The three nuts on the exhaust manifold where it mates with the exhaust pipe had loosened them selves. Tightned them up and checked the valves, had to adjust a few. The plugs looked a bit white on the tip and dry black around the ring. Gonna take it for a re-test next week. Hopefully it was the exhaust leak that tricked the O2 sensor.

Yes they could be the culprit, since when the ecu tried to comp by reducing air nothing happened, it would have richened the mix to protect the engine from running lean.

on a similar note, is there a way to seal the exhaust manifold leak/downpipe w/o changing those donut gasket rings?


I put in new rings & it's still leaking. Is there some sort of gasket i can wrap around the seal outside (w/ hose clamp) that would work well at high temp (700c?) & high pulses?

There are two types of sealant, one silicone and one more of a paste. Neither are permanent, the silicone melts away and the paste flakes off after a while. They work for short term repairs or for smog issues.

It sounds like you have rust deposits on one or both of the flanges that is preventing them from sealing up, have remnants of the old doughnut gasket, or got gaskets that were made wrong. I would take it apart and see what it looks like, pick up a new set of gaskets and see if it doesn't seal up.

When you have the down pipe off, make a template of the flange, to use to make a paper gasket in the future, if nothing changes after pulling it apart. You can pick up high temp sheets of gasket material and cut your own gasket, they run about $8 for an 8x11 sheet. This is what I had to do for the supra I am restoring, after making my own turbo elbow, since I don't have the tools to machine a recess for the doughnut gasket. It seems to be working so far.

Thanks snowtoy,

i've tried the sealant/paste around & yes it only lasts for so long.

Can you possibly post a link/brand model to the paper gasket you are refering to? I've been asking everywhere in local parts store & none of them knew what I was talking about.

Oh, 1 more pita for me...1 of the 3 studs (the inner one closer to engine) is stripped while I was undoing the nut. The nut itself is probably stripped too. Right now it sits half way along the stud. I can't tighten or lossen to take it out, it just spins & stuck in the middle... I'm so screwed...how do i take off the downpipe or seal the leak? <img src="/forums/images/graemlins/angry.gif" alt="" />

The stuff I have is made by Mr.Gasket, and is 3/32" thick. It is white on one side and has Mr.Gasket logo printed on the backside. I picked it up at NAPA auto here in the states. IIIRC, it is rated to 1200 degrees.

It sounds like you are going to have to pull the exhaust manifold and the down pipe. Oh yeah, more work than you wanted to do.

If you have access to a welder or a friend that odes, I would just weld the down pipe to the exhaust manifold and install it like a header. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Thanks for the Mr Gasket paper name.

Believe it or not, I did pull the original exhaust manifold and put another manifold in 2yrs ago due to the same reason (stripped stud)...The only difference was that the downpipe nut was lucky enough to be removed from the stripped stud...

Also while re-torquing the replacement manifold nuts to the cylinder head studs...I also ended pulling 4 studs out of the head!!! Ya, I removed the manifold again, helicoiled my head, reinstall the manifold, and barely managed to tighten the manifold/head nuts to get a good seal.

I really don't think i'm going all out to mess with R&R exhaust manifold again...especially with the stripped stud and sketchy head studs...I though about welding actually. But questions are:

1-How is the mig gun fitting in there? It's the inner side that needed to be welded, in an overhead position.

2-How do we weld cast-iron to downpipe steel plate?

...
<img src="/forums/images/graemlins/ignore.gif" alt="" />

I was meant weld it up after you removed it <img src="/forums/images/graemlins/lol.gif" alt="" />

I know you aren't supposed to weld cast to mild steel, but IME it can be done when there isn't any sheer/pulling forces being applied. I did one up a few years ago on a truck I was getting ready to sell and it worked fine for the de months I had it.

W/354k Km's on the engine and burning oil, I think your '91 is in need of a rebuild once the spring thaw arrives. You could probably do an in truck rebuild as long the as the cyls are OK.

Good one. I wonder why i never though of doing it the easy way... <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

I had a 22re specialist look over the 22re 3 wks ago. Compression test was 220/220/175/220. Injector #1 & #4 was louder than the other ones (using a rod to listen to). We haven't yet figure out the oil burning issues but for gas mileage consumption, he's saying the injectors/fuel filter are in need of a cleaning when spring comes. I asked him about rebuilt but he said it wasnt needed yet, especially since the 22re has a head swap just over 100k ago.

Would it be my rings or valve seal on cyl 3?

I'm not a professional wrench but it seems to me that a leakdown test would be in order to help determine where the problem is.

If I recall correctly 220 is a little above spec on a 22re and 175 is closer to what it should be.

More experienced minds will certainly offer more information.