trilkb

iTrader: (4)

Just curious where you guys stand on this. Do you think a power flush is worth the cost? I normally lean towards the power flush but recently read about just doing a drain and fill every 2 years on green coolant, I'm sure Dexcool would benefit from it as well? Unless it's been some time between servicing, or coolants were mixed, what are your thoughts? Doesnt the system kind of power flush on its own when operating correct? You are not doing a 100% fluid change when doing the drain and fill, but I would imagine you are changing at least 50% or more of the fluid.

RPM WS6

iTrader: (3)

Really depends on the application IMO. If it's a daily driver that sees a bunch of miles then it's probably best to do a flush every 3-5 years (assuming extended life coolant) depending on mileage.

On the other hand, for limited use/garage queen type cars that don't see much mileage, you can certainly get by with drain/refills on a more frequent basis. This is what I've been doing with my '98 for the last 12 years now (drain and refill every two years), and the entire cooling system is 100% original (including gaskets, hoses, etc....all of it) without a single leak or issue. The inside of the radiator is extremely clean and the coolant (Dexcool) has never turned brown or produced any sand/slime/sludge. I did one full system flush in 2004 as it still had the assembly line coolant so I wanted to start completely fresh, but since that time it's just been drained and refilled every two years without a problem. Granted, this is a limited use car that only sees 1-2k miles between drain intervals though; again I wouldn't recommend this practice for daily driven cars unless you're going to do much more frequent drain/refills to replace more of the coolant.

LS6427

iTrader: (2)

I was a Dexcool supporter for about 13 years. Then I went GREEN fluid and wished I would have done it 13 years sooner. I never had the bad issues with Dexcool that a lot of people have, but man....GREEN fluid is perfectly clean...and my temps are running ABSOLUTELY cooler.

No, your system is not being power flushed during normal operation.

Here's my flush write-up to get the entire cooling system including block, heads and all hoses 100% clean like new. THEN GO GREEN......

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.
-RECOMMENDED FOR ANY FLUSH:
((If you want to, you can wait till it runs clear, shut the engine off, let the radiator drain completely, close the drain valve, add one gallon of degreaser and let it run for 10 minutes to get it all warmed up. Let it sit for 2 hours. Then drain it all again. Then open the drain to start draining it out, put the hose back in the radiator for about 5-10 minutes and run it all out till its CLEAR fluid. The degreaser will help break up the crap thats stuck DEEP in the BLOCK that sits and swirls and doesn't like to come out. It may take longer than 10 minutes to get all the degreaser out. Degreaser will bubble up like soap, so you know its all gone when there's just clear water and no more suds/bubbles.))
-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 separate 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)
OR GO GREEN....HIGHLY RECOMMENDED.
-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, radiator cap OFF, and let it warm up till the t-stat opens. I rapidly squeeze the upper and lower 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. When the t-stat opens you’ll see the level drop as you squeeze it, its sucking the coolant through the system. You will also see the coolant start to flow in the radiator fill neck, once it starts to flow the level should drop down a lot, immediately top it off with coolant/water. Then the flow will stop when the t-stat closes. 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.

.

1 FMF

iTrader: (1)

was that a typo?
i would think a car that just sits with minimal run time can go longer between coolant changes like the full 5 years, verses a high mileage daily driver where you would be better off changing every 2-3 years.


i am of the opinion if there was no cooling problem, and there was no contamination in the coolant like power steering fluid from the power steering cooler, then do not use a chemical flush because any that is of it's worth will be very caustic or acidic and that is not good for rubber hoses and gasket material in the long run.
since 2002 till now i have changed the coolant on mine 2 and a half times by just drain and refill, around 2006 and 2010, the half time was i think 2014 when changing water pump and that was because the cheap oem gasket between the pump and block would drip every so often. the inside of the water pump passages looked no different than the new pump from napa, i never got around to pulling it apart to look for any evidence of erosion or cavitation.

there are 2 brass coolant drain plugs on the ls1 block,
one above the starter uses a 5/16" allen head (probably metric equivalent)
the other behind/near the starter and uses a 16mm allen head, do not use 5/8" allen it's too small and will round out the brass.

the one thing i would power flush with a garden hose and a little soap or other chemical is the plastic reservoir under the battery, that is easy to completely remove and clean out.

RPM WS6

iTrader: (3)

Not at all.

The issue is that a simple drain/refill (especially if you're just draining the radiator like I do, I don't ever pull the block plugs) leaves behind about 2/3 of the old coolant, so even in a limited use application I wouldn't want to go 5 years between changes since only about ~1/3 of the coolant can be drained via the radiator. For a daily driver seeing a lot of miles, a drain/refill would need to be even more frequent if I was never going to flush it. Even then, I think daily driven cars with lots of run time would benefit from a proper flush every so often, considering many of them see as much usage in one year as what mine would see in 20-25 years.

Having said that, if you're going to do a full flush then I think 5 years is fine even for a daily driver (this is what I've always done with mine, no issues to speak of) as you'll be getting out all the old coolant and starting completely fresh unlike the basic drain/fill method. If you're not going to flush it then, even for a limited use car, I'd recommend more frequent changes (much more frequent for a daily driver.)

trilkb

iTrader: (4)

See my thinking was to read up on my radiator capacity compared to the entire system, then do a drain and fill once every weekend until it's changed. If it's 1/3 the capacity, then do 3 drain and fills.

wssix99

iTrader: (5)

My first bit of advice is to not drink the coolant. It does horrible things to the brain and you obsess about things way too much. ...Like changing your coolant. ^

As is the case with many things that are marketed to us, I think the "Power Flush" implies it does things it doesn't really do and has super capabilities it doesn't really have. I have taken advantage of the service when I wanted to save some personal time and really wanted all of the old stuff circulated out.

I think of coolant changes similar to oil changes:
- A lot of people get too worked up about them. (Partly due to the brain transplants we receive from oil/coolant companies while we are watching football on Sunday. Can I have also have a Miller Lite, please???)
- Most people probably do them too often.
- A fluid change will never get out 100% of the old stuff, which is fine. If you remove 95% of the stuff periodically, it will keep 99% of what you don't want out of the system.

So, if you use the car normally, I'd recommend:
- Change your Dexcool normally, have a Miller Lite, and relax 10 years until its time to change the Dexcool again.

If you have a real need for moving off Dexcool, then I'd recommend:
- Follow LS6427's instructions and clean that sucker out - don't rely on someone else to get it clean.
- Have a Miller Lite and prepare for your next coolant change.


I think the Power Flush makes sense if you have some sort of abnormal contamination (gelled Dexcool, P/S fluid in the system, etc.) and you really need to get as much of the stuff out as possible. Other than that I'm not sure you'll get any measurable return.

wssix99

iTrader: (5)

Before anyone flames out on my comment that people "probably" change fluids too often, I will explain further.

A lot of people buy in to changing fluids early or every 3000K miles, like our grandfathers did on their 19XX's-whatever running dinosaur goo out of a real oil can. The oil is different now and the engines are different now.

If you do the math of what a oil change, etc. costs (maybe add in what your personal time costs) and look at the minimal effect that an early change has on engine longevity/rebuild interval and then compare that to the cost of what an engine rebuild will cost - it's just throwing money down the drain. (Unless... you have a Ferrari with a $100K engine, drive a fire truck/ambulance that can't break down-ever, etc.)

So, I worship the guidelines in my Owners Manual and my oil life monitor/nanny and change my oil so that I won't get stranded somewhere by a breakdown. If I need to rebuild my engine - that's OK. I've saved thousands over the life of my car by changing my oil by the oil life monitor and not every 3K miles.

^ The same economics can be applied to coolant.

RPM WS6

iTrader: (3)

Cooling system capacity is 12 quarts, and I'm usually able to get out about a gallon (give or take ~1/2 quart) with a simple drain of the radiator. This is how I arrived at the 1/3 capacity figure for a drain and fill. If you do additional drain tasks (such as flushing the overflow bottle, pulling drain plugs from the block as mentioned above, etc.) then you can get more out in a single change. I don't do the additional tasks but, again, I change it often enough that it doesn't seem to matter (probably too often, as indicated by wssix99 above - but that's OK because he's saved enough money by NOT changing his to issue me a grant for bulk coolant purchases.)

I see your thought process behind the "3 drain and refills" to completely change the system, but this won't work as planned if the system is highly contaminated/neglected. If the old coolant is really bad, and/or you have junk in the system, then it would likely take quite a bit more than just 3 cycles to get everything clean again. The small amounts new coolant added each time will be contaminated by the junk that's in there, so it'll take extra drains/refills to overcome this effect. This is part of the reason why I do mine so [relatively] often; if the system is clean to start with and the "old" coolant is still somewhat fresh, then you can maintain this balance even with just a simple drain/refill that only changes 1/3 of the capacity. The other reason I do it so often is specifically to annoy wssix99.

Darth_V8r

iTrader: (4)

Try this. Make three gallons of salt water. Drain out a gallon and fill the bucket with a gallon of fresh water. Do it two more times. Water still salty right? Just less so. There is continuous dilution. By this method it would take something like 21 drains to get rid of the old coolant. At work, we figure seven volumes to fully change the chemistry from the old batch to the new batch.

wssix99

iTrader: (5)

I'm going to put a padlock on your draincock.

RPM WS6

iTrader: (3)

That sounds hot.

wssix99

iTrader: (5)

Radiators - hot and steamy.

trilkb

iTrader: (4)

Ha, sounds like a male chastity belt.

I wasn't expecting to get 100% of the fluid changed in 3 drain and fills. If it got 90% I'd consider it better then before. I guess since I don't know the trucks history (2000 gmc 6.0) it would be best to start with a flush and then keep up on it with drain and fills? Or do you guys truly believe dexcool is good for its advertised lifetime?

RPM WS6

iTrader: (3)

That would be my exact recommendation, if you want to do the basic drain/refill process; I'd want to start with a known fresh system if it were mine.

If you don't mind doing a complete flush every time, then the 5 year recommended Dexcool program should be fine (this is what I've done with several daily drivers, including one of my LS1 cars, and it has worked just fine as well.)