MR2 Owners Club

Hello all,

I have been lurking on the forum, reading and learning for the last few months, but now it's time to say hello and ask my first question.

My name's Mike, live in Kidsgrove Stoke-on-Trent and have a Red 1994 G Limited T bar, 2 ltr NA SW20 for the last 18 months.

I am in the process of trying to change the Lambda sensor which is located on top of the front exhaust section just above the rear subframe, which is another way of saying you can't see it

The nuts are shot on the sensor, so my plan is to remove the front exhaust section to allow easier repair etc. All I need to do is undo the three nuts that bolt the exhaust to the manifold, but they are very tight.

So my stupid question is:-

Are they nuts?

They appear to be in good condition and I can see what looks like a torx end to the stud and anti vibration nuts, but they are unbelievable tight, so I just want to make sure they are nothing special before I get the breast bar on them.

Try heat?

Am I about to break something or "yes they are tight"

Thanks for any help

Mike

Moved to the correct forum.
They will just be tight, I'd suggest soaking them overnight with Plusgas (or similar) before trying the breaker bar, also worth trying to tighten them slightly before slackening them

Yes they are self locking nuts on studs that use the torx end to fit.
As said a good penetrant (not just wd40) will help as will getting them cherry red with heat and then spraying the penetrant. If you have a rattle gun with impact extension pieces they come off easy. Just make sure you use a quality 6 sided socket (14mm IIRC) as a 12 sided socket has more chance of rounding.

Thanks for the confirmation, I'll get them hot and soaked before I swing on them.

Sorry if I posted in the wrong place originally, first post, think I have the hang of it now.

Poo!

This car is fighting back at every turn.

Soaked them for weeks, heated them cherry red and turned them slowly in both directions to avoid binding and they all snapped one by one --- poo again!

The good news is the exhaust is off and their was no way I could have changed the lambda without doing so. The bad news is I now need to repair or remove the remaining studs in the manifold without this turning into a full engine strip down.

Now bits are out was I can see that studs appear to be brass and the nuts / studs are peened to hold them in place, I guess I was doomed before I even started.

Still, at least I can get a drill in

Whilst you are at it now might be a good time to remove the manifold heat shields and then the manifold as there will be stubborn bolts that break and need drilling out. Then you can drill and tap and replace all at the same time. I used stainless bolts on my heatshield and now they come off easy.

Well just an update some 7 months later!!!

This whole saga started with a list of MOT fails, by far the hardest to understand was the emission fail with 5% co but pass on HC. I guessed it was the Lambda sensor and so ensues months of snapped bolts etc.
Well managed to drill out all broken studs and replace with new. New front exhaust section needed as flange to cat end rotten. Many, many new parts fitted to rectify the MOT list and finally a new Lambda. Refitted it all, run my own gas tester and result, 0.4 to 0.5 CO2.
So happy days.
Time for MOT.
All fittings now stainless steel to prevent repeat performance.
Mike

Way to stick at it dude

I forgot I'd replied to this thread it was so long ago lol