Head gasket failure? I’m not sure.

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On Tuesday I was at a red light and started to get a little bit of a rough idle on my 97 LC. I gave it a little throttle and it smoothed out and the light turned green shortly after. I didn’t notice any smoke from the exhaust and it didn’t happen again for the rest of the drive (about 15 minutes). It remained parked in my driveway until today as it’s not my daily.

Today I went to start it up and immediately noticed the rough idle and jumped out and sure enough there was a little white exhaust coming out. I turned it off and decided to go get the block test kit from autozone (in my other vehicle). I did the test twice and it was negative both times (no exhaust gasses). I checked the oil and everything looked fine visibly (I’ve ordered a test from blackstone). I do burn a little oil, but no over heating and no noticeable coolant loss.

While looking under the hood today to check hoses and and wondering if it’s an intake manifold gasket leak, I noticed a bit of the gasket sticking out near the belts (see photo). I don’t recall ever seeing that sticking out before and it’s been out for a while as I had to wipe the red dirt dust from the trails off of it.

I’m curious what everyone here thinks. Thanks in advance.
7E420478-09EC-4CE0-875D-7987871B5EFF.jpeg
 
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Pull the plugs and check for water in the cylinders. Generally cylinder 6 is the culprit.
 
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So after looking a little more this morning I think it may actually be that the engine wiring harness is melted by the egr. I started it up again this morning and nothing at first but then it started doing it after a minute or so. I move the harness back and for (slight as there isn’t much play) and was able to recreate it each time I moved it. I think the culprit might be a wire for the injectors grounding out.

I know the harness is around $700. A couple questions, is it difficult to replace? I have some wrenching experience (lifts, axle seals, wheel bearings, etc.) but not a ton. What would a local shop charge to do this? I have plenty of tools and a space to do it, but don’t have a ton of spare time as work is pretty demanding and I have a 2yo and an 11 month old. Is it worth getting the new harness and replacing the old and then mending the old as a spare or just trying to mend the current one? Lastly all the hoses around there are still in pretty good shape and are plenty pliable, but is there anything else I should go ahead and do as PM?
 
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So after looking a little more this morning I think it may actually be that the engine wiring harness is melted by the egr. I started it up again this morning and nothing at first but then it started doing it after a minute or so. I move the harness back and for (slight as there isn’t much play) and was able to recreate it each time I moved it. I think the culprit might be a wire for the injectors grounding out.

I know the harness is around $700. A couple questions, is it difficult to replace? I have some wrenching experience (lifts, axle seals, wheel bearings, etc.) but not a ton. What would a local shop charge to do this? I have plenty of tools and a space to do it, but don’t have a ton of spare time as work is pretty demanding and I have a 2yo and an 11 month old. Is it worth getting the new harness and replacing the old and then mending the old as a spare or just trying to mend the current one? Lastly all the hoses around there are still in pretty good shape and are plenty pliable, but is there anything else I should go ahead and do as PM?

Definitely doable if you have the time, space and an extra car to drive in the mean time. I know Joey @NLXTACY sells the OEM Toyota harness.

My rig is a 94 so I wasn't able to go with a new OEM harness, I needed to source a known good one and I had Scott Higgins @Cruiserhiggs do mine @ Higgins Cruisers here in Mesa, AZ.

Also, check where your harness runs along the head, injectors I have heard there are supposed to be some mounts to keep the harness in place there. Mine does not have them but I am thinking of using insulated cable clamps.

1655046131241.png


Prior to putting the rig back together I would use some type of heat resistant tape or exhaust wrap on the tube for the EGR.

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and heat resistant tape to protect the $700 investment

1655046329543.png
 

baldilocks

Battle Ground, WA
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Might as well replace the entire harness. I had the same problem on a 94 model back in 2015 and probably bought one of, if not the last, engine harness for the 93-94 models. I’m glad I replaced instead of repaired because the entire harness exhibited signs of degradation not to mention the confirmation every time I read a thread where members are searching for new connectors and making bandaid repairs to an old, brittle wire harness.
 
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Might as well replace the entire harness. I had the same problem on a 94 model back in 2015 and probably bought one of, if not the last, engine harness for the 93-94 models. I’m glad I replaced instead of repaired because the entire harness exhibited signs of degradation not to mention the confirmation every time I read a thread where members are searching for new connectors and making bandaid repairs to an old, brittle wire harness.

Yeah, I’m thinking the same thing. Buy the new and use it, then attempt to mend the old as a spare.
 
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Definitely doable if you have the time, space and an extra car to drive in the mean time. I know Joey @NLXTACY sells the OEM Toyota harness.

My rig is a 94 so I wasn't able to go with a new OEM harness, I needed to source a known good one and I had Scott Higgins @Cruiserhiggs do mine @ Higgins Cruisers here in Mesa, AZ.

Also, check where your harness runs along the head, injectors I have heard there are supposed to be some mounts to keep the harness in place there. Mine does not have them but I am thinking of using insulated cable clamps.

View attachment 3031996

Prior to putting the rig back together I would use some type of heat resistant tape or exhaust wrap on the tube for the EGR.

View attachment 3031997

and heat resistant tape to protect the $700 investment

View attachment 3031998
Great tips! Thanks!
 

baldilocks

Battle Ground, WA
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Yeah, I’m thinking the same thing. But the new and use it, then attempt to mend the old as a spare.
I don’t think you will ever need to replace the harness again barring an engine fire. Haha
 
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So I checked with a dealership in the area to get a quote on getting the harness replaced. I separately bought the part through Olathe Toyota per the suggestion above (thank you). The dealership estimated $2,500 for this. Seems super high to me. I checked with them as I don’t have much free time, maybe one or two days per month, but I might have to make time. It’s not my daily so it might just have to sit in the garage for a while.
 

mudgudgeon

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The dealership estimated $2,500 for this.

Labor cost? Or parts too?

What is their hourly charge? Seems like a huge gouge!
I would think a competent mechanic would have this done by lunch time?
 
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Labor cost? Or parts too?

What is their hourly charge? Seems like a huge gouge!
I would think a competent mechanic would have this done by lunch time?
Labor only I’ll be supplying the parts. I mean it’s kind of extensive I guess if you remove the upper part of the intake manifold, which the fsm says to do. But it still seems quite high
 

mudgudgeon

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Labor only I’ll be supplying the parts. I mean it’s kind of extensive I guess if you remove the upper part of the intake manifold, which the fsm says to do. But it still seems quite high
Yep, my comment is on the assumption they remove manifolds, clean parts and reassemble.

I may be underestimating how long I spent on this portion when I did all this on mine recently.

Even at $100/hr, they are saying 25 hours shop time??
 
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Yep, my comment is on the assumption they remove manifolds, clean parts and reassemble.

I may be underestimating how long I spent on this portion when I did all this on mine recently.

Even at $100/hr, they are saying 25 hours shop time??
Most shop rates are in the $165/ hour now.

Get with the times. :rofl:

The shop will also have to provide replacement gaskets for the manifold, throttle body, and any hoses they destroy in the process. If you're having the top half of the intake off, change your fuel filter and all your vacuum hoses underneath.
 

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