Hey everyone,

I am going to change both of my O2 sensors soon, but the front sensor is positioned in such a way that I probably need to take off the heat-shield. However, the 4 bolts on the heat-shield are rusted and I don't really want to brake off the heads like how I did a couple on the front frame. So my question is, which "bolt loosener" should I use (like PB Blaster) that won't catch on fire when exposed to the heat coming from the engine (shield). I did look at a few videos on Youtube that tests these, but they are all exposed to a lighter. WD is flammable in the air, but when you spray it on the ground, it won't catch fire. While PB Blaster will catch on fire with a lighter while it was sprayed on a bolt. I understand propane lighters (blowtorches) are around like 1000C, but I don't wanna take any chances. Thanks!

 

I've used lots of the PB Blaster on hot parts, but never put an open flame to it. I've had the luck of not having to use a torch to loosen up bolts or nuts. Sorry, I know this didn't help, but the PB Blaster is great stuff.

 

Thanks anyways, but I seem to have solved it.

Liquid wrench produces a bolt loosener that is specifically non-flamable (green can). Not as good as PB Blaster probably, but I'll give it a go and will reply back.

 

I don't think it is. I've soaked parts in PB then hit them shortly after with a MAPP torch and I don't recall anything flaring up.

 

nope.. just tried it..

doesnt make the same flamethrower that brakleen does

 

That stuff evaporates pretty quickly, so you probably shouldn't have to worry about it - that and you really can't work on a warmed up exhaust system.

Just let it cool down, and leave the pb on overnight, then pull the O2 sensors in the morning.

 

PB blaster is the best. As long as you don't put a flame to it, it wont catch on fire. And it will evaporate over time, so by the time you start the engine, there won't be anything left to start on fire.

 

I just used PB blaster on exhaust manifold heat shield bolts and also on some of the turbo outlet housing bolts. Decided to try this at a later time once looking into this removal. After 24hrs. Started the car up and drove around the block for 5 mins. Pulled into the garage turned off. Bad burning smell from the PB blaster and visible smoke coming out of hood. No fire lol. I am wondering if this could be a concern as I know how hot these parts get. Nothing to worry about and safe to drive it to hotter temperatures?? As it was only 5 mins, definitely didn’t get that hot.

 

You can light it with a (very hot) open flame, like a torch, but it just evaporates off hot exhaust parts.