Head gaskets and the 1FZ (1 Viewer)

[ChiTown]

I've had to replace dozens of Cometic gaskets in multiple applications so I'm not a big fan of them. They always seem to fail at the fire ring.

 

[Phil H]

I too lost the 1st OEM HG at 119k in '07. I have owned our '97 since nearly new. Well maintained. TRD S/C added ~60k.
Lost the 2nd "new" and redesigned OEM HG in '14 @ 170k mi. I have had to let it sit for past yr and starting now to determine best path for a 3rd HG and found this post.
I too wonder why the new OEM HG failed. Till I disassemble it, I will not know for sure. If I do rebuild the 1FZ, I too plan to follow Robbie's and other advice to use an MLS HG and an ARP stud kit. Deck the block to the reqd finish. Which then means a likely rebuild of the bottom end since I have the block out. Painful.
This is an older thread but anyone have any other updated news on best MLS gasket set to use? ARP stud kit still preferred?

 

[baldilocks]

For better or for worse, in blown HG and in Rubicon runs, I vow to honor my 1FZ and speak of it only in positive terms. How about those who have run beyond 400k on the same HG? Keep your cooling system in shape and live long and large brothers.

 

[Whileemptyheadsdream]

From another thread: "This is why I keep advocate getting a Blackstone sample before buying an 80 - or just assume there is a head job in the near future. The more I hear about "recently purchased" 80's, the more I think a case of overheating, and the following suspicious HG issues, are pretty much the primary reasons people put their 80's up for sale. (Mudders excluded of course!) I mean, unless a person is facing a multi-thousand dollar repair bill why in the world would they sell a good Land Cruiser - particularly with current gas prices?"

This ought to promote some good discussion.

The people who sold the 95 I have said the main reason was the huge oil spots on there new homes driveway. I believed her, she was a Realtor and I understand how that Is a problem for them. That said I agree with your theory, I believe a high % of L/Cs are unloaded because of bad headgaskets the case history's prove It. Good Luck,,!

 

[rc51kid]

My completely unscientific opinion is that the vast majority of HG failures are secondary to old poor coolant systems. No saying the HG is not weaker than some other designs. But i think a LOT of people are over heating these things and then crying about a HG. I am not saying you guys did this or most Mud members. But mostly the general public.

 

[aae42]

The more I hear about "recently purchased" 80's, the more I think a case of overheating, and the following suspicious HG issues, are pretty much the primary reasons people put their 80's up for sale. (Mudders excluded of course!) I mean, unless a person is facing a multi-thousand dollar repair bill why in the world would they sell a good Land Cruiser - particularly with current gas prices?"

just wanted to mention that mudders are not excluded.... ask me how i know


but in adding to the content of the thread, i had a PO that poorly maintained the cooling system... he claims he had replaced the radiator in the past few years, and that may have been true, but the PHH was blown up like a balloon, there was (is) a small leak in the last few heater hoses above the heat shield, and the fan clutch was shot

 

[toyotaspeed90]

Sometimes I question the HG failures mentioned and wonder what means people are generally using to make the determination.

I got my 80 from someone others have said is reputable with 80s, and unsure whether he personally diagnosed or someone else... story goes that a customer brought it in for running rough, diagnosed as a HG failure, and instead of fixing sold it to the shop.

2 years later, HG not fixed, I got it.

After a few tests I found the HG wasn't the problem at all, but basically electronics overly sensitive to outside of normal ranges caused a CEL, and it ran rough, like a cylinder had dropped.

Been daily driving it nearly 7 months now and the motor is strong. It's at 297k miles.


To what ChiTown said, I've owned probably 20 4age and 4agze (even throw in some high comp 7age's) motors (all but 20v variants) and ever only had 1 HG failure, which was actally purchased disassembled, so not known if thats even accurate. Most of them were used in autox or racing situations along with daily use - for those engines they are far more prone to spinning a bearing and throwing a rod than a HG failure. My 2jzge IS300 (3.0 I6, cast block alum head) I had up until 160k miles and never a whiff of a HG nor cooling system failure.


The reason I sometimes questions it - is that the root problem that's causing runability issues will many times be disassembled/reassembed if not outright replaced, during the HG replacement.

 

[aae42]

Sometimes I question the HG failures mentioned and wonder what means people are generally using to make the determination.

I got my 80 from someone others have said is reputable with 80s, and unsure whether he personally diagnosed or someone else... story goes that a customer brought it in for running rough, diagnosed as a HG failure, and instead of fixing sold it to the shop.

2 years later, HG not fixed, I got it.

After a few tests I found the HG wasn't the problem at all, but basically electronics overly sensitive to outside of normal ranges caused a CEL, and it ran rough, like a cylinder had dropped.

Been daily driving it nearly 7 months now and the motor is strong. It's at 297k miles.


To what ChiTown said, I've owned probably 20 4age and 4agze (even throw in some high comp 7age's) motors (all but 20v variants) and ever only had 1 HG failure, which was actally purchased disassembled, so not known if thats even accurate. Most of them were used in autox or racing situations along with daily use - for those engines they are far more prone to spinning a bearing and throwing a rod than a HG failure. My 2jzge IS300 (3.0 I6, cast block alum head) I had up until 160k miles and never a whiff of a HG nor cooling system failure.


The reason I sometimes questions it - is that the root problem that's causing runability issues will many times be disassembled/reassembed if not outright replaced, during the HG replacement.

i had a rough running truck, but chose not to continue running it after leaving a plume of steam behind me while forcing the poor 1fz to lubricate itself with chocolate milkshake...