GQ 4.2L Petrol Engine Expected Lifespan

[keluangus]

Hi Folks,

Umm, real newbie here. I'm just about to get my grubbie fingers on a 1990 GQ 4.2L Petrol Auto (carbie). It's a family wagon and pretty decent condition, but has about 250k kms on it. Does anybody know - assuming it has been reasonably maintained and hasn't been bush-bashed - how long does this engine live for before it dies without possibility of resurrection? It's less than $5k, and I can't afford anything more... I intend to use it for bush use, but, not hardcore rock crawling and stuff. Thanks for all your help and comments.

[1patrol]

There pretty hard to kill from the stories/people i know with them. Mine has 340 on it (last 70 from me driven hard and bush bashed regularly) and is still going strong, slowing down but still strong and reliable HTH

[bogged]

has the head been redone at all, they have issues with cracking heads.. not rarely either.
apart from that, totally depends on history of it, 300,000 would be a great run out of one.

YMMV

[create]

I've got 408,000 on mine and its thrashed daily!

[jessie928]

i had a 92 EFI with over 490,000. it was still running SWEET!

my first SWB also had over 500,000 and 250,000 of that was with lpg.

Jes

[keluangus]

Thanks you guys for the feedback. If anyone out there has any idea, how much it would cost to fix up a cracked head - in case it does happen to me??? (Gulp). Or, perhaps it's cheaper to whack on a replacement from the wreckers? Mine will have LPG installed on it. Cheers!

[jessie928]

Thanks you guys for the feedback. If anyone out there has any idea, how much it would cost to fix up a cracked head - in case it does happen to me??? (Gulp). Or, perhaps it's cheaper to whack on a replacement from the wreckers? Mine will have LPG installed on it. Cheers!

cracked head, depending on where its cracked, on a tb42, its only ever going to be a temporary repair, and yoru labour costs are going to be wasted once it cracks again....

you can get a bare head brand new for around 1000.

if your doing install work yourself, a head from the wreckers that you then preceed to harness test, machine and the install may be marginally cheaper, BUT, you end up with an OLD head, that may or maynot be any good.

if you going to pay someone to replace the head with a new one, expect to pay just over 2k to do the job which i think is the going rate.

remove old head
1200 new head ( is probably what you will be quoted)
surface the head to increase compression ( i would HIGLY reccomend this for LPG)
seat the valves
assemble the head
vrs kit
install the head.
^ all of the above, plenty labour

JEs

[keluangus]

JEs mate: thanks for that. If I was going to replace it, it would be a brand new head and I'd get someone to do it: have it done right the first time. Question: 2k you mentioned would be for labour ONLY?? Or does that include the head? I know they're all estimates but at least some idea... Thanks again.

[jessie928]

JEs mate: thanks for that. If I was going to replace it, it would be a brand new head and I'd get someone to do it: have it done right the first time. Question: 2k you mentioned would be for labour ONLY?? Or does that include the head? I know they're all estimates but at least some idea... Thanks again.

hi mate, the just over 2k mark is the entire head-job labour and parts.