ZD30DDTI Head Gasket replacement.

This post is directed toward anyone looking for some encouragement to get there hands dirty and save a ton of money.
It may get a little long winded but I want to explain my symptoms very thoroughly.

Up until 2 weeks ago my mechanical experience was limited to petrol engines.

For 12 months leading up to now I have had an issue with an over pressurized cooling system (exhaust in the radiator). Local driving never saw an issue, highways and hills on the other
hand saw coolant slowly vacate my overflow bottle.

On Tuesday last week I finished work and went to my car, It took an unusual amount of time to start with a lot of chugging and hesitating before it fired up. It lacked power during my
5 minute commute home and had very odd boost behavior. I managed to limp it home.

The next morning I went out to diagnose the issue with the thought it could be a clogged fuel filter as it was over due to be changed, I turned the key and after 30 - 45 seconds of chugging and hesitating it started and idled extremely rough so i turned it off again. I replaced the fuel filter and it made no difference but whilst doing so I notice an odd noise coming from my intake.
After pulling the intake down to the turbo and starting it, it sounded a lot like I had air going in and exhaust coming out of the intake. That cant be right.

After speaking to a mechanic from a local workshop here in Geelong and explaining the issue with the cooling system he basically told me i may as well pull the top end down and I will no doubt
find my problem, So armed with my extreme patience, an amazing attention to detail and a workshop manual I began doing so and after a few nights after work I had the head off and found this.

Attachment 76653

It was pretty obvious what my issues where now, No compression in cylinders 2 & 3 and running on 2 Cylinders so I rang back the same mechanic workshop and spoke to another mechanic about where to go next. This mechanic seemed hell bent on selling me a new head for "anywhere up to $2,200" plus labour to fit the cams and buckets, he was very un-willing to entertain the fact that my head was OK and "didn't want to charge me $250 to tell me its buggered". After talking him into it I told him I was on my way and when I arrived I was greeted by locked doors.

I began to ring around looking for another mechanic who could do the tests and found Precision Motors in Moolap, Geelong, and I tell you what, their customer service was second to none.

They took my head and they done the hardness test right there in front of me which was an old way of testing with a tool that basically consisted of a ball bearing in a glass tube. They Pressure tested the head hot and cold, they vacuum tested the valves, they machined the head (had to take off 10-thou due to a very slight warp) and they supplied me with a full top end gasket set with
new bolts. It turned out my head was very usable still and my total repair bill was under $600 including changing my A/C bearing while I was at it.

As daunting as these motors look they are actually very easy to work on, albeit time consuming. If i had taken it to a mechanic it would have taken a few days less but it would have cost me
at least $2000 just in labour (I was quoted by the first un-named mechanic, upto 20hrs) and possibly got stung for a new head for another $2,500.

Here is some more pics I took during the tear down and re-assembly.

Attachment 76654 Attachment 76655 Attachment 76656

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Finezy mate, I love reading and hearing stories like this. Good job.
Diving into the deep end sometimes pays off doesn't it.

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It most definitely does, As the sole bread winner in a family of 4 there is no way I would have afforded it if I went down the mechanic road. It would have ended up as another dead “grenade”.


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Quote:

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Originally Posted by Finezy

It most definitely does, As the sole bread winner in a family of 4 there is no way I would have afforded it if I went down the mechanic road. It would have ended up as another dead “grenade”.


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And now just imagine how many people out there would have actually handed over the large amount of cash ...
I suppose some people out there aren't mechanically minded or hands on comfortable. Fair enough .
But there are some out there who like to swing a spanner and yet would have seen the job you attacked as " extreme" . I am one of them.
I'd have to think long and hard before tackling something like that ... Lol .
Well done again.

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Your a brave man. Kudos to you....

looking to do this on my 2005 STL ZD30, is there anywhere i can find a manual?

I get inspiration from guys like you who take a deep breath and dive in.

Good work Finezy, did you remove the butterflies
and block the egr, well done i had the tools and know
how but body would never allow todo it
@Finezy Question does it now run 2 or 2 degrees warmer now

Quote:

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Originally Posted by threedogs

Good work Finezy, did you remove the butterflies
and block the egr, well done i had the tools and know
how but body would never allow todo it
@Finezy Question does it now run 2 or 2 degrees warmer now

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It now runs at 76 degrees when cruising on an average temp day, when on the highway at 100 it floats between 78-86 depending on weather. I have taken it into the vic high country since and on a 44 degree day with a/c on and a long steep slow climb it manage to just click over to 100


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@Finezy have you updated your intercooler yet??

Quote:

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Originally Posted by threedogs

@Finezy have you updated your intercooler yet??

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Not yet, still a crimped aftermarket standard replacement cooler. An upgrade is on the cards but not really a priority currently, my egts aren’t to bad.


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As long as its not oily you should be right,
not a big cost to replace

When I did my head gasket in November I gave my turbo and intake a clean and it was pretty much pristine so the EGR block and catch can are doing there job.


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Hey everyone, i've got a 3.0 crd in my gu patrol, was bleeding the system recently and noticed that the bubbles didn't stop coming up. After half an hour i was basically certain that my head gasket went. How hard of a job is it to pull the head off with repair manual and a basic automotive garage set? Just curious, i really don't feel like taking it to a mechanic considering there aren't any good ones in my area so just want a rough idea from someone who has done it.

Much appreciated !

Cheers!

Thanks mate.

Hi Everyone thanks for the posts they have given me the encouragement to have a go.
Same thing, blowing bubbles and overheat (can crawl home at less than 30kph) (3 days after I finished I finally found the cause! - go to the end to see). Quoted 6K - 8K+ and no one really wants the work. So took out the workshop manual and got started a few days ago, with a couple of hours a day. Have the intake side off so starting on the outlet tomorrow.

Skill level is fairly good, have been working on cars for 30+ years and trained as an aircraft mechanic, tooling required is fairly basic though reasonable for any serious back yard mechanic, make sure you keep a few hundred in the budget to buy anything you need (like a 12, 14 16, and 17 mm 6 sided sockets, a good impact set should work) A cordless ratchet will help (I have a pneumatic one)

tip 1 - deflate the tyres a bit, the extra cm's makes a huge difference (180 cm tall here and its not lifted), and get a good solid box 15 cm high or so to stand on.

It's doable, but very time consuming, and anticipate finding a few problems along the way, so far the Drive Belt Tensioner has given up the ghost, and factor in everything that you normally would for a full service, plus replacement of additional hoses, serpentine belt, (glow plugs?) thermostat etc. and use only 6 sided sockets and penetrating spray. I will post photos and guides as I go with updates.

Just finished the job, mostly by the book, though I will include highlights and errors below.

Disassembly:

Got the intercooler piping, intercooler and air box off, first problem, cracked the Intake Hose Air Cleaner Box to Turbo Inlet, will replace with a silicon aftermarket.
Stripped the exhaust side, the catalytic converter is covered in rusty crud, recommend full eye protection, later on dropped a 12 mm socket in the open exhaust (cover it with a rag and rubber band). Extracted with a magnet.
Rear 12mm nut on oil return (back of head) use a ring spanner, need to remove the foam piece bolted onto the firewall for better access.
Remove the turbo and exhaust, notice some exhaust leakage around the manifold. (Where is the water cooling for the turbo that appears in the workshop manuals?).
Note. Store the turbo upright to prevent oil leakage past the seals, they are designed to allow push the oil out without leakage (otherwise you will need to clean the inlet with brake cleaner before you reassemble).
Fuel lines (17 and 19 mm spanners) remove the egr, strip the Intake manifold, oh my goodness its got years of greasy crud in there.
remove the rocker cover, get the glow plugs out,

Broke the Serpentine belt tensioner (a sign it was worn out) be careful and just remove the alternator if its to tight.

Pull the front of the timing cover (vaccuum pump and power steering pump) and the, once your stripped, rotate the engine until everything lines up (EVERYTHING) all your alignment marks for TDC. make sure you mark the TDC with a paint marker. Getting the bolt off the cam shaft sprocket is a bugger, us a breaker bar and 6 sided socket, make sure it is seated properly.

Oh - big mistake - get the radiator out, just do it, I cracked the overflow pipe out (will need to fix that later) ordered the cover for it from one of the major Patrol Parts suppliers. Interesting the Auto Trans pipes hardly leak any fluid, but block them with a bung or bolt. You will need that space later.

Get the head off and discard the bolts, vaccum out the coolant from the block, there is always some residual and it is a bugger when you use a compressor to blow out the block.

Clean and scrape, check the pistons for cracks.

Due to the high cost of Head Gasket replacement (its in the hours) I chose to buy a replacement head. $1699 with a gasket kit. I may or may not need to replace it though figure at 175000km it is just preventative maintenance.

Cleaning, degrease everything that you can, clean the Turbo with brake cleaner, the intake manifold was hit with the high pressure wash and rounds of degreaser. Finished off with degreaser, and then a final rinse with brake cleaner. EGR clean and scrub with a small brush. I use a brass wire brush on the drill to clean all steel parts and mating surfaces. (DO NOT WIRE BRUSH Aluminium FACES, they pit and will reduce the quality of the seal) clean the aluminium mating faces and then finish them off with a fine sanding block, run it across the flat surface. Brass wire brush all pipe fittings, I manually clean the tubes, and put the metal tubes in an ultrasonic cleaner (in a ziplock plastic bag with some degreaser inside the ultrasonic bath, keeps the fluid clean) and then use a fishing tank pipe cleaner to final brush them out. The glow plugs are metal, so wire brush them to get the carbon build up off. Bolts - Clean them, Vicegrips and a brass wire wheel will clean the threads, dont forget the crud under the head of the bolts, nice flat mating surfaces. I use a minor smear of antiseaze on the threads of anything that looks a less than perfect. Did I mention to torque everthing, get yourself a 1/4 inch ratchet drive torque wrench, even for the big bolts. Go around all bolts in sequence a little at a time, I usually went around anythign about 3 - 4 times before I torqued them up.

Injectors - dont mess with them unless you are 100% confident, and realise that you wont be able to modify them. Keep them in order. They are an extreme High Precision part, consider a rebuild as the springs and shims may have altered the pressure needed to pop over time. BUT the Fuel Pump may also have degraded, and these systems can degrade at the same rate and could only work together. Talk to an expert. I disassembled mine and cleaned them in an ultrasonic bath. Though was lucky they still worked after I was finished. BUT they can take an age to prime, see the end of this story. I am thinking that they are empty when I put them back in, fuel is not compressable so will flow under pressure (thats part of the automatic feature of the injectors) so whne they are empty they are just pushing through gas (highly compressable) so I am guessing that it takes ages for them to bleed. thinking next time I did this I would assemble the injector in diesal.

Reassembly

Use a torque wrench. I bought a small 1/4 in drive that only goes up to 24nm, and was surprised at how much I used it, the majority of bolts to the aluminum head is 25 - 28. though you will need a standard 1/2 inch drive that goes up to 90 nm.

Intake studs, check the location of the rear stud, its the lower one, use the gasket to double check. Torque them all to the correct spec. Double check, dont overtighten, double check!

Lube your bores (1/2 a turn on the crank and then back NOT forward)

Reassemble and put everything in order, Torque everything slowly. Follow the guides and especially the "Nissan ZD30 Cylinder Head Fitting Faults" guide (search for the PDF). I used aviation sealant as well as the gasket between the timing cover and head. Lube the cams and liberal use of oil before putting the rocker cover back on. Injectors, make sure the copper washer is seated in the head, if not a quick blow with the air hose may right it. Lube your injector seals, and they just pop in about 10mm. I use a touch of aviation sealant on the injector seals (where the fuel pipes enter the head).

Serpentine belt tensioner; make sure you cycle it in a vice a couple of times to make sure it does not leak (dont open it), and when putting the belt on be gentle with it.

Warning Warning. The turbo gasket kit is not included in the head gasket kit. If you're going to get a cheap one, order this early. Otherwise, major suppliers (regular parts suppliers will be able to get them quoting around $200 but ask for the trade price, $159)

Great news is that all wiring has only one way to go. Same with vacuum hoses.

Radiator. snapped the overflow, drilled it out the plastic fitting (8mm) and bought a HOSE TAIL STRAIGHT MALE BRASS 5/16″ x 1/4″ at SCA. I filed off the hex fitting and that gave me about 24mm of thread and a round body at about 12mm diameter. Then get some JB Weld Steel epoxy around the "air fitting" and it's an interference fit, tap it in with a light mallet and use enough epoxy to create a nice seal. Bought a couple of silicon radiator hoses, fittings are too tight, so will deal with that later. Clean and refit the original hoses.

Top up water (NOT Coolant) and lube with your 8 liters (approx) of oil. turn over by hand a few times to ensure adequate lube under the camshaft journals.

Starting.
OK - pump the hell out of the fuel filter. And you are still going to need to crank the buggery out of it. I have heard 5 - 20 minutes. First time I did this it did not start and I freaked, thinking I had buggered up. BUT it was just the injectors and lines needing priming, after I read that it can take an age I put the battery on the charger overnight (to max it up) and had a go the next day, after 3 minutes one cylinder, then another 2 minutes later, then it kicked over about 3 mins later. Yeah.
Lots of smoke (the oil in the bore) but it started up and ran so smoothly.

Now for the worst part. Went out for a test drive, as soon as over 40km/h it starts to overheat again AHHHH - same overheat as before, got back home. Bleed the radiator and try again. No luck. This is what got me into trouble in the first place. So what happens, I drive and put it under s tiny bit of load, it overheats, then I stop and let it idle, it cools down, I stop and rev it h Then found an interesting post on water pump problems. "A good trick to tell if the water pump may be bad is to put it into neutral and rev the engine up a few thousand RPM for a few seconds. If the temperature went down, that can indicate a bad water pump. Why? A dying pump may get spinning enough to move the coolant with the increase in RPM."

Took the water pump off today - Use the right spanner a ring spanner with an offset handle, Dont mess with this one, just buy the right set from Bunnings or SCA, make sure the offset is about 15mm - 25 mm - I rounded off a lower right nut and had to spend 3 hours with a cold chisel and grinder, will then need to replace the stud. The very bottom nut came off in 30 seconds with the right spanner.


OK so found the problem. Water pump has a plate inside that has corroded, and is blocking the majority of the water flow. This has cost me about 60 + hours (2 months) and $2500 so far. Oredered a replacement from an Online supplier today, and Aus Post justr advised it should be here tomorrow for $108. I will make a seperate post on overheating to save everyone else the frustration. Still glad I did the job. great learning opportunity (biggest Auto job i have every done, and so much fun that I might buy something else next year to rebuild. If you have the capability it is a long process, more than a single weekend. Did it all myself, the only help was the Mrs cranking it over while I kept up fuel pressure to get fuel to injectors.

I will upload images as soon as I work out how.

Would love to see those images ? 😃👍

Great post!

Definitely if you've got the time, working on your own vehicle and figuring it out for yourself is the way to go.

They really are easy motors to work on, heaps of space in the engine bay once you pull the radiator out :)

Quote:

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Originally Posted by Finezy

Not yet, still a crimped aftermarket standard replacement cooler. An upgrade is on the cards but not really a priority currently, my egts aren’t to bad.

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I think he's referring to the potential boost-loss which is common with crimped intercoolers.