Right so I've just got my father's CD manual back on the road after finally solving a hesitation problem that it's had for the best part of 2 years (long story short, it was a faulty fuel pump).
Anyway, just as it was on its way back from the garage after passing it's MOT, the radiator fan packed up!
After trawling the internet trying to find the right part, I managed to source a new fan.
Fitted it, and hey presto! Working fan.
Only one problem, once it comes on, it doesn't turn off.
I thought it might be the fan switch so I changed it for a new one but it made no difference.
Today I've done some testing to see exactly what's happening.
I plugged in the tech1 so I could constantly measure the coolant temperature and ran the engine until the fan kicked in.
It came on at 108 degrees, after a few minuets it had cooled down all the way to 89 degrees and there it sat at a constant temperature, fan at full blast for a good 10 minuets until I turned the engine off.
I thought I'd do a control experiment so I did the same thing on the CD auto (this is a no cat 20NE but it's mostly the same engine).
It must be said that this engine took allot longer to get hot. It got up to around 90 degrees quickly but it took some encouragement to get much hotter.
Eventually the fan turned on at 109 degrees, stayed on for about one minuet and turned off once the engine was down to 100 degrees.
The CD manual has always been a pretty hot running engine. It always got up to temperature faster than my other two (C)20NE equipped Cavs and the fan came on allot more.
I did try and eliminate the problem a few years ago by completely replacing the coolant system; I changed both temperature sensors, fitted a new radiator, fitted a new thermostat, had the water pump replaced, fitted a new fan switch and replaced the coolant and flushed the system several times.
None of this made any difference.
In the end I give up trying to solve the issue and just accepted that this is a hot running engine.
I've thought that it could be a few things, like a lean air/fuel ratio or a blown head gasket.
However I've done a sniffer test and it indicates that the head gasket is fine.
Not 100% about the air/fuel ratio but there is nothing odd about the smell of exhaust gasses or anything coming up as odd on the tech1.
Does anyone have any ideas?
Radiator fan won't turn off
Moderator: Robsey
- James McGrath
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Re: Radiator fan won't turn off
Is there a relay that controls the fan?
Just wondering if the relay kicks in correctly, but then sticks in the on position once triggered.
Just wondering if the relay kicks in correctly, but then sticks in the on position once triggered.
- James McGrath
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- Joined: Tue Aug 11, 2009 11:35 am
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Re: Radiator fan won't turn off
I don't think so.
I've not got the extra fuse box in the engine compartment on this car so if it does have one I'm not sure where it would be.
I've not got the extra fuse box in the engine compartment on this car so if it does have one I'm not sure where it would be.
Re: Radiator fan won't turn off
Just had a look in the Haynes manual, it shows the fan is supplied with a live from ign switch then the rad switch pulls it directly to earth, no relay in the circuit.
Don't see how the fan can run if the rad switch has opened?
Are you sure it's opening once down to temperature?
Alan
Don't see how the fan can run if the rad switch has opened?
Are you sure it's opening once down to temperature?
Alan
- Envoy CDX
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Re: Radiator fan won't turn off
If it does have the relay it will be a ceramic type that bolts to the radiator.
Is the wiring to the fan the same on the new fan as the old one (I recall 2 and 3 pin fan headers).
Is the wiring to the fan the same on the new fan as the old one (I recall 2 and 3 pin fan headers).
- James McGrath
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Re: Radiator fan won't turn off
Yeah it's the same two pin type.Envoy CDX wrote:Is the wiring to the fan the same on the new fan as the old one (I recall 2 and 3 pin fan headers).
It's exactly the same part actually, same GM part number.