Overheating issues

[JDM Journeys]

The chances of a 1KZT head going is probably about the same as a 4M40. Definitely not as bad as a 2LT or a 4d56 for example. It all depends on how it was treated before you got it, how many hours on it, and even what vintage it is. Like the 2LT, I think the 1KZ's got better as time went on. I think it's wise to consider the possibility of having to do a head at some point however. Account for it in your budget. I'd say on average, the 2LT's needed cylinder heads within 100,000km, where the 1KZ's seem to last more like 200,000km+ before needing one.

Thanks. I was hoping I was falling victim to the hysteria. I always drove the 4d56 and 4m40 conservatively, and watched the egt guage like a hawk when towing. Nice to know that similar behaviour with a Prado will likely yield similar results. Although my wife's new to her 100 series will get towing duties now, so whatever I get won't have to anymore...

Thanks @GTSSportCoupe . Your advice has already been sage in many threads.

 

[Lomoski]

I'm possibly in the hunt for a KZJ78 (or a PZJ, but it depends what comes up for reasonable $), so just wanted to shout out to the contributors of this thread. Lots of info and misinfo about the 1KZ out there. This is good solid stuff for owners to act on. Thanks!

So newbie question, just to add onto this thread: is there a high probability of a head replacement on the 1KZ like it seems to be on the 2L in these otherwise stout rigs, or are the later 1KZ's a little more forgiving overall? And just for clarification, once the cooling system has been gone through, is an EGR delete and trans cooler separation still recommended?

I've had two Mitsu 4D56's, a 4M40, and a 4M41, and have not (knock on wood) lost a head or head gasket on any of them, even though urban legend says I should've. So I fear I'm falling into the google-hysteria of thinking its a given on the 1KZ?

So with my kzj78 I replaced the head at around 280k km. I had 2 cylinders with cracks. My cooling system was definitely tired and contributed to the cracked head. Knowing what I know now I could have made it a lot more reliable, but alas there is 22 years of history prior to my ownership. Once I replaced the head I also installed a EGT and replaced the turbo as well. The cooling system is completely overhauled and I drive accordingly. I am more than happy with my kzj. I'm running 33s and have a 3 inch lift. It wheels comfortably with a lot of my Tacoma owner friends. The only real driveline changes I want to make is adding a locker. Super happy with the truck, it's not without its quirks and headaches but overall it's well worth it if you already are familiar with JDM