Full Coolant Flush

[tkoforpresident]

Ok, so i want to flush the coolant system. Not just the radiator but the whole thing. My haynes manual says there is a knock sensor located on the bottom of the engine block to release the coolant (no not the knock sensor in the computer) but the pic in there is crappy and i have no idea where it is. Does anyone know exactly where the thing is located? Second, the manual says to put a garden hose in the radiator cap and run it til it runs clear at both exit points (the radiator petcock and the knock sensor) but i've heard if the water is not distilled then it will **** up the coolant. Or is that only with dexcool? because i'm still running the green coolant, would that make it ok to use a garden hose? Finally, i realize to flush the radiator you would run the hose through the radiator fill cap but what about to clear out the block? Right now i've got the thermostat housing off. Would it work if i ran the hose to there and flushed the block that way? BTW i have a 93 3.4

A few more general Q's.

1. To remove the radiator overflow tank you just have to remove the battery right?
2. If i fully flushed the system how much coolant would i need to completely refill it?
3. What would be the procedure to refill a completely empty coolant system?

Look guys, i know this is a lot to ask, so if you just want to pick a few Q's to answer by all means please do.

thanx

max

[cam98aro]

Re: Full Coolant Flush

i have no idea what you mean by its not the knock sensor in the computer, the computer doesnt have a knock sensor, it gets its info from the sensor in the block.

i wouldnt be too worried about using the garden hose with the green stuff, thats usually with dexcool.

yes, you have to remove the battery to get to the overflow tank

when i did mine, it took about one and a half bottles, i used the 50/50 mix

to refill an empty coolant system, you just pour the fluid in until the rad is full, start the car for a little bit, you dont need to put the rad cap back on, you can if you want, then refill it again.

keep doing this until the fluid level quits dropping.

next you need to find the bleeder screw, once you find it, loosen it up a bit, start the car up, and wait until the fluid comes out as a steady stream with no drips/air coming out.

after this, refill your coolant bottle and rad, and you should be good.

if you are using a garden hose, just close your petcock with the knock sensor out, and start the car, and spray water into the rad, it will run into the engine and out of the knock sensor.

personally, i wouldnt go through all of that trouble, but if your coolant is messed up, you may have to.

[tkoforpresident]

Re: Full Coolant Flush

its not really that big of a deal to do, since the car is up on jack stands and i've already emptied the radiator. The pcm does have a knock module inside of it, i know because i've pulled it out before. But apparently they call the drain plug the same thing. Not sure if my car has a bleeder screw, i thought i just had to wait till all the bubbles went out or sumthin. Thanx , this is good info and answers most of my Q's.

[techsan23]

Re: Full Coolant Flush

water out of the tap is always more corrosive than distilled water no matter what type of coolant your using. the water in my area is full of calcium deposits and other crap. i have used tap water mixing my antifreeze before and i also see signs of rusting probably from my block.

at first i thought the previous owner had mixed antifreezes which usually results in a pudding like substance.

your bleeder screw is located on the water neck coming from your thermostat.

[greasemonkey]

Re: Full Coolant Flush

I think this has been covered a few times, but heres my way. I've been doing it like this for years and never had a problem.

Go out and get some flushing solution from a parts store. Along with about 2 gallons of global antifreeze (you can use dexcool, I like global).
Put the solution in your radiator then drive around for a while and give it time to loosen up any gunk.
Wait for your car to cool, then pop the cap and drain the radiator through the petcock.
Refill the system with tap water, run for a while, drain. Repeat until the water runs clear. I've never had a problem with tap water being corrosive, coolant should be acting as a lubricant to protect from that.
Then fill the system with (what I recommend) a 60% water, 40% coolant mix and a bottle of royal purple coolant additive (or equivalent). Make sure the car is running and heater is on full blast when re-filling.
I never use the bleeder screw, I just run the car with the cap off for about 10 or 15 minutes, squeeze the upper hose gently to see if any air comes out, then cap it up. An LT1 or 351 Cleveland with reverse flow cooling is a different story :)
For the coolant bottle, your probably have gunk in there, being dexcool and all. So you should remove it and clean it out real nice like.

Hope that helps some.

[cam98aro]

Re: Full Coolant Flush

I think this has been covered a few times, but heres my way. I've been doing it like this for years and never had a problem.

Go out and get some flushing solution from a parts store. Along with about 2 gallons of global antifreeze (you can use dexcool, I like global).
Put the solution in your radiator then drive around for a while and give it time to loosen up any gunk.
Wait for your car to cool, then pop the cap and drain the radiator through the petcock.
Refill the system with tap water, run for a while, drain. Repeat until the water runs clear. I've never had a problem with tap water being corrosive, coolant should be acting as a lubricant to protect from that.
Then fill the system with (what I recommend) a 60% water, 40% coolant mix and a bottle of royal purple coolant additive (or equivalent). Make sure the car is running and heater is on full blast when re-filling.
I never use the bleeder screw, I just run the car with the cap off for about 10 or 15 minutes, squeeze the upper hose gently to see if any air comes out, then cap it up. An LT1 or 351 Cleveland with reverse flow cooling is a different story :)
For the coolant bottle, your probably have gunk in there, being dexcool and all. So you should remove it and clean it out real nice like.

Hope that helps some.

he shouldnt have dexcool in a 93' camaro.

also, the rad cap method usually only works with imports, i did this with my car, and had rad fluid gushing out of the filler

[CDNFB]

Re: Full Coolant Flush

When I flushed my system, this is what I did:

1) Add coolant system flush to the radiator.
2) Ran the engine at operating temp for 10 min. Shut down the engine.
3) disconnected the upper rad hose at the radiator and redirected it into a container.
4) started the engine and while the old coolant flowed from the upper rad hose into the collection container, I used a garden hose to keep the radiator filled with clean water.
5) when the clear water is observed flowing into the container, stop the engine and drain the radiator with the petcock.
6) Close the petcock and fill the radiator with new clean coolant.
7) start the engine and while the clean water flows from the upper rad hose into the collection container, keep the radiator filled with new clean coolant.
8) when the the new clean coolant is observed flowing into the container, stop the engine.
9) Install the upper rad hose to the radiator.
10) run the engine until operating temp is reached and open the bleeder screw to vent any air in the system.
11) close the bleeder screw when a steady stream of coolant is seen flowing from it.
13) shut off the engine.
Done.

[CDNFB]

Re: Full Coolant Flush

Forgot the last thing,

14) top up the overflow tank to the proper level. If you are using dexcool, fill it to just under the top of the tank to reduce it's exposure to air (suspected cause of the mysterious "mud" formation, according to GM).

[tkoforpresident]

Re: Full Coolant Flush

CDNFB, this will clean out the block too? i don't have to remove the plug in it?

[HeadyFirebird'00]

Re: Full Coolant Flush

i am still wonder where that blasted knock sensor is too!? i have never been able to drain the block. really grinds my gears

[LarryMow]

Re: Full Coolant Flush

In TKO's signature, it says he has a 93 Firebird with a 3.4, this is the same thing that I have. Ok heres my question (and possibly a dumb one): a few people have mentioned some sort of bleeder screw...uh, where is it? I know there isn't one on the thermostat housing. If there is one, I sure as heck haven't seen it.

[DegrezzE]

Re: Full Coolant Flush

i am still wonder where that blasted knock sensor is too!? i have never been able to drain the block. really grinds my gears

You have 2 knock sensors one on each side of the block, below is a picture of the sensor on my old 3.8 engine.

[tkoforpresident]

Re: Full Coolant Flush

well since the coolant recirculates into the radiator, technically we can just run the car with a hose in the radiator and eventually all the coolant will come through the rad right? and put the heater on high so we can get it out of there too right?

[cam98aro]

Re: Full Coolant Flush

well since the coolant recirculates into the radiator, technically we can just run the car with a hose in the radiator and eventually all the coolant will come through the rad right? and put the heater on high so we can get it out of there too right?

correct, which is why i said to just take the drain petcock out and do it that way

[tkoforpresident]

Re: Full Coolant Flush

Yeah That Sound Like A Better Idea, And Let Me Get This Straight....
After Your Running All Clear Water You Then Empty The Radiator Of Water, Fill It With Coolant, Run The Engine Again While Pouring In Coolant, Than As Soon As You Have Coolant Running Through The Petcock Than Your Ok??