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Discussion Starter #1
So, my manifold (1.6hdi) was leaking oil all down the back of the engine. I took it off and cleaned a crapload of crap out of it, and a lot from head too. The airflow was quite restricted going into the head. I couldn't\didn't get all of the crud from the inside (lower down in the head), I wasn't sure how much crap was acceptable to fall down inside, so I kind of wussed out.

The car is running much better now, but I'm still thinking of cleaning out the rest of the head. I was getting ~20km\l (47mpg) before, now it looks like 25km\l (58mpg) give or take, and more power. So..

Is it ok to let bits of carbon\goop fall down inside when cleaning? If so, how much? I'd assume big chunks are a no-no?

Is there an easier way of cleaning all the crap out? Water? Some kind of recommended spray?

Is the carbon build up in the manifold, and in the cylinder head, a sign that there's more crap down inside the engine?

All the levers, and cranks, etc, under the rocker cover look spotless, so I assume the whole engine isn't totally bunged up. 'Seems' to be just around the intake.. I assume gunk from the egr and turbo oil mixing.

Is it common for just the manifold and head to be clogged, but the rest of the engine ok?
 

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The build up in the intake system is entirely due to the EGR system. In older cars with non-direct injection system, it would be partially cleaned out by the injectors spraying fuel into the intake manifold. With the modern direct injection, this does not happen anymore so the intake gradually blocks up with sticky oily crud generated by the exhaust gases/crankcase ventilation system.

Cleaning is possible via different commercial methods, one being walnut blasting, but difficult to find reputable people to do it, and is normally not cheap.

You can get the bulk of the crud out by removing the intake manifold and simply soaking it in a strong degreaser then spraying it with a high pressure cleaner.

The intake system in the head is more tricky, but you can also do it yourself if you are careful. Obviously you need to remove the manifold to expose the inlet tracts in the head. Then you need to do only one port system at a time. You have to ensure that you rotate the motor so that the port being tackled as the intake valves in the closed position, i.e. cylinder on TDC/firing stroke. You can then spray a degreaser into the ports and leave it to soak for a while to loosen off the gunge caking the valves and port. Reapply degreaser as necessary. Then you blow the bulk of the loosened gunge out either with air, pressurised water/paraffin/degreaser using an air line/paraffin gun/pressure washer/whatever you can fit into the area you have to work with to get a spray directly into the port you are trying to clean. Carry on/repeat with cleaning it until you have a clean/ish port [how clean is up to you]. Then move onto the next port, again making sure the particular cylinder is on TDC/firing. Once finished, replace the intake manifold and enjoy the now sweet running, more fuel efficient and powerful motor!

A small amount of crud will inevitably find it's way into the cylinder, but it is mostly made up of oily gunge, so will have little effect as it blows out of the exhaust. The more thorough you are in blowing the ports clean after applying the degreaser, the less crud will get into the cylinders... all up to your effort.

When you are finished, do yourself a favour and blank off the EGR system to prevent further inevitable blocking/bad running/more pollution.... the EGR system is a good thing in theory, but quickly becomes a burden as it blocks up and then generates more pollution because of the blocked/ineffective intake system than would be generated if there was no EGR system. ;)
 

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Discussion Starter #3
Nice one!
A few question though.. The inside of the engine is one of the few things I'm not too familiar with, except for the concepts. It's one of the few things I haven't taken apart yet (I've done a LOT of "jobs" in the last year!)

How do you know when the valves are closed, can you see them? I didn't take much notice the last time, had my fingers well down inside the ports!

How do you turn the motor, just rotate the crank?

Are the valves far down inside, would I get away without an air compressor? I've got a mini car vacuum with a long flexible nozzle, that'd probably get down into the port alright.

When I did the initial cleaning yesterday I found that a little clean engine oil softens up the crud nicely.. It turns it into a goo so it doesn't just flake away and fall straight down. Worked wonders too around where the O-rings were too.

Yea, my EGR is blanked off alright, from the previous owner, probably not soon enough though. It would be nice to get a little "umbrella" tool that you can stick down into the port and let all the crap fall into it, don't know if there's such a thing. Might have to go to a fancy bar and steal a few.. :)
 

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You can normally see the valves if you remove the intake manifold but best way to ensure the particular piston is at TDC and firing is to remove the rocker cover and rotate the motor at the crank till the intake lobes are pointing up.

You can use vacuum to suck the gunge out, wont be as effective as air as you will struggle to get in behind the valve stem unless you can make up a small suction pipe to get in behind.. Probably best here would be to loosen the muck with degreaser then flush with a fine jet of water which will get in all around the valve and tend to wash the muck out of the port as oily residue tends to float on water, and then, once it looks clean, suck the remaining water out with the vacuum.

You can make your own air blower if you get an adaptor to fit onto a tyre valve stem which depresses the valve, [or even remove the valve]. Pipe and air gun attached to the inflated tyre and you have a mini blower..
 

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Discussion Starter #5
Some good ideas there!
It opens up a lot of options when you realise you can close off the valves. I can reverse my normal house hoover to a blower, and it can suck liquid too, so I should be able to duct-tape some tubes together alright I'd say.

The rocker cover has to come off anyway so that's grand. I did temporarily put it back on the last time, while I was cleaning the rest though.

Thanks for the info, I'll probably give it another shot over the weekend, it'll be interesting to see what, if any, crap built up over the week, it'll probably be a good indication if I need to get new o-rings too. Impossible to tell the last time, but the rings themselves seemed fine.
 

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Did my 407 a while ago, ports and MAF were really gummed up. Took me a whole day to get the ports/MAF/intake manifold clean. Performance/running/consumption was in a different league afterwards and still great as EGR is blanked off. MAF still spotless inside.

Port on head


MAF
 

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I'm looking at doing this on my 2.7 hdi, but it looks like a royal pita on this engine :( Has loads of baked on oily crud in the intake just like yours.
 

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Discussion Starter #8
I inspected my maf shortly after I got the car, last year, and it was pretty clean, maybe a bit oily but more like fresh oil. Possible the previous owner cleaned it. All the rest of the air system was pretty clean too.. up until the manifold ( the egr hole really I suppose!)

My Ports were pretty much the same as these though. I just remembered last night that I have a domestic steam cleaner that has lots of attachments. I wonder if I could be totally lazy and stick it in the egr opening and blast it while the car is running?
Isn't that basically how those carbon cleaning machines work? I think they have some other chemical too though, hydrogen peroxide or something.
 

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Discussion Starter #9
I'm looking at doing this on my 2.7 hdi, but it looks like a royal pita on this engine :( Has loads of baked on oily crud in the intake just like yours.
Just had a look at the 2.7 engine online there. Looks like a serious piece of machinery alright.. I don't envy you! Well, I do envy you for owning it.. but not for the cleaning job!
 
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