Intake valve carbon build up on my 2011 N/A 5.0 XJ with 88,000 miles. This engine does not have a rough idle. Fyi. Not too bad. I only use Jaguar oil

 

I wonder how mine looks on my SC XJL, I'm at 45k

 

You should be fine. I also change my oil every 7500 miles

 

Cooked oil on the back of the intake valves normally spells a valve stem seal leak.
Not at a critical point yet looking at the photo.
You will know when they need changing because you will get a puff of blue smoke out the pipes on start up when the car sits overnight or for a few days, then clears within a minute or so.

 

Not even close.

That is from DI (Direct Injection) NOT from anything being wrong with the engine. Completely normal and really does not look bad at all.

We need to understand the basic problem. That is with direct injection the fuel is ONLY injected into the cylinder. So all the crap from the PCV system is deposited in the intake system all the way to the back side of the intake valves. Which is what that picture is showing.

This is a MAJOR problem with Audi's and other brands of cars.. Some need to be cleaned regularly and I have seen over 100HP loss of power because of the carbon build up. We are lucky because so far Jaguar engines that use DI don't seem to have a lot of problems. Just be aware there have been several case's on the 5.0L that have carboned up in a big way. Don't know why as I think the engines are the same but Land Rover 5.0L's are worse.

Be aware that cleaning can be as simple as sucking some solvent into the engine and letting it work to taking the top half of the engine apart so you can walnut shell blast the carbon deposits away. As you can guess taking the engine apart and blasting parts is not going to be cheap!

As I have posted before on boosted American Performance cars (Turbo or mechanical super charger) it is extremely common to install PCV catch cans to prevent the oil getting into the intake.

There is also many running Methanol injection (Corn). This keeps the intake spotlessly clean as well as lowing your intake air temperature which is critical in a boosted engine.
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I also had the dealer do the BG cleaning service 4000 miles ago. I don't think it helped much with the Jag or my wallet!!!

 

Interesting because that is recommended to clean the carbon. But I have never heard anyone report back if it really did anything or not?

You can't see anything so unless the car drives different how would you tell?
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Where does Jag make such a recommendation?

 

Well that's a good point because Jag does not have any procedure that I can find?
Not sure they even admit that carbon buildup happens.

It's a large problem that has a lot of dollars involved if it turns out to be a warranty item. So I think they are a bit shy about releasing any info.

The BK products have a good reputation but that could be due to advertising it to commercial shops to increase revenue too.
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Has anyone tried CRC GDI Intake Valve Cleaner? There are tons of good reports from other brands and forums. Not much verifiable proof though. The procedure seems similar to the Jag recommended BG cleaning, except no need for any specialized equipment.

 

Because look at the first post photo. That is my car with 2000 miles after the BG treatment from the dealer. We had to remove the intake manifold to replace the rear crossover coolant pipe.

 

As clubairth1 says it is a DI issue. Since fuel is injected into the engine below the intake valves it does not "clean" the valves.

So putting any "cleaner" into the fuel system will not work on cleaning the valves.

Earlier Audi DI engines were estimated to lose 30-40% of available HP after only 30-40K miles.

I did a lot of research on this before buying a Range Rover Sport with a DI 5.0 engine and I have not seen any truly effective way of decarbonizing the hard carbon on the intake valves other than a physical attack method such as walnut grains.

I am considering installing a water/meth system on the Rover similar to what I have on my non DI Jaguar.

 

I would question whether or not they actually did the cleaning service.

 

All I see is 1 picture?
Do you have a picture before the treatment was done?

I don't know how effective these intake cleaners are?
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If you do a google search you'll see they can be fairly effective, depending on the amount of buildup. They most likely won't get the valves spotless but the combination of cleaner, engine heat, and air pressure does seem to make an impact.

Walnut blasting is the most labor-intensive but it will have the best results.

 

hi so thank you for all replies

 

So is the majority of the build up due to the PCV system? Make sense I guess because the fuel isn't cleaning it off the valves I get the theory behind the oil catch can before it goes into the intake. Is that effective? How bad would it be to not put the PCV fumes back into the intake? Couldn't someone make a contraption that sends it into an external filter assembly and not dump it back into the intake at all. Yeah, I know.....yeah, emissions ***** will loose their minds. And also it could possibly be very messy. But is it doable in theory?

I guess not because the vacuum in the intake is what pulls the air through the system.

I guess we are back to the oil catch. Are they effective? Who sells them?

 

Oil catch cans can be "effective" in that they do catch oil if they have a good baffle system.

The question is what % of the oil do they catch?

I have one on my 2005 XJR which obviously is not DI and it certainly catches oil.

I do not have one yet on my 2013 DI Rover but am seriously considering it. The Rover has plenty of power and no running issues, at the moment with 83,000 miles.

I bought my oil catch can on Ebay where there are lots to choose from. Avoid the cheap ones they are cheap for a reason.

 

The catch cans are still plumbed into the intake of the engine. So your emissions are still being consumed inside the engine.
What the difference is the liquid oil is trapped out in a container that we need to manually empty. I guess the ultimate would be to have this catch can drain routed into the oil pan so you would not need to empty it?

I think the reason the factory does NOT add a catch can is it requires increased maintenance and we can't even get people to check their oil level or tire pressure!
Also the PCV systems can get complex depending on the engine. I come from the Ford SHO/MKS cars. These need a model designed to fit the factory hoses and other things, it's also DI but a twin turbo engine.

So for us Jaguar guys it's like the meth injection stuff. No direct bolt on kit but you could manage to install one with some effort and customization.
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It might be telling to hook up two catch cans in series. If the second can catches the same amount of oil you could conclude the catch cans don't do much good. If the second can catches nearly nothing then you know the first can is effective.

The best solution for the DI guys is to dump it to the atmosphere. Not sure what effect that would have on running conditions in the engine and it would break many emissions laws but it would eliminate the problem