Cleaning intake manifolds/runners/ports?

[Rich84]

Hi guys,
I had to replace my water outlet a few days ago due to a leak along the seam, which involves removing the intake y-pipe / EGR butterfly housing. Only 1x 10mm bolt holds this on to the engine and then it just pulls out with a bit of maneuvering. I noted the entrance to my intake manifolds were about 25% or more clogged with EGR gunk, which is a tar like mixture of oil and carbon build up. In fact upon removal of the y-pipe, the top most portions of the gunk promptly dislodged themselves and hung off - both about 6x6x30mm worth per intake! Car has 206K, I cleaned the MAP at 170K and noted it is now just as bad as before I cleaned it the first time!

I replaced the coolant flange, which was 5 minutes with the y-pipe removed, then set about cleaning the y-pipe, MAP and entrances to the intake manifolds.

About 1 hour, 1 full can of carb-r-clean, 1 full can of degreaser and a huge collection of absolutely black rags later, I was satisfied that I could not clean the intake manifolds any more without removing them from the vehicle (which was beyond the scope of the tools I had available). The y-pipe and MAP sensor both spotless after having to use numerous scraping instruments to assist with layer after built up layer of hard gritty crud. The MAP I cleaned with contact cleaner, not wanting to hit it with the extra strength carb-r-clean.

So, knowing that a small amount of the carby cleaner would've no doubt made it down into the intake valves, and knowing that this would be fine as I've cleaned all my PETROL vehicles in this manner for the last 15 years, I put it all back together and fired her up - quite a horrendous diesel knock for the first few seconds!! So much I turned it off and double checked nothing was stuck in the visco fan/fan belt! Turned back on. Knocked again but much softer, went away completely after about 30 seconds. The sound was reminiscent of when I once helped a mate start one of his diesel tractors with "Start-ya-bastard" (ether) although that was worse - at the time we really thought "she was gonna throw a leg outta bed!"

In order to test out my results (and test for leaks at the new water outlet) I took it for an extended drive through the Adelaide Hills. Now 5 days and about 750km later the car is running extremely well and I'm looking forward to road tripping it to FNQ next week. Fuel economy is down to 9.0L/100km - just got 930km to a tank which is a record for my normal driving run, so pretty happy with that!

What I'm wondering though is how many people have actually done the next step and cleaned the intake manifold completely and even the entire intake ports on the head? Assuming the remainder of the intake manifold, the intake runners and the intake ports (including the valves ) are just as clogged, would it be worth it to go as far as removing the heads and hot-tanking them at set intervals (168K with the belts?) or just the once for those who have blanked their EGR setup. I know it's a horrendous job, but think about your engine!

[Graeme]

I understand that the addition of some 2-stroke oil to the fuel cleans-up and keeps clean the inlet manifold but have no experience myself.

[Nicky]

.. and the car is ???

[Ean Austral]

I clean the y pipe and MAF every 20,000ks and have wondered the same thing as you about the intake manifolds. The old adage let sleeping dogs lie comes into my head every time I think about doing it.

Cheers Ean

[Rich84]

.. and the car is ???

2008 RR Sport TDV6.

Graeme, I have actually been using 2-stroke in it since about 165K and the MAP sensor has definitely clogged back up again with oily gunk. I was hoping the 2-stroke would help with that too.

In future I'll clean it at 20K intervals as per Ean Austral and monitor it a bit more closely.

[PhilipA]

I understand that the addition of some 2-stroke oil to the fuel cleans-up and keeps clean the inlet manifold but have no experience myself.

Er How?
Only air goes into the manifold: diesel into the combustion chamber.
I don't think it could make any difference to the EGR contents as that is already burned.

I did the full clean on my D2 TD5 at 140KK when I pulled off the manifold to replace the FPR. A not very nice job. I filled it with carb cleaner got my ALDI gerni on to it and promptly transferred all the gunk to my clothes , face , and hair.

The inlets and valves were pretty clean so I think most of the gunk settles before it gets to the head.
I think the only thing you can do is make sure the oil is a good spec synthetic with low ash. Maybe the dealer used crap as they do.
Regards Philip A

[Rich84]

Er How?
Only air goes into the manifold: diesel into the combustion chamber.
I don't think it could make any difference to the EGR contents as that is already burned.

I did the full clean on my D2 TD5 at 140KK when I pulled off the manifold to replace the FPR. A not very nice job. I filled it with carb cleaner got my ALDI gerni on to it and promptly transferred all the gunk to my clothes , face , and hair.

The inlets and valves were pretty clean so I think most of the gunk settles before it gets to the head.
I think the only thing you can do is make sure the oil is a good spec synthetic with low ash. Maybe the dealer used crap as they do.
Regards Philip A

Thanks Philip, I've been using Penrite Enviro+ 5w30 for the last 60,000km, it's a low SAPS oil so it's probably not an issue with engine oil.

The 2-stroke oil is in theory supposed to make the diesel burn more cleanly with less carbon to clog things like the EGR and turbo vanes, and also improve lubrication to the HPFP and injectors.

[Redback]

Thanks Philip, I've been using Penrite Enviro+ 5w30 for the last 60,000km, it's a low SAPS oil so it's probably not an issue with engine oil.

The 2-stroke oil is in theory supposed to make the diesel burn more cleanly with less carbon to clog things like the EGR and turbo vanes, and also improve lubrication to the HPFP and injectors.

All 2 stroke will do is stop your exhaust system from rusting

[Graeme]

All 2 stroke will do is stop your exhaust system from rusting

These late model LRs don't leak enough oil from the engine and gearbox to stop everything from rusting so have to find another way...

[Nicky]

What, the auto rust-protection points are gone???