2007 "Red Yaris" RS Restoration

[zoidberg444]

Literally a nightmare scenario for me with the exhaust manifold. I'm very fortunate on my 1 litre engined Yaris that the exhaust manifold is on the front of the engine facing the radiator. I literally just replaced my exhaust manifold last weekend. It had a very large crack in it which was causing it to set P0420. I also replaced both the Oxygen sensors with new Denso sensors. I have also had to replace the water pump (leaking and rattling) and the radiator as I think it has a pin hole leak or two which is why I was losing coolant.

In my case all the bolts came out without too much of a fight.

From what I have seen your best bet would probably be to weld a nut onto whats left of that bolt and use as much heat as possible. Hopefully it has the effect of freeing the bolt. Using a torx isn't such a bad idea either - unlike other kinds of extractors it doesn't have such an "expansive" force on the fastener which might increase the friction you're trying to overcome by getting it out. Those other extractors you have which have teeth inside the socket are fairly decent. I have a set and I have used them as well a few times successfully.

Best of luck mate - you will need it.

[06YarisRS]

Originally Posted by zoidberg444

Literally a nightmare scenario for me with the exhaust manifold. I'm very fortunate on my 1 litre engined Yaris that the exhaust manifold is on the front of the engine facing the radiator. I literally just replaced my exhaust manifold last weekend. It had a very large crack in it which was causing it to set P0420. I also replaced both the Oxygen sensors with new Denso sensors. I have also had to replace the water pump (leaking and rattling) and the radiator as I think it has a pin hole leak or two which is why I was losing coolant.

In my case all the bolts came out without too much of a fight.

From what I have seen your best bet would probably be to weld a nut onto whats left of that bolt and use as much heat as possible. Hopefully it has the effect of freeing the bolt. Using a torx isn't such a bad idea either - unlike other kinds of extractors it doesn't have such an "expansive" force on the fastener which might increase the friction you're trying to overcome by getting it out. Those other extractors you have which have teeth inside the socket are fairly decent. I have a set and I have used them as well a few times successfully.

Best of luck mate - you will need it.

Yes, I am quite apprehensive about this operation. My intention is to tackle it on the weekend. I have been worrying about the 'expansive' force on the bolt that you mention. I see it as a bit of a catch 22 in that using too large of a drilled hole and extraction tool would likely increase the friction, yet using too small an extraction tool could result in it snapping off inside the hole. I really think that the bolt head and washer are the parts that are rusted to the manifold flange and attempting to break them free is what might cause the head to either strip or shear off. The threads of the bolts themselves - the ones that I already removed - don't appear to be rusty. I am considering grinding the head and washer off and just tackling the shank. Welding a nut on would be my preferred approach and I may yet do that. If I can grind the bolts flush to the manifold flange, theoretically I could remove the manifold and have a stub of shank to weld to. Regardless, it would require leaning the engine forward quite a bit. I simply couldn't get the welder perpendicular enough to the head to get down inside the nut due to space constraints. I do intend to let heat be my friend. I have a propane torch and in testing, have managed, quite easily, to get a bolt head glowing cherry red. I just put a similar sized bolt in my bench vice and heated it. I'm not sure if I have enough BTUs to get the shank of the bolt red hot as it's sitting in quite a heat sink (the head). If I'm applying heat for a period, should I worry about melting the aluminum head? Then again, I doubt I could do it as there is likely water in the water jacket surrounding the bolt. The other option, I suppose, is to drill out the bolt completely and tap for a larger bolt. However, I don't have any info on how thin the aluminum is and if it poses a risk to entering a water jacket. I can put a slightly shorter bolt in but not knowing how much wall thickness I have to work with would concern me.

I really appreciate the feedback and am open to additional suggestions.