Offical 1FZ head gasket debate (1 Viewer)

[Cattledog]

I support Cruisedan on the headgasket, I just bought the gasket kit from him about a week ago. I will be doing the headgasket as a PM. A $175 and my time and place is better than $1500 at a random dealer/service station when you are broken down.
Landtank summed the situation up well. Even Toyota has redesigned the gasket... I don't think that the large displacement nor the above average length of the block and head help the situation. I also wonder if the fact that the # 6 ctlinder is the problem due to it's closeness to the firewall or that the egr is routed through that part of the block thus increasing the thermal load in the area. Could there be a differance in the heating and/or cooling rate when comparing the front vs the back of the engine once the engine is shut off, hmm.

I had no idea that Toyota made a cast iron head. Is the head still a 24V DOHC for fuel injection? I would be interested in this head.

Raven Tai, Where did you get the information that Carbon/graphite and Cast Al are incompatable materials? I would assue that the head is an alloy of Al, but I don't which alloy. I am a organometallic chemist, and have never read nor heard of this issue. Please share your source.

 

[RavenTai]

First I heard of it was in A&P school, you are never to use a pencil (graphite) to do layout on aluminum. We use fine point sharpies.

Graphite and aluminum are near opposite ends of the galvanic series

http://www.corrosionsource.com/handbook/galv_series.htm

I'll try to find some more sources.

 

[MH_Stevens]

Trying to take a middle road here my thoughts are that upgrading the head gasket on a wagon that is running OK seems overkill and a poorly performed PM HG job could leave the wagon at greater risk than leaving the factory job alone, while not doing the PM with a truck that is showing signs of weakening is stupid.

There must be some indicator of when the PM is to be done. I've asked this before but no one has addressed this. Surly there are testable signs to indicate when PM HG replacement is due such as non-consistant head temperature measurements, CO in the coolant, dissolved air in the coolant or varying manifold temperature and pressure at each cylinder, cylinder imbalamce/knock sensors.

I'm thinking we need some more advanced gauges like on aircraft engines that will give more warnings of inpending doom so PM can be done timely but without waste or unnecceasary risk.

 

[e9999]

practically speaking, seems like the basic work involved in replacing the gasket is about the same before and after failure. On the other hand, after failure there is a high likelihood of other problems (warping etc) that will be costly to fix. Seems like the new gaskets may be significantly better. Add to this the fact that one could do a lot of other desirable PM work when taking the head off and it seems like it would be a good idea to do this once in the life of the engine when one has a couple of days available. Not to mention the fun factor...!

Probably, one of the main factors to consider is that Toy *did* change the design on these. Surely, that must mean they know something is wrong...

Now, what I would like to see is some serious tech feedback from some Toy engineer familiar with this issue. Anybody has contacts?

 

[wsdavies]

When I sell my c280 and buy another fjz-80 the first thing I'm going to do is replace the head gasket and bring the cooling system back to new...It's def. cheaper in the long run..and if you get the code # 28 take it to the shop and have them check the head gasket...don't reset the efi fuse

 

[landtank]

Cattledog, I only live just south of the border in MA. I would love to drop buy and take a look at your old gasket as it would be the 3rd that I will have seen before a blow out.

Please IM me if you don't mind.

Thanks

 

[alaskacruiser]

Someone please repost robbie's old post about his take on the HG issue. Very valuable coming from him. I can't find it...

 

[IdahoDoug]

Cattledog/Eric,

Just pulling something in here from another similar thread on the "because Toyota changed the HG, something was wrong with the original" comments. This simply is not true. Toyota and other manufacturers make thousands of running changes every year to components for a variety of reasons. To speculate that they "must have known something was wrong" is simply unfair and a wild guess. I used to sign off on these Engineering Change sheets, and it was common to have a half inch thick document identifying everything from a blinker gasket change to upgraded wheel bearing seals for each vehicle in the model line. Most were transparent to the owner, some were due to a cost savings, others to a supplier finding a better way, still others simply to improve NVH or other vehicle qualities. I would say that 99% of changes were for reasons OTHER than fixing a problem.

DougM

 

[semlin]

hmm

1. let's separate head gasket failures into those caused by a mechanical breakdown of the gasket (caused by chemicals, improper installation, mating tolerances, design weakness etc..) and those caused by heat exceeding the capacity of the h/g.

2. head gasket failures caused by heat can be a good thing. presumbly if the h/g didn't go you could do damage to your head or other engine components. presumably it is possible to determine the temperature at which a head warps. I would design a head gasket to fail just before then as a "fuse". I have read somewhere that this is exactly what Toyota does.

3. therefore, provided the headgasket is installed properly, I would still expect it to fail fairly regularly in older high mileage vehicles that generate a lot of heat. Big heavy trucks would be top of the list. This would be a designed failure and would occur whenever the vehicles cooling system was not working properly or the motor was leaning out and the result was a threat of engine damage. A head gasket failure in this situaion would save you money.

4. so to me the objective of the h/g design is to blow only at a defined temperature target and to be less susceptible mechanical failures. A bulletproof asbestos or metal h/g would just expose your head to failure.

5. in that light, the 80 h/g design seems to have historically had a tendency to fail at #6. that's a mechanical issue. Indications are that Toyota changed the design specifically to address that problem.

6. Indications are that late model 80's had h/g failures more often than early ones. This could be a design change in the h/g making it more susecptivle to failure, or a problem with later 80 cooling systems or engine management (running lean). if we discount the possibility of a h/g design change, these were "good" failures unless the performance temps of later 80s exposed the originbal h/g as too temp sensitive. Either way, Toyota has updated the design since 1997.


6. In that light I would not want an aftermarket metal or asbestos head gasket unless I intended to run the 1fz in a high performance mode that would involve engine temps that would exceed toyota's design parameters. I would trust the Toyota OEM head gasket as the best option out there.

7. also in that light I would do an h/g replacement in a late model 80 or in an 80 where I expected it to run at high temps a lot.

 

[landtank]

Cattledog/Eric,

Just pulling something in here from another similar thread on the "because Toyota changed the HG, something was wrong with the original" comments. This simply is not true.

Well their crystal ball was well oiled and highly tuned the day they decided to strengthen the sealing ring and water jacket of the #6 cylinder knowing nothing of it's consequences. Talk about sticking a landing blind folded!

 

[e9999]

Doug, point well taken, you know more about this than I do. thanks.

sem, the fuse concept seems a bit much, considering the serious damage that could happen (e.g. coolant in the cylinders...). Wouldn't it be easier to put some sort of kill switch based on temp?

 

[bjowett]

Speculation/BS... most of the gaskets were and are failing well out of warranty. Toyota makes new gasket and sells many, why new? if the NEW gasket fails, no one is going back to Toyota to buy it or fix the problem.

 

[semlin]

Doug, point well taken, you know more about this than I do. thanks.

sem, the fuse concept seems a bit much, considering the serious damage that could happen (e.g. coolant in the cylinders...). Wouldn't it be easier to put some sort of kill switch based on temp?

well the problem is likely to be from cumulative running at high temps that don't merit a shut down for short periods so you would need a pretty smart sensor. the temp gauge ought to tell you as well, or the a/c cut off, but folks just keep on driving. people keep on driving after they blow the h/g as well. a kill switch would be dangerous. Maybe a "pull over now you idiot" sign on the dash?

 

[e9999]

well the problem is likely to be from cumulative running at high temps that don't merit a shut down for short periods so you would need a pretty smart sensor. the temp gauge ought to tell you as well, or the a/c cut off, but folks just keep on driving. people keep on driving after they blow the h/g as well. a kill switch would be dangerous. Maybe a "pull over now you idiot" sign on the dash?

ooookaaayyyyyyy.... you had fun in the 70s, didntcha?

 

[BOUNDER]

I call BS on everyone. Toyota knows how to make good HGs in iron block/AL head motors. Look no further than the amazing 2JZGTE. These cars not only have no HG issues, but they take INCREDIBLE power outputs, and, by my own experience, INCREDIBLE punishment without failures. How about nearly 800HP on a motor that was built to handle 320HP? How about that as a DD in TX heat and humidity? How about me running 1.5 bar of boost (~23psi) DAILY on this motor? How about the dozen cars that do almost 1500HP on stock HGs?

Toyota figured out how to do it. They didn't put this technology into the 1FZ. That sucks, but I'm OK with it. These trucks run nearly forever anyway, just think of the HG as an (expensive) maintenance item. Just wish I could get the nice metal HG from my 2JZ on my 1FZ.

We Bostonians (Brighton/Newton Corner) are good like this

 

[MH_Stevens]

hmm

1. let's separate head gasket failures into those caused by a mechanical breakdown of the gasket (caused by chemicals, improper installation, mating tolerances, design weakness etc..) and those caused by heat exceeding the capacity of the h/g.

YES. SOME SCIENTIFIC ANALYSIS OF HG FAILURE IS REQUIRED. WAY TOO MUCH PERSONAL OPINIONS HERE NOT BACKED UP BY STATISTICS.

2. head gasket failures caused by heat can be a good thing. presumbly if the h/g didn't go you could do damage to your head or other engine components. presumably it is possible to determine the temperature at which a head warps. I would design a head gasket to fail just before then as a "fuse". I have read somewhere that this is exactly what Toyota does.

USING HG FAILURE AS A PROTECTION DEVICE HAS ITS PLACE BUT LETS NOT STOP USING OUT TEMPERATURE GAUGES. SEEMS WE NEED MORE THAN A HIGH VS LOW WATER TEMPERATURE GAUGE. SEE MY LAST POST. WE NEED USEABLE RELIABLE SENSORS ON HEAD AND MANIFOLD OR SOMETHING SIMILA TO BE SUGGESTED BY THE ENGINEERS HERE OR AT TOYOTA



5. in that light, the 80 h/g design seems to have historically had a tendency to fail at #6. that's a mechanical issue. Indications are that Toyota changed the design specifically to address that problem.

DESPITE IDAHO'S NOTE THAT SOME DESIGN CHANGES ARE FOR LITTLE GOOD REASON THIS DOES SEEM TO BE THE CASE HERE. WHAT DO TOYOTA SERVICE BULITONS SAY?


6. In that light I would not want an aftermarket metal or asbestos head gasket unless I intended to run the 1fz in a high performance mode that would involve engine temps that would exceed toyota's design parameters. I would trust the Toyota OEM head gasket as the best option out there.

WHO RUNS THERE FJZ AT TEMPERATURES ABOUVE SPECIFICATION. WHAT IS THAT ANYWAY - WITH THE NEEDLE NEAR THE RED INSTEAD OF IN THE MIDDLE? wHY WOULS ANUONE DO THAT?

FOLLOWING ON FROM #6 AND ADDRESSING #7 PLEASE DEFINE HIGH TEMPERATURE RUNNING. I HAVE BEEN DRIVING MY '97 THIS WEEK ON LONG RUNS FULLY LADEN WITH THE A.C ON MAX AND THE TEMP GAUGE STAYS IN THE MIDDLE JUST AS RUNNING UNLADEN IN COLD WEATHER. HOW DO I RUN HOT?

7. also in that light I would do an h/g replacement in a late model 80 or in an 80 where I expected it to run at high temps a lot.

.....

 

[semlin]

mike, do a search on "temp gauge" or "temp gauge flat spot" for an answer to your question, the factory gauge will not move until you are basically overheating. you are probably running hot.ter than usual but do not know it

 

[Rainy Day FZJ]

Well I guess that I will share my take as well.... I replaced the HG on my 95 with 137k on it as PM. I added the blower and after talking with Dan I took the plunge. I am a well rounded mechanic and have a 2yr degree in auto mechanics and 5 1/2 yrs field experience at a shop that fixed EVERYTHING from cement mixers to pitching machines, porsche, bmw, ferrari, toyota, and every pos made in america. The hg on mine was distorted at the metal combustion ring on #1 cylinder of all places, go figure, the new HG was of greater quality and looked better designe. I have replaced every little gasket and seal that I could, had the injectors ultrasonicly cleaned. The thing ran perfect and I had no question of the integrity of the HG after replacement, or the torque to yeald bolts.

Just think of all of this as PM just as new tires.

Have you replaced the HG on a 22re multiple times with the cheap s*** Felpro etc and then demanded from your cheap @ss boss to just get the one from toyota! well I have and then looked at the difference. and watched the poor discusted customer leave or the last time, cause it was finally fixed with the right parts..

I think that Dan is trying to stir up more biz! well I can't blame him much we all are very paranoid people who own or are makig payments on the very best vehicle that Japan has to offer..

 

[LandCruiserPhil]

well the problem is likely to be from cumulative running at high temps that don't merit a shut down for short periods so you would need a pretty smart sensor. the temp gauge ought to tell you as well, or the a/c cut off, but folks just keep on driving. people keep on driving after they blow the h/g as well. a kill switch would be dangerous. Maybe a "pull over now you idiot" sign on the dash?

I would agree

I have talked to many owners about the ac shutting off and most view it an inconvenience rather an overheating issue. In my head getting your engine hot greatly increases your HG percentage failure. I make it a point not to go over 210 degrees.

mike, do a search on "temp gauge" or "temp gauge flat spot" for an answer to your question, the factory gauge will not move until you are basically overheating. you are probably running hot.ter than usual but do not know it

On my junk the gauge does not move at all until it goes above 210 degree.

 

[alvarorb]

How many on this forum have had their headgasket replaced? At how many miles?
I had mine replaces at 100K. Good thing it happened near a Toyota dealership. Too bad it was 500 miles away from home.

Anyway, for curiosity's sake, I would like to know how common is this issue.

Regards

Alvaro