I know I'll get some crap about this but I just got back into cars.Bought a 2000 Z28 and want to service it before the wife drives it too far. Does the LS 1 coolant system need to be bled? I can not find any bleed screws. I got the engine oil, Trans(stick) and rear end done but would ilke to do coolant before too long.
Thanks in advance from an old fart.
Darrell

2000 Z28, 6spd, Flowmaster, and more to come.

 

wel sir, every coolant system needs to be bled no matter what vehicle. i have a funnel and radiator neck attachment that i keep filled. makes it a hell of alot easier than watching for bubbles in the radiator and less of a mess. cost about $20 from napa

there are no bleeder screws on the LS1s, just watch for bubbles and make sure you wait a while and let the t-stat open then top off again

 

Thanks for the info, I kindof figured it was simpler than I was making it. I will probably chage the t-stat while I'm at it, and flush it.
Darrell

 

If you're gonna take the t-stat out you might as well do a real, 100% flush.

Here ya go:

Best/easiest way to flush and get every drop of old coolant out.

-Cold engine.
-Remove radiator fill cap.
-Remove the t-stat from the housing. Leave the housing attached to the rubber radiator hose, just remove the 2 housing bolts and pull it away from the water to pump to get to the t-stat. (2-3 minute job).
-Put t-stat housing back on. (1 minute) Just put one bolt in, no need to put them both in, there’s no pressure in the system during the flush.
-Take the entire radiator drain valve (petcock) "off" and let it drain, don't just open the valve itself. It'll drain faster with it off and that’s what you want. ((Buy a new petcock valve before starting this flush process, sometimes they break when you remove them all the way just because they're cheap plastic and they get briddle over time, they're like $2.00))
-Take a hose and stick it in the radiator fill cap, running medium to high.
-Start the engine.
-Turn heat on full blast
-Let it run for about 15-20 minutes or until the water is running out the drain CLEAR.
-((If you want to, you can wait till it runs clear, close the drain valve, add a bottle of radiator flush and let it run for 15 minutes, then drain it all again. Then open the drain and put the hose in for about 5 minutes run it all out till its CLEAR. The flush chemical will help break up the crap thats stuck DEEP in the BLOCK that sits and swirls and doesn't like to come out.))
-When it runs clear your entire system is clean.
-Remove the overflow reservoir from the car and clean it out real good. (I had to use gasoline to clean mine out because the sludge and grime was so thick inside. The gas broke it all down and then it flushed right out. I filled it about 1/3 up with gasoline and shook the hell out of it real vigorously, the black stuff kept coming out. I did that like 4 seperate times with gasoline till no more chunks of black crap came out. Make sure the lines that go to the reservoir are also cleaned out. Or just buy a new piece of 3/8" heater hose and replace that line, 3 feet will do, then cut to fit. My sludge came from my power steering fluid leaking into my coolant system.)
-Put the t-stat back in.
-Put the overflow reservoir back in.
-Put the drain valve back in. Use the new one, what the hell.
-Put half a jug of Dexcool in the radiator. (Or if you live in very cold places, 1 to 1 ½ jugs of Dexcool)
-Fill the rest with water.
you do not need to use distilled water, clean hose water is just fine, just make sure your city water is clean and not total crap quality.

**Bleeding the system of air:
Start it up and let it run and warm up till the t-stat opens. I rapidly squeeze the upper radiator hose like 20 times while its warming up to help move any air bubbles through the system and by the t-stat on the engine side. You’ll see the level drop as you squeeze it, its sucking the coolant through the system. You wioll soon see the coolant start to flow in the radiator fill neck, once it starts to flow the level should drop down alot, immediately top it off with coolant/water. Then the flow will stop. Wait one more time for the t-stat to open again and start to flow, if it drops down again top it off again. Do it a 3rd time if you want to make sure. I always massage the upper hose during the whole process to keep any air bubbles moving through. Always works like a charm. Just keep checking your temp gauge until the t-stat opens for the first time to make sure it’s not sitting there overheating from a trapped bubble. May take 10-15 minutes for the t-stat to open the first time.
If you do start to get hot while sitting there and the t-stat will not open…..you have an air bubble on the engine side of the t-stat. Shut the engine off and rapidly squeeze the upper and lower radiator hoses again. Then start the engine again and see if the t-stat will open. Sometimes you just have to work those hoses to move the air through. Even after it seems topped off after a couple cycles…check it the next time you have a cold engine…top off if needed.

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FYI - If there are small amounts of air in the system, the car will purge the air as the coolant goes through heat/cool cycles.