I just want to say thank you to kmor panda for posting above. I wouldn't want him/her to feel discouraged from joining in any of our conversations and everyone's experiences have value.
I have to agree with jrk on the WD40 issue though. Like him, I always have a can of the stuff (actually 3 at this time) to hand and it certainly has it's uses. However when it comes to loosening corroded threads/components it's not what I would find myself reaching for. As has been mentioned on this forum, I believe WD40 stands for Water Dispersant formula 40 and was their 40th attempt at formulation of a WATER DISPERSANT. Although it has a multitude of uses it's seems best at what it was originally designed for - dispersing water? If you're specifically trying to loosen rusted up nuts,bolts and other components then a product aimed specifically at that task will perform better. My two favourites are Plus Gas Formula A or P B Blaster but other folk will have their favourites I'm sure.
Here's a link to The WD40 website which makes very interesting reading if you've a few minutes to spare:
https://www.wd40.com/history/
One for Plus Gas:
https://www.plusgas.co.uk/en-gb
And one for P B Blaster:
https://blasterproducts.com/about_blaster_corporation/#:~:text=Born and bred in Cleveland,a phosphate mine in Florida.
Not so easy to find over this side of "the pond" is Kroil:
https://www.kroil.com/ I've never used it myself but an American friend swears by it.
WD40. as you correctly state is named from Water Dispersant No. 40, but that is all the name means. The formula has changed since WD40, but the name stayed the same. It is a penatrating fluid that removes (disperses) oil and water from metal. It also disolves / liquifies rust which allows one to loosen a bolt / nut etc, but since it is a dispersant for not only water, but oil also, if oone does not soak the fittings in oil etc to recoat them, the fitting will re-rust even tighter than it was before.
Metal has pores which holds oil / water, and WD40 is good at getting into it to be able to release a tight / stuck nut / bolt / hindge. However, it is NOT, and I have to shout that one, NOT a product to prevent rust. It actually promotes rust as it removes the misicule oil layer that exists on metal - I know as I have sprayed it in items as a protector that eventually have ended up scrapped as they were a ball of rust. I kinda laugh at jrk's statement that he uses it on garden tools, as they would rust very shortly after spraying it. A lot of people follow WD40's advertisements blurb on the web that states that it is an oil / lubricant, but it is not. They also believe in the ads that show a squeaking hinge / nut etc where they spray WD40 and the squeak goes. What is not shown is the day/week afterwards where the hinge / bolt is no longer squeaking - it is frozen solid. So, under the terms of advertising, it does remove the squeak - but most people do not want the result.
Most bolts that need to be removed in the 169 are either steel bolted into aluminum (exhaust manifold into head) or steel into steel (exhaust sensors etc) where they are exposed to hightemp changes. As a result, normal heating usually doesn't 'crack' or remove them and care has to be employed to remove same. The third set of bolts in the 169 that lock are the rear seatbelt bolts where the bolt goes through the car frame and the outside of the bolt is exposed to the mud/muck within the wheel arch. That needs a wire brush (on the outside) plus WD40 to remove it, AND to be soaked in oil before it can be reinstated. Heat in that location is normally difficult.
Most mechanics, before they attempt to loosen bolts / fittings, soak them with WD40 so that they can remove same without braking the bolt. Youtube has thousands of videos showing this, so I am not the only one... and I have broken enough bolts in cars over the years to know, by feel, whether a bolt is going to open / shear. One of the most recent was a bolt in the rocker cover on the 169 where I had to dremel a slot in the remaining shaft to remove it, but again I'd expect a certain few trolls here to tell me that I did't do that. They already told me that the block that the bolt was in was not aluminum, and attempt to prove themselves correct by stating that I am talking about a 1.2 and not a 1.1 engine!
I, maybe foolishly, thought that this site didn't tollerate trolls / liars like that. One of them admitted that he lies on posts. Of what use is that to the members here? This liar is prolific, posting 4-6 items a day (on average) for the past eight years continosly. To be correct, he must either have been an ex-employee of Fiat, or one of their service agents. However, to have the time to post 4-6 day, 7 days a week continously for the last eight years, he really must be isolated / retired where in real life, people avoid him as experience has told them to do so. As a result, I do same. He just does not have the personality that I want to deal with, as all he does is drag people down to his level.
