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1KZ-TE versus D4D?... 90 Series versus LC4?...


Well-Known Member
Jan 20, 2021
I'm know aspects of this have been mentioned in many a thread but, as I'm still questing manfully for my first Land Cruiser, I'm trying to collate the various snippets in one place.

First off, the 1KZ-TE versus D4D debate. From what I've gleaned so far:

* Mechanically simpler = easier for DIY spannering & cheaper parts but mechanical pump likely to be worn at this age
* Cooling system needs to have been well maintained or cracked heads and strawberry milkshake auto boxes can ensue
* Otherwise pretty bullet proof

* More complex. More to go wrong. Not so DIY friendly
* Better fuel economy & performance
* Injector seal issues with earlier models [years?]

Anybody got anything more to add to that? I'm minded more towards a 1KZ-TE, just because I'm an old curmudgeon who likes to work on my own motors and am a bit dubious about too much electrical jiggery-pokery in an engine. So relative mechanical simplicity is a big factor in favour of the 1KZ-TE. Then again, being a newer engine, a D4D would theoretically be less worn, so might be less likely to need me to get the spanners out. And I'd get better performance and fuel economy.

The head cracking issues with the 1KZ-TE do concern me though. I've read the epic thread on that...

...a couple of times and the situation seems to be preventable with a bit of attention to the cooling system and fitting of a more precise coolant temp gauge.

If I got a 1KZ-TE I'd likely fit a separate transmission oil cooler anyway, as well as flushing the cooling system and refilling the viscous fan. But, obviously, buying a 20+ year old truck, you don't know if it's been well looked after before you got it. I know to look for sludge round the radiator cap, listen for bubbling from the heater, look for strawberry milkshake trans fluid, etc. But an unscrupulous seller who's aware of these issues could change those fluids and clean up the evidence. Any other tips for spotting evidence of head problems or transmission fluid contamination while doing a pre-purchase inspection?

Then the 90 Series vs LC4 debate:

I was quite surprised, when getting insurance quotes to find that [exorbitant though they all were] it wouldn't actually cost me that much more to insure a mid 2000s LC4 than to insure a late 90s J90. [BTW I'm specifically saying LC4 as opposed to LC3 or LC5 as that seems to hit the sweet spot as regards extras, but without the overly complex air suspension system]. So I'm wondering if anyone has any opinions on that particular choice? I know this is the 90 section of the forum, so expecting a bit of bias. But I would be interested in honest opinions as to how the LC4 stacks up against the 90 series?

I should say that my use case for my Land Cruiser would be every day driver most of the time. Not really used that much though. Maybe a couple of shopping missions a week. But, away from the day-to-day missions, I'd be using it for lots of wild camping trips [mostly round UK and Ireland] and also I have several friends who live at opposite ends of the country. So a fair few long motorway journeys to visit them. So, while I'm reasonably mechanically competent and don't mind getting my paws oily when required, I'd much rather that be in the pursuit of adding improvements to an already reliable vehicle, rather than spending that time and money trying to keep a vehicle reliable in the first place. Which is why I have slight concerns about the 1KZ-TE as I'm already thinking I might have to budget a few hundred £££ to bullet-proof the cooling system if I got one of those, which would buy a nice set of new tyres for a newer model, where that wasn't an issue.

Hmmm... Decisions! Decisions!
Think you'll find that the E in 1KT-TE stands for Electrionic rather than mechanical pump. They're pretty much fettle free. The D4D is a far superior engine in terms of torque and power delivery. As long as all the factors are in your favour naturally. I've had both and there's no comparison really. Much more lively. That having been said, a 1KZ in good fettle is still a mightly fine power plant. Just suffers a bit on long overtakes when you want to get past a logging lorry!
Think you'll find that the E in 1KT-TE stands for Electrionic rather than mechanical pump. They're pretty much fettle free...

Ah. I didn't know that about the electronic pump in the 1KT-TE. That's the trouble with collecting opinions from the intarwebs. I'm certain I read a review of the 1KZ-TE the other day where someone was opining that anyone buying a 1KZ-TE should budget for an overhaul of the mechanical injector pump as they are pretty worn by 150000 miles.

That having been said, a 1KZ in good fettle is still a mightly fine power plant. Just suffers a bit on long overtakes when you want to get past a logging lorry!...

Planning my overtaking manoeuvres a week or two in advance wouldn't be anything new to me. I've previously had a couple of those old series 1 VW LT vans. So slow on hills, Continental Drift used to give them a nosebleed!
For my sins I have a KZJ95W-1KZTE. I am not a mechanic by any means, but I do whatever work that I can do myself on the car, which is a fair amount.

I have only experienced overeating issues once, and that was fully loaded, with an RTT too, travelling up a dirt track on the side of a mountain in the Pyrenees in ambient temps of 42 degrees! The first I knew of it was that the factory temp gauge was creeping up in a very alarming fashion. I put the cabin fans on full heat (not that pleasant when already hot outside) and stopped with the engine running and bonnet open, praying that the temps would drop. The overflow bottle was bubbling like a volcano, but the temps eased. We nursed the Prado up the trail in that fashion until we got to the top. It was quite an unpleasant experience, and the heating issues plagued us for the rest of the trip (we did coast to coast pretty much) Anyway, we made it home safe and sound.

Time for investigation. The long and short of it was that the viscous coupling was almost bone dry when I removed it and cracked it open, and the rubber seal was so distorted that I just had to buy a new coupling (I still intend to remove the new one and check the fluid levels for peace of mind, maybe refill it with 8,000 cst). The second thing that I found was that my radiator (which was fairly new from RoughTrax) still had an amount of Salisbury Plain clogging some of the vents in the outer extremities of the rad, despite me being quite anal about flushing it out after every Plain trip, perhaps 15 to 20% was obstructed. The third thing was that I fitted the lower temp rated thermostat over the standard one. Everything else was ok; I had replaced all the fluids, oil etc before we left on the rip as we knew it would be a biggy. Something else that I have added since is an in-line transmission cooler on the feed side to the radiator, to try to remove a little more heat before it goes through the rad for cooling, and for shits and giggles, I have also fitted an electric fan on top of the intercooler for when travelling at slow speed under load. Now I will not know if any of the things that I have done will work until I get back to that mountain, in similar heat conditions. I am also thinking of removing the fan shroud to add some heat resistant foam tape to the edges to maintain a decent seal, so that as much air as possible is dragged in through the front of the grill, and not pulling some hot air in from the sides from the engine bay. Apart from that one time heart attack inducing incident, the vehicle has been fantastic in every other aspect. It has plenty of welly and will cruise well at 90mph if you do not mind spending a fortune on fuel, myself, on highways I prefer 60 mph. I get an average of 24.9 mpg, or 11.3 litres per 100km, running 265/75 R16 AT tires.

I cannot comment on any other 4x4 because this is the first that I have ever owned, and despite it being a ‘baby’ Land Cruiser, without even a proper diff lock, I love it to bits. It has gone everywhere we have wanted it to, and more importantly, got us back home again!
It sounds as though you did some good research. I was also looking at Colorado’s and later LC4 s. In the end I found a Collie in excellent condition with a mint chassis. I had read about the cooling issues so I changed the rad, water pump, viscous fan and thermostat. I only use mine as a road car and for lugging stuff around with some towing. They are pretty simple things compared with the later models and I find that it does everything I ask of it. I used to have a Land Rover Discovery 3 which was a great car but as they get older the electrics can start playing up and they have other issues which can prove expensive. All in all I have been very pleased with the Collie and wouldn’t hesitate to recommend one, but do look at the history and check the chassis and back axle for corrosion if you look at any.
I've read someone else describe the 1KZ-TE as being like a ferryboat engine. You barely notice it's there apart from a low rumble but you get the impression it will shift and keep on shifting, and that's not a bad analogy. It's certainly not showy but it is a thing to fall in love with (in a low key kind of way).

I've not driven a D4D in Collie form, but have driven the (smaller I think?) version in various Hiluxes years ago for work when the engine first came out, having previously used older the 2.4td Hiluxes. The contrast was amazing, with the newer engine being much more lively and freer revving. Would I choose one over the other? Not necessarily. Would I choose a younger vehicle with fewer miles on the clock? Well, yes (all other things being equal).
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Have you thought about manual vs auto? I have owned a manual KZTE (sold) and now an auto (Prado with intercooler). I somehow missed the manual flexibility and control I have on higher gears, 4th 5th region. The auto tend to hunt up and down a bit between over drive and 3rd at that speed especially if you are on an long incline. And manual hasn’t got the transmission overheated issue, as there is no cooling via the cooling system.
While looking for the car I have also driven a Colorado auto, I.e. without intercooler, I have to say the different is obvious. Without the intercooler to increase another 15hp or so, the “drag” while accelerating and at higher speed is a bit frustrating and feel under power compared to a manual and one with intercooler. But a manual one is hard to come by now.
But apart from that, this car is just a good size, spacious, capable vehicle for family long trip, soft overlanding (without mod) reliable as a Toyota is...
When I was looking I really wanted a manual but they are hard to come by. In the end the one I bought was an auto really because the condition of the chassis and the rest of the vehicle was so good. Up to now the auto has been a nice thing to drive especially in town. I think someone else mentioned that because of the torque of these engines in a manual you don’t need to change gear that much and can almost use it similar to an auto, I know this is the case with my V8 Ninety Land Rover.
Thanks for all the replies folks.

I'm probably being a bit paranoid about the over-heating issue as most of the horror stories I've read have involved people towing heavy loads [which I'm unlikely to be doing] or doing hard driving in very hot climates [which, living in the UK is also pretty unlikely]. Any Land Cruiser I get would be unlikely to be asked to cope with anything much more arduous than the Highlands of Scotland, North Wales, or the West of Ireland. Mind you, that long M62 Summit climb coming back from Yorkshire into Lancashire has been a buttock-clenching drag in a few of my previous motors. --wondering if I'll make it to the top before the temp gauge goes into the red.

It's also good to hear that the 1KZ-TE is poky enough to sit at 90 on the M/Way. That sounds like more nippiness than I'll ever need. Having mostly driven old vans and 4x4s all my life, I found the fact my last VW Syncro would sit fairly happily at 70 to be a novelty. I'd got so used to being the guy crawling along at 55 in the slow lane and praying there wouldn't be any traffic cops about when I reached the next hill. Imagine the embarrassment of being pulled over for not meeting the minimum speed limit for a motorway!

All in all, and given the choice, I think I'd be more minded to go for an older Colorado/Prado, rather than a newer LC4 D4D although, as someone advised me on here a while back. "Just buy the first decent one you see!" --which, given the amount of "mint" ones on eBay with a litany of "underbody corrosion" advisories on their MOT history, is probably sage advice.

Ditto the Auto vs Manual debate.

Having only ever driven manuals, I set out on my hunt, determined to only buy a manual. But available manuals seem to be outnumbered about 10-1 by autos. So I've come to the conclusion that holding out for one that's both relatively rust free AND a manual, I'm going to be searching for the rest of my life. So, buoyed up by the many reassurances I've had from the people on here who have been in the same boat and have no regrets about opting for an auto, I've decided not to restrict myself on the transmission options. That said, if I had a choice between an auto and a manual in about the same condition and for the same money, I think I'd probably still go for the manual. Just because of the familiarity aspect.
My D4D 3.0 Hilux defo more powerfull than (even before I chipped it) the 1kzte Colorado I had, both auto. The Hilux also has a steinbauer chip now, so even better for power.
But mpg is the same pretty much same in both about 22-25mpg. Both modified with winch, lift, underbody skid plates etc.
Can't speak for the D4D but I had a 1KZ-TE manual Hilux surf for 15 years and it was awesome. Pulled like a freight train, easily cruise at 90 all day on the auto-route and an awesome tow-truck too, better infact than the 4.5 litre 80series that I've replaced it with. One memorable tow involved towing a 3.1 Isuzu trooper, itself towing a horsebox with two large horses in it!
It did crack a head at 330000kms. You'll see a few of my posts on the cooling the IKZ trail - I'm convinced their cooling problems are down to the bottom-hose thermostat causing the cooling system to thermally cycle, so if I had one again I'd definitely convert it to a top hose thermostat, plus all the colling-related stuff you've mentioned. Awesome engine IMHO but definitely don't trust the standard temp gauge, it is so damped to mask the inherent thermal cycling of the cooling system that it has basically 3 readings - bottom=Cold, middle=not cold, top=head gone
What is involved in order to convert to a top hose cooling system? Radiator obviously, all hoses to and fro engine. But what other model of radiator will fit the KZTE?
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You just need to fit a remote thermostat kit in the top hose and remove the innards from the standard thermostat. I'd definitely recommend fitting a good aftermarket temp gauge too. I fitted one of these as it also has a user-settable alarm. You can get a 2-channel one to monitor trans temp also if you're running an auto - ENGINE WATCHDOG TM4, Engine Temperature Sensor and Low Coolant Alarm - [Leaving Land Cruiser Club]

I have a remote thermostat kit here unused if you're interested - just PM me. The only reason I didn't fit it on the Hilux was the top hose is quite short and I was a bit concerned about remaining flexibility. Not sure if the 90 series is similar or has a longer top hose
I have both the 1kz-te and the d4d 90 so i can say from a sensible and practical point of view the d4d is the better engine , smoother and more powerful with better fuel consumption .

Whether its because the 1kz in mine has been significantly modified to give perhaps as much power and delivers it in such a way as to make even the mrs who doesn't much like driving grin is harder to explain , but we are in agreement that when the time comes to let one go to a new owner it will be the d4d .

I never fitted the aftermarket temperature gauge i bought for the 1kz because having towed a circa 750kg trailer hundreds of miles at 70 to 90+ mph for several days without a worry i reckon my 3" diameter turbo downpipe eliminated the overheating problem .

Different gearing to and i'm quite sure if i swapped the diffs truck to truck the d4d might be more fun to drive around town with lower gearing but i've no wish to do 120mph in a jacked up and modified 1kz .

In standard spec the d4d is better for motorways but for me it will never have the old school character of the 1kz-te .

Whats a pro for me might be a con for you so i will say once i drove a 120 and luxurious comfort for some translated to bland and boring for me . Different strokes for different folks .