100 series exhaust manifold (1 Viewer)

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I went the DT route, and other than the ticking from the leak going away, I noticed no difference in sound at all really. Maybe a bit when at WOT, but I wouldn't worry about droning.
Appreciate the input but from my understanding I can not go the DT route and pass emissions testing. Just looking for some input from individuals who have had replacements installed for some time to see how they are holding up.
 
I just installed new OEM ones. you can buy them from McGeorge Toyota for pretty cheap and they have them in stock.


Its a pain of a job to do and the OEMs lasted on mine for over 300K miles. Also I went OEM because I really don't want any droning noise with the DT.

Its amazing how quiet my engine sounds now with new manifolds.
Did the new OEMs seem to be constructed of a heavier gauge than the existing? I think I had seen somewhere that it was mentioned that they increased the material gauge which might help prevent future cracking.
 
Appreciate the input but from my understanding I can not go the DT route and pass emissions testing. Just looking for some input from individuals who have had replacements installed for some time to see how they are holding up.
Ah, right, CA...carry on.
 
Anyone made their own? I know there are a lot of talented ppl here.
 
Did the new OEMs seem to be constructed of a heavier gauge than the existing? I think I had seen somewhere that it was mentioned that they increased the material gauge which might help prevent future cracking.
It seemed to be the same to be honest. if they did I didnt see a difference.
 
Does anyone know if Toyota ever improved on the manifold integrity? Trying to plan what parts I should go with for this job and would like to go OEM if I could
 
Does anyone know if Toyota ever improved on the manifold integrity? Trying to plan what parts I should go with for this job and would like to go OEM if I could
Yes, they did. It’s not really an issue with the 03-07 model years because of the improvement.
 
Yes, they did. It’s not really an issue with the 03-07 model years because of the improvement.
Wonder if they're backwards compatible with the 98-02? I wouldn't be opposed to using a late production manifold on my 01 that's ticking.
 
hey guys I’m going to do the big job here in the next few weeks. I am not going with DT (emissions test) so please don’t try to sell me on it😂 can anyone vouch for one of the more available brands (oem/dorman/napa auto oe) that they’ve had success with. Ideally don’t want to do this again so I’d like some help picking a good one.
The obvious choice seems to be not to go back with Toyota manifolds since they failed on most 100s. I heard they redesigned them for later years but how do I know if I’m getting one of the newer versions? Any help appreciated thanks.
 
The obvious choice seems to be not to go back with Toyota manifolds since they failed on most 100s. I heard they redesigned them for later years but how do I know if I’m getting one of the newer versions?
They were redesigned for the later model years (04-07, IIRC), which do not have the cracking issues that the earlier model years had. The original design was promptly discontinued, so it's impossible to buy anything other than the newer improved design version from Toyota.

I am not going with DT (emissions test) so please don’t try to sell me on it😂 can anyone vouch for one of the more available brands (oem/dorman/napa auto oe) that they’ve had success with. Ideally don’t want to do this again so I’d like some help picking a good one.
I couldn't install DT because of emissions testing either. I installed SKP manifolds a few years ago with new OEM Toyota gaskets, studs, and nuts, and haven't had any issues since (~28k miles). They may be good for another 20 years or might crack tomorrow - who knows. I was in a bind back then and couldn't get the Toyota manifolds for over a month, which is why I gambled on the SKPs. Although I have zero complaints about the SKP manifolds thus far, if the circumstances were different back then, I would have bought new Toyota manifolds instead.
 
They were redesigned for the later model years (04-07, IIRC), which do not have the cracking issues that the earlier model years had. The original design was promptly discontinued, so it's impossible to buy anything other than the newer improved design version from Toyota.


I couldn't install DT because of emissions testing either. I installed SKP manifolds a few years ago with new OEM Toyota gaskets, studs, and nuts, and haven't had any issues since (~28k miles). They may be good for another 20 years or might crack tomorrow - who knows. I was in a bind back then and couldn't get the Toyota manifolds for over a month, which is why I gambled on the SKPs. Although I have zero complaints about the SKP manifolds thus far, if the circumstances were different back then, I would have bought new Toyota manifolds instead.
Sounds good, although 1278$ from my dealer for all parts sounds a bit crazy 🥲
 
Sounds good, although 1278$ from my dealer for all parts sounds a bit crazy 🥲
IIRC, I paid like $375 total for both SKP manifolds from RockAuto and another $100 for all new OEM gaskets, studs, and nuts from PartSouq.
 
Until this month, I though Toyota corrected exhaust manifolds, in all 2003- models. I just replaced DS exhaust manifold in 03LX MFD Date Oct 2002. #1 crack at head flange (typically) at weld.
 
I’m thinking I’m gonna go with the OE manifolds from NAPA.
Anyone who has used these that can chime in on quality would be helpful.
Most of the stuff I’ve replaced with aftermarket parts was from napa and I’ve been happy with them, so far…
 
Correct. The issue primarily affects 2000-2002 model years. There may have even been a TSB about it (100 Technical Service Bulletins - https://forum.ih8mud.com/threads/100-technical-service-bulletins.138386/), but I have not read them in-depth to verify.

Perhaps @hoser could chime in.

I don’t know the exact production date but it was indeed improved in and around that time (2004 or 2003ish). All new replacements from that point on were of the improved design. 06-07 is a different manifold.
 

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