99 td42 head cracked

[Andre Steyn]

About a month ago my 99td42 started an overheating issue, so I started by replacing and checking everything water pump, thermostat,fan and visco clutch radiator and even belts and pulleys. Unfortunately a month later still the same and getting worse so this morning I took the head off and sadly there it was a crack on numbers 34and5 as Well as all the pre combustion chambers! Sleeves have a slight ridge But pistons look great from above so I'll take them out today or next week and post an update.

[Andre Steyn]

I'm already weighing the options against each other do I replace the whole motor with a already turbo motor and where do I find one or do I RECON this one and then turbo it Whats going to be most economical and better in the long run.

[ricster]

Cool ...this is much better...

Your precoms will almost always have small little cracks on them. This is normal and acceptable.

The head is the main problem. Here you cannot compromise. I bought a new non genuine head from %$@%&&.... but anyway it turned out that the water ports were not allowing water to flow freely, and one was completely blocked. So Genuine Nissan is the way to go. Mark White Nissan assisted me with getting a new head and head gasket. Shout if you want assistance here. I think I still have Nissan the part number. I believe that the head I now have from Nissan is the head that can handle a turbo. I'll have to hunt down the e-mail with the part number.

Personally ..... I don't know which way will be more economical.... but I KNOW i now have a 99 Patrol 4.2 TD motor with 30 000 Km on the motor clock !!

Who knows what the replacement motor looks like inside.... you might still have this

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[ricster]

That photo was of the non genuine Nissan head that failed on me after about 10 000km

[ricster]

You have high milage on that motor.... so you have to start with the first step. I hope Frans ( tour de Frans ) looks in here on this post.... there is nobody that knows the 4.2 motor like that man !!( my opinion )

1) why did it over heat? - was the coolant in the radiator rubbish... ie, no or little antifreeze? What do the water ports look like? ( post a photo and lets have a look) Was there a small water leak on a hose or radiator ( heater radiator included)? Thermostat?

The economical way would be to slap a new head and gasket on and torque down the head and Bob is your auntie........ BUT

Before you slap a new head on ..... are your piston sleeves protruding above the block?? THIS IS %#@%^ important !!! Due to the age of the motor, they may not be. YOU WILL HAVE TO MIC THEM !!!There are options now you need to consider....
1) piano wire the block..... learnt this from Frans... apparently the racing guys do this to their motors...... and then slap a new head on and off you go.
2) You buy 6 new sleeves. Remove the block, strip out EVERYTHING, and send to engineering shop to press out old and press in new sleeves to the correct protrusion. Check this old post for references

http://patrol4x4.co.za/viewtopic.php?t=1266

This way you can check pistons and either replace pistons if need be or replace with new rings. Obviously you replace the big ends and small ends while you are busy.... but pistons and rings are the same as the 2.7 diesel and are a lot cheaper....

replace thermostat, and get radiator properly flushed my Silvertons and replace with either genuine Nissan Antifreeze or from Silverton Radiators ( this is their game so they should know their stuff)

You can reuse the crank, camshafts, rockers, push rods, con rods etc, so all you are buying is 6 sleeves, 6 pistons ( I would while the motor is open ) 6 sets rings, big end bearings, small end bearings head and head gasket + complete gasket set.

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I know what you are going through... so if you can... spend the little extra and do it properly... you won't regret it

[ricster]

I've also now got Alfin pistons and rings, which apparently are meant for turbo diesel motors.... remembering that you motor has an aftermarket turbo fitted, so the pistons and rings are 99% not Alfin type.

[Peter Connan]

To a large extent I agree with what Cedric is saying, but make sure you take special care that the work is done cleanly, and pay special attention to running the motor in correctly.

Just on the off-chance, give Engine Den in PTA West a bell, I know they are expecting some TB45's, so perhaps they have TD42's as well. If a TD42 can be had for the price they are charging for the TB45's, (about what a head will cost you) I personally would go for the second-hand motor.

[ricster]

Absolutely... it all will come down to what you want to spend.... and if you have a little time on your hands to do the job yourself.... mine cost me a lot more than what your repair would/ could cost as I replaced Injectors as well as reconned the old injectors and reconned the diesel pump and which landed up being over the R10 K mark.

but I have a virtually brand new motor and it runs like a dream...

You will have to adapt the motor you would get from Engine Den or the likes as they are normally aspirated 4.2's. So sump change or mod will be needed for oil feed and exhaust manifold will need changing. Diesel pump will need to be either swapped to cater for the turbo extra fueling requirements or re calibrated.

[Andre Steyn]

Well Sjoe thanx everyone for the tremendous response, the pistons look good from the top But the sleeves already have ridges run in the so they'll have to come out so its new sleeves rings big ends and mains and obviously gaskets and then the head and the aftermarket turbo and all the add ons for that. So at this stage I'm starting to lean towards a complete td42t motor if I can find one. As to the question of Why it had an overheating issue I still don't know, it never lost or used water never smoked badly or was low on power. The guys from silverton says its the age of the radiator so I'm having a new one built anyway wil post pics of everything as soon as I can. The pistons will be out by monday!

[dieselfan]

and pay special attention to running the motor in correctly.

It's funny how many people say that you don't have to, you just gun it from day one so that "later in life" it will be loose and powerful.