1KZ Cracked Head

[Roktruk Junior Member Find all posts View Profile Close Roktruk]

Well, the verdict is in - the head on my 1KZ Prado is cracked and is to be replaced. I would like to collect some stats on how many other people this has occurred too. Really interested in "this happened to me", rather than "I have a mate who knew someone" stories.

The problem has occurred within the 3 month statutory warranty period, but I get the feeling that the <unnamed> Toyota dealer is having a bit of a wriggle and I'd like some information as ammo if they start to argue.

Vehicle is an '01 TX TD auto, I bought it with 95K and it has performed faultlessly until the head gasket quit very suddenly. It stated to idle rough, first thought was bad fuel/pump/ electronics, few minutes later temp shot up so I shut it down. Leaking water into number 3 cylinder. Any info appreciated

[Mick Lurker Find all posts View Profile Close Mick]

Re: 1KZ Cracked Head

Well, the verdict is in - the head on my 1KZ Prado is cracked and is to be replaced. I would like to collect some stats on how many other people this has occurred too. Really interested in "this happened to me", rather than "I have a mate who knew someone" stories.

The problem has occurred within the 3 month statutory warranty period, but I get the feeling that the <unnamed> Toyota dealer is having a bit of a wriggle and I'd like some information as ammo if they start to argue.

Vehicle is an '01 TX TD auto, I bought it with 95K and it has performed faultlessly until the head gasket quit very suddenly. It stated to idle rough, first thought was bad fuel/pump/ electronics, few minutes later temp shot up so I shut it down. Leaking water into number 3 cylinder. Any info appreciated

Hi
I realise your original message was a while back, but I thought I'd drop you a line anyways!

I have a '00 GXL Prado
I went to get my 1KZTE head serviced at a reliable machine shop in my region and they denied me. Instead I had to buy a new head which was over $2000.
Apparently the manufacturers went as skimpy as they could with the wall thickness in the casting of the heads to save money. This doesn't leave any room for machining to be done and to go on to be reliable - they are high compression and need the full wall thickness. This bloke said you wouldn't get to the next town as she'd crack the head and die if I got him to machine it.
He's not the kind of bloke to just say stuff like that either - he's a tradesman, not a salesman!
I don't think you are on your own with a cracked head on a small japanese diesel (not only prado's), but i reckon you were real unlucky being only just out of warranty.

I hope she's going strong for you now. Either that or she's someone else's problem now!

Cheers!
Mick

[Guest Close Guest]

Cracked Head Prado Diesel

Realise your message is over 12 months now but I have same problem and wonder how you got on getting any documented statements about weakness in Prado diesel head walls.
Mine over heated suddenly and diagnosis was cracked head. All other cooling components tested ok. Head testing claimed internal crack between coolant chamber and exhaust valve port.
Extended manufacturers warranty claim being denied because "heads just don't crack by themselves". But according to reliable mchanics in specialist 4WD centres this appears to be common occurence for this model - and supported by views of others on this site.
Where do we get documented evidence that this is a faulty component, not caused by a failure of some other cooling component?

[damonat Advanced Member Find all posts View Profile Close damonat]

i have seen this 3 times before (customers rides).
good luck trying to find any documentation stating pre-existing issues
with the 1KZ heads.
the 1st head we ever did 2001 (dealership), we did it 3 times as the head
was skimmed and tested (cold) ok.
fitted and once warm bubbles through cooling system.
got the machining company (i'll call them EM) up to check before restrip
(they had not seen these heads before).
gave back to EM, and all was ok, just slight warp from removal, so reskim slightly.
same thing happened.
toyota aust couldn't/wouldn't give us any info as to what to look for,
so checked out the forums (back then), to find it had happened before elsewhere in the world (NZ from memory).
then we found out that if the head was heated to operating temp,
then checked, that we had a crack behind the pre-combustion chamber.
once we found this, toyota were more forth coming and supplied a new head.
fitted up (customer was :evil: over time taken) and problem solved.
the next 2 vehicles, we had EM check heated heads and both the same problem.
so we got new heads (still under new vehicle warranty).
hadn't seen any after about 2003, so hopefully they fixed the cause.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Just to add to this...

Some months ago I helped a friend of mine change over his 1kz-te head. (1996 Surf)

I did a chemical crack test (cold) and couldn't find anything.

In the end he sent it out to be tested at Chris Milton Engine Developments and they found a crack inside the exhaust port.

The head we put on was out of China and the cost of these is under $800, it was visually identical to the Yota one... I mean down to the casting marks.

I must round up the pictures.

Mick

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1KZ Cracked Head

This is a post which maybe someone could help with - otherwise it may at least help someone else... I have a 2003 diesel Prado bought from new - done 105,000 kms fully serviced t/out... About a month ago, while starting a holiday, the engine starting overheating while towing a caravan after 150km. The cause turned out to be combustion emissions getting into the cooling system causing coolant loss via the radiator expansion tank. Took to Toyota dealer who did TK test and found no problem. Had cooling system completely tested, repeat of TK test (I now know is pretty u/s anyway...) etc - no-one could confirm the problem - assumed radiator cap was the issue, took off again with new cap - but same problem at 150 km. The actual sequence of events with Toyota and other mechanics is too long and frustrating to recount... The upshot is that no-one has been able to diagnose the cause of the problem. No water in oil or vice-versa. Turbo taken off line from the cooling system - combustion gases still entering cooling system. The head has been off twice, pressure tested in heated bath with dyes, ultra violet light 3 times - nothing. Cylinder "liners" (they are not actually lined) seem ok from visual inspections. No signs of scores or marks on the head gaskets. Two noteworthy events during all these diagnostics were 1. after hard run, while at idle, copious steam began pouring from ehaust pipe but engine seemed to run normally - haven't been able to repeat this event since 2. after hard run, next morning with cold engine, taking the radiator cap off led to very obvious release of compressed air. It seems to me that there is a hairline crack in the head that only opens up when the engine is actually operating but closes very quickly when engine cools. I can drive the vehicle as hard and long as I like with the radiator cap loose so it allows the gases to be released without throwing coolant, without a hint of overheating. At this stage, I am getting a new head (Chinese - because $$$'s are now mounting up) put in, in the hope that it is a head issue that hasn't been able to be confirmed from the available out-of-vehicle tests. If anyone has any ideas on the problem, it would be appreciated - otherwise I'll do another post when the new head is fitted and I know for sure whether it was the head or not...

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Far out David.

My first, and probably only thought, would be a cracked head.

I'm pretty surprised that the rack of tests hasn't found it .... but, like you've come to find out, they can be tricky little buggers sometimes.

... and like Mick says .... inside the exhaust port.

Good luck.

Cheers
Chippy

[ntp Addicted PP Member Find all posts View Profile Close ntp]

Re: 1KZ Cracked Head

This is a post which maybe someone could help with - otherwise it may at least help someone else... .... I'll do another post when the new head is fitted and I know for sure whether it was the head or not...

Bugger of a first post!! :|

[Guest Close Guest]

Re: 1KZ Cracked Head

Seems the old 1KZ diesels are suffering a contageous outbreak of cracked heads.

After months of trying work out why I had an intermittent rough idle on cold start which involved changing glow plugs and the primer pump assembly, we find she has a cracked head.

Seems there are several cracks in all four cylinders.

The thing I found surpsrising is she never overheated, lost power, etc. Although one of the symptoms included a very thirtsy radiator when inspected, there was nothing to suggest a head or gasket problem in day to day use.

So after 167000 km and around $4000 to get it replaced it should all be good for another few years.

[Tiger_DFT Lurker Find all posts View Profile Close Tiger_DFT]

Re: 1KZ Cracked Head - Another one!!!

Hi,

I have a Mar 2001 1KZTE that just suffered a cracked head. It cracked underneath No4 cylinder pre combustion chamber.

Vehicle never overheated, has done a lot of towing, never used all, no change at all in performance....until I heard bubbles in heater (in Alice Springs).

It was blowing top of radiator empty into coolant bottle.

Limped to Darwin and got it fixed by McIvers (Peter - good guy)head reconditioners. They sourced a new bare head and fitted my bits to it. Mechanic Dave Cooper did the spanner work (also great guy).

All up cost - $2950.00.

Now headed back to Perth.

[Tiger_DFT Lurker Find all posts View Profile Close Tiger_DFT]

Re: 1KZ Cracked Head

Hi again,

My post should have read....never used oil....

Too much sweat in my eyes to type up here in Darwin!!

Cheers
David

[KZJ90 Member Find all posts View Profile Close KZJ90]

Re: 1KZ Cracked Head

I think I have the cracked head too. :cry: Water temp is always been normal and it still is, but yesterday when hot it started to make steam and bubbles when radiator cap is taken off. When cold, everything is normal. It is started poorly some mornings lately (makes smoke and start with 3 cylinder few seconds). Maybe there is hairline crack in some cylinder and leaks water in it. I have added 2 liters of water within 2 weeks now...

What do you think about these cheap chinese heads? Worth of trying? David Pitt, did you got it installed?

[Guest Close Guest]

Re: 1KZ Cracked Head

KZJ90,

I didn't notice any drop in performance in fuel economy either. Had this constant cold start problem that cost me hundreds in wasted glow plugs and the fuel filter pump assembly. It wasn't until I told Toyota that something was wrong and they needed to find out that they discovered the bubbles in the water and found the hairline cracks.

Without knowking what was wrong at the time I towed a caravan from the Gold Coast to Adelaide and back via the Oodndatta and Birdsville Tracks, did Big Red, the development road and back via Charleville. It still pulled 100 KPH in 5th with the van on! Stilll drove around for another 6 months before they found the cracks!

So don't be too worried, if it were a Patrol 3.0 Td GUII "hand grenade" there would be reason for concern.

[KZJ90 Member Find all posts View Profile Close KZJ90]

Re: 1KZ Cracked Head

What do you think about these cheap chinese heads? Worth of trying?

And cracked again!!! After 4 months/6500 km. Do NOT buy a chinese (eBay) head. Inside the 4. cylinder combustion chamber is crack, symptoms were now just like Tiger_DFT told. Same failure too.

[Davros Advanced Member Find all posts View Profile Close Davros]

Re: 1KZ Cracked Head

There are plenty of Chinese heads that are bad, and some that are good. Remember..... China now makes engines and components for many car companies around the world, Honda included. There is a guy selling on ebay, as well as conducting his regular engine reconditioning business. I have purchsed heads and other stuff from him, and the quality is good. I think he goes by willyengines or similar on ebay.au. Remember, it doesn't matter how good the head is.... if you go with a cheapy gasket, or do something stupid like reusing head bolts, or not fixing the cooling system, the head will fail. Just becaused a head fails, doesn't mean it is a bad quality head.