2L-T Engine Warning

[JuanJ]

Hello,

I just found a warning on an old owner's manual regarding 2L-T engine operation. It applies to the 13B-T as well.

The notice advises to let the engine idle for a while after heavy loads (i. e., sustained operation at high speeds, towing or negotiating slopes,) before shutdown. Failure to observe this can result in "severe engine damage." I wonder if this has something to do with the infamous cracked head syndrome.

I am also wondering if JDM LJ7x owners ever cared about this. This could explain why so many of them puked their entrails in Canada.

Could there be a connection?






Juan

 

[Falco80]

I'm pretty sure that would be because those engines are turbocharged. Shutting down a turbocharged engine straight after it has been working hard will no doubt shorten your turbo's life. The turbo needs engine oil pressure to lube it and to take some of the heat out of the core. It would probably still be spinning quite fast if the engine was really loaded up so once you shut it down the shaft is still spinning but has no oil feeding it, which is no good for the bearing.

I'm not fully aware of the 2L-T's shortcomings, but i would've thought that a cracked head would be common due to poor cooling system design or something like that. A factory turbocharged engine's cooling system should be more than able to handle the added heat from the coolant flowing through the turbocharger.

I'm sure others more knowledgable on the 2L-T will chime in.

 

[PERUVIAN]

I agree with FALCO80.. premature shutdown without sufficient cooling/spooldown can cause turbo damage.. mostly oil boiling and coking on the bearing areas and and/or compressor or turbine wheel edge damage due to the oil cushion disapeering and the wheels contacting the housing .. and in super extreme cases.. seizing - in our aircraft that run high performance turbos.. if coming in hot.. ( not a controlled descent and cooldown peroid..) mandatory 5 minutes on the ground at 1000 rpm.. ( in our cases.. idle (650) doesn't provide enough oil flow to prevent scoring, coking, or other damage ) I agree with Toyota.. cool your turbos-

 

[Stone]

I always idle my 12HT prior to shutting down no matter what kind of driving I've done. This is why all turbo diesel engines need to have pyrometers...I idle mine until the EGT's are down to at least 400*F. When doing normal city driving, it only takes a few seconds to cool down that low...after a long highway pull with a loaded truck and boat on a trailer, it takes a few minutes.

Did the same thing when I had the BJ74.

2LT's in Canada are puking their entrails out because there's really no way to be sure how they were treated in Japan during the previous 15 years of their lives, is there? No matter how pretty and low kms a truck is, it could still have been severely neglected in terms of basic maintenance. Some JDM owners who think that the "turbo" in turbo diesel means "Ferarri" probably also contribute to the demise of their rigs.

 

[prado t]

Like the others have said it is for cooling the TURBO and internals of the motor.

 

[crushers]

install a pyro and go by the temp...
below 600F and you are golden... and the temps drop very quickly .

i guess it pays to read the manual, i never saw that page before, interesting.

but

LJ --- LIKE (a) JEEP ??

 

[JuanJ]

Hello,

No matter how pretty and low kms a truck is, it could still have been severely neglected in terms of basic maintenance. Some JDM owners who think that the "turbo" in turbo diesel means "Ferarri" probably also contribute to the demise of their rigs.

You confirm what I suspected. JDM LJ7x's seem very prone to this kind of abuse. Add to this the fact that it is a small engine powering a rather large vehicle...

LJ --- LIKE (a) JEEP ??

It seems to be the case for JDM LJ7x's in Canada.






Juan

 

[Hilux]

oil coking? My 22RTE's have that same warning...

The oil will cook, dry and solidify in the return tube, which is surrounded my ambient air... Sorta like an intercooler.


"Because the turbocharger will heat when running, many recommend letting the engine idle for one to three minutes before shutting off the engine if the turbocharger was used shortly before stopping (most manufacturers specify a 10-second period of idling before switching off. This gives the oil and the lower exhaust temperatures time to cool the turbo rotating assembly, and ensures that oil is supplied to the turbocharger while the turbine housing and exhaust manifold are still very hot; otherwise coking of the lubricating oil trapped in the unit may occur when the heat soaks into the bearings, causing rapid bearing wear and failure when the car is restarted. Even small particles of burnt oil will accumulate and lead to choking the oil supply and failure. This problem is less pronounced in diesel engines, due to higher quality oil typically being specified."

http://en.wikipedia.org/wiki/Turbocharger#Temperature_considerations

Coke (fuel) http://en.wikipedia.org/wiki/Coke_(fuel)

 

[crushers]

cute, 10 sec idle time...
oil can cool THAT fast?

well, my FJ75 has a engine oil temp gauge and the oil does not cool that fast, not even close to moving the needle. i know, i know, it is talking about the oil taking the heat away from the turbo but seriously, 10 secs? how much heat will be moved in 10 sec? very little if any. you will remove more heat from the turbo just pulling into the pumps or parking lot.

but i agree with "the lower exhaust temperatures time to cool the turbo rotating assembly" which is where the Pyro comes into play. if they pyro reads cool then shut it down.

but if someone wants to set their turbo timer to 1-3 mins of idle time so be it ... (but in Ontario you can get a ticket for excessive idle time so be careful there) ... but to me it would be a waste of fuel.

 

[Radd Cruisers]

The other 2LTE warning should be obvious, but this is not the thread for that

Surprised Crushers is behaving himself so well these days.


~John

 

[Hilux]

lol, "The other 2LTE warning should be obvious"

 

[canucksafari]

The other 2LTE warning should be obvious, but this is not the thread for that

Surprised Crushers is behaving himself so well these days.


~John

That's because he's probably rid himself of anything related to a 2LTE.

 

[crushers]

too tired to care right now, wait a bit and i will be back bashing the L(ike)J(eep) again.

 

[Radd Cruisers]

too tired to care right now, wait a bit and i will be back bashing the L(ike)J(eep) again.

Awaiting the next tirade.


~John

 

[Stone]

Wikipedia...lol.

 

[bbpjunk]

I never read the warning, but knew it was an important thing to do and it was my normal practice. Where I work it is at the end of a long gravel climb. I only drive up it at about 40km/h but it ends at the parking lot. I usually let it run for a couple minutes and then shut it down.

I forgot once and walked by the truck and heard stuff "bubbling" inside the engine. It sounded like coolant boiling. It was had to tell if it from the turbo, or from the head but it was disconcerting. I never had problems with coolant loss or overheating on the 2LTE but I decided then and there that this noise wasn't good.

I've since gotten rid of the 2TLE for a 1KZTE. Same practices should apply to any turbo engine and dare I say any engine at all. It isn't good just shut them down after flogging them. As for 10 seconds being too short-depends on the speed of the engine and the turbo when you park it.

If your turbo internals are glowing red then 10 seconds of relatively cool oil and engine coolant passing through the chambers will make a HUGE difference. Kind of like dipping red hot metal in water after welding to cool it off. It just takes a second to make a big difference. The bigger the turbo the longer time it will take. I think a minute of idling is probably the most I'd do after a pretty extreme climb at high speeds with the little Toyota turbos. That's based on my own BS...not an engineering background.

On aircraft engines they state in the manual to idle 5 minutes before shutdown. Of course they have massive turbos with no engine coolant to help. The water jackets on the turbo are there to improve the reliability of the turbos in these kind of situations. Shutting down too fast lets it boil, as I discovered myself with the 2L. I haven't tried it with the KZ yet, but I imagine it might make the same scary sound.

 

[crushers]

good advice and practice...

 

[Prado-kirk]

I have a pyro senser mounted about 2" back from the turbo on the down pipe. After 110km/hr driving 750-850deg,F temp I wou ld idle till temp dropped to 350 and would take about 3 mins.