The images below show the homemade holes and the factory made holes. The image on the far right (which has factory holes with solid state components) is a fuel pump relay known to be reliable. Holes will not affect the solder joints once the solder joints are properly soldered.
Holes are not recommended on every main relay repair, but desolder and solder the joints properly is highly recommended.
In fact, if the holes are improperly done dust may collect on the relay contacts
and they will increase in resistance. This is noticeable by the extreme temperatures that
the relay may exhbit. Remember dust settles from top to bottom. Holes shouldn't
be facing up similar to the factory fuel cut-off relay.
Heat rises to the top of the relay and helps to weaken the solder joints. Mounting the main relay upside down may slow the development of a dry joint. This is dependant on luck, however. The Crx has its main relay mounted upside down may explain its low number of main relay failures.
This image explains why heat tends to rise to the top. The top part of the relay is hot the touch. If the relay is flipped upside down water contamination could occur if there is a body panel leak, usually from the antenna on some vehicles. Relays that are mounted upside tends to have a cooler affect on the top side of the relay, the joint should not be as hot. You can try this experiment.
Member's story: My car won't start and I have to wait a couple minutes for it to start. I don't have a soldering iron and never worked with solder. I have worked with drills and wood. From my lacking of soldering experience, I decided to drill holes on the relay cover. The starting problem have not return since.
The relay is not a vacuum arc suppressing type of relay that operates in an oxygen-free environment that can tolerate high currents. So the relay should be fine in open air but not in dusty environment.
"The main relay problem lies in the bad solder application (caused by the wave solder process [which dips wafers into heated liquid solder] by Mitsuba.) Once the solder joints have been properly repaired the relay should last the life of the car" regardless of the moderate heat created from the relay and regardless of having the holes.
If your relays run too hot then you may end up with the same no start or stalling symptoms unless you follow the desolder and solder application instruction carefully to achieve a strong joint. If the main relay continues to run too hot, your relay will need to be replaced.
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