This is gonna be a longer and somewhat thourough article so brace yourself !
First of all lets briefly check out 2 high mileage examples of this Toyota, since it’s gonna help to make a better picture of these cars before we get to the more serious stuff.
595 000 mi / 957 000 km
HERE is an article about a 2004 Land Cruiser Prado with the 161 hp 3.0 D4D diesel engine with almost 600 000 mi. The car has a 5 speed automatic gearbox and the optional air suspension on the rear axle.
If you can’t open the article here are the things which were replaced on this car:
- injectors after 60 000 mi
- rear suspension air struts
- air suspension air compressor
- alternator (a few times)
- the multimedia system broke but was repaired
- regular maintenance items (batteries, brakes, wheel bearings)
- currently the AC is not working
service is carried out every 10 000 mi-oil change and filters, and the timing belt is replaced every 60 000 mi
the car has original engine and gearbox
484 000 mi / 779 000 km
HERE is an article about a 2008 Land Cruiser Prado with the 170 hp 3.0 D4D diesel engine with almost 484 000 mi. The car has a 6 speed manual gearbox and a standard coilover suspension.
If you can’t open the article here are the things which were replaced on this car:
- injectors under warranty
- drivers airbag squib (the component that sets the airbag off)
- windscreen wiper linkage
- starter motor
- brake calipers
- regular maintenance items (battery, brakes, wheel bearing)
service is carried out every 10 000 mi-oil change and filters, and the timing belt is replaced every 60 000 mi + gearbox and differential fluids are replaced every 95 000 mi + the owner never lets it idle for long periods when warm
the car has original engine and gearbox, clutch and turbo
So as you can see the 3rd generation Toyota Land Cruiser Prado – a.k.a. the Land cruiser 120 is capable of reaching very high mileage without much issues. There is no doubt about that. If you need a comfortable well-built off road car and you don’t want the legendary bigger Land cruiser then this really is a great choice. And according to those 2 examples it has bulletproof reliability !!
But is it really that straightforward? Well not really. While it’s true that the petrol engines in these cars are great and reliable, the diesel engines can have a couple of issues which can destroy them. So let’s check them out more closely.
Believe it or not, this Toyota was available with 3 3.0l 4 cylinder diesel engines:
The 5L-E is very simple and very reliable, but it doesn’t have a turbocharger so it has that much power as a retired snail smoking weeeeed, and it’s so rare, that even I’m not sure if it was really available in these cars (it was, they say). So let’s just move onto the other, slightly more popular engine, which is the 1KZ-TE.
This 1KZ is not that powerful either, but it’s generally speaking reliable without unexpected issues. However if you manage to overheat it then you will end up with a cracked cylinder head, so make sure that the cooling system of the engine is working properly:
- check for coolant leaks
- check the viscous fan hub/fan clutch which can fail (video about fan hub issues)
- check the radiator if it’s not clogged
- it’s better to not tow very heavy stuff or don’t push the car very hard in hot weather
(cracked cylinder head symptoms: coolant loss without visible leak, oil in the coolant, bubbles in the coolant overflow tank, overheating, white gunk under the oil cap, steam from the exhaust)
Also if you change the oil in this engine every 8 000 km / 5 000 mi then you will maximize the lifetime of the mechanical components a.k.a. the engine is gonna live forever with this oil change interval (until you overheat it). Before buying it’s good to rev the engine and check for smoke from the exhaust – if you see smoke from exhaust during acceleration then most probably the injectors are already worn out so occasionally it’s good to replace them-like every 300 000 km to keep the good efficiency and performance of the engine.
This is the newer, most known and most common engine which can have various power outputs: 120 KW, 122 KW, 127 KW. It has an iron cylinder block, an aluminum cylinder head, 1 turbocharger, common rail injection and a timing belt. All of this sounds ok. And actually, I can’t say that this engine is bad since all the main mechanical components can withstand more than 500 000 km without much wear (except the pistons). Yes, the pistons… Once upon a time in the year 2006 Toyota slightly upgraded these engines to comply with the EURO 4 emission standards, and they also got new pistons! But let’s not overtake the things because there are also the injectors!
INJECTOR SEATS LEAKING
First of I have to mention the metallic sealing washers under the injectors which can, and they will leak at some point. This is not good → since carbon soot contaminates the engine oil → this soot will clog the oil pickup strainer → restricting the flow of oil → which will cause oil starvation → which can kill the engine if you don’t catch it early enough!!!!! Now, the most important, the most easiest and the cheapest thing is to: check the oil pick up strainer every oil change – which is easy since after you remove the oil drain plug you will see at least part of the strainer and if its clogged or not.
So you should definitely check the strainer right after buying and every oil change + if you want to be very thorough you can buy a small endoscopic camera and use that to check the whole oil strainer thru the oil drain hole.
Symptoms of leaking injector washers:
- clogged oil pickup strainer
- louder knocking noise from engine after cold start
- white/grey smoke from the exhaust at first engine start – when the engine is cold
“replacing all the injector washers + all the required seals can cost approx.: $560 (if you want to have the injectors tested too → and you should, then keep another approx.: $300 for the testing)”
This issue affects mostly cars made to 2007 since Toyota used weaker injector washers in these cars which can easily leak before 200 000 km (there have been numerous cases of total engine failures because of this issue in these 2007 and older cars with less than 200 000 km). But from 2008 Toyota updated the washers + in some countries there was also a recall for this. So the good thing is: plenty of these cars do have the updated better washers already fitted. But the bad thing is: in many countries there was no recall so there are still cars equipped with the weaker washers-mainly lower mileage cars-with less than 200 000 – 150 000 km, and even the updated washers are not gonna last forever! That’s why it’s good to replace these washers preventively mainly on these cars made to 2007 if you don’t have a proof that they were replaced in the past.
Why is it a good idea to preventively replace the injector washers?
The problem can be if the previous owner replaced the injectors and he either re-used the old washers or if he used aftermarket washers which can fail prematurely. So always use genuine injector washers! Now you can ask, how often you should replace these washers? Well, nobody knows when exactly these washers are gonna fail! The genuine updated washers can easily last way over 200 000 km, but as with the injectors it’s good to consider replacing them preventively. The interesting thing is that the service manual says that: you should check the valve clearances on this engine every 40 000 km. During this procedure you have to remove the injectors as well, and if you remove them then you automatically have to replace the already mentioned washers+seals on the injectors. Now, if someone removed the injectors in the past and re-used the old washers then obviously they are gonna fail prematurely. This valve clearance measuring procedure requires some disassembling so it’s not the cheapest and that’s why I don’t think many of the owners actually do check the valve clearance every 40 000 km. On the other side the valve clearances are usually fine even at 100 000 or 150 000 km and even after that the valve clearance can be just a little bit out of spec. So checking the valve clearance is most of the time not necessary this often, even though if you want to follow the service manual then you can. ALL IN ALL: if everyone would follow the service manual to the last word and did the valve clearance check every 40 000 km then THERE WOULD BE NO ISSUES with the injectors washers like EVER, since they have to be replaced every time you take out the injectors!
“The worst combination is when the previous owner put bad quality or even used injectors in the engine in the past + he re-used the old washers or put bad type of aftermarket washers there! And this is why after buying a used 1KD engine you should preventively at least remove the injectors → have them tested even if they look fine → and replace the washers with the genuine Toyota washers! Of course if you want to spend the extra money then you can replace the injectors at the same time as well + while doing all this check the valve clearance and eventually adjust it. Obviously if you have a good proof that the previous owner already replaced the injectors and the injector washers with good quality parts, then you don’t have to do this.”
Fun fact: Toyota got rid of this issue only in the newer 150 models from 2015:
The 1GD 2.8 l diesel engine made from 2015 in 150 models has improved injector mounting – the injectors are more like externally mounted so the oil pickup strainer clogging issue is not common on these engines. It’s also because the injector rubber oil seal is mounted way upper on the injector so it’s more away from the heat-the lifetime of it is bigger, and if the washers on these injectors do start to leak, then the leak will be externally visible on the valve cover. But all in all, the injector washer lifetime should be similar on these engines too so they will last 200 000 km, but after this mileage point it’s better to replace them.
The next issue related to the injectors are the injectors themselves. They can fail even before 200 000 km and even on the newer land cruiser 150 equipped with this engine. How can they fail?
- they can be weak
- they can leak
- they can have bad spray pattern
Symptoms of bad injectors: rattling noise from engine, loss of power, jerking, limp mode-check engine light, smoke from exhaust when accelerating, bigger fuel consumption
But the worst thing is that they can cause wrong combustion. Wrong combustion… keep this in mind you will hear it later. Anyway, if you got one of the symptoms of bad injectors then have the injectors at least tested or replace them, and if your car has more than 200 000 km then it’s a very good idea to replace the injectors preventively if you want them to be reliable, efficient, and to perform as they should!
Some owners are replacing the injectors preventively every 130 000 km, 100 000 km or 150 000 km. Some mechanics recommend replacing them preventively every 100 000 km, but to be honest this looks like a wasting. The most optimal is to replace them every 200 000 km with new genuine washers of course, and check the oil pan pickup screen for debris every oil change + monitor your car for weird behavior which can indicate issues with injectors like: light grey or white smoke from the exhaust, strange fuel consumption rising, jerking while driving, or bigger rattling noise from engine.
To be honest, most of these cars already have more than 200 000 km so it’s definitely a good idea to replace the injectors preventively, and if you buy a car with 300 000 km or with 400 000 km then there really is nothing to talk about. And yes, the injectors can last 300 000 km or 400 000 km but if you want them to be reliable, efficient, and to perform as they should then replace them preventively. But of course if you want to leave the injectors there for a longer time it’s fine-it’s your choice, and maybe you will be lucky to experience no issues with them. However after 200 000 km the performance of the injectors is gonna be much weaker than it should be anyway + the spray pattern is not gonna be great at all, and also there is a higher chance that they will fail – like for example start to drip fuel.
PISTON FAILURE / CRACK
And now we reached the scariest and the most expensive issue these engines can have – cracked pistons.
- The piston can crack suddenly without any prior symptoms! Symptoms of a sudden piston crack: knocking noise from engine, black smoke from exhaust, lack of power, misfire/uneven engine running, excessive crankcase pressure
- However the piston can also crack very slightly which means that the car is going to drive fine for a longer time only with one prior symptom – a louder knocking from the engine + oil consumption can appear too. But obviously sooner or later, in this case the engine is gonna stop running as well.
Keep in mind that nobody knows when or if this issue is gonna happen – it can happen anytime! There are cases when this piston failure happened even before 100 000 km so it can occur in low mileage cars too, so obviously there are also cars which had a new engine fitted under warranty because of this. Then there are cases of cracked pistons before 200 000 km but also after 200 000 km, or just later after 400 000 km for example.
What does that mean if you actually end up with a cracked piston? Well, in this case usually not only the piston is gonna be damaged, but also the cylinder wall – so you have to disassemble the engine, repair or replace the engine block + replace all the pistons and some other parts + of course you should check the crankshaft if it’s not damaged. All in all be ready that the repair cost of this issue is usually somewhere between 5 000 € – 11 000 € – obviously if you are going to replace only the 1 faulty piston itself then the price is gonna be much lower, but it’s not worth it since the other pistons can crack anytime as well. So in this case definitely replace all the pistons with the latest updated/revised/stronger pistons-made from 2017, since Toyota updated the pistons several times and the latest revision was in 2017 (or there are also aftermarket pistons which are designed with improved cooling channels).
But I have to add that this issue is not extremely common. However you should keep in mind that even if the chance that your piston cracks is not that huge, it can still happen, and that’s why it’s good to know the possible reasons behind this!
Some say it’s because of the faulty/weak piston design and someone is perfectly sure that it’s caused by the faulty injectors only. But one thing is for sure, this issue affects cars made from 2006 which comply with the EURO 4 emission standard. Mostly cars made from 2006 to 2009 are prone to this failure, BUT the newer 150 models equipped with these engines – mostly up until 2013 are not safe either, there are only less cases of piston crack from these newer 150 models. But since the latest piston revision was in 2017, we can speculate if the 150 models aren’t slightly affected even until 2016!
Toyota acknowledged the problem so in 2014 they released a document about this issue. According to this document, Toyota improved the injectors and they changed the piston shape to get rid of this problem. So the injectors causing wrong combustion and the pistons themselves should be the 2 main reasons:
—First, let’s check out the pistons: I would lean more towards the bad piston design, since according to the parts catalog in august 2006 Toyota updated the pistons, and from 2006 there is this possible issue. A big contributing factor to the crack is also the heat. So it seems like the top of these pistons can overheat and it also seems like the oil channel in the pistons is not sufficient either.
To make things even more interesting this kind of a piston crack can sometimes occur in other diesel engines too. But I have to add that on the other diesel engines the crack is mostly caused by faulty injectors only. On the other side in these 1kd Toyota engines the piston cracks are suspiciously common and well known. So yes, a faulty injector can cause a crack in the piston, but if the piston is weak or if it has bad design then it can crack even without an injector failure. This is why specifying an only, single and concrete reason for this problem is not really accurate and there are also many shady variables which can contribute to this.
—Then there are the injectors: the injectors are gonna get worn over time, yes they can work even after 400 000 km or 500 000 km but their performance is gonna be weaker as the mileage and age increases and the possibility of failure is gonna increase.
- An incorrect injector spray pattern is going to cause wrong combustion and a wrong combustion is going to increase the chance of a cracked pistons
- The faulty injectors can drip fuel which can easily damage the piston as well
- And lastly, the injector can end up stuck in open position – so the injector fails and over fuels the cylinder which can melt the piston and also damage the cylinder wall – but this is pretty rare
“In many cases owners said that bad fuel caused an injector failure and a burnt hole through piston. Can a bad fuel cause an injector failure? Well, if you are like really unlucky then yes, but this is more of a side contributor I would say.”
Now you can ask: if I change the injectors do I prevent piston failure? Well no, since you still have the pistons with seemingly improper/weak design fitted. However with new injectors and with using good quality fuel you will at least eliminate the incorrect combustion.
HOW TO AVOID PISTON CRACK?
The most important thing is a list of things which you can do to minimize the chance of this issue. Yes, minimize, since you can’t eliminate or avoid it for 100%. (Well actually you can eliminate it, but only if you replace all the old pistons preventively with the newest updated pistons. But I don’t think many of the owners are gonna choose this expensive preventative measure… ) So how to minimize the possibility of cracked pistons?
-Eliminate the possibility of wrong combustion!
- have the injectors in good condition (have the injectors tested regularly or replace them preventively)
- use good quality fuel (bad quality or contaminated fuel can also contribute to the piston crack)
-Protect the pistons from bigger stress!
- avoid engine performance upgrades (but there are also many cases of piston failures on completely stock cars)
- don’t tow very heavy shit (but there are also many cases of piston failures on cars which were not towing)
- don’t use the maximum power of the engine at all or use it only for a very short time
- change the engine oil regularly after max 10 000 km (+keep the oil strainer clean)
- keep the cooling system in a perfect condition + you should know the temperature of the engine, exhaust, and gearbox so fitting additional temperature sensors is a good idea as well, and make sure your radiator is not clogged, the water pump is fine and there is enough coolant
- avoid high speed long duration drives – in other words driving on the highway at 160 km/h or more is NOT a good idea especially in hot weather
Also keep in mind that the high temperature on the top of the pistons is a contributing factor to the cracks. And high speed, high load, high rpms and long durations of these are going to increase the temperature on top of the pistons which is gonna increase the stress and the chance of cracks. So don’t cruise on the highway at higher speed keeping the rpm near or past 3000 – in other words cruising at 140km/h is fine, but cruising at 160 km/h or even faster while keeping the RPMs higher is not good especially in hot weather!
Lastly I have to highlight that doing all this is not going to eliminate the possibility of piston crack, but it is gonna at least reduce the chance of it happening ! So In other words even replacing the injectors preventively, using good quality fuel and paying attention to the other already mentioned things is not going to eliminate this issue, but it is going to reduce the chance of it happening. And by the way all these issues also affects the Toyota Hilux from this time equipped with the 1KD engines.
OTHER COMMON PROBLEMS
-check the frame for excessive rust mainly on cars used on winter salty roads, since the frame on these cars is going to rust you like it or not. But this rust is usually still not a big concern today, however in the future it’s definitely going to be a problem if you leave it as is!
“The car can look great from the outside but it can have already a big amount of rust on the frame”
–the front brake caliper pistons can more often rust and seize up: mostly cars used on winter salty roads. This will cause: uneven brake wear, slightly weaker brake force, eventually noises from the front brakes. (“the brake caliper piston repair kits are cheap”)
-the wheel bearings can get worn more often mainly in the front even before 200 000 km
-the optional air suspension on the rear axle is gonna sooner or later fail: the air struts are going to leak and the air compressor is going to break at some point
-occasionally the transfer case actuator can act up
–there are many cases of usually slight oil leak from the transfer case
-AC gas leaks can occur
-coolant leaks from the radiator can happen too
–the fuel filler hose under the car can leak (more often on petrol engine cars)
–the steering rack can slightly leak more often
-the turbo actuator can fail, as well as the EGR on the 1KD engine, the turbo actuator can fail causing: limp mode/loss of power and a P1251 fault code, the actuator can be replaced separately – you can buy it under $500
–SCV valve can fail on the 1KD engine, causing: limp mode/loss of power, weak acceleration, check engine light, bad engine starts
-water leaks in the trunk can occur because of the trunk door seal or because of the 3rd brake light
-the dashboard is going to crack sooner or later if it’s not cracked already
“REPLACE THE GLOW PLUGS IN DIESEL ENGINES AT LEAST EVERY 100 000 km, mainly preventively because sometimes the glow plug tip can fall off into the combustion chamber and that’s obviously not good.”
That would be it I guess. But if you still don’t know what to do and if you are still completely confused, let me summarize the things up a bit:
If you are buying any of the 1KD engines then right after buying you should definitely:
–check the oil pickup strainer:
- if the oil pickup strainer is clogged → then remove the oil pan and clean it and replace the injector washers + have the injectors at least tested or replace them if you want to be on the safe side
- if the oil pickup strainer is clean, but you don’t have any solid proof that the injectors or the washers were replaced in the past → then consider removing the injectors to have them at least tested + replace the injector washers and seals, but if you want to be on the safe side then replace all the injectors
-if you don’t want to spend money then at least pay attention to the faulty injector symptoms
-if you are frightened from the piston crack issue then choose a car made before 2006 which is not complying with the Euro 4 emission norms
And if you have personal experience with this car or if I fucked something up then you can write it into comments!
1KD Piston Technical Service Bulletin