How-to Guide: ZD30 Air Intake Manifold Removal

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ShortyNavros

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How-to Guide: ZD30 Air Intake Manifold Removal

I by no means declare this how-to the proper way of cleaning your air intake manifold and if you decide to follow these instructions you do so at your own risk, but I have done it this way and my Nav is still working.

Okay, originally when I was looking at doing this I was trying to find info; I found some stuff on the patrol forums.
http://www.nissanpatrol.com.au/forums/showthread.php?21954
this and
http://www.nissanpatrol.com.au/forums/showthread.php?13144

This is my original thread: http://www.navara.asia/showthread.php?t=25369

I wanted to do this because when I blocked my EGR I saw all the crap which was in my throttle body y-pipe section and I wanted to make sure the manifold wasn’t the same. Albeit the manifold was no where near as bad as what I was thinking it was going to be, however my Nav only has 115000kms and has had a catch can and EGR block since 110000kms.

I don’t think I have really gained any performance or fuel savings from this as in my situation the intake build up from soot/oil was minimal. But others with lots of build up may find their Nav feels amazing to drive after.

The workshop manual is very vague on the removal process so hopefully this can help a few people. When I was first looking at this I almost got scared off by other people saying they had done it and it was not a job for beginners. I am by no means hopeless with a spanner but I wouldn’t call myself an expert, I have no trade qualifications as I am actually a university graduate and work in the health field. This job can be done with basic tools and know how; the main pain this job presents is the time it takes. If doing it for the first time, probably allow at least 5-6 hours.

Tools Needed (from what I can remember):
• Needle Nose Pliers (to undo the clips securing electrical looms and plugs)
• Socket Wrench (I used ½ inch drive)
• Socket Extensions (I think I used 125mm) and one of the uni-joint flexible extensions is probably handy to get in tight spots, this is my socket set I have for reference: http://repcoequipment.businesscatal...rchID=27763566&ObjectID=5626070&ObjectType=27
• Breaker Bar (I used a long ½ inch drive one)
• Standard sockets (8,10,12 and 14mm)
• Standard spanners (8,10,12,14, 17 and 19mm)
• Gasket Goo (not essential)
• Degreaser with Plenty of Rags
• Replacement Intake Manifold Gasket (Not needed, as the one in there is one of those aluminium jobbies which you can just put back on if you are cheap bastard like me haha)
• Extra cranking power (spare battery or a mates car) with jumper leads.

1. Okay first things first You should really take pictures of your engine before you start, so you can work out where everything is if you get stuck trying to put it back together.

2. You need to remove all the wiring harness crap sitting above your intake manifold. This is basically all held by a single bracket which is held in by three 12mm bolts. This wiring harness is the one which has all your solenoid for your swirl control and EGR plus all the vacuum lines. Also there are four grounding points located on the edge of the front of the manifold which are also secured by 12mm bolts so remove that as well. To remove all the wiring looms and plugs, disconnect them and then unclip them from the bracket, use your pliers to compress the backs of the little securing pegs which allows you to wiggle them so they pop off. Also remove those vac lines so you can take the whole bracket off.

3. Remove the y-pipe intake from above your crankcase, you’ll have to pop off the vacuum lines from the EGR valve and Swirl valve controls either side of the y-pipe. Then the easiest way to remove this part is to loosen the clamp on the silicon hose closest to the turbo and then undo the 3x12mm bolts holding the y-pipe to the intake manifold and lift the entire thing out as one long L-shaped piece.

4. Also once you have freed all that wiring up you should be able to just push it out the way so it sits near the back of the engine. There is a clip at the rear of the manifold holding the bulk of the wiring, just undo the 12mm bolt holding that is so you can push all the wiring back to where those two silicon hoses are at the rear of the engine.

5. Remove the oil dipstick, it’s held in by one small bracket with a 12mm bolt, once the bolt is out you can just wiggle it round till it comes out, as it isn’t secured at the bottom in the sump, it just sits in there with a o-washer at the far end. Take note of where this hole in the sump is, so you can put it back in when the time comes.

6. Ok now you need to remove the EGR volume control unit and EGR pipe which connects to the intake manifold (As a note most of the bolts here are pretty tight if they have never been moved and a breaker bar will be useful here). This for me was probably the hardest bit because I went about it the wrong way. What I would do is first remove the bolts (2x12mm) securing the EGR tube to the manifold (this is the place most people place their EGR blanking plate) and then leave the bottom bolts (2x14mm) which are a pain in the ass to get to at the bottom.

The bolts on the bottom face forward to the front of the car and its virtually impossible to get a socket in the bottom bolt because the fuel pump is there and I think I ended up getting mine out with a 14mm spanner for the bottom and a 14mm socket for the top bolt, you’ll see there isn’t much room to use a spanner on the bottom bolt due to the proximity to fuel lines/other shite there. Plus if that bolt has never been moved and it’s stuck in there nice and tight, unless you have hands made of steel its going to be hard to budge it with a little 14mm spanner.

So I would say to make it easier leave those bottom bolts connected to the EGR volume control and just undo the bolts on the EGR tube (2x14mm) coming from the exhaust manifold round the back of the engine. This will allow you to pull out the EGR volume control unit with the intake manifold EGR tube connected to it. Also you will have to undo 1x12mm bolt holding the EGR volume control onto a support bracket, once that’s off the volume control unit should just be hanging there connected via two coolant hoses.

Now here is a trick I thought of, instead of draining the block and all your coolant before you start this, you can just unplug the two hoses from the control unit and block the one hose up which will leak coolant once removed from the control unit. The hose with the coolant coming from it when you disconnect it will be the one which runs into the engine block, whereas the other hose is connected to a fixed metal pipe leading round the back of the engine. Now to block up this hose which is leaking coolant all over your engine bay, just use that 12mm bolt which came out of the bracket you just undid to remove the EGR volume control to plug up the end of the coolant hose as it is almost a perfect fit for the internal diameter of the hose, once you use your pliers to move that little spring clamp back over the end of the screw to secure it, it SHOULD stop leaking coolant everywhere. Failing that you could use some sort of adhesive tape to seal up the end as well. Just make sure when re-assemble everything that you run the engine for a bit to bleed the cooling system of air and then refill the lost fluid as inevitably you’ll lose some on the ground.

7. There is a small y-shaped bracket beneath the front of the intake manifold which is secured by 2x12mm bolts and just provides a point to clip in two holders for a wire which runs past it, it is virtually useless and you hardly need to re-install it as it serves no real purpose other than to support a single wire which can just dangle there if you like. Also there will be a vacuum line coming up through the front part of the manifold, you can just pull this off and remove it to give you clearer access.
 

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8. Okay now you have to remove the injection pipes, this is the part which everyone said is hard but it honestly isn’t. There are two small clamps holding the injection pipes in place; one in the middle holding all 4 pipes and then one at the front holding just the two most forward pipes. Each has one or two 10mm bolts clamping two pieces of metal and rubber inserts. Again these seem hardly necessary and if you are strapped for time you could just throw these away on re-installation as well.

Now this is a good time to take a pic of how the injection pipes look before you dismantle them. I removed them in the order of top to bottom, back to front as if you are looking straight onto the right hand side of the motor where you have been working. This is the logical way to remove them as there isn’t much space and this means you get the most space to work on each tube at one time. The bottom nuts are 19mm I think, while the top nuts which connect to the crankcase are 17mm, use open ended spanners to undo these, they shouldn’t be too tight so be gentle with them. I then laid them out on some clean towel in the order I removed the so I could install them in the reverse process when I was done.

9. Okay now there should be virtually nothing between you and the manifold bolts (12mm). The furthest nut to the front will be obstructed by a metal vacuum pipe, just undo the bolt holding the bracket for that pipe so you can easily push it to one side to get that front manifold nut off. Also the most rear nut will be obstructed by that metal coolant pipe travelling round the back of the engine, just loosen the 12mm bolt holding the bracket in so you can just push it aside when you need to remove that rear manifold nut. There is a diagram in the workshop manual on which order to loosen them, from memory you start at the back and then alternate to the front and so forth till you get to the last bolt in the middle, mine were pretty tight so I used the breaker bar to loosen most of them, you may need a uni joint extension to get to some of the tighter ones. Also the very front and back fitting points of the manifold are secured by nuts not bolts, these screw onto threads which are captive in the engine block itself. Once you get all the bolts/nuts off you are able to just lift the manifold off the gasket should be sitting there next to the engine block hanging from the furthest forward and backward threads.

10. Now you just have to clean the bastard. I used my blanking plate to block the EGR port on the manifold and up ended the entire thing so I could fill it full of degreaser, you might want to re-attach that y-pipe you removed earlier so you can let that soak in the degreaser as well. Let it sit and stew for a good while as the stuff is tough to remove. Having some sort of metal/wire brush on a stick to shove down the intake and exhaust ports is also helpful. I made the mistake of just using an old sock and shoving it down with my hands to clean it and I cut my hands to pieces on the engine manifold surface, as it is pretty sharp haha. I also then used a sock soaked in degreaser and cleaned the intake ports on the engine block and used a screwdriver to shove it down far enough to remove most of the gunk in there as well.

11. Okay now you can re-assemble everything in the reverse order, I used some gasket goo between the gasket and engine block to hold it there. Also don’t force your injection pipes, they only fit one way, also don’t do the nuts on each end up too tight, there is virtually no give in them, you can screw them on all the way with your fingers then you can only tighten them a fraction with a spanner, you wouldn’t even get 1/5th of a full revolution to tighten them.

12. Once everything is all back in place you’ll realise that because you have removed the injection pipes you’ll need to prime them with fuel again. To do this you just need to use the primer on the fuel filter, this is where you may need the extra cracking power of another battery with a set of jumper cables. Prime the fuel filter as much as possible before you crank the engine. Get someone else to crack the engine over while you simultaneously continue to prime the fuel filter. This took about 15-20 seconds of cranking while I was pumping the shit out of the filter, probably got a good 10-12 pumps in and it finally spluttered to life, keep pumping till the revs are right up and stable cos if you stop the engine will probably stall out.

And remember: Run your engine for a while with the radiator cap off to bleed out that little bit of air out which you introduced when you removed the EGR volume control unit/cooler and top up if the coolant if it gets a little low.

As a disclaimer all the bolt/nut sizes I am quoting may be incorrect as I am doing this how-to all from memory as I did this about 4 days ago now.

Cheers,
Shorty
 

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Sorry had to do it in two posts as it was too long. Here are also some pics of my intake manifold while it was still attached so you can see the vegemite carbon/oil build up
 

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Great write up mate. Thanks for taking the time to tell us about your experience. I will give it crack when have some spare time!
 
As a note guys, there are little gaskets on both the EGR pipes entering and exiting the EGR control unit and a gasket on the throttle body air intake pipe attaching to the air intake manifold. So when disassembling, don't lose these! I didn't use any gasket goo on them I just put them back in and tightened all the bolts back up.
 
I am not sure mate, I am assuming the swirl valve is the main valve before the pipe splits in two to create the y-section where the EGR valve is? When I pulled the y-pipe off the intake manifold it is exactly how it appears in the pictures, ie open.
 
Yeah mate sorry I was talking about the other butterfly, but both appear as if they are open, and thats how it looked when I pulled them off the engine
 
Last edited:
Cleaning the engine part

Thanks heaps for the write up, very helpful! I'm not really that experienced with mechanical endeavours but I'm learning and guides like this are just amazing t give the confidence to have a go.

I've gotten he inlet manifold off and soaking with degreaser, is it best to just rinse it all with water after a good scrubbing?

Question about cleaning the inlet on the engine block. I'm a bit hesitant to stick a rag on a screwdriver down there in case I can damage anything? Is it. To put degreaser on a rag and en push down those wholes to clean? Does it matter if some of the gunk ends up in the engine (obviously try to avoid but it seem inevitable)? Does it matter is some degreaser (few drops I guess) end up in the engine?

Just want to get a bit of an idea before giving the engine a clean so I know how careful I should be (or not) and ultimately how clean I'll be able to get it.

Will post pics of my inlet manifold before and after for reference once done.
 
My engine had hardly any stuff down that far at the inlets so I couldn't knock anything off that was substantial to go into the cylinders.

If you are worried about the degreaser being in your engine just buy one which is hydrocarbons based as it will either evaporate before you get everything back together or if any is left it will be simply burnt like a fuel. I didn't worry about this though and just used a alkaline salt degreaser and I had no problems.

I didn't stick a rag down far just into the bores just to clean the black soot off the walls (what little there was anyway) with a screw driver in a rag. Really unless there is substantial gunk down there you dont even have to bother
 
Thanks again for the write up shorty and your response to my questions. I decided not to be too pedantic about it and just do what I could with a rag soaked I. Degreaser and a screw driver as suggested. Before and after pics attached. It was dark so the photos are not great as it was dirtier than the photos attestImageUploadedByTapatalk1405313584.523200.jpgImageUploadedByTapatalk1405313598.352599.jpgImageUploadedByTapatalk1405313618.615161.jpgImageUploadedByTapatalk1405313627.810333.jpg
 
Great how-to Shorty, cheers. Did you disconnect the battery before popping off all the electrical connections at all?

I'll have the luxury of a gurney and compressed air line when cleaning so that'll hopefully stop 'manifold rash' when giving it a good wipe out... that's if I manage to dodge some spanner rash at removal!:rofl2:

Thx again, very detailed write-up.
Rusty.
 
Nah mate I didnt even think to disconnect the battery terminals, there is nothing which I removed which would have had active voltage anyway. Probably best to be safe than sorry though haha.

Scott well done mate, it looks nice and clean. The square ports are for exhaust only so it hardly matters if you clean the soot off those, but you may as well do the whole lot while the manifold is off so its nice and shiny haha. You can tell they are for exhaust only as there is no oily residue in them, only black exhaust soot.
 
The square ports are for exhaust only so it hardly matters if you clean the soot off those, but you may as well do the whole lot while the manifold is off so its nice and shiny haha. You can tell they are for exhaust only as there is no oily residue in them, only black exhaust soot.

the square ports are for EGR and air mix. the soot is from the EGR.
there may be no oil due to catch can but also the soot tends to suck up the oil and turn into the black crap.
 
Yep by exhaust I meant exhaust gas from the EGR system. Mine the square ports only had soot, while the circular ports which contain the air from the intake were the ones gummed up with oily residue.
 
both will get oil down them as both have air flow down them. the soot tends to soak up the oil so its not noticeable.

just to add, the clean air only port is the one with the swirl valve on. so it shuts and blocks off half the air flow into the engine.
 

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