DTI 2.0 Decoke?

**Thom** · 8th November 2010, 17:12

I'm looking to decoke as much of my veccy as i can whilst at uni, which means i've no jacks or significant tools, can anyone tell me what i could possibly get to without a garage and what should be cleaned after 87000 miles?

Thom

**Jonsey** · 8th November 2010, 17:23

I would start with Boost sensor and EGR valve, might not need doing but just peice of mind knowing you have at least started, there is a how2 on how to do a decoke. http://www.vectra-c.com/forum/showthread.php?t=98947 should be the same for any diesel. also there are how2's for cleaning the boost sensor and EGR Valve

I did mine (Boost &EGR) yesterday when I did a service on my 2.0 DTi

**mick.n** · 8th November 2010, 21:22

As above. Would be worthwhile doing the swirl flaps too, involves removing the inlet manifolds & its a messy job.

Did mine last weekend & still getting the carbon stuff off me fingers!

**mozzer99** · 9th November 2010, 13:49

As Mick.N says:- swirl flaps and inlet manifold

**Thom** · 10th November 2010, 14:42

Cheers lads, i'll look into waiting to do these jobs afterall as it would appear im going to need more time than i have at the moment. what do you use to remove the carbon?

I've used caustic soda on 2 stroke exhausts before, would that be wise here?

**mozzer99** · 10th November 2010, 20:04

Originally Posted by Thom

Cheers lads, i'll look into waiting to do these jobs afterall as it would appear im going to need more time than i have at the moment. what do you use to remove the carbon?

I've used caustic soda on 2 stroke exhausts before, would that be wise here?

The carbon is soft and sticky, scrapes off easily but still needs loads of degreaser or spray brake cleaner to properly clean. I'd take it to a engine shop and pay to have it cleaned/dipped in a caustic tank - it really is so filthy! Take the boost sensor off before cleaning.
Cleaning into the actual inlet ports once the manifold is off is a bit tricky as you really don't want to drop large chunks of carbon into the valves/cylinders. I use a 15mm piece of copper tube connected to (an old) vacuum to get out 80% of the muck.

**mick.n** · 10th November 2010, 20:28

@ Thom, You might fancy getting new gaskets, o ring for the egr & new lower manifold nuts (7) just in case?

I did it by the book & replaced the lot....was only around £18 from the dealers.

Back to the swirl flaps........... when i got mine stripped i found that there wasnt as much gunge as i expected to see. Some pic i have seen on the net from people who have done this job maked me wonder how any air got into the pots!

My inlet ports on the head were not too bad at all.....just needed a bit of a clean. Most of the gunge on mine was around the EGR.

Ooh, dont make the mistake i made when cracking off the injector pipes.......they are torqued up to around 30lbs ft. I cracked number 1 off while the inlet pipe to the turbo was still attached...slicing me finger down to the b****y bone on the sharp end of it!

**cont1204** · 10th November 2010, 21:13

Originally Posted by mick.n

Ooh, dont make the mistake i made when cracking off the injector pipes.......they are torqued up to around 30lbs ft. I cracked number 1 off while the inlet pipe to the turbo was still attached...slicing me finger down to the b****y bone on the sharp end of it!

Bet that was painful! How easy to remove are the injector pipes? I'm still in two minds about doing mine.

**mick.n** · 10th November 2010, 21:48

Originally Posted by cont1204

Bet that was painful! How easy to remove are the injector pipes? I'm still in two minds about doing mine.

Aye, it ****** well hurt mate! had to leave the job till the next day as i kept knocking it & getting gungy carbon into it.... a marigold glove helped though

The pipes are really tight & the leak off pipe in the way doesnt help, but if you take your time & make sure the spanner has a good bite on the pipe nut they will crack off with a bit of a "shock" sort of turning.

Just make sure you give yourself plenty of time and dont rush it.

When you remove the top rubber intercooler pipe (passenger side of engine) from the manifold, i would put a big bit of clean rag over the pipe that goes to the intercooler to stop anything falling into it............you dont want to drop anything down there!

Also be carefull not to loose anything into the inlet ports when the manifolds are off. As soon as i got the lower manifold removed (the bit with the swirl flaps) i put a clean length of cloth\rag over the intake ports in case anything dropped into that area.

EDIT, just remembered.........when cracking off the injector pipes at the injector pump end, make sure you put another 17mm spanner on the pump stem to "counter hold" it so the pump stems dont loosen. There is no need to remove the injector pipe clamps that hold the pipes together (in banks of 2)