What’s up fellas I have a question which I hope you guys have the answer tooooo…

so right now my 2011 Jaguar XF premium is having some issues.
i took it in recently due to water pump exploding but I had
radiator, thermostat housing, water pump replaced all of it.
ever since then I had white smoke coming from my left exhaust figure it was a blown head gasket which explained the loss of coolant. Took it to another shop did a test and they said my head gasket was holding strong. Couple weeks later I went ahead changed the old coolant to a different one (pink) and the white smoke went away but I’m still losing coolant at a fast pace.

mind you I flushed my entire coolant system myself. My car sometimes end up shaking when I start it and it goes away after a few seconds.

 

Hi. Some more details on your car (engine) would be helpful to answer your questions.
Chris

 

It’s a 5.0 V8 engine

 

Here's three things to check first before suspecting a headgasket. One is a PA66 nylon crossover tube between the two cylinder heads at the very back of the engine, very hard to get at. Another is the big nylon y-pipe at the front of the engine that goes into the block deck behind the water pump. You'll be shocked when it comes out in three pieces is how bad it often is. We've pretty much decided that those are so common that they need to be replaced as a matter of preventative maintenance at around 50K miles. And we've had a few posts about the reservoir leaking too.

 

but if that’s the case would that explain coolant lost and white smoke coming from the left exhaust? I was also getting misfire codes as well then goes away then comes back. But what does the front one do That needs to be replaced? pa66?

 

PA66 is just the specific type of hard nylon. They make all sort of things out of it from assault rifle stocks to automobile cooling systems. But it lasts a lot longer as gun parts than engine parts and we've got other threads on that topic.

You said another shop tested and told you that your head gasket was OK. They probably did a chemical test of the cooling system to detect if exhaust gases had gotten into the cooling system. And you said the smoke went away later. Changing the type of coolant or doing a flush wouldn't have changed anything if the headgasket were blown and it should still be smoking if it was leaking. That leads me to think there may be other random conditions causing exhaust smoke and maybe its not related or only indirectly related. Plus I sometimes have a hard time telling what color exhaust smoke is unless its really thick. With a misfire code, it could be running a little rich or unburnt fuel could be coming through making a light grey smoke that could look white depending on the lighting conditions. I haven't seen it so I'm trying to think positive and not have you pulling your cylinder heads just yet.

In order to minimize money wastage whenever I have a car problem, I follow the rule of investigate/test/diagnose in the order of cheapest thing to fix first and progress on to most expensive thing to fix last. The only thing you seemed sure about is that you are losing coolant and the nylon pipes and nitrile hoses around the engine are cheaper to fix than a head gasket so I'd say start there and try not to worry yourself about the worst case scenario until you've ruled out lesser expensive problems. Fingers crossed....

 

Can you check and post back any codes the car has?
Please erase everything when done so we can see what comes back and is a current valid code.

Hard to say otherwise.
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wow thank you for all the information. I’ll do more test myself before I go and take it in. But the Smoke part so before it had a sweet smell then after the flush that’s when it went away the smoke color itself was white to grayish if that makes any sense at all. Yes the other shop did do a chemical test like you mention. it was holding good for more than 10 mins. Also to make more sense of it I did do the flush I flushed it entirely. That’s what made the smoke stop now the coolant obviously was disappearing way to fast. Now I don’t see leaks so it makes me assume that it could be my thermostat but I had that replaced entirely even the housing but im not sure why I’m losing so much unless I had a blown head gasket or see any oil white stuff in my coolant reservoir cap. It’s very stressful trying to see what my options are or do it myself and solve it.

 

Is it supercharged? If so you may have air in the supercharger cooler circuit and as it bleeds off your coolant level drops as they share the same coolant.

 

No they don't circulate the coolant between the two systems. They only share the degas bottle or the top tank where the hoses go to.
Here is how the inter-coolers are plumbed. This description is from the shop manual.

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Last sentence... Enables filling and draining in the supercharger system.... Air in the system will purge, and get refilled from the coolant system and thus lower the level in the coolant tank... Had it happen in mine....

 

Have you pulled your spark plugs out to see if there's any gunk in there that shouldn't be?