Well, add me to the list of cracked manifolds. I had suspected as much...I knew the muffler had a hole in it but was experiencing more loss in power/acceleration than I expected from just the muffler. I SeaFoam'd the Taco today and immediately my suspicion/fear was correct. Smoke was just pumping out from under the heat shield.

I had done a compression check on it and cyl#2 is around 100 psi while the others are 160/170/180. Poured small amount of oil into #2 and compression only went up to 120 psi....so sounds like burnt exhaust valves too. YAY!!!

I already have Thorley ceramic coated headers ordered, new O2 sensors, new cat and will do exhaust at local muffler shop. But none of that stuff is going on until I rebuild the top end so in the meantime has anyone had any success with a patch job??? I don't believe JB Weld will hold up to the heat and I don't think it's sensor safe.

Anyone on here have a tried and true "Band Aid"??? The Taco won't even stay running without the heat shield on the manifold as that is "plugging" the crack...I had to laugh a little at that one.

 

go to an auto shop, ask em if u can buy a little bit of their metal shavings from the rotor turning machines. mix a little bit of that with JB weld, it will hold stronger than steel.

 

Shoot id just see if you can get someone to weld up the crack.

And yeah Im burning a little bit of oil (10-40) syn. I believe because the mani was cracked for too long and it burnt a valve, I've only had it for 10k miles though.

Back on topic.

Why not just throw the new headers on now..?

 

I don't have the headers yet, in fact it should ship today. The headers, new O2 sensors, new exhaust aren't going on until I pull the head, rebuild the top end and replace the valves.

So...in the meantime I was just looking for a band aid to hold me over especially since with the heat shield off there was such a loss of back pressure the engine wouldn't even stay running. I found a product called Thermo Steel (right next to the JB Weld and Quick Steel putty) at my local AutoZone. Hit the mani with a wire brush to scrub off dirt/carbon residue, wiped it with denatured alcohol, mixed up the ThermoSteel and spackled it on.

I've only had it on there for about a day now and seems to be holding up and got back some power...I will have to see how it holds up to the heat, but it specifically says "...for exhaust manifolds".

 

x2. This has worked for me in the past as a temp fix.....or at least until you can order a header.

 

really , i have used jb weld but never thought of metal shavings mixed in--cool idea i wont forget

 

Are you going to put a cam in that motor to compliment your header when you rebuild it?

 

mine sounds like it might be leaking slightly, i need to check it out this weekend.

who makes some good headers for the 3.4? if it is cracked then i'm putting headers on

 

I would like to put a cam in it but would probably only do so if I were doing a complete rebuild. With 270k on the clock I think that by putting a cam in with that many miles would force me to do a complete rebuild...because the added hp will stress out the already tired rings and bearings.

The article on 3RZ tuning in this issue of 4WD Toyota Owner certainly makes me want to put a cam in to go along with that header.

 

did ur manifold just crack at 270k?
Or has it been cracked for a while and u ignored it??
Also is your motor the same one as the 2000 4runner 2.7 4cyl?

 

I'm afraid I can't answer any of those questions...I bought the Taco a couple of weeks ago "as is" https://www.yotatech.com/forums/f2/f...botage-183234/ . I went into this knowing I would have to put some work into it...and boy was I right about that.

 

Eh...it ain't purty...but it holds (so far)!!!