Cracked Block 1FZ-FE (1 Viewer)
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Me too after 553,500 KM 
Engine block serial number 1FZ0346586
1997 FZJ80L-GCMNUV
Engine block serial number 1FZ0346586
BillyGoatMTB
SILVER Star
I'll get my serial number, is someone looking at them for a pattern?
Maybe....
BillyGoatMTB
SILVER Star
I'll pull mine and post it, I'm betting there's a whole lot of people out there that have the same hairline crack.
I have a crack below the freeze plug- identical to all the pictures, also located at 6 o’clock, with just under 300k mikes on the odometer.
Here are some pertinent crack facts (based on my experience doing Root Cause analysis in the nuclear power business)
1) This is caused by hoop stress from the freeze plug. It is likely not a fatigue crack owing to the stiffness of the block.
2) Possible reasons that the hoop stress leads to a crack are as follows:
a) the plug is too big
b) the block hole is too small
c) the casting around the hole is too thin (this is my pick), or
d) the casing metal has a defect / discontinuity in the block.
Reasons a) and b) are not likely, the required interference fit for freeze plugs is a common specification. And I am betting most people (like myself) have the original freeze plug installed when they first saw the leak.
Reason c) would indicate it will happen to most / all of our engines given enough time and heat cycles.......Let that sink in a minute......... And going to a short block replacement will reset the clock, but it will crack again (!)
Reason d) would indicate only a lucky (?) few of us will have the crack.
I suspect that many people have this crack and it goes unnoticed. Mine drops no coolant and I only add a 1/2 quart of coolant or so every 10k mikes.
Corrective Actions / Fixes:
A) Liquid internal stop leak poured into the coolant system- There could be some good high tech solutions out there worth trying. I am also concerned about clogging up coolant passages and the radiator, so more research needed.
B) I believe that drilling a stop hole (just beyond the crack end) IS NOT required- the crack will naturally stop at a structural boundary such as the freeze plug casting boss to the block itself. If anyone see a crack going past the freeze plug boss (the raised embossment around the freeze plug) - please send a picture......
And if you drill a stop hole, then you have to deal with plugging that hole too. And I would not try welding this block......
C) Provided B), above, is correct, then a repair that removes the freeze plug and applies a internal sealant to the crack itself appears a promising repair. This assumes that you can reach inside the freeze plug hole sufficiently to clean the surface to get a good bond between the crack area and the sealant.
D) The machinist repair (stitching) using drilled and tapped holes that are then plugged with bolts might be viable, but I have no first hand knowledge of this technique. And you would need to remove a lot of the engine top works to get your drill motor in there.
Since my leak is still small, I will ponder this and welcome input from others as to the efficacy of their repairs.
Handy Al
(Had mine since almost new)
It would be nice to know if the Toyota factory/ foundry in Japan has changed/improved the block design and or their casting techniques since the original blocks were manufactured. The parts gurus would know better, but maybe since the part number has changed that might indicate something has changed or been improved in either the design and or the manufacturer??
BillyGoatMTB
SILVER Star
Great conversation, and awesome insight!!!
I'll take a picture of mine today and repost.
I'll take a picture of mine today and repost.
BillyGoatMTB
SILVER Star
Here's my before and after.
The before shot is today and about 5,000 MI from the last time I cleaned it.
The cleaned pic is today also and I'm relieved to see the crack hasn't migrated.
she's been under heavy use this winter lots of Sierra mountain trips snowboarding from just outside the Bay Area, hi load RPM heavy use.
The before shot is today and about 5,000 MI from the last time I cleaned it.
The cleaned pic is today also and I'm relieved to see the crack hasn't migrated.
she's been under heavy use this winter lots of Sierra mountain trips snowboarding from just outside the Bay Area, hi load RPM heavy use.
I have a crack in the plug right of the oil filter but it looks like it goes pretty far down beyond the flat area of the hole. There was a thick layer of calcium buildup and I started scraping away at it and it showed the crack much better earlier, but as i started cleaning more off, it became harder to see. I haven't looked at the one behind te fuel filter yet. I'll get to that tomorrow. Anyone know if something like that is salvageable or do I need a new block?
Yes it is fixable. You fix it by adding more coolant. Once it fails catastrophically or starts causing overheating issues than it is time for a new block. This may never progress beyond its current condition and you might throw a rod or total the truck before the crack becomes an issue so just drive it.
So I took a dremel wire brush attachment and scrubbed the area real good. You can now definitely see the crack better. My plan is to grind down a small groove down the crack and jb welding it. But does anyone had a good way to seal up the mating surface of the plug? Area where I have circled.
Also I am contemplating using bars leak liquid copper in the coolant but I am kind of hesitant on using any kind of stop leak on a new radiator. Kind of paranoid that it will shorten the life of a new radiator and thermostat. Anybody know if it will have any ill effects on the new parts?
Thanks
Also I am contemplating using bars leak liquid copper in the coolant but I am kind of hesitant on using any kind of stop leak on a new radiator. Kind of paranoid that it will shorten the life of a new radiator and thermostat. Anybody know if it will have any ill effects on the new parts?
Thanks
How bad does it leak?
Don't add stop leak.
What you really want to do is stop the crack from spreading. Maybe you could try drilling a 1/8" diameter hole at the end of the crack. Only take it about 1/8" deep or less.
The JB weld will probably stop the leak but I doubt it would stop the crack from growing. Maybe drill the small hole, the groove the crack and fill it all worth the JB.
Don't add stop leak.
What you really want to do is stop the crack from spreading. Maybe you could try drilling a 1/8" diameter hole at the end of the crack. Only take it about 1/8" deep or less.
The JB weld will probably stop the leak but I doubt it would stop the crack from growing. Maybe drill the small hole, the groove the crack and fill it all worth the JB.
I wouldn't advise removing any metal near the termination point of the crack. JB weld won't do anything to stop further migration of the crack.
That will happen naturally as the stress decreases to a point where the material is stronger than the strain being put upon it. Except to 'stitch' it....I wouldn't take any measures in hopes of adding strength. You can however do whatever you like to 'seal' the crack and stop or attenuate leaks.
Consider that the block (metal) goes through cycles of heating/expanding and cooling/shrinking. With that in mind a good quality stop leak product along with a flexible exterior patch (High temp RTV) should take care of small leaks. If the leak isn't too bad....then nothing need be done IMO.
That will happen naturally as the stress decreases to a point where the material is stronger than the strain being put upon it. Except to 'stitch' it....I wouldn't take any measures in hopes of adding strength. You can however do whatever you like to 'seal' the crack and stop or attenuate leaks.
Consider that the block (metal) goes through cycles of heating/expanding and cooling/shrinking. With that in mind a good quality stop leak product along with a flexible exterior patch (High temp RTV) should take care of small leaks. If the leak isn't too bad....then nothing need be done IMO.
Yea my goal is to just stop the leak. I'll probably go with a new block if and when the engine has a catastrophic failure.
I actually am not sure how bad leak is, it has been awhile since I last drove it but I remember the coolant tank fluctuating quite a bit and when I add coolant to the tank when low after driving, it would start to overflow as the engine cooled
I actually am not sure how bad leak is, it has been awhile since I last drove it but I remember the coolant tank fluctuating quite a bit and when I add coolant to the tank when low after driving, it would start to overflow as the engine cooled
Overflow tank will fluctuate when the vehicle has been driven (coolant expands) and then again when it cools. That is normal.
'Overnight' readings (engine cool, coolant from reservoir returned to radiator) would be helpful, but bear in mind some evaporation occurs.
ONLY if you saw a significant level change (less coolant) in a two day period would I give it a second thought. Keep your radiator FULL and check the level in the overflow tank periodically. It is common to need to add to the reservoir from time to time.
Here is my stop gap patch job till I fugure out what to do for long term solution.
I grinded down a groove along the crack. Then I popped off the old freeze plug. Replaced the plug with a layer of permatex sealer around the new plug. Then I filled in the groove with jb weld.
Let's see how long this holds up.
I grinded down a groove along the crack. Then I popped off the old freeze plug. Replaced the plug with a layer of permatex sealer around the new plug. Then I filled in the groove with jb weld.
Let's see how long this holds up.
So after I put her back together, and ran her for a couple days, the jbweld couldn't hold the leak.
You can see in the photo that it broke through the jb weld and is leaking. Maybe a bad application of jb weld or just not the right fix for the job. So i resorted to using bars stop leak. It's been two days of driving, and the leak area has been dry so far. Where as before bars stop leak I could actually see the leak area sweat and form a droplet of water every few minutes.
It leaks because it's under pressure.
It doesn't matter what someone places on the outside of the block, it will leak because it is pushing from the back side with 15 PSI.
That's why I have suggested the Permatex #1 or #2 and use a finger to apply it to the crack from the INSIDE while the freeze plug is out.
(Clean and dry the area inside first, of course...)
Then apply some to the freeze plug hole before freeze plug installation.
Bar's leaks is what it needs to be until someone decides they need to do a flush with an acid-based product to clean out all the rust (and sealants) in the cooling system.
Good Luck!
