Why don't our LJs suffer the same head problems as the JDM models?

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Canarias

Canarias

10 Year
Joined
Jul 10, 2012
Threads
20
Messages
354
Location
Canary Islands (Spain)
I did plenty of research before buying an LJ73, and one thing that confused me was the reputation in other markets for the heads cracking, which didn't match up with the experience of the professional mechanics I share a workshop with. Asphalt is a newish phenomenon here. Every other car is a Hilux or a Landcruiser (exaggeration but only a slight one). With so many 2LTs going strong after 25-30 yrs - in some cases with half a million KMs or more, there must be something fundamentally different with the JDM models (and perhaps other markets too?) So I'm trying to get a complete picture of the differences between the engines we have here, and the engines that suffer the problem. And whether that means that here in the Canary Islands we can relax and not worry about this problem. I'm going to put my LJ73 up for sale & want to be able to give an honest representation of what its strengths/weaknesses are.

- Problem affects the 2L-TE found in JDM models more than the 2L-T. Apart from the lower compression and lack of electronics, what other differences are there that might contribute to the -T being stronger?

- Lack of EGR. I'm thinking this might be THE main factor. How have people with JDMs who have deleted their EGR faired, is it deemed to "solve" the problem or at least make a huge difference to recurrence of overheating?

- Coolant. It's subtropical here. The coolant we use has a freezing point of -4C. Does the lack of antifreeze properties give it a higher boiling point?

- I've seen mention of cracked 2L-TE heads on UK & Aussie forums. Do the 2L-Ts in those markets suffer too, and if so do they have EGR?

- Anyone have info on which markets and models got 2L-T vs 2L-TE and more interestingly which 2L-Ts got EGR vs non EGR. I know there are some -TE models here but I don't hear of bad rep for them, could just be because of the smaller sample size? Particularly interested to hear of experiences and data from mainland Spain. I've heard that Canary Islands got models spec'd for African market and models that were never offered in mainland eg BJ40 but no idea how much truth is in that. If we've got a heavy duty non EGR spec of the 73, what other differences are there?

Below is a pic of my 2L-T intake manifold. Circled is where you would expect the EGR to come in. That's not a blanking plate, it's machined that way. But the bolt holes for the EGR pipe are there. So the manifold doesn't predate EGR, it seems it has been deliberately omitted in the factory? Why? Different emissions laws or known problem in hot countries?

NoEGR.webp
 
Also interested in an answer to your question. This is an LJ70 2LT. Delivered via Antwerp 1986 in what I've assumed was a standard configuration for the European market. All stock with 320,000 km., doesn't appear the head has ever been off, or anything else for that matter. Runs cool and strong (relatively).


20150316_0757329669.webp
 
My hypotheses is that the it's the roads, or more specifically, the usage of the engines on the roads, which causes the blown heads. Here in North America, where every smart 2LT owner has a Hello Kitty PEZ-style dispenser for spare heads in their garage, the freeway system seems to invite long, high speed, high heat runs in these engines which are, frankly, under powered for these conditions. I propose that head's can't handle that. Lower speed or shorter runs may be gentler on the heads and help them live long. Does anyone have data to disprove my null hypothesis with p-value <0.05?
 
I don't offer anything to prove or disprove. Have made several short trips to the key's to slay Panulirus argus, 400 + miles one way, mostly highway, mostly wide open. It'll burn more fuel at those speeds, (75 or so) but that's about it.
 
We can't do a 3000 mile coast to coast run but where I live has the third highest volcano in the world and Spain's highest point. Roughly half the driving here is up a steep hill and the other half is down a steep hill, including our motorways which are generally travelled at 70-80 mph (or die trying). Gets to 110F once or twice each summer. Bonafide head cracking country, replacing head gaskets is a national industry. But not specifically for the 2LT.

I can't disprove your theory but I'm still leaning towards the technical differences between the engines being a factor.
 
Canarias said:
I did plenty of research before buying an LJ73, and one thing that confused me was the reputation in other markets for the heads cracking, which didn't match up with the experience of the professional mechanics I share a workshop with. Asphalt is a newish phenomenon here. Every other car is a Hilux or a Landcruiser (exaggeration but only a slight one). With so many 2LTs going strong after 25-30 yrs - in some cases with half a million KMs or more, there must be something fundamentally different with the JDM models (and perhaps other markets too?) So I'm trying to get a complete picture of the differences between the engines we have here, and the engines that suffer the problem. And whether that means that here in the Canary Islands we can relax and not worry about this problem. I'm going to put my LJ73 up for sale & want to be able to give an honest representation of what its strengths/weaknesses are.

- Problem affects the 2L-TE found in JDM models more than the 2L-T. Apart from the lower compression and lack of electronics, what other differences are there that might contribute to the -T being stronger?

- Lack of EGR. I'm thinking this might be THE main factor. How have people with JDMs who have deleted their EGR faired, is it deemed to "solve" the problem or at least make a huge difference to recurrence of overheating?

- Coolant. It's subtropical here. The coolant we use has a freezing point of -4C. Does the lack of antifreeze properties give it a higher boiling point?

- I've seen mention of cracked 2L-TE heads on UK & Aussie forums. Do the 2L-Ts in those markets suffer too, and if so do they have EGR?

- Anyone have info on which markets and models got 2L-T vs 2L-TE and more interestingly which 2L-Ts got EGR vs non EGR. I know there are some -TE models here but I don't hear of bad rep for them, could just be because of the smaller sample size? Particularly interested to hear of experiences and data from mainland Spain. I've heard that Canary Islands got models spec'd for African market and models that were never offered in mainland eg BJ40 but no idea how much truth is in that. If we've got a heavy duty non EGR spec of the 73, what other differences are there?

Below is a pic of my 2L-T intake manifold. Circled is where you would expect the EGR to come in. That's not a blanking plate, it's machined that way. But the bolt holes for the EGR pipe are there. So the manifold doesn't predate EGR, it seems it has been deliberately omitted in the factory? Why? Different emissions laws or known problem in hot countries?

View attachment 1046249
Click to expand...

Some great questions and ideas here. Thanks for addressing this. I've done a LOT of reading on this topic, and have also noticed the 2LT and 2LT-II seem to suffer head damage much less than the 2LTE. I think there are a few key differences, some of which you have identified. A couple comments on your points:

- The EGR is detrimental primarily because the soot mixes with the crankase ventilation oil and builds up a thick layer of sludge in the intake manifold, head intake ports, and even on the backs of the valves. This means less air enters the engine, which in turn causes higher EGTs. When I cleaned this sludge out of my 2LTE, it made a big difference.

- Perhaps the coolant you are using is more thermally efficient? I know the higher the water ratio, the more efficient a cooling system is. But of course it is more prone to corrosion, freezing, and less lubricative.

There are a number of other things to keep in mind I think:

- The short wheel base is lighter than the long wheel base. This means the engine in an LJ73 works less hard than an LJ78 for example. In Canada, it seems to be the long wheel base version suffer more of the head failures.

- A manual transmission verion will run cooler than a automatic transmission. Most of the LJ's here are automatic. The automatics use the radiator to cool the transmission fluid which contributes greatly to increased load on the cooling system. When climbing large hills with a stock LJ78 in Canada, the transmission often ends up in 2nd gear out of lock up. This means the torque converter is generating an immense amount of heat at the wrong time.

- Are your LJ's air conditioned? A hot A/C condensor in front of the radiator means hotter and more restricted air entering the radiator.

- The LJ78 in Japan was a semi luxury vehicle. I know for fact that Toyota setup the cooling fan viscous hub differently in luxury models so that they would run quieter. This is also prevelant on the Lexus 80 series in North America. The fans are set to engage late, and the fluid is less viscous than other landcruisers (less viscous means less power transfer to the fan). I upgraded the fluid in mine, and adjusted the thermal valve spring, and it made a world of difference to the cooling.

- Most of the LJ78/LJ71 coming to Canada from Japan were very poorly maintained. The radiators are clogged, and the systems often full of rust. This certainly does not help the situation. Perhaps in other countries they have been better maintained.

In my opinion, the head cracking of the 2LTE occurs when the coolant entering the engine from the radiator reaches a point that it cannot sufficiently cool the head. As you know, the L engines are indirect injection, which means they have pre-combustion chambers in the head. The problem with this design is they loose a lot of heat (efficiency) into the head (as opposed to more efficient direct injection engines). The areas in the head around the pre-combustion chambers and between the valves are very hot. Under heavy load, with high EGTs, as the coolant begins to heat beyond a certain point, localized boiling occurs in the head. This localized boiling occurs long before the temperature gauge indicates a problem (in my experience it happens just over 1/2 on the indicator) This boiling creates a vapor barrier, which prevents adequate heat transfer, and causes hot spots in the head. The hot spots with no way to cool down, can reach very hot temperatures (100's of C, maybe even up to EGT temperatures), compared to the rest of the head which is at coolant temperature of around 100C. This stresses the metal. After repeated stressing, the metal finally cracks.
 
I should also add that I think the electronic controlled diesel injection system in stock configuration on the 2LTE is detrimental to the motor. Toyota did things to make the motor run quieter and produce less emissions (Nox). I think they also try to get more power out of the motor. None of these things to the benefit of keeping the motor cool and lowering EGTs. The high compression ratio makes for some very high pre-injection temperatures, doing nothing to help keep the motor cooler.
 
Great info, thanks. I've seen the issues discussed on MUD in many threads, but I've never seen discussed the fact that there are 2L-T engines that come from the factory without EGR. Has anyone ever heard of a non EGR equipped 2L-T suffering from a cracked head or even any kind of overheating event apart from in cases where there's a failed fan or leaking radiator? I'd love to know if the EGR delete is job-done or if owners still need to take other measures such as intercooler, EGT gauges etc. I can't get my temp gauge to halfway, even on fast runs uphill.

And yes I can see how the lack of Aircon and the manual box are working in my favour. Additionally, the radiator fan is always on. If its sposed to be viscous and its broken it would be always off?
 
I know that 2LTE's with the EGR removed still crack heads. So that would indicate removing the EGR alone is not enough to stop the problem.

The fact is there are a number of differences on the non-EGR factory engines that all contribute to less of a heat problem on those engines.

I'm pretty certain I've heard of cracked heads on all turbo L series engines, but I agree that they are far fewer on the 2LT and 2LT-II.

The viscous fans are always spinning to some degree, they don't completely stop, they just move more or less air depending on how engaged the internal hydraulic mechanism is. It should be very noticeably when you rev the engine cold (after maybe 5 min of running for the internal pumping system to work), vs when you rev the engine after some hard hot driving. When fully engaged, the fan moves a massive amount of air. Out of curiousity what color is your fan hub? The 2LTE ones are blue. The color apparently indicates the destination market/climate.
 
The 2LT is also notorious for cracked heads. I'm sure the egr on the 2LTE adds to the problem, but the problem exists because the head is aluminum. The 2L naturally aspirated engine was a good design, but once toyota introduced the turbo to the equation, it became an overheater. Rule of thumb, "never put alluminum on a Diesel engine"! The 3L is a 2.8 liter diesel with a steel head, these motors perform very well when a turbo is added.
How you drive these vehicles has a lot to do with how cool they stay. If you are driving at highway speeds in top gear and you hit a steep hill without gearing down, your egt will climb and cause the engine to overheat. If you live in a country wihout asphalt you're probably never getting past third gear anyway.

When I import these 2LT vehicles, I always put he 3L head on them and they never overheat!
 
mudandrock said:
The 2LT is also notorious for cracked heads. I'm sure the egr on the 2LTE adds to the problem, but the problem exists because the head is aluminum. The 2L naturally aspirated engine was a good design, but once toyota introduced the turbo to the equation, it became an overheater. Rule of thumb, "never put alluminum on a Diesel engine"! The 3L is a 2.8 liter diesel with a steel head, these motors perform very well when a turbo is added.
How you drive these vehicles has a lot to do with how cool they stay. If you are driving at highway speeds in top gear and you hit a steep hill without gearing down, your egt will climb and cause the engine to overheat. If you live in a country wihout asphalt you're probably never getting past third gear anyway.

When I import these 2LT vehicles, I always put he 3L head on them and they never overheat!
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Can't say I've ever heard of a 2LT/2LTE (or any L engine for that matter) having an aluminum head. Are you thinking of the 1KZ engine? You're right though, the problem is ultimately the extra heat resulting from the turbo (more air more fuel, more heat). Thats why all the normally aspirated L engines don't have heat problems.
 
All the jdm 2LT/E have alluminum heads including the North American 2L. If the European one's have a steel heads then we've discovered why they have a better reputation, but I've never imported one so I don't know for sure. 90% of all the jdm ones come in with cracked heads, the other 10% we rebuild any way because we know it's just a matter of time.
 
When I put the steel 3L head on, I don't even delete the egr. No overheating issues! Just delete the alluminum, problem solved!
 
Cool, well that's good to know that the European one's have steel heads. I'll look into importing one. I think the jdm ones are easier to get parts for though.
 
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