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-   -   Jaguar intake valve carbon build up (https://www.jaguarforums.com/forum/xj-x351-53/jaguar-intake-valve-carbon-build-up-188414/)

Polyesterpig 08-30-2017 07:07 PM

Jaguar intake valve carbon build up
 
1 Attachment(s)
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

Mr.Dapper 08-31-2017 12:01 AM

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

Polyesterpig 08-31-2017 01:56 PM

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

stevep10 08-31-2017 05:19 PM

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.

clubairth1 09-02-2017 09:44 AM

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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Polyesterpig 09-03-2017 01:39 AM

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!!!

clubairth1 09-03-2017 09:54 AM

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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Mikey 09-03-2017 10:09 AM

Quote:

Originally Posted by clubairth1 (Post 1753101)
Interesting because that is recommended to clean the carbon.
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Where does Jag make such a recommendation?

clubairth1 09-03-2017 10:18 AM

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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XJ8JR 02-13-2018 02:43 PM

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.

Polyesterpig 02-14-2018 09:25 AM

Quote:

Originally Posted by clubairth1 (Post 1753101)
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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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.

jackra_1 02-14-2018 09:45 AM

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.

XJ8JR 02-14-2018 12:25 PM

Quote:

Originally Posted by Polyesterpig (Post 1842303)
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.

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

clubairth1 02-14-2018 12:43 PM

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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XJ8JR 02-14-2018 12:55 PM

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.

hichamaziz 02-17-2018 12:32 PM

hi so thank you for all replies


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