Okay, Now I'm Completely Convinced: ALL Original HG's Are Actively Failing!

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bjowett said:
We will discuss this to no end, just as it's been done before. Most folks will be fine with the bolts, for a while. :D

Hypothesis. Coolant must pass and cool 5 cylinders prior to reaching #6, so it already has some heat, not an issue yet. Problems really begin with EGR cooler being built into the back of the cylinder head, right behind #6. Hot exhaust is always there, placing more heat into the coolant at #6. After being cooled, it goes to the EGR valve, and when in operation, the EGR runs along the #6 intake runner. Hey why not preheat that air a little more before it enters #6? Proof of all this heat is also shown via the PHH, which takes coolant from right behind #6.They blow all the time, as most around here know. What say ye?
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My experience with head bolts is that new ones put in correctly are no worse than what you have from ARP. There may be a threshold or specific application where that may change, but I'd sure want to see more concrete evidence (which ARP doesn't provide) that shows where that may be. Otherwise it's a huge chunk of money better spent elsewhere. I'm intimately familiar with those exact parameters on the I5 turbo, and couldn't pry an alternative answer to 'proprietary' or guilt by association testimonials. I want to justify them, but not without good reason. Just IMO/E

Ok, take the other #6 outlet, instead of sending it up to the throttle body, disconnect it and put a small cooler there. Benefit is two fold, you now aren't preheating the intake air at the tbody, and you are relievng heat at the back of the head with or without the heater in operation. Question: Why don't the throttle body heater hoses fail?

Could head gaskets be failing because the recirc of the water at the back of the head is restricted when the heater is off?

Just tossing this out for discussion

Scott Justusson
 
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I read this post last night before I went to sleep and had a realy really BAD dream. The dream went like this: I went to the dealer for some reason and they found that my HG and 2 other seals are blown :frown:. They gave me an estimate of $6K to do all the work. I woke up and didn't go to sleep, that was around 5:00 AM. I don't usually remember dreams but this one has been stuck in my head all day long. I think I'm gonna buy that HG DVD and start the process.
 
tech_dog said:
I don't have a mechanic I trust enough to do a head gasket as PM. I'm not going to crack this open until necessary, but when I crack it open I'll probably go deep.

Just out of curiosity, are new engines available for the FZJ80s, and what do they cost? I'm hoping that a new engine and tranny for an FZJ80 would be less than the cost of a new Geo Metro, and would make the me coolest guy on the block.
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CDan quoted a price of $12,000 for a new engine.
 
Man, where to start?

The triangular port that looks blocked at the beginning of the thread is supposed to be. The other one has a hole in it for flow.

The head bolts are designed to be reused. There is a measuring procedure for them in the FSM. On my 97, they've been used 3 times including the factory's initial install and were measured by a professional machinist for the 3rd use. I had new ones on hand in the even they were not (over $120 for them IIRC).

Uh, what was the other? Oh, the theory on water flow across the other cylinders. Nope, the water comes up evenly vertically around the cylinders.

That the heat on #6 is the culprit is questionable since a percent are also failing clear at the opposite end - cylinder #1. It's a gasket construction/material issue to me.

When I put my heads on, I did the factory sequence, then let it settle overnight. The next morning, I checked torque (roughly 100ft-lbs IIRC) and set them all at whatever the highest was. IIRC, there were typically 5lb discrepancies.

Agree with the "too strong" comments on the aftermarket studs. What if they were so strong they did not allow movement and created stress risers around each bolt? I find it interesting in the quote from their site they say something is a "fact" regarding factory bolt problems. Is it? Do they provide some statistically valid test data? Or is it a compilation of personal testimonials and only coincidence that they are the ones reporting it and further coincidence that they sell a competing product? Bolt technology is pretty mature, so assigning freely an error in this area crosses the line into la la land.

I truly think that the problem is solved with the new design gasket from Toyota. You'd have to have one of each on your work bench to really appreciate all the upgrades.

For whomever had a head gasket edge shredding your belts, I think you are talking about replacement of your exhaust manifold or intake manifold gaskets. No way the HG is contacting the belts, but I can see an improperly installed intake or exhaust doing it.

DougM
 
I just replaced the head on my 22RE truck and I’m psyching myself up to take on the Cruiser HG when the weather and my bank account thaw out a bit. ARP head studs are expensive, but after I got the head off the 22RE, the first call I made was to Summit to order a set of the ARP studs. The reason was rather simple: IMHOP there is way too much crud down in the head bolt threads and the holes through the head to get bolts tightened accurately. Only under perfect conditions can axial loading on a bolt head determine the tensile stress through that bolt. Given the carbon build up, coolant and oil everywhere this is far from perfect conditions. I spent hours cleaning the mating surfaces; chasing the threads and trying to vacuum fluid and crud out of the thread holes and still would not have been confident using the OEM bolts.
The ARP studs have a provision to use an Allen wrench to get them into place. Like the 80, the 22RE head will not fit into place with the studs installed. But the studs go into place easily after the head has been set onto the gasket.
:beer:
 
good thread. turbo, your cylinder tops look mighty clean to me. I am assuming those are not "afters". did you use any kind of fuel treatment etc.. to try to decarbonize recently?
 
cruiserman said:
The motor and tranny are actively dying too. They just take a while to do so (for some of us).
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Our bodies are dying as well as much of the Universe included - we're all doomed! :crybaby:
 
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IdahoDoug said:
Man, where to start?

The triangular port that looks blocked at the beginning of the thread is supposed to be. The other one has a hole in it for flow.

The head bolts are designed to be reused. There is a measuring procedure for them in the FSM. On my 97, they've been used 3 times including the factory's initial install and were measured by a professional machinist for the 3rd use. I had new ones on hand in the even they were not (over $120 for them IIRC).

Uh, what was the other? Oh, the theory on water flow across the other cylinders. Nope, the water comes up evenly vertically around the cylinders.

That the heat on #6 is the culprit is questionable since a percent are also failing clear at the opposite end - cylinder #1. It's a gasket construction/material issue to me.

When I put my heads on, I did the factory sequence, then let it settle overnight. The next morning, I checked torque (roughly 100ft-lbs IIRC) and set them all at whatever the highest was. IIRC, there were typically 5lb discrepancies.

Agree with the "too strong" comments on the aftermarket studs. What if they were so strong they did not allow movement and created stress risers around each bolt? I find it interesting in the quote from their site they say something is a "fact" regarding factory bolt problems. Is it? Do they provide some statistically valid test data? Or is it a compilation of personal testimonials and only coincidence that they are the ones reporting it and further coincidence that they sell a competing product? Bolt technology is pretty mature, so assigning freely an error in this area crosses the line into la la land.

I truly think that the problem is solved with the new design gasket from Toyota. You'd have to have one of each on your work bench to really appreciate all the upgrades.

For whomever had a head gasket edge shredding your belts, I think you are talking about replacement of your exhaust manifold or intake manifold gaskets. No way the HG is contacting the belts, but I can see an improperly installed intake or exhaust doing it.

DougM
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Doug:
I saw the reuse measure on the head bolts, you have more confidence in that as a measure than me. The measure is how far it's been stretched, heat usually adds memory to that. A lot of heat can make that measure less accurate. I don't believe in ARP's, but I do think 100bucks for a new set of bolts is a no brainer.

ARP is a marketing company, somewhere I saved the email exchange I had with one of their reps. It became funny, I asked those pesky detailed questions, and I got "all race guys use them" and other assorted 'facts'. My last email indicated that I completely understood what was said.

Revised/improved head gasket designs are pretty commonplace. A lot of it came about with the shift from the typical green coolant, to the specific long life or spec'd coolants. Some of this was brought on by the eco crowd, some brought on by manufacturers looking for more 'factory parts' dollars, very little of it has to do with cooling technology.

A lot of fibre gaskets using a given coolant, when swapped to another coolant type, actually compromises (rots) the head gasket material. I won't go so far as to say that's what is happening here, but it could be a contributing factor.

IDoug, what intrigues me a bit is the flow at the back of the head. FSM routing shows two specific returns from the back of the head, thru the heater core, and thru the tbody warmup line. Since there is no bypass in that circuit if the valve is closed, that appears to be a big shutoff of the coolant circulation at the back of the head. I know a lot of manufacturers have since change climate controls so that flaps dictate heat more than valves, so that the heater core and return is always in the circuit.

I'd be interested in your comments to this, as well as any design changes in the newer toyotas possibly addressing this.

Scott Justusson
 
My understanding is that the heater valve doesn't actually completely close either so it still "leaks" coolant past it. Probably designed to partially counteract the complete shutoof of the coolant flow back there?
 
This has indeed been a most informative thread. There is one element relating to overheating, or the inability to remove excess heat, that has not been raised here, and that is the benefit - if any - of auxiliary cooling.

There are numerous places outside of North America where overheating has to be a much greater problem than it is here, Southeast Asia and the Middle East, among others. In these markets, Toyota has seen fit to add rear air conditioning to the 80, and an auxiliary (pusher) cooling fan in front of the radiator to help compensate for the added load on the cooling system. (I would really be curious about HG failure rates in these markets!)

While such added cooling contributes nothing to the fundamental issues of dissimilar metals, the dynamics of coolant flow through the block, closed heater valve, and the like, it does provide additional cooling that might have some positive effect on the system.

I know this would be mostly speculation, but I would be interested in the opinions of some of the more experienced, mechanics, etc., who have already contrubited here as to the potential, or perceived benefit (or not) of such added cooling, without the additional load of supplementary air conditioning.

Thanks for all the good info!

Cheers, R -
 
I'll have to recheck my facts to ensure accuracy but while I had the head off the first one I recall thinking that I wanted to take the opportunity to fix something that's always annoyed me on the heater system. These trucks never seem to provide outside temp air in the summer - it's always heated slightly and makes me yearn for the FJ40's opening fender flaps that pull outside air directly in. Never got to it on the 97 but on my beloved 93 I took more time and looked into the water flow.

Turns out that the heater valve cannot shut off flow to the heater cores. It is designed with a relief in the actual valve so that in the full closed position there is still a small amount of circulation. So, there is no bypass as Toyota intentionally designed the heater valve to always allow circulation through the heater(s). Probably to preserve the cooling capacity of the massive system and ensure the heater circuit has a steady supply of coolant additives, etc.

My Brother in law happened to be in town as I was doing this and he's an automotive engineer. Together we pored over the flow diagrams and studied the actual block and things and he felt the system was well designed to cope with far more heat than a low stressed engine like this would put out. We studied the EGR system in particular. It's quite fascinating how Toyota actually made provision for the EGR gases to travel from the exhaust side to the intake/EGR side around the back of the head in a port cast into the head rather than routing it externally with a pipe. It becomes a pipe once it has gotten to the intake side. I suspect that an external pipe would have cooled too much and choked itself with deposits, where the cast-in port does not (mine were clean).

So, the EGR routing was not a stopgap measure. It and the heat it produces were clearly comprehended in the block and head design.

It is worth pointing out that we've had head gasket issues surface at the #6 (most often) and #1, which is to say at both ends of a very long straight 6 block. If it were strictly #6 I would not be able to say this, but I believe the thermal cycling and attendant differential expansion of the block and head break down the gasket. The ends suffer the most because that's where most of the movement is (the center expands both directions and as you get closer and closer to the ends, there is more distance moved). The rear #6 fails more often because it does have more heat due to the EGR valve and possibly because the block attaches to the tranny back there and the normal torque flexing of the block adds a measure of movement that the front of the block is not subject to. Dunno on that one, but it's something to consider.

Overall, I believe the new gasket to be a permanent solution. By that, I'd expect a proper HG replacement to mean the 1FZ would run into the 400,000 mile range and eventually need piston rings or something else that would put another HG on.

DougM
 
Paradise- the added pusher fan is in front of the condensor on those vehicles. I've added such a fan, with both A/C compressor and thermostatic control w/ radiator fin-type sensor. This setup does not seem to affect coolant temps according to my aux. coolant temp. gauge. :(
 
Doug that is a very good point that the outside cylinders have the most movement. In the middle there will be very little difference.
Aluminum being .0000126" expansion and Cast Iron being .0000059".
Temp being 20 deg F to 180 deg F a swing of 160 deg. The length of the block being approx 29"
Head = 160 x 29 x .0000126 = .0584" growth
Block = 160 x 29 x .0000059 = .0273" growth
.0311" difference divide by 2 = .0155" difference at each end.
The closer you get to center the less difference you get.
So do you clamp tighter to to have the block hold the head back from sliding so much, does the gasket slip, A gasket that held firm on the bottom and top but flexed in the middle? How is the gasket supposed to work? Is it supposed to let one side slide a little back and forth?

The cooler the climate the worse off you are it seems.
Every 10 degress gets approx .005" total length diff between Al and Cast Iron
 
How is the new gasket different than the old one? I have a new one but the old is not out quite yet.
 
The question still remains: Does the head gasket fail due to a poorly designed HG or does it fail from some other shortcoming such as cooling issues, head bolts, acts of GOD, etc.
In medicine these questions can be answered with data; observe thousands of individuals and their habbits and see what kills them-thats how we know smoking and being male places one at risk for having a heart attack.
If those who replace their head gaskets with new ones have no more problems with their head gasket then the problem probably isn't associated with the head gasket. The answer is with data.
It sure would be great if service records could be searched. Is there a way to search toyota or Lexus headgasket replacement and then see if those same trucks came in again for another replacement? there must be a way as data is what determines recall. A few hundred cases would be enough to draw conclusions.
There are confounders and biases of such a study but it would be interesting
 
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Long heads will warp further from the center, as will long manifolds, which the audi I5 suffer from. I too doubt that this list will solve it with just the who and when polls, but hey it's better to commiserate I suppose. It's solved in turbo exhaust manifolds either by dividing the long manifold up, or putting in elongated holes to allow for expansion. Not practical for the I6 head I suspect.

IDoug, most valves do allow some coolant, it's more to prevent cavitation (ala the air valve in the stock thermostat), not really to address the heat. One certainly could summarize that an open heater valve is doing more good than a closed one, small bypass or not. Probably still offset by the point above that expansion rates are higher in colder climes (where the valve will be open more)

This certainly could be a situation where the expansion is accomodated by a head gasket in good working order. When it gets old, it doesn't accomodate that as well/at all, and the head gasket pops. If that's the case, ARP's aren't helping the cause, and if the ridge at the threads is still in their design, it could actually be worse than stockers. I'm sure we won't get any further asking their folks...

Heat stability would still be a primary objective. Any truck that goes to 215, and never 220 because it has massive aux cooling, will do much better than one without the cooling.

Interesting on my 4R turbo, there was a bypass of the heater valve the same diameter as the valve, and that valve didn't fully close either. Since a closed loop 15psi system will send all water equally around it's circuit, I'm very tempted to go after this bypass...

Thanks Doug

Scott Justusson
 
I agree that it's only a matter of time before the HG fails. Mine failed at 178k and it cost me 5K + to rebuild the motor. IMO just bite the bullet and replace it. The peace of mind is worth the money alone. I'm friends with a mechanic(works for the dealership here in Bakersfield) who is really good and affordable. He basically figures up what the dealer would charge and charges half.:)
 
again, good thread. I think there is strong evidence that the heat around #6 is more than Toyota bargained for

1. the factory heat wrap on the harness on my truck beside the egr valve at #6 disintigrated into dust when i touched it. this is a notorious issue that can lead to wiring issues on 80s. I had to use a vacuum cleaner to get all the little bits out. I am sure toyota did not expect the harness to get that hot or they would have used more or better wrap or some other remedy.

2. there is a factory plugged off extra molex connector at the firewall end of the harness that plugs into the injectors (e.g., between the firewall and the #6 injector plug). on my truck this connector/plug was partially melted so I could not remove the plug if I wanted to (! wonder what it is??). I am sure toyota did not expect that to happen or they would have heat shielded it or taken some other precaution.

I don't necessarily buy that the EGR routing is at fault. although I suppose a blocked egr valve might cause an issue, the egr valve is closed a lot of the time anyway so I would expect toyota would have engineered for temps with the egr valve closed.

What I think is the problem is that it is just too cosy in that area and so it gets too hot and there is not enough air circulation in the engine bay to dissipate it. You have, in close proximity, a ton of heat sources, the PHH, the #1 return hose, the heater valve (potentially closed so that cooant circulation is constricted), the EGR valve, the tranny and the block, all reflecting their heat off the firewall. It is its own little world in there. It needs a little air circulation to get rid of the heat that is being shed.
 
Biff- Prior posts from people who have done this indicate that, while louvres do reduce underhood temps, they do not reduce oil or coolant temps at all. So I'm not sure this would have any effect on the HG.
 
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