The reality of the Landcruiser Head Gasket Issue

[Rifleman]

what are the effects of EGR removal regarding HG longevity?

There are Alot of Mud members who know these engines way better then i do, that feel that keeping the HOT exhaust from the EGR away from cylinder number 6 might be beneficial. And that may lead to your head gasket lasting longer.

 

[MoJ]

Interesting read.

Uncovering the Culprits That Cause Head Gaskets to Fail - Engine Builder Magazine

Most installers should know the first symptoms of a head gasket that is failing are usually a slowloss of coolant with no visible leaks, engine overheating and/or aCheck Engine light with cylinder misfire codes. The Onboard DiagnosticII (OBD II) system should detect any misfires that occur due...

www.enginebuildermag.com

 

[weigellj]

My wifes old DD and now my trail rig we've had for 10 years..... Did the EGR removal probably 8 years ago, currently has like 320K on it and I have never did the headgasket and I'd assume from the lack of maintenance the whole rig had from the PO, it has never been done.

In the last 4 years of wheeling, it has been overheated Multiple times... I'm talking 220-240 degrees on the scan gauge and the temp gauge was pegged to the H. It was so hot one time that it exploded the upper plastic part of the stock radiator and it sounded like a shotgun going off under the hood. Also has been completely swamped with mud/swamp water in the intake, and we had to pull the plugs out to get the water out of the engine.

Thing still runs perfectly after all that abuse.

Same thing goes with the 3.0 v6's toyota had in the mini trucks and 4 runners. Had probably 10 of those over the years and I only had 1 that I did the headgaskets as "preventative maint" - Anyone you talk to says the 3.0 headgaskets are junk and its a junk motor, but it does what it was intended to do in the late 80's early 90's.

I won't deny that people have obviously had issues, but i'd say if it isn't showing signs of a bad gasket, leave it alone.

I do think the EGR going to #6 is the cause of the failures and this would be my first mod if you can get away with it in your state.

I'll also add that toyota did have a recall on the 3.0's for headgaskets being bad, and it could be that there where batch's of LC headgaskets that maybe had issues as well (was the same era), but it just never hit toyota's radar.

 

[MoJ]

Regarding EGR, from the article I posted above.

“Detonation Damage

Another reason head gaskets fail is because of damage caused by
detonation (spark knock). Detonation causes a sharp spike in combustion
chamber pressure, which, over time, can overload and crack the gasket
armor that surrounds the cylinder. This leads to burn through and loss
of compression.

Detonation
can be caused by a variety of problems. One is an accumulation of
carbon in the combustion chamber that increases compression. Many
late-model import engines run fairly high compression ratios, and some
require premium octane fuel. If compression reaches a point where the
fuel ignites spontaneously before the spark can set it off, the engine
will knock and ping under load.

Mislabeled fuel that does not have the octane rating claimed on the
pump can also lead to trouble in high-compression or turbocharged
engines, especially when the engine is working hard under load or high
boost pressure. If there aren’t enough octane-boosting additives in the
fuel, the engine may experience mild to severe detonation.

Other factors that may increase the risk of detonation include an EGR
system that isn’t working (by diluting the air/fuel mixture slightly
with exhaust, EGR actually helps cool combustion temperatures under
load). Over-advanced ignition timing can also cause detonation, as can
an overly lean air/fuel mixture. Any problems in the cooling system
that make the engine run hotter than normal will also increase the
chance that detonation may occur.

Pre-ignition is a related problem that can also cause detonation.
Pre-ignition occurs when a surface inside the combustion chamber gets
so hot that it becomes a source of ignition instead of spark. The hot
spot might be the exhaust valve, spark plug or a sharp edge in the
combustion chamber.

The underlying cause is often an overly lean air/fuel mixture or a
cooling problem. If pre-ignition occurs, it will ignite the air/fuel
mixture before the spark plug fires, causing combustion pressure to
peak too early on the compression stroke. This, in turn, can cause
detonation that may damage the head gasket.”

 

[80t0ylc]

Interesting read.

Uncovering the Culprits That Cause Head Gaskets to Fail - Engine Builder Magazine

Most installers should know the first symptoms of a head gasket that is failing are usually a slowloss of coolant with no visible leaks, engine overheating and/or aCheck Engine light with cylinder misfire codes. The Onboard DiagnosticII (OBD II) system should detect any misfires that occur due...

www.enginebuildermag.com

I like the part that tells you how you can differentiate between overheating damage and detonation damage:

"How can you tell if overheating caused the head gasket to fail? A head
gasket that failed because of overheating or a hot spot will be crushed
and measurably thinner in the damaged area when checked with a
micrometer. By comparison, a gasket that has failed due to detonation
or pre-ignition will usually have cracked armor around the combustion
chamber, which leads to burn-through."

And also:

"Replacing the head gasket will cure the leak, but the underlying cause
that made the engine overheat in the first place also needs to be
diagnosed and repaired — otherwise, the newly installed gasket will
suffer the same fate the next time the engine overheats."

 

[AJP]

When my HG failed it was at the rear of number 6 .... oddly enough the only headbolt that was out of spec (ie diameter was too 'thin') was the one adjacent to (and closest to) the HG leak ... only one other head bolt was close to minimum - it was also by the No.6 cylinder. I replaced these 2 headbolts. FWIW

Perhaps the EGR valve location is relevant .... but there is a lot of distance - and large aluminum valve cover and head - between the EGR pipe and the head gasket .. but who knows. I am convinced that something is allowing those headbolts to stretch and that this contributes to the problem. Probably heat buildup due to poor/insufficient cooling at that location.

 

[ppc]

The exhaust manifold at #6 has an additional path that is routed across the backside of the head which is the source for the exhaust that feeds the EGR. The location of the EGR isn't the relevant cause of head gasket failures but the routing of the exhaust gas making the head temperature at #6 higher than all other cylinders.

 

[bromistagw]

The exhaust manifold at #6 has an additional path that is routed across the backside of the head which is the source for the exhaust that feeds the EGR. The location of the EGR isn't the relevant cause of head gasket failures but the routing of the exhaust gas making the head temperature at #6 higher than all other cylinders.

and if we disable the EGR? does that reduce the temps? some people have said the EGR reduces combustion temps.. i sure do love the EPA
Thanks

 

[Marco Lau]

Was into e36 BMWs for a long time, and the BMW M52 engines are very similar to the 1fz, with an inline 6 iron block mated to a long aluminum head, and it also has HG issues around the same time as the 1fz. Many feel that the different rates of expansion and contraction between the two metals is hard on the HG, and I would agree that that may be a contributing factor. The thing that really sticks out in my mind is that both the e36 BMWs and the fzj80 have weak points in the cooling systems. For us, it's the phh, for them it is a few plastic fittings that become weak over the years and break. I think with proper preventative maintenance on the cooling system components, the HG is likely never going to be an issue, but most of the time, cooling system maintenance happens after an "event" which likely pushes that old head gasket juuuuust over the edge and it fails shortly thereafter.

Totally agreed. I also been around the S52 engines for a little over 10 yrs prior to the offroading world, done the engine mod, M50 manifold swap, basic bolt ons to upgraded cams on those and have seen significant gain in hp, and had never had a HG failure on those motors, and had been doing SCCA track days, autoX and beat the crap on those engines and zero problems. The weak points like you mentioned, is usually the culprit for these engines....the stock cooling is adequate for stock driving styles, adding age, weight, hot climate condition offroad, bigger tires, etc., now you are seeing the engine working 10X harder with cooling being the weakest link. I really can't speak for my 80s as i am lucky to have a 3FE and even for myself, i have upgraded all my cooling, replaced all hoses and such make sense especially if you are going to be using the rig for offroading.

 

[Plains Cruiser]

~190k miles and my mechanic says he tested hydrocarbons in the coolant. Looks like I’m in for some expensive work soon.

 

[COYS]

When my HG failed it was at the rear of number 6

+1

I changed my vote. My og '97 engine failed non-catastrophically at 273K miles. I noticed coolant loss in the radiator so I just stopped driving it. I promptly began to source OEM parts to build a new 1FZ-FE from scratch (a time sucking 6 month endeavor).

9K miles down, another 264K to go.

 

[Plains Cruiser]

~190k miles and my mechanic says he tested hydrocarbons in the coolant. Looks like I’m in for some expensive work soon.

My 80 is my daily for about another month. Is it likely I can make due with short commutes until I can park it and get it scheduled for HG work? So far my only symptom is a weeping coolant line (no drips on the ground) and slow coolant loss (I had a new radiator installed in May and it was down around 2 quarts). Engine temp has been dead center and no white smoke from exhaust.

 

[jpoole]

mechanic says he tested hydrocarbons in the coolant

Is it likely I can make due with short commutes until I can park it and get it scheduled for HG work?

The hyrdocarbons are from a leak between the combustion chamber and a coolant passage I assume.

If you run this with a known HG leak that leak will worsen to some extent. You could see increased erosion/damage to the block or head surfaces around the leak. You could also run into a starting situation where water was in the cylinder causing a hydrolock which means you just expanded the scope of repair work to include bottom-end repairs or a new shortblock. You could also experience a sudden catastrophic failure of the HG while driving and need a tow and repairs from any damage that occurs in that event. Or maybe, nothing will change and no additional damage will be done... I'd only take these risks if you are considering full engine replacement anyway or some similar situation where these risks are negligible for you.

If I were in your shoes and the 80 had been running well previously I'd try to limit the scope of repair work to just the head gasket, head service and while in there items. 190k is relatively young for a 1FZFE and just a HG replacement, if all else is good w the 80, would not be a waste of time/$ in my opinion. I would avoid starting it again if at all possible, unless to drive it to where I was going to do the work should there be no other way to get it to that spot. I would pull the plugs to inspect them and scope the pistons/cylinders soon. If it was going to be a while before I could work on it I'd consider draining the oil and spraying a good bit of WD40 ("water displacement 40") into each cylinder just in case there is moisture present that could cause ring/bearing/etc. rust while you wait to do the work. Some of that may be overkill if coolant leaking into the engine has been truly minimal but you don't want to find out that there is water where it shouldn't be the hard way.

 

[landtank]

Interesting and very helpful responses so far, thank you SO MUCH. My intent and I haven't really been hyping it is that I'm leaving in 8 weeks or so (sooner if the snow flies) to travel and live full time out of my LC80. I am currently selling everything I own including my house. We are spending $$$ to baseline and reasonably upgrade the vehicle including the prinsu roof rack, arb front bumper, second battery, solar, RTT, tall skinny tires, and interior sleeping platform. A HG has been on my mind, but I see no indicators including a very nice #6 spark plug that looked just like its other 5 brothers. I'm tempted to rent a EG radiator test kit and oil analysis to ensure no contact with exhaust gasses in my radiator fluid. Then every 10K do it again.

For the time being and the purpose of this poll...I just want to separate the hype from the reality and so far it seems like it's working.

3 things

Head gasket
Engine harness
Rear heater pipes

This three things will crush you out on a trip if they fail.

 

[canman]

Had mine done a long while back. Can’t remember the mileage but I’m only at 338K kms now - 211K miles. Even then it was an expensive repair even having it done “under the table” by member who was a mechanic at the local Lexus dealer. I think it was around CAN$2K at the time. It had been weeping for a while before I noticed it dripping down the trans. There were no damages to the head or block as a result of a “sustained” leak.
Not sure what the consensus is now here about an “LS” swap as I’ve been away from the tech forum for a long time, but if I had to do it all over again, I would of went with a swap with what I know now.

 

[67cruiser]

Mine's sitting at 361,700 miles with the OG Head Gasket

 

[SpenserAK]

I’m always curious to know further details of trucks who are making it pretty far on their original. What kind of life has it had, has it ever overheated or run hot in general, is it a daily driver or trail rig, etc.

I’m at ~230k on the original with no issues.. checked again recently. Who knows how far off it is, but I do know this truck has only been a daily driver that’s been taken care of, so hearing reports of original HGs well into the 300ks gives me hope. Granted, there’s the variety of other issues that can happen as they age.

 

[67cruiser]

I’m always curious to know further details of trucks who are making it pretty far on their original. What kind of life has it had, has it ever overheated or run hot in general, is it a daily driver or trail rig, etc.

I’m at ~230k on the original with no issues.. checked again recently. Who knows how far off it is, but I do know this truck has only been a daily driver that’s been taken care of, so hearing reports of original HGs well into the 300ks gives me hope. Granted, there’s the variety of other issues that can happen as they age.

Mine over heated when the PHH went south....
Oil changes roughly every 10,000 miles since I acquired it at 307,000 (previous PO was an "oil change every 5,000 miles at the dealership" nazi)

 

[Irish Reiver]

I just finished my 3rd head gasket change - two on' 96's and one on a '94. None had failures of the head gasket but all of them burned oil beyond my tolerance level. I am lucky that I can do my own wrenching and doubly luckily that my machine shop guy charges under $400 for the stuff I can't do. My costs have mostly been below $1K because I have little to no "while you're in there" items. For me it is definetly worth it for having a clean engine and a new HG to boot...

 

[gorbilax]

Mine went out at 272k ('94 FZJ80 US spec) - on #6 right near the EGR pipe. It was consuming coolant. Previous owner also overheated it several times when the PHH went out around 190k but it didn't blow then. I have since blocked off the EGR and replaced with a new OEM HG.