3: Overheating/Cooling Issues
A high efficiency aluminum...
A high efficiency aluminum radiator and high-flow electric fan combination, like this excellent Flex-a-lite Flex-a-fit radiator kit for early Mustangs, is an excellent upgrade. Just remember, it’s not a catch-all cooling fix for other ailments that create overheating!
Nobody likes a coolant leak, but overheating is the worst. Overheating not only shortens the lifespan of your engine and ancillary hardware, but at best is embarrassing and at worst can leave you stranded in the middle of nowhere. Cooling system issues can happen to any Mustang, old or new, stock or modified. Generally speaking, many people don't understand how the typical automotive cooling system works and they think a pretty aluminum radiator is the savior of cooling issues. We're not knocking aluminum radiators—we prefer them actually—but they aren't going to fix a cooling system that overheats if the issue is the head gaskets are on wrong, too large of an overbore on an engine rebuild, too low or no thermostat, and so forth.
If you're looking at a Mustang to purchase and you see a new radiator, new water pump, new radiator cap, etc. it should be a warning sign that maybe, just maybe, the owner is throwing parts at a cooling problem. We've seen people spend hundreds of dollars on radiators, fans, cooling flushes, and more only to still have a “problem” and it turn out to be a bad gauge! Again, this comes back to knowing your Mustangs. Properly diagnosing the issue is key as well. Short of a concours car these days EVERY Mustang on the road should have an overflow system with a proper radiator cap that allows the system to expand and contract properly to prevent fluid loss. Of course major mechanical issues like the previously mentioned overbore and head gaskets will require digging deeper and possibly bigger dollars to fix.
2: Electrical/ Wiring
There are several ways to...
There are several ways to connect add-on circuits or repair damaged wiring. The hardware you see here is NOT how to do it. The white and blue plastic wiring tools are called insulation displacement connectors, or more commonly by the 3M brand of Scotchlok. They have no use outside of an emergency or temporary installation in a location that will not see rain/dirt/snow. The small brass terminal is called a fuse tap and is designed to slip over an existing blade fuse to allow an additional wire to be added on. These things usually damage the terminals in the fuse box when used. Learning to properly connect, crimp, solder, and shrink wrap wiring with quality terminals (not the 1,000 pieces for $4.99 garbage) is a must for any enthusiast.
The true weakness of most car enthusiasts we know; electrical repairs/upgrades often separate the men from the boys. We'd need another six pages to tell you about just the top 10 electrical issues we've seen over the years, many culled from human error or lack of knowledge/understanding. There's nothing that'll stop a car in its tracks quicker than an electrical issue (or even prevent it from making said tracks in the first place, as the case may be). Understanding basic electrical systems and how a circuit works will go a long way to ensuring you repair or upgrade your electrical system properly using the correct size wiring, circuit protection, and more.
When the owner of this Mustang...
When the owner of this Mustang told us he had an issue with the battery always dying on him and burning up ignition switches a quick inspection found this bundle of burned and shorted wires shoved up under the dash. Part of the harness was resting on the edge of the firewall opening and cut through the insulation, creating a short/draw on the system. It’s been patched for now, but this car needs a whole body harness solution.
Wiring in 40 year old Mustangs is downright scary. Once again, short of a concours type Mustang we encourage owners to upgrade to full replacement harnesses. These kits not only offer modern TXL wrapped wire with modern blade fuses, but they include additional circuits for modern upgrades like high-output headlights, electric cooling fans, power windows, and more. Even Fox Mustang wiring is getting into the twenty-plus year age and we see many broken connectors when trying to service Fox electrical components.