I have a 2011 XF SC that's blowing smoke from the vents until warmed up, it has a burning coolant smell but im not losing very much. I'm also getting small amount if smoke from back of engine until driven and warmed up fully. Could this be the heater core? I've already had the dealership replace the water pump and cross over pipes. And they said the head gaskets were fine. What could it be?

 

After a cold soak, preferably overnight, use a cooling system pressure tester to pressurise the system to 1 bar and check for leaks.

 

I have tried that and did not notice any leaks, and I noticed the smell is more burning rubber rather than coolant.

 

A leaking heater core will steam up your windscreen in my experience and warm coolant has a distinctive smell. There is an electric auxilliary heater on some models (mine does not have it, Australia isn't cold enough), assuming your car has the aux heater you could try disconnecting it as in this thread
https://www.jaguarforums.com/forum/x...-issue-254980/ post #7
see if the burning rubber smell disappears with the heater element not powered.

 

I have noticed that if I dont have the heat on theres no smoke or smell from the vents, but it still comes from under the hood.

 

If you're losing some coolant and you have smoke (probably more accurately steam), you have a leak. Retest with the pressure tester. Common failure points are the water pump (either from the pump itself, or from the platic tube that goes into the back of it), or the rear crossover pipe, which is a pain to get to (requires supercharger removal).

 

I have replaced both crossover pipes, the water pump and all misc coolant pipes that were the crap plastic and pressure tested with no leaks so im Fairly positive it's not leaking. When i say losing alittle, in 5 months I've only gone from high to low on the coolant tank. No coolant smell from exhaust either and no excessive exhaust smoke. Smells like burning rubber and the smoke is coming from back of engine, and through the vents when the heat is on.

 

You have done the rear water manifold? That's a bit unusual as the dealers seem to forget that one.
Do you know what part number water pump was installed?
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I have, I had them replace both, and all the brittle crap plastic, the water pump number is AJ813909, is this the wrong one? Why would that produce a burning rubber smell and smoke through the vents?

 

Can't help with the smell but you do have the latest and greatest version of the water pump.
Also glad to hear the other plastic stuff was replaced too.

I know it's been a long time since the repair but it always seems to me that I can smell hot coolant in the engine compartment on my car and I am not losing a drop of coolant!
Any chance that there still are some puddles of coolant down in the engine somewhere? Maybe worth a gentle hose down to flush it away?

I did not see where it had been replaced but maybe a micro crack in the top coolant tank? Just guessing here.
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Maybe this old thread can help you..https://www.jaguarforums.com/forum/s...l-cabin-49768/

Not sure but it has some tips.. good luck