1kz manuals overheating

[J_Dub]

So I've done a shite load of reading on 1kz's in regards to their overheating issues and it seems to be majority of the problem is with autos. Is there a reason for this or is it purely because most are autos, the manuals are rare and a lot of the problem is that the 1kz is in the larger auto Prado where they are used for towing so are over worked and bang????

I'm looking at buying a manual 1kz surf for cheap, and haven't found anything on the manuals being a problem.

Cheers

[derk]

those 1kz's go good but always factor in the cost of a replacement head, bigger exhaust, egr, egt shit etc when you consider buying one the trucks are worth nothing when the heads go bung

[J_Dub]

Cheers for that, but that didn't really answer my question, are the autos more susceptible to blowing headsor is it that the manuals are rear so obviously your gona hear about more autos going bang

[evolution02]

Autos load the engine more and have the trans cooler in the radiator.
But most problems will be common. A good radiator and good working viscous fan should keep temps normal

[oldblue]

IMHO I can't see any link between manual and Auto as far as head cracking. It is all to do with the year of manufacture, and cooling of the motor.

[UBZ]

my 1kz manual surf still got hot if I put it under too much load . ie powering up hill or deep soft sand
and that was with EGR / Exhaust / EGT / Lower thermostat / Heavy Weight oil in the viscous / New bigger radiator , water pump , timing etc etc etc .
once the heat got into the oil the water temp would climb fast .
Just because the the power is there doesn't mean you should use it .
they are a Small 4 cyl turbo diesel that only seem to be good for 300-400k before major work is required .
at 250k mine ran beautifully , didn't use any oil or smoke , but I never liked the hot idle oil pressure of 5-7psi. They would defiantly benefit from an oil cooler

[J_Dub]

IMHO I can't see any link between manual and Auto as far as head cracking. It is all to do with the year of manufacture, and cooling of the motor.

Because of what's stated above with trans cooler being restrictive to the cooling system and I guess with an auto you have less control over engine revs..

But yes I'm sure over all they need to be treated with caution, one im looking at has been owned by current owner since 80ks and its at 220 now, he's done no major work to it, it will only be a daily with a bit of beach driving to get to my fishing spots.

[Crash bandicoot]

I can count on one hand the amount of manual prado's i have seen.(not that ive really paid attention or interested in them).

As for cracking heads, It is a combination of things as apposed to one specific fault.

The exhaust system is rather restrictive compared to say a nissan TD27/QD32 or a isuzu 4jb1...even the late 80's early 90's 4d56 T pajero had a pretty neat designed and freeflowing exhaust manifold, following on from that the mass produced crush bend exhaust systems and a diesel's general ability to clog up mufflers with carbon deposits leads to a rather choked engine within 100,000 kms.

Next is a generic issue with any tall block petrol or diesel is the taller the block the more at risk of air locks in the cooling system. I will use nissan R series striaght six as an example. the 2/2.5/2.6 litre engines never had an issue but the 2.8 and 3.0 are known for cracking the head as the water jacket sits very close to hieght of the radiator and for simple lack of a check once week can lead to an expensive repair.

Another example i have noticed is the LN130 surf 2.4 where the heater core hoses and top radiator hose are higher then the radiator.
have always been suspicious of that set up.

Next on the list is trans coolers, under load trans oil (effectively low viscous hydraulic fluid) can get hot enough to deep fry frozen chips.......
(not that i have tried or recomend eating them) and since coolant temp only gets to around 110 C(or should) it tends to make the coolant hotter then the engine does.

Then there are exhaust gas recirculation valves. Good to get engines under the tier 3 emissions laws. but thats about it other wise they are more detremental then beneficial to an an engine already struggling to keep cool.

After that is meterlurgical or forge quality was the grade of aluminium used good/ recycled(made in china) was it QC passed by or recomended by the manufactureer of said vehicle/ head bolt quality gasket quality.

[Swamped]

they are a Small 4 cyl turbo diesel that only seem to be good for 300-400k before major work is required .

I assume its relevant but I've had my 1kz manual hiace since 80thou ks and now its done just over 480thou
Surely the van motors would be more prone to failure with overheating?
On top of normal service items it's had a new head (120k), flywheel, clutch slave cylinder, a couple frost plugs and glow plugs modded since I've had it. For the ks I've done I'm quite happy with how it's lasted given the loads its pulled and the fact it has no aftermarket exhaust or egt componentry. It still pulls hard, gearbox is quiet and turbo has no shaft play. Touch wood it remains that way for a while yet.

[zukmeista]

^^ I would call a new head 'major work'.

[Crash bandicoot]

^^ I would call a new head 'major work'.

yeep......bit like calling a crack whore clean...

I got a TD27-T well on its way to 500,000 kms. I dont think it'll ever get rebuilt cause i suspect all the bolts are siezed in place and would propbably snap if i tried to undo them.
And here's the real kick in the guts for yota owners. It's bolted to an auto thats done the same kms and spends its life towing a car trailer with another truck on it around.

sucks to own a prado i guess.

[Swamped]

...banging on with the old nissan engines again

I guess the head damage was likely done with the previous owner from poor servicing etc as its now done 3x the kms it did on its original head. Was cheap for a part from a dealer, I spent more rebuilding my patrol inj pump than the new head.
They don't last like a lot of the TD series do but still not a bad motor when regularly serviced being considerably gruntier than the 2.7 nissan imo. I'd much prefer not having a timing belt though.

Back to the man/auto overheating thing, a manual being lugged at low revs should heat up more with the increased fuel in the exhaust than having it rev when forced to down shift like in an auto? The radiator/cooler combo could have some effect but most likely as you say the prevalence of autos will mean they are over represented.

[J_Dub]

^^ I would call a new head 'major work'.

yeep......bit like calling a crack whore clean...

I got a TD27-T well on its way to 500,000 kms. I dont think it'll ever get rebuilt cause i suspect all the bolts are siezed in place and would propbably snap if i tried to undo them.
And here's the real kick in the guts for yota owners. It's bolted to an auto thats done the same kms and spends its life towing a car trailer with another truck on it around.

sucks to own a prado i guess.

So like like Nissans then??

Give it a rest, your obsessed

[J_Dub]

Good bits of info guys, cheers.

Will be picking it up today.

I'm sure it will be fine for now for the 40km round trip to work.
But definitely doing viscous van and fitting a temp gauge straight out

[tweake]

Cheers for that, but that didn't really answer my question, are the autos more susceptible to blowing headsor is it that the manuals are rear so obviously your gona hear about more autos going bang

most of what you hear about is from the auto's simply because they are far more common.

but the auto does add quite a large amount of heat and also it puts it into the cooling system on the cold side of the radiator just before it goes back into the engine. so it basically removes some of the cooling ability to the engine. factor in that they run, like most typical jap engines, rather hot. then all you need is a decreases in cooling ability, like any engine, suck as partly blocked radiator and it goes from working fine to head cracking.

the other thing is oil cooling, jap engines typically run the oil very hot. unfortunately the oil cooling again is on the cold side of the water circuit. so there is a limit to how much heat you can put in before you remove to much cooling ability of the water.