kwd1

Man, talk about messy job. Today, I managed to change the oil without a drop hitting the floor, something I only manage about 1 in 5 tries, and then I dug into flushing the cooling system. Coolant got everywhere, on the floor, clothes, eyes, all over the car. I had a large rubbermaid container 6"x1'x4' to catch the various downpours, but that stuff splashes on everything. And the shop manual is less than clear on how to get past the various vapor locks.

Right now it's cooling off with about 4 gallons of distilled in it. If this comes out clear, I'll go for the final fill. I used distilled for the flush part too, 12 gallons total.

Anybody use the cooling system sealant pellets? Manual says to put six in, but the chevy parts guy I bought them from said that was way too much, recommended 2.
Ken

tempest

i recently used the pellets - used only 2. it does discolor the coolant a little, but no other ill effects.

however, someone on the Forum later mentioned to me that there was a TSB recommending NOT using the pellets.

jabez

Take it to Jiffy Lube and have them suck all the coolant out.
No mess.
Just make sure they don't dump the Orange coolant in.

runner140*

I use Jiffy Lube a lot but when I go, I take my own parts. Fluids, parts and everything else.(synthetic oil , K & N Filters, fuel filters, and everything else).

onedef92

When I flushed mine, I found the easiest was to use a Shop-Vac and attach the hose to the blower outlet. I then opened the radiator petcock, opened the radiator cap and placed the hose over the black coolant reservoir container (LT1 engine). The forced air flushed every single drop of water out of the system!

I was then able to refill with radiator flush, run the engine for 10 minutes, open the system, then blast it empty again using forced air. Try it!

And BTW, I added the pellets, too. Crush them first to ensure they get completely dissolved.

Nathan Plemons

???

Open the draincock on the radiator, put a bucket under it, wait.

Once that is empty close the draincock on the radiator.

Carefully remove knock sensors, but a bucket under it, wait.

Now your cooling system is about 90% empty, the only thing left is what is in the heater core. Put the knock sensor back in, then fill the cooling system with clean water. Start it up and let it run for a little while, run the heater to make sure that you circulate all the coolant. Repeat until you're satisfied that it's all out, then fill with the proper mixture.

kwd1

thanks for the heater tip, forgot about the heater core!

With the knock sensors still out, I found you could pour water into the surge tank and it would flush out the block some more. Same with the radiator, ie with knock sensors in, keep adding water until radiator is draining clear.

If you just followed the manual, it said to open everything, drain and close up then top off. But it would only take about 2 1/2 gallons, had to open the radiator to let out the air.

It's an easy job, just messy as he11.

I bet jiffy lube isn't using distilled water or GM dexCool.

Ken

kwd1

Onedef, that worked great! I did my final fill tonight and I rememebered your trick. With the block plugs out and petcock open and all water drained out, I put the shopvac to it and another 1/2-3/4ths of a quart came out. Most came out the radiator but some out of the block too.

If you leave the block plugs in will your method empty the block to?

Ken

onedef92

I believe it will. Like I said, I did mine with the block plugs and knock sensors in and let the vac run until ALL the coolant came out. I then closed the petcock, filled with the proper water/coolant mix, added the pellets, closed the radiator cap and bled the line (VERY IMPORTANT).

I started it up, let it reach operating temps and verified there were no leaks.

kwd1

bled what line?

I ran it to work today and the temp sat at 194 going down highway. It used to run around 205!

onedef92

On an LT-1 engine, there's a bleeder screw near your throttle body. Check your manual for details, but it's important you bleed any air pockets out of your system before closing it up.