I am wondering if anyone can tell me the difference between SC pump and the aux coolant pump on XF s/c. I know what they do just want to know if they function the same or is there a reason the SC pump is upside down compared to the aux coolant pump. Can i simply replace the SC pump with another aux coolant pump? They both seem to do the same..
Has anyone done this?
Cheers

 

They are both water pumps but no you can't swap one for the other.
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clubairth1..Care to explain a little. If they do the same thing whats the difference between the pumps?

 

The Aux cooling pump is used for the heating water circuit. Is smaller than the SC pump and mounted high on the radiator
The SC pump is used for the SC inter cooler water circuit. Is larger than Aux cooling pump And mounted low on the radiator.
Here's when I replaced mine on my 5.0 SC engine, it uses only the SC pump but from what I understand the 4.2 SC pump replacement is about the same.

https://www.jaguarforums.com/forum/x...pgrade-152574/

 

Bigg Will.. Thanks for that. One more thing. I understand then that the s/c pump is on constant when the car is on even without engine running but what about the aux pump is this the same do you know? Do they share the same relay?
cheers

 

That I don't know. But I would think No they don't share a relay.

 

Bill Will explained it. Sorry I was so short.

It might change depending on the car but my old 2005 S Type R ran both pumps 100%.

If the SC pump went out you knew it because the car would heat soak easy and reduce power.

If the AUX pump went out you tended to NOT have any heat at idle but usually you got heat at highway speeds. We were told that was because on the S Type the heater core is above the engine and the mechanical water pump could not push the coolant uphill very well and needed the additional boost from the AUX pump.

In fact on the S Type the coolant bleeder was a hose with a valve that was mounted up high by the master cylinder so you could get the air bubbles out of the heater core. Even then we have many posts of people thinking the car is overheating when you just have not bled all the air out. It can be a job sometimes!
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Clubairth1..Thanks for that it makes sense. Can you tell me where that upper bleeder valve was. maybe there is one on these cars. The one by the radiator is easy to get to perhaps there is one up higher too?
BTW i have ran the car in Sport mode with the aux pump switched off and the vents not in use. She drives great. Wish i had done that before. Anyhow i am fixing the wiring for aux pump and all should be back to normal..
cheers

 

Sorry again!
BIGG WILL!
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Since the XF is pretty much the same as the S Type with a new outer shell I think you might be right BUT I have never worked on an XF so not sure?

Here is where it's at on the S-Type.



Post back if you can?
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I'll go check that out right now.

 

They have been known to be hard to find to!
Slips back behind the M/C stuff.
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