Question about 1998 Jaguar XJ8L

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1998 xj8 heater only works when engine at higher revs

I have a xj8 that the heater only blows heat when you are driving the engine under load.....when you stop at lights or junction etc the air blows cold...pull away and its hot again...any suggestions....could it be air locked or auxillary pump?????also drivers check strap broke is this an easy job cheers

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  • Jason coombes Feb 26, 2009

    hi checked coolant level but thats fine

    i checked the pump and both hoses are warm/hot

    i checked the heater valve when engine at temp 3 hoses were hot and one (the top nearest bulkhead )was still this it.....or do i need to look further


    again jason

  • Jason coombes Feb 27, 2009


    i dont suppose you remember what fuse and rating it was i do have a blown 25a fuse in the rear right heel board but i think that is number14 and protects the cigar lighter......i think????

    would i be correct in thinking if the pump was not working one of the hoses would be running cooler than the other?

    thanks for you time

  • Jason coombes Feb 28, 2009

    hi guys

    it was fuse 3 10amp in the front fuse box it also controls the fog lights

    if you have the same problem as this then this could be your solution.....i belive the problem is the alarm sounder on this circuit (front of engine bay between rad and engine) this gets full of water and shorts it all out.....just disconnect it.....get a new one or leave it off i think the horn will still sound...

    i just changed fuse and its all working like new...cheers for all your help

    jason fixya indeed



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There is an Electic Water Pump for the Heater that is located under the hood near the left fenderwell. If it's not a fuse, then likely, this pump is bad. Mine went bad in my 1999 Jaguar XJR. It runs close to $400 for the pump, so hopefully that's not the problem. Price does not include labor.

Since I'm comfortable with Electronics, I replaced the brushes in my motor and it works fine now. Heat all the time and only cost $1.00 You may be able to find a shop to rebuild the motor for you at a fraction of the cost.

Posted on Mar 28, 2009

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Just had same problem with car in workshop found fuse to pump blown

Posted on Feb 27, 2009

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The heat issue is likely to be a low coolant level (hopefully) issue.

Posted on Feb 25, 2009

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