Injector problem

[RTB]

G'day
I'm a newbie to this site. Have a 95GQ 4.2D beautiful beast, over 500k on the clock, only One clutch replacement, regular services and everything going fine until recently.
Lent the car to my son for a weekend, the temp gauge was high and the car started running a bit rough. He had it towed to a mechanic, who advised the thermostat was jammed open? The car was repaired by this guy who replaced the pistons, rings, big end bearings, head gasket, radiator coolant, oil, and of. Course the thermostat. My son paid for all of this. Hum!
The vehicle was returned to me, but in just over a thousand kilometres the engine got hot real quick and. Stopped whilst driving down the M1 (old F3) at approx 90km/h
The vehicle was towed to the same guy (unfortunately) due to him doing the repair previously. He advised that the engine got hot and stopped due to an injector failure and advised no warranty and a new engine or second hand one required.
I've had diesel vehicles since the eighties, had injector problems, and had them replaced, but nothing suggesting engine replacement, especially after what I consider to be significant engine work just being done. Any suggestions would be. Greatly appreciated.

[Parksy]

My first step would be to pull the sump off and inspect the sump and oil for metal particulate and take photos. If there are contaminates, my suggestion is a shoddy rebuild, as you can't just put in new bearings without checking a lot of other things. This is just to help you gain any possible warranties as your mechanic sounds like a dog.

[nissannewby]

It's a hard one. Sure there may have been some dodgy work but you have driven to the point where it has shutdown because of overheating which will make warranty very hard.

[RTB]

My first step would be to pull the sump off and inspect the sump and oil for metal particulate and take photos. If there are contaminates, my suggestion is a shoddy rebuild, as you can't just put in new bearings without checking a lot of other things. This is just to help you gain any possible warranties as your mechanic sounds like a dog.

Parksy thanks for the reply. I can't take the sump off as the vehicle is at the mechanics, however after the vehicle was towed home it started but ran rough, as if it was missing on one cylinder.
It was then towed to the mechanics.
The mech contacted my son and advised that number two injector was brown in colour, and he was waiting for someone from the institute of mechanical engineers to come to his workshop to diagnose the problem. Wtf?
He then advised they didn't turn up, but a new or second hand engine is needed, or the cylinder re sleeved, I don't think he can make a decision.
Maybe the MTA can help.
Thanks again

[RTB]

Thanks for the reply, yeah the engine shut down but with very little warning. The mech has said it was due to number two injector failing?
The mech said he would re tension the head after 1000km or so, but before I could do that it had this problem.
$4000 of repair work, for 1000km of local road driving. The first time I drove it more than 50km in one go and this problem occurred.
The basic question I guess is, can a failed injector cause a 4.2 diesel to overheat rapidly and shut the engine down?
The vehicle was able to be re started, after cooling, albeit rough, and then requiring an engine replacement?
Thanks again for your time.

[nissannewby]

If an injector has failed it would be noticeable especially if it has failed in such a way that fuel is pouring instead of being sprayed.

It's not really advised to retention bolts on a td42 as for the most part these are a torque to yield application and the head bolts should be a single use item.

The engine shutting down would have been because of the overheating. It might be possible but for the most part you should be able to see temp fluctuations before overheating occurs.