So after a 5 day soaking braker cleaner this stuff is not coming off without a fight, theo only place with a thread chasers for rent has them rented out.

I have a system for cleaning them up that works if slowly,but anyone know what this might be and why it is on there. It looks almost like a plumbing thread paste product.


after and before

after soaking for 5 days

 

I only had it on the two front bolts and I thought it was antifreeze sludge.....

 

@XRAD I am pretty sure it is plumbing paste to stop water, which weird these bolts do not enter the water jacket. I did a bit of research while I had a coffee.