With DI engines the backside of the intake valves get deposits from the PCV system. Some engines are worse about this than others. After reading how to do it and what product to use I decided to give it a cleaning. 2014 XJR just turned 63K miles. Currently the car has no problems.

Used this stuff;




I got a 4 pack from Amazon for about $62 so it's not cheap. I am always unsure about any "miracles" in a can but it is an easy thing to do and not much downside.

Next was where to inject it and that turned out to be simple to do and I have not seen it posted before.
There is a large vacuum line right at the mouth of the intake. Remove the factory hose with the little clip at the base. Then attach some tubing. I wanted to sit in the car and rev the engine as I sprayed so got a couple of feet of tubing. Used a smaller bit of tubing to adapt down to the small straw on the spray can on the other end.





Followed the instructions about keeping the engine around 2000 rpm's while spraying this in bursts. Did not seem to make the engine stumble much so I increased the spray interval. Can took a while before it was empty. Again follow the instructions and rev the engine to 3500 rpm a couple of times after you finish the can. Then shut the engine down and let it cook for an hour (At least).

Started the engine after an hour hot soak and revved it to 3500 rpm with somewhat large clouds of smoke. Took it out on the highway for about a 20 mile hard run. Ran it in 5th and 70 mph to keep the revs up around 3000 rpm.

I was surprised but the car has a noticeable smoother idle now. Not sure but the throttle response seems crisper but that is just the ol' butt dyno speaking so maybe just me. Was expecting some check engine lights and temporary codes but the only thing I got (Which is the first time I have seen this?) was a loose gas cap warning with a yellow triangle on the dash. Not an error code! Stopped and cycled the gas cap off and on a few times got back in the car and all was well and I finished the drive.

So I think it was worth it and will start this as a regular service. Just don't know the interval? 10K miles, 20K miles? You can't over do it as it's just a cleaner. I should have used my snake camera to look at the valves before and after.
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These guys did the before and after. Not much difference. If you have ever hand-cleaned the hardened, thick goop on these valves, like I have, a spray treatment seems unlikely to help.

 

Yea I was hoping it would help.
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When I was cleaning the valves by hand, I tried a lot of different products, and the best one was a common carb spray cleaner. The CRC valve cleaner did very little to dissolve the tar-like gunk even after soaking the valves in it. I rotated the engine by hand to close the valves and made a pool of the CRC product in that intake port. Pretty disappointing.

 

In my opinion, the best method for cleaning the inlet valves is using the walnut shell blasting technique with the valves in situ.

 

That's what the dealers use. All methods that I know of have the valves in situ. I am not seeing anyone remove the valves to clean them.

If you are going to hand clean them, it's worth investing in a top creeper. One of my smarter purchases.

https://a.co/d/0lnGGJU

 

This Jaguar engine isn't know to have issues with carbon build up on the intake valves. Also i doubt this small can of cleaner can clean 16 valves without any physical contact. I have tried HHO cleaning on my 2012 50k mile supercharged v8 and didn't notice any difference and that was spraying for an hour.

 

The dealerships in my area use a BG induction cleaning system.
I've used a couple of sprays in both our AJ133, specifically the CRC and the Sea Foam off-the-shelf GDI induction cleaners.
Both of them have helped.
I've also had intake manifolds off of both and looked into/cleaned valves as needed (actually took the heads off of the Range Rovers AJ133), and they did have some amount of carbon build-up, but not a lot.
The thing is it doesn't take a lot to impact airflow into the combustion chamber - not that the heads are ported & polished, but they're good for production line work.
And they should be, it's a Jaguar.
But from what I've seen induction cleaning doesn't hurt & can help depending (especially) on how oil changes are treated, since that's a big influence on what is coming across the intake valves from the PCV flow.
But of course this is only my opinion and one person's opinion is another's snake oil.

 

Thanks for the added comments. With further driving it definitely idles smoother and I will using the other 3 cans as well in the future. I got them so might as well use them up. I do like Techron too as a gas additive and now I run that after doing some research on PEA as before I was using the BK44 product. Both seem to be good additives.
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I believe I mis-spoke before, it is the BK44 induction products that my local dealerships use.
And all X351s would do well to be as cared for as you're doing for yours - your fuel & intake system will serve you well for as many years as you ask of it.

 

Thanks and yes I am hoping the care now will help extend the life of the car.
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I did the same a couple years ago at the same time as I did "the big plastic" replacement job. I can't imagine a spray can doing much of anything to what I was up against. That gunk was thick, about the same consistency as tar-based undercoating and just about as hard to remove (Learned my lesson the hard way, I'll never take on another classic car restoration project that's been treated with that stuff). I probably spent an hour per cylinder, soaking in carb cleaner and agitating with stiff bristled bottle brushes. However, what I could imagine tho is that starting with clean valves, it you used such a spray right before each oil change, that might make a big difference in keeping them from getting so badly gunked up in the first place. Come to think of it, maybe I'll get a can and start doing that as the next oil change is due in June.

 

I let the valves soak in carb cleaner, then sucked out the carb cleaner and hit the valves with a very hot heat gun, and that helped to make the tar much easier to scrap off with wooden tools. Then I used more carb cleaner to get off any remaining residue.

 

This video shows the walnut blasting is excellent, and the BK44 induction spray is more snake oil. I am ok with the BK44 fuel tank additive for cleaning the injectors.

 

That's a pretty neat trick. Wish I'd thought of using a heat gun. Thanks. Will try that next time.

 

Please guys it's BG 44K not BK44!

 

Muy importante!

 

Sorry about that - it's been a while since.
Great post to correct & clarify!

 

Best post ever!

 

Good point and I was wrong and should have read closer!
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