PaulieWalnuts

Quick question, apologies in advance if its been answered already a quick search revealed no relevant results, worth it to wrap the exhaust crossover on the 3VZE to mitigate underhood engine heat issues? (HG failure) logically it makes a bit of sense but reviews seem mixed on the idea.

87-4runner

I think a custom made heat shield would be better than wrap... wrap is tricky to do and must be done correctly.

millball

It is very unlikely that heat radiated from the crossover pipe into the engine compartment contributes.to headgasket failure.
If any fault is to be attributed to the crossover, it would be to excess heat conducted into the head because of flow restrictions where the exhaust from the right and left head come together near the downpipe bung.
Seems to me that wrapping the crossover could only make this heat issue worse.

aztoyman

IDK if it would help with head gasket problems but I wrapped my 3.4 swap crossover and the pipes under the cab and it definitely helped with heat at the firewall and under the cab. I originally did this back in 2010 when I did the swap in my 88. And now it's going in my linked 86 Xtra Cab. I added a home built heat shield between the cat and my trans this time as well.

I hear the wrap can rust out your exhaust but I live in Arizona and obviously it hasn't rusted mine out in 13 years.

Hairyberry

Your best bet is going to be to delete the crossover in my opinion but when I had a 3vz I was considering modifying the crossover so that it still would dump into the left manifold but had another point of flow so that part that went into the left manifold would act like an H pipe found on old school muscle cars but the majority of the exhaust gasses would merge down farther in the system but my engine got screwed up and I just did a 5vz swap instead

Very rough idea of what I was thinking but would have taken a lot of work for what it was the red circle represents where I would have drilled big hole in the exhaust and the blue represents the exhaust pipe I would have welded onto it and merged it into the stock pipe

Onto the exhaust wrap I’ve always wrapped certain areas of my exhaust and I’ve never had the pipe rust out because of it and I drive in lots of puddles and salted roads. My theory is that as long as you drive far enough and keep the exhaust hot all of the moisture will boil out before it can cause any major rust problems but I also paint my exhaust with high heat spray paint before I wrap it

PaulieWalnuts

Do nothing, wrap or heat shield hmm

I have a mechanic might be able to help me out with that, main reason i like the wrap is its budget and DIY friendly, but the heat shield sounds like a better long-term solution.

Overall i think the engine on this single owner 93 t100, 199k mi runs pretty well, just doing research and seen some red flags about the HG issue on the 3vze, so trying to stay one step ahead of it, some have stated just not let it overheat and i'll be fine, which is great advice, maybe am overthinking it?

My whole thinking is If i can take small steps to prevent/delay a major engine overhaul, I'll be wanting to do that.

Thanks all for the replies.