Thread: coolant and thermostat

Well i am just a kid that knows some stuff bout motors but by far not an expert. I want to change my thermostat to a 180 degree and i was wondering if i could just clamp off the upper radiator hose and change it, or would i have to drain all the coolant then change it?

You're better off just draining it. Pull off the lower rad hose... I had trouble with it the first time, but it's actually really easy. Coolant has to be changed every so often anyways so might as well get it done and learn that job too. You might end up just damaging the hose, and you're gunna lose a bunch opening that up no matter which way you go.

if the motor is cold, just unbolt the thermostat housing and change it, you will maybe lose a a few cups of coolant, just add some back into the overflow tank.

But why are you changing it tho?

Going colder with net you less MPG's but only a small amount, these cars love to run at 195º.

And if you do change it, make sure you bleed the cooling system afterwards.

What do u mean by bleed?

taking the thermo out, lets air get into the cooling system, which will cause hot spots and make the coolant boil faster and could make motor go boom boom.

So you need to bleed the cooling system with the bleeder on top of the thermostat housing.

Ok thank you.

I'm surprised you didnt ask how to do, because I'm sure you dont.

Do everything to replace the tstat and put it back together. Then start the racecar and let it run up to operation temp, while its warming up, open the bleeder (1-2 turns) with a 7 or 8mm or screwdriver depending on what it has. Once its warm, air bubbles will start to come out along with some coolant, wait for it to be a steady stream of coolant and then close the bleeder and take it for a drive, if it starts to get hot, bleed it again to make sure all the air is out.

Originally Posted by MurphyGTP

I'd just pull the drain plug out the bottom of the rad to drain it instead of pulling hose.

Use prestone 50/50

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Thats quite a Easy solution. Although most of these cars are a few years old and the plastic becomes brittle. Nothing like taking a Simple job. And breaking the Plug or the Radiator Petcock housing. I dislike pulling the plugs.

Pulling the hose will empty it faster and more complete then breaking the petcock trying to turn it

I'm wtih the yank two bolts and dry up the garage floor after crowd here. It's really not that much coolant that you'll lose by not draining. Then the bleeding is so much quicker/easier.