The car would start and run fine, never cut out bogged down or died on me at all, but once the engine got warm if I turned it off and tried to start the car again it just wouldn't fire up. Almost like the fuel pump wasn't working. Sometimes if I removed some fluid from the rad and topped up with cold water it would work, which to this day baffles me and I think it's just a coincidence. I flushed the cooling system, replaced water pump and thermostat, and was thinking it was something to do with my radiator when the car started cutting out on me.
The cutting out turned out to be the battery, which was under warranty so I went and got a brand new one for free
hehe. But still it didn't want to start when warm. I started checking fuses and relays and noticed that when the problem occurred I wouldn't hear any noises coming from the main relay (next to the interior fuse box). So I ripped the sucker out and tried to get a new one. Only 1 local parts supplier had one, and they wanted about £180 for it! No chance. I found 1 on eBay from the US, shown below:
But even £87 delivered is too much for some piddly relay so I thought "hey!! might as well try fix it". I popped off the casing and let's just say the problem couldn't have been more obvious if it had jumped up and slapped me in the face with a wet fish. I didn't get a picture of it but basically the solder on the 5 points (circled in red below) was clearly cracked. At this point I didn't even need to test the components in the relay, just needed to reflow the solder. Real easy. I started by cleaning the surface with solvent cleaner, then pasted a generous amount of my favourite flux (Kingbo RMA-218) and was staring at this:
EDIT - I reflowed more points than were damaged, this was just personal preference and took me all of about a minute to reflow all points.
Good flux makes soldering really easy. Once my iron had warmed up I touched it to the solder point that I wanted to reflow and applied some solder. Your iron is at a good temperature when it melts the solder in about 2-4 seconds of contact. If it's too hot you risk damaging components, if its not hot enough the solder won't flow correctly and you end up with ugly work that probably won't last. I melted the bad solder, and applied a reasonable amount of solder. Because relays get hot you want a decent quality solder. If you have a little spare silver-based solder lying around use that it will last forever, but if not DO NOT buy any. Rosin Core solder wire with an Sn60/Pb40 composition will work perfectly, and it's actually my "go-to" general purpose solder. You can pick up a 100g reel of it for about £5 and will only probably use a couple of inches on this project.
After you have finished soldering, make sure you clean away all excess flux and residue with a good quality solvent cleaner, I like 99% pure MEK as it evaporates really quickly and doesn't leave any marks or residue. You should be left looking at something like this:
Beautiful! From dull and cracked to shiny and perfect, you couldn't ask for better work and it's so easy thanks to good flux. It's all cheap too, You can buy an iron for £5-10, RMA-218 flux for £5, Sn60/Pb40 Solder for £5, and 1l of MEK for £10 all from Amazon!! I brought all that stuff a few years ago for working on circuit boards, and it's a bit 'overkill' for this application, but it's cheap enough to buy that you would probably spend just as much on low quality products. There's no need for you to use these specific products if you have other stuff you can use, but if you don't have flux, solder and solvent cleaner I recommend spending the the £20 on the stuff I use so you can solder like a pro with little to no effort.
Thanks for giving this a read and I hope it can be of some help to someone.
Solvent is just for cleaning really, seems a bit silly but it is important. Especially after 'cause you don't want sticky flux everywhere (even more so when you consider it's highly toxic). I've used all sorts and in my experience nothing cleans like MEK.