Early Model LC200 Head Gasket

[njbrain]

How is the progress? Just buy the Engine overhaul kit from Toyota. It will have everything you need and then some. The drivers side tensioner should be replaced. The main tensioners should be replaced, but the rest might be fine. The chains on these engines do not usually stretch, but if you have it won't hurt to replace them. Chances are the black coating has peeled off the head gasket.

 

[bentonrover]

Wow my 2008 LC mirrored the same thing. Missing coolant was my valley cover. Brought it to dealer to get it fixed. Told me #8 cylinder headgasket blew. No engine light but I did feel a vibe under hard acceleration though. My tech stream confirmed the code. It had 237k with full Toyota history. I didnt want to pay the $7700 to repair it. I could have but didn't seem really worth it to me. CT mechanics are super lazy. No other shops wanted to touch it. Not sure why. Got $12k as is. Shame smh. Good luck with the repair

 

[Yossarian]

To the OP, what is the current status of the repair? And have you seen this.

The Car Care Nut talks UR V8 blown head gaskets

forum.ih8mud.com

 

[alexvallorosi]

How is the progress? Just buy the Engine overhaul kit from Toyota. It will have everything you need and then some. The drivers side tensioner should be replaced. The main tensioners should be replaced, but the rest might be fine. The chains on these engines do not usually stretch, but if you have it won't hurt to replace them. Chances are the black coating has peeled off the head gasket.

Thanks for the tip. A kit will make my life a heck of a lot easier than digging through for part numbers.

To the OP, what is the current status of the repair? And have you seen this.

The Car Care Nut talks UR V8 blown head gaskets

forum.ih8mud.com

Yes I have seen that. Kind of unfortunate. I'll verify that the same issue was present on my head gasket when it comes off. This certainly makes me want to do the driver side as well in order to replace it with a fresh gasket, but also makes me concerned about finding that the block has warped when I pull the head.

Still working on the repair. I just unbolted the exhaust manifold from the cat on the passenger side tonight. Next to pull the head

 

[alexvallorosi]

Also, this head gasket drama makes me wonder if there is a coolant product that maintains lower acidity over time, which may be better suited for our motor...

 

[bloc]

Also, this head gasket drama makes me wonder if there is a coolant product that maintains lower acidity over time, which may be better suited for our motor...

Lots of data in that thread showing users here without increased acidity in their coolant despite a broad range of mileage on it.

 

[alexvallorosi]

Alright the day has finally arrived. Passenger side head is off so that I could see the mode of failure.

Below you can see the gasket with the notorious failure on the coolant passage between Cylinder 8 and 6.

You can also see that it was dangerously close to failure between cylinder 4 & 6.

Well. I put a tri-square over cylinder 8 every which way and shined a flashlight behind it. No daylight. So that’s promising for the block. I will get a precision straight edge and measure distortion with feeler gauge.

 

[rexington14]

Yep, looks like the same mode of failure from the multiple examples of blown UR head gaskets shown in TCCN video.

That is good news on your block though!

Any background history on this truck you can provide? How long you owned it? What was the coolant change history? Did it ever overheat?

 

[alexvallorosi]

Yep, looks like the same mode of failure from the multiple examples of blown UR head gaskets shown in TCCN video.

That is good news on your block though!

Any background history on this truck you can provide? How long you owned it? What was the coolant change history? Did it ever overheat?

Still not out of the woods yet until I put the precision straight edge on it.

I have owned the vehicle since 212,363 miles. It currently has 239,000. I don’t have much background before that. Two owners.

I added coolant to the overflow reservoir at 218,541. Added coolant again at 230,180. I do pay attention to the gauge while driving. It was rock steady the entire time I drove it. I know there’s a dead zone but it never even showed any cause for concern.

 

[rexington14]

Still not out of the woods yet until I put the precision straight edge on it.

I have owned the vehicle since 212,363 miles. It currently has 239,000. I don’t have much background before that. Two owners.

I added coolant to the overflow reservoir at 218,541. Added coolant again at 230,180. I do pay attention to the gauge while driving. It was rock steady the entire time I drove it. I know there’s a dead zone but it never even showed any cause for concern.

So no known overheating event. Thanks for the info.

Good luck! Have you considered pulling the other head as well to replace the HG given your this far in?

 

[alexvallorosi]

After seeing the CCN video with all the problems between 5&7 - I absolutely will pull the DS head. I'm sure the gasket is in about the same condition as the PS head and ready to go at any moment.

 

[alexvallorosi]

Also if it’s relevant I always used premium fuel which is 91 around here

 

[ryanCA]

Also if it’s relevant I always used premium fuel which is 91 around here

290 k miles of 87 baby!

Having owned land cruisers for over 40 years in se asia and africa and how those are “maintained” and nothing happens to them —— yours getting 91 is living the life of a princess for sure

 

[alexvallorosi]

DS can tower off. That’s probably all I do tonight. I thought the exhaust was bad on the Passenger side but the driver side is killing me

 

[alexvallorosi]

I lied. I decided to pull the head along with the attached exhaust header (which I actually did on the passenger side as well)

I’m pretty glad I pulled this head as well, since it looks like this gasket could have gone at any second. I’m starting to think that the actual mechanism of failure is a poor design in putting coolant passages with such a small amount of material between the cylinders. As you can see here, at this stage, this confirms the gasket is failing from the inside (coolant passage) out towards the cylinder. Whether this is a result of acidic coolant or electrolysis or air in the system or whatever I don’t know, but it: 1. Looks to be a consistent failure amongst those who experience it and 2. Doesn’t seem like an overheat was the root cause. I guess there would be more to be said if every one of these ALSO had the valley plate leak and/or replaced radiator or neither

Has anyone put an o-ring on this motor?

 

[rexington14]

I’m starting to think that the actual mechanism of failure is a poor design in putting coolant passages with such a small amount of material between the cylinders. As you can see here, at this stage, this confirms the gasket is failing from the inside (coolant passage) out towards the cylinder. Whether this is a result of acidic coolant or electrolysis or air in the system or whatever I don’t know, but it: 1. Looks to be a consistent failure amongst those who experience it and 2. Doesn’t seem like an overheat was the root cause.

This.

 

[alexvallorosi]

This.

I rehabbed a 5VZ-FE which literally corroded away the freeze plugs. Some previous owner must have used the wrong mix or flavor of coolant. They were so rusted that they were crumbling and weeping coolant out of the sides of the block. Who knows how long it had been running that way. The coolant passages were coated in rust inside the block. I replaced a bunch of components, flushed the system with Thermocure, and put fresh coolant in. That motor has never had a head gasket issue. Granted, cast block - but aluminum head. Certainly not a healthy cooling system. But go look at the design of the block, there are no tiny little coolant passages with no material between the cylinders.

 

[alexvallorosi]

I found these warpage specs for the 3UR-FE online. Can anyone verify this? Presumably if we are within STANDARD spec then I don't need to machine. If we are outside STANDARD spec but within MAXIMUM spec I do need to machine the head. The Block does not list a "standard" warpage spec. So what is your opinion? If there IS warpage but WITHIN maximum spec, am I good to go? I would guess yes.

 

[rexington14]

The Block does not list a "standard" warpage spec. So what is your opinion? If there IS warpage but WITHIN maximum spec, am I good to go? I would guess yes.

Same thing came up in the TCCN UR video. The block warped but it was slightly under the maximum spec. Apparently he still didn't have the confidence to offer a warranty for just the HG replacement

 

[alexvallorosi]

Looks to be very close to the spec on passenger side - .063mm in one spot (between 6 & 8). A .076mm feeler will not fit there. The driver side is the same story. One low spot, between (1 & 3).

It looks like people who are rebuilding aluminum motors seem to agree that anything under .003" is fine. Every other spot is pretty much zero warpage. I'm almost willing to bet that if you tore down any Land Cruiser (even one that didn't fail) you would see the same amount of warpage at this mileage.

The head has almost no warpage whatsoever which you would think would be the opposite. A .063mm feeler would not fit under the straight edge.