taking place before coolant temperature reached 230°F (110°C) will remain in effect. Primary cooling fan temperature switch stage 2 contacts will open when coolant temperature reaches 221°F (105°C) and primary engine coolant fan will shut off. At coolant temperatures above approximately 230°F (110°C), all 3 coolant fans are operating at full speed. Only 5 of 6 relays operate at this time, unless air conditioning system is turned on. In this case, fan control relay K87 and A/C compressor relay K60 will also operate.

Engine Cooling Fans (A/C Operation):
 When A/C compressor is turned on, fan control relay K87 is energized and auxiliary engine coolant fans 1 and 2 will operate in low speed. In order to prevent inadmissible high refrigerant pressure in refrigerant circuit, auxiliary engine coolant fans 1 and 2 are switched from low speed to high speed at refrigerant pressures above approximately 275 psi. When pressure drops less than about 217 psi, auxiliary engine coolant fans 1 and 2 are switched back to low speed.

Water Auxiliary Pump:
 When ignition is off and engine coolant temperature reaches 212°F (100°C), primary cooling fan temperature switch stage 1 will close, enabling fan control relay K26 to energize. When fan control relay K26 energizes, battery voltage from fuse 52 is applied through normally closed auxiliary water pump relay K22, allowing water auxiliary pump to operate. Fan control relay K26 will also supply battery voltage to engine coolant resistor, allowing voltage to pass through resistor to electric cooling fan. Engine cooling fan resistor will cause engine cooling fan to operate at low speed. When engine coolant temperature reaches 203°F (95°C), primary cooling fan temperature switch stage 1 will open, de-energizing fan control relay K26. This will turn water auxiliary pump and engine cooling fan off.

I believe the components and relays will need to be confirmed for various models.

In case it helps.

[24_Valve]

Thanks TestOmega very helpful, need to read a second time to assimilate all the information 

Does the PFL usually have a relay (K67) in space shown on my pic??? or am I missing one  :-/

[RobG]

K67 should be the fourth one from the left. Second from left is K97, should be for headlamp washers
http://www.omegaowners.com/forum/YaBB.pl?num=1176542235

[TestOmega]

Thanks TestOmega very helpful, need to read a second time to assimilate all the information 

Does the PFL usually have a relay (K67) in space shown on my pic??? or am I missing one  :-/

http://i976.photobucket.com/albums/ae249/londoner06/Omega/FanTest-1.jpg

My model relays slightly different as below,



If you have two auxiliary fans in front and a fan on the radiator as well as AC, I conjecture you may need same number of relays as me.

In case it helps.

[24_Valve]

Thanks RobG, I will take your word on it, thought second from left was for K67 as shown in this diagram (identical to my layout) http://i863.photobucket.com/albums/ab197/philrich1064/Fan_test.jpg

The OOF diagram for V6 with a/c (mine) differs from my relay box... compare with pic above 

[24_Valve]

Thanks testomega, yours is same a FL layout which 2nd diagram shown for V6 models...http://www.omegaowners.com/forum/YaBB.pl?num=1176542235  but you seem to have K67 blue relay in second space? not black headlamp washer K97 relay as shown on diagram... but you're conjecture is right I do have A/C and therefore 3x Fans... So would agree that I should have same number of relays... except I don't have headlamp washers (your'e catera should have) so that would tie in with RobG's explaination 

[TestOmega]

Thanks testomega, yours is same a FL layout which 2nd diagram shown for V6 models...http://www.omegaowners.com/forum/YaBB.pl?num=1176542235  but you seem to have K67 blue relay in second space? not black headlamp washer K97 relay as shown on diagram... but you're conjecture is right I do have A/C and therefore 3x Fans... So would agree that I should have same number of relays... except I don't have headlamp washers (your'e catera should have) so that would tie in with RobG's explaination 

I have no headlight washers