So shortly after I bought my truck, my 1987 radiator sprung a massive leak and sprayed coolant everywhere. So I bought some "Stop Leak" and it worked great for like 20 miles.
Things you will need:
- You will need to buy a radiator, you can get a used one from your local junk yard for around $70. But i would suggest just buying either a brand new one, or a re-cored one. A new one goes for around $120. NOTE! When you get it make sure it's the right one, I made the mistake of buying the radiator for the 350ci motor, not the 305ci motor. But it's not that big of a deal because pretty much all chevy parts between 1973 and 1987 are interchangeable for all small block motors.
- New Radiator hoses, they can get pricey, just get the cheap ones tho because the more expesive ones aren't any different, just a waste of money
- More than likely get some hose clamps
- Buy a new thermostat and gasket
- Buy STRAIGHT coolant, not pre-mixed, straight will make 2 gallons of 50/50 for like 20 cents more
Starting out:
- Drain what ever coolant is left by taking off the lower radiator hose
- While it's draining, start taking off the fan shroud and radiator brackets
- Take off the upper radiator hose and overflow hose
- Disconnect the transmission lines and drain the fluid out of the radiator
- Once everything is disconnetcted, pull out the radiator (it might take a little wiggle-jiggle to get it out)
- After the radiator is out, disconnect all the old hoses from the block
- Now pull out the thermostat, there should only be like 2 bolts
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Installing the thermostat:
- Clean off the thermostat housing where the gasket goes
- Go out and buy a thermostat and gasket
- Put a little RTV sealant to hold the gasket in place
- Put the thermostat in the same way it came out or it won't work
- Put the housing back on and tighten the bolts
Flushing:
- You are going to want to flush your system to prevent any clogging in your block/motor components
- First you take a garden hose and put it in the upper radiator hose hole
- Turn the hose on and start the enigine (this is gunna make a mess)
- let it run for a minute or 2 with the heat on full blast
- Shut it of
- *CONGRADULATIONS* you just flushed your motor, you are going to want to do this every 20,000 miles or the coolant gunks up and it isn't pretty
Intallation:
- Basically do everything in reverse
- Put the new radiator in place
- Put the brackets back on
- Put the hoses on and clamp them into place
- Re-connect the transmission lines
- MAKE SURE everything is hooked back up before you put coolant in
Bleeding the system:
- With the motor off poor 50/50 coolant mix in the radiator
- Keep pouring until it doesn't fill anymore
- Start the motor
- Turn the heat on full blast
- Wait for the coolant level to go down
- Squeeze the upper and lower hoses to force out any air
- Keep pouring coolant in until air bubbles stop completely
- Check your temp guage periodically to see when it hits operating teperature (the needle is on the first line)
- If it's at operating temperature and no air bubbles are comming out anymore then you are good
- Fill up the coolent resevoir to factory specs
- Then when you are driving around the next few days keep a check on your temp and coolant level to make sure everything is good
And this is how you put in a radiator, it's pretty much the same process on all American vehicles. And like i said, if you get the radiator for the wrong engine size on your 1987 and lower chevy, they all are interchangable so don't panic.