Overheating problem

[jonot]

G'day.

I do a lot of the work on my ute, but I've got an issue that is a bit more mechanical than anything I've done in the past.
I'm happy to have a a go at fixing it (it can't get much more broken that it is).

If it makes a difference, I drive an '04 D22 ZD30, 240k km.
• I've got an overheating problem (every time I drive it).
• I've replaced the radiator (was quite blocked) and thermostat.
• Still overheating and I've got bubbles coming through the overflow reservoir (not frothing or foamy).

From what I've read, this is looking like a head or gasket. Is there anything else I should be checking before I pull the head?

Also, if have to pull the head off, is it best just to replace it or have it checked and put it back on? I don't want to be troubleshooting head issues forever.
Cheers

 

[tweak'e]

99% of the time its head failure. overheating cracks the head. by mem its between the valves and its easy to see.

 

[BarneyB]

At 240,000 kms...if u do pull the head, I'd fit a new one regardless.
There's plenty of aftermarket heads at different price points.
If your head has repeatedly been too hot, it's not worth refitting it.
But make sure you figure out exactly what was/is causing the higher temps before refitting...
(Just my opinion YMMV)

 

[jonot]

At 240,000 kms...if u do pull the head, I'd fit a new one regardless.
There's plenty of aftermarket heads at different price points.
If your head has repeatedly been too hot, it's not worth refitting it.
But make sure you figure out exactly what was/is causing the higher temps before refitting...
(Just my opinion YMMV)

Thanks @BarneyB. Are there any netter heads, or heads to avoid?

 

[jonot]

G'day again.

I've started pulling everything apart and learning as I go. The part I'm stuck on at the moment is how to get the water pump off. I've removed all of the bolts, but can't get to the 4 nuts. I've tried sockets from 3 different sets and 2 different spanners. I'm getting fouled by the water pump pulley and the insulator that the fan to. Is there a trick to this?

Also, I've read I can pull the head off without doing the timing. I believe I need to lock the scissors gear. Is this correct? Also, is this done through the plug hole below the water pump? I found this pic in the manual.

Thanks.

 

[MickR]

They are 10mm bolts, I used a 1/4 inch Sidchrome drive, with its long extension. They are not tensioned super tight, and I was able to get enough purchase just with this set up. The second time I did it, I added in one of those multi angle 1/4 inch bits, it made the job even easier.

There is an excellent set of manuals on this site that i was sent the link - the relevant part of the manual. The head details start at page 133. Download the lot, brilliant reference material, read it in detail.

Getting the ZD30 to align the timing marks (so that you can lock the timing as you discuss above) using only those timing marks visible at this level of strip can be somewhat problematic. if you stick at it long enough it will eventually happen...................... If you want to understand why it takes so long and have a laugh at my expense read this one, on this forum

Aggggghhhh TDC No 1 cylinder.​

The first head I purchased was from a wrecker, it was not a good head, and the car would only crank, not fire. The effort, energy and time I lost in eventually coming to this conclusion was huge.

I then did some research on where to buy a good ZD30 head, including on this forum and purchased the second head from Mr Cylinder Head. shttps://mrcylinderhead.com.au/product/zd30-complete-assembled-cylinder-head-for-nissan-gu-patrol-d22-navara-zd30ddti-free-post-copy

The new head and my Nav with it fitted haven't missed a beat, running brilliantly.

Good luck with the head change.

 

[jonot]

Thanks @MickR .

I have this manual and have been following it. It's been smooth sailing, but I was stuck on the last 4 water pump nuts. I'll keep tinkering with different sockets and extensions.

I've had a read of your post. I was really hoping to not do the timing..... sigh..... You weren't working on your nav from December to July were you (the time between your posts)?

I'm stoked you've had a good run with Mr Cylinder Head, it's the one I was looking at. Did you use the supplied gaskets and does it have everything you needed (gaskets, bolts, etc)?

 

[MickR]

Not quite that long, but once i had replaced the head with the one that didn't work, I then had to go thought all possibilities, and i could really only spend time on it over the weekends. Once i got the new head, it was literally one days work to remove the original cracked head, and replace with the Mr Cylinder and i was up and running, quite literally in a few pumps of the primer and cranks of the starter.

The kit supplied, including the gaskets worked really well on mine mate. I actually can't remember if it came with head bolts, but I'm pretty sure it did, just check, and get yourself a good angle tensioner (i got one from total tools for not too much). Simply put i used all the bits Mr Cylinder Head supplied and its been working well since i got it on.

The only other addition i use (and i use it on all my rebuilds, including my bikes) was a good quality automotive engine silicon. Personally I like the black JB Weld, but any should work. If you are going to remove the gear timing cover, this is really a must have, as this whole part is designed to be resealed in this way.

If you do choose to remove the gear timing cover, there is a trick to getting it off easily without removing the sump, so if you chose to go down that path let me know and ill talk you through my solution (if you're interested)

Really apart from just the sheer number of items you have to remove and put back on its a pretty straight forward job, and that even includes if you choose to reset the timing like i did. Had i got a good head straight up, i would have been up and running in two days (after i worked out the agghhhh timing thing).

 

[jonot]

I'm off to get some 1/4" gear.

 

[jonot]

The water pump is off. That has been the hardest thing so far. I found one of the nuts is especially hard to access.

I think I've found my problem though. This was inside the pump housing, any ideas what it is?

I haven't heard any strange noises, but the water pump blades have seen better days.

 

[tweak'e]

that is whats left of the separator plate that fits under the pump impeller. you will see it when you get the new one.
looks like it rusted out so badly its fallen to bits. make sure you run enough coolant as it stops the rust.

 

[tweak'e]

 

[jonot]

Me again. I'm trying to work out the best way to get the timing in the correct position before removing the head. TBH I was trying to avoid buying a huge socket just for this, but I think this is going to be easiest. Is there any other way?

I've had a search and found 2 options, the socket and turning the rear wheels.

I'm leaning towards the socket, is it size 42?

Also,
• can I just line up the cam gear marks with the idler gear before locking the scissors gear,
• or do I need to remove the chain cover and line up the other timing marks?

 

[Erick]

Me again. I'm trying to work out the best way to get the timing in the correct position before removing the head. TBH I was trying to avoid buying a huge socket just for this, but I think this is going to be easiest. Is there any other way?

I've had a search and found 2 options, the socket and turning the rear wheels.

I'm leaning towards the socket, is it size 42?

Also,
• can I just line up the cam gear marks with the idler gear before locking the scissors gear,
• or do I need to remove the chain cover and line up the other timing marks?

Ok. Having just replaced injector pump and head on my ZD30 I can offer a heads up on timing if ur only doing the head. No need to remove large(gear) cover. Remove timing chain cover and align timing chain marks and see if the camshaft marks are aligned. If so ur off and running. If ur feeling really confident u can just mark timing chain and camshaft with ur own marks , but in either case don’t rotate/move the engine. Better to get the cam chain and cam gear marks lined up as ur new head should come with new camshafts. One more thing, if ur cam chain has 10-12 mm showing on tensioner and guides are good it’s goo for a while yet. Don’t let the tensioner plunger come out. U won’t get it back in again. Head bolts, when it comes to final 1/4 turn, mark with a white pen - the one u have been using to do timing marks, lol- so u know which have been done and how much turn u have given them. So long as u put everything back the way it came off ur good

 

[jonot]

Thanks @Erick . I may have made the job a little bigger than I needed to. I really wanted to get the head off yesterday so I could place orders. Anyway, I got everything into the right position, locked the scissors gear and removed the timing chain. I thought there was too much tension on it just to pull it off. Oh well.

 

[jonot]

So the head it off. I was expecting to see something obviously cracked, but I'm not sure what I'm looking at. Something I noticed is the the head gasket has delaminated at both ends. One bent while I was removing the head, can this cause issues?

 

[tweak'e]

i can't tell with all the muck still on the head. they typically crack around the glow plug hole.
don't throw the head gasket out as you need to ID the markings so you get the right size replacement.

also take the injectors out before hand. now you risk damaging the tips. follow the procedure in the manual.

 

[jonot]

Thanks @tweak'e .

I checked the gasket when I pulled it out, it's a two notch.

I've got the head sitting upside-down on some blocks. I had hoped this was enough to protect the injectors.

I'll clean the head up and upload some more pics. Although I was planning on just replacing it, someone posted they can get weak after overheating. I just wanted to make sure i knew all of my issues.

 

[c2fe3]

Looking at no 4 cylinder seems to be lighter colour compared to the other three burning hotter ?

 

[tweak'e]

Looking at no 4 cylinder seems to be lighter colour compared to the other three burning hotter ?

rear cylinders do run a bit hotter with inline engines. its not an issue. only thing is looking for cracks once the head is cleaned a bit.