No diff. in any vehicle should go much above 125 degrees Fahrenheit.
No, it's not OK. You should use at least 5W30. In summer you can use 10W30.
Check the owner's manual for specifications and amount. Also, Autozone can tell you what will work. For the viscosity, recommend SAE 90 for most Toyotas.
Refer to your owners manual.
You can try to see if you can see the spark plugs, if you can count them, should have one per cylinder. On my 2002 Camry when you open the hood all the way there is a little sticker that tells you the model number of the engine you can match it up with the owner's manual to find out.
It should be in the owners manual
You acces the oil filter on the 4cylinder engine through the passenger side front wheel well. There should be an acess area for you to go through.
A start would be look in the owners manual, secondly checking under your hood an looking on the engine itself. It should say v-6 or 4cylinder with the amount of liters. you could also look at the engine computer mine has the engine model 5sfe on it
You should check your Toyota Tacoma's owners manual. There should be a diagram for the location of your thermostat.
You have to remove the differential cover to drain the lube. It should take aprox 4 pints to refill it.
A person should have a diagram when they are working on a carburetor of any car. A diagram for the 1987 Toyota Corolla carburetor can be found in the maintenance manual and the repair manual.
The library should have a shop manual with a guide:)
5w 30. In the manual too