No "how-to" head gasket posts for a Gen4?

BiomedO1 · Aug 12, 2026 at 11:10 AM

C Clay said: ↑

View attachment 301872 View attachment 301873 View attachment 301874 She definitely needed a head gasket. It’s the same engine as the gen 3, using the same Felpro gasket as I used on the others I did this year.

I’m in the middle of this and it is raining, so I am on break. I have a couple of thoughts here:
1.Ive always thought the engine looked “new”, specifically all hoses, water pumps, everything you can see. However, when I get into the engine more- it looks kind of chalky on the surface. I’m wondering if someone didn’t do an engine swap. Which…if they did, makes you wonder about the argument about head gasket vs engine swap. For my labor costs- I’ll do head gasket
2. The head gasket has a red material that was all over it and the surfaces. Previous head gaskets I changed were black. Wonder what type of head gasket this is?

If it’s not on the CARFAX, there’s really no way to tell if an engine swap has been done is there?

Also- somehow my searches had been missing a good head gasket video for this generation by Gasketmasters. It’s a good reference if you have nothing else, but they go kind of quick. Nothing like the awesome video from NutsAboutBoltz for the Gen3.

In this experience, I can confirm that the Gen 4 EGR cooler issue does appear to be solved- there is no carbon clog here that needs to be addressed.
Click to expand...

So you at least have a cross-leak between the coolant and engine oil passages. If that cross-leak was at the head gasket; you should be able see the tracing/rupture on either side of the head gasket. If you don't; the cross-leak is someplace else.

BiomedO1 · Aug 12, 2026 at 11:11 AM

C Clay said: ↑

View attachment 301872 View attachment 301873 View attachment 301874 She definitely needed a head gasket. It’s the same engine as the gen 3, using the same Felpro gasket as I used on the others I did this year.

I’m in the middle of this and it is raining, so I am on break. I have a couple of thoughts here:
1.Ive always thought the engine looked “new”, specifically all hoses, water pumps, everything you can see. However, when I get into the engine more- it looks kind of chalky on the surface. I’m wondering if someone didn’t do an engine swap. Which…if they did, makes you wonder about the argument about head gasket vs engine swap. For my labor costs- I’ll do head gasket
2. The head gasket has a red material that was all over it and the surfaces. Previous head gaskets I changed were black. Wonder what type of head gasket this is?

If it’s not on the CARFAX, there’s really no way to tell if an engine swap has been done is there?

Also- somehow my searches had been missing a good head gasket video for this generation by Gasketmasters. It’s a good reference if you have nothing else, but they go kind of quick. Nothing like the awesome video from NutsAboutBoltz for the Gen3.

In this experience, I can confirm that the Gen 4 EGR cooler issue does appear to be solved- there is no carbon clog here that needs to be addressed.
Click to expand...

So you at least have a cross-leak between the coolant and engine oil passages. If that cross-leak was at the head gasket; you should be able see the tracing/rupture on either side of the head gasket. If you don't; the cross-leak is someplace else.

Mendel Leisk · Aug 12, 2026 at 11:48 AM

C Clay said: ↑

In this experience, I can confirm that the Gen 4 EGR cooler issue does appear to be solved- there is no carbon clog here that needs to be addressed.
Click to expand...

All the 3rd gen owners got to be guinea pigs for Toyota, and the reward was to "pound sand".

The red stuff on the head gasket is a coating, not loose? Wouldn't be a stop-leak product?

GLCReviews · Aug 12, 2026 at 12:59 PM

Mendel Leisk said: ↑

One thing, it’s early years of gen 4 that we’re having the exhaust heat recovery (EHR) system leaks. My memory’s flakey, but it might have been resolved by model year 2019. Not sure though.
Click to expand...

2016-2018 were the primary years for that. By 2019 (not sure what production date month maybe) they should have all been remedied by then. But YMMV as usual.

No "how-to" head gasket posts for a Gen4?

BiomedO1 Senior Member

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No "how-to" head gasket posts for a Gen4?

BiomedO1 Senior Member

BiomedO1 Senior Member

Mendel Leisk MMX GEN III

GLCReviews New Member