Cooling fans.

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moomoo
Donor 2020
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Cooling fans.

Post by moomoo »

Hello all again,
I'm steadily rectifying all the teething problems after fitting a low mileage 1.9td into my van. No more black smoke and sounding bang on!
The problem i have now is that the cooling fans mounted on the radiator are not kicking in when the engine creeps above 90 centigrade...
The fans are actually working fine ...ive tried them directly from the battery by disconnecting the terminal sockets.
There are two sensors housed near the thermostat housing..(3 actually but one is blanked off)....
The blank and the blue sensor are side by side at the front and there's a green one at the back.....i believe this one is for the fans on the radiator....it has only one terminal inside when you lift off the connector.
Ive run the engine up to temperature whilst its been parked up but it doesn't quite reach 90c....and it stays that way....however if i drive it up a hill for instance the temperature begins to rise above 90...and its a bit worrying.
When i took the connector off the fan sensor i shorted the two wires that feed the sensor...i noticed a clicking sound but the fans still didnt start up.
The fuse for the fans is a 30A and thats ok too.
Once again I'm at a loss.
I have a multimeter ....does anyone know how to test the sensor to make sure it's working properly?.....
Thanks

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white exec
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Re: Cooling fans.

Post by white exec »

Can you give us some more info about the exact engine? - or even its engine type/number from the small plate on the block.

The XUD engines can have up to three coolant sensors, usually colour coded Green, Blue and Brown.
Depending on whether the engine has an injection ECU (or just a mechanical injection pump), and some other control parts, there may be only two temp sensors.

Twin fan speed are usually controlled by a bank of three relays.
These get the signals to go Slow (fans in series) or Fast (fans in parallel) EITHER direct from a double-temperature-sensing sensor, OR (on ECU vehicles) from the injection ECU.
Most likely mechanical injection, but need to be sure.

So, several possible scenarios.

Can you post some more details of the engine and what is around it.
Include a photo of the water outlet/thermostat housing, where the temp sensors are.
Confirm the type of injection pump on the car.
Is there a bank of 3 relays close together, operating the fans?

Sorry to have to ask all this, simply because it is an engine transplant.

moomoo
Donor 2020
Posts: 29
Joined: 15 Dec 2020, 18:11
x 8

Re: Cooling fans.

Post by moomoo »

Hello again,
The engine number is 6001644 (1.9TD ).....I think its XUD. It's from a (2002) Peugeot Boxer it's exactly the same as the 1998 engine that I took out.
It's a mechanical injector pump I think.
The thermostat housing has only two connections....one is blanked off with the red plug.[img]
I don't know where I'd find the relays unless theyre housed in the box attached to the radiator...you can see it in the image directly in front of the dipstick with the large wiring going in.
When I shorted the connector on the green plug to the sensor I could hear a clicking sound but I don't know where it was coming from...maybe the relay/s are damaged?
Hope this helps!
Thanks
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white exec
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Re: Cooling fans.

Post by white exec »

What is in the black box close to the yellow dipstick top?
How many wires are there at the blue and green sensors?
What is under the red cap - a sensor or a blanking bolt?

Can you also post a photo or two of the complete engine bay (not closeups), and one of the fuel injection pump?

Thanks.