flushing cooling system? (L67)

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[TurboSedan]

i suppose i should have just combined this thread with the heater core thread but oh well.

obviously i'm going to drain the radiator, but i am wondering if there is a plug near the bottom of the block that would allow me to drain all of the old coolant from the engine (and i don't mean a freeze plug).  i know my LH0/LG5 blocks do.  the coolant looked so bad to me that i'd rather drain it all out before i begin, then flush it out with new coolant, then drain it all out again and fill it with new stuff.  should i convert to the green stuff or stay with Dexcool?  how/where should i flush it?  i know there are flush kits available, but should i use this method or??  this is the first car i've owned that uses Dexcool and i'm not too familiar with the Buick engines yet.

also, is anything like Redline Watter Wetter or Royal Purple Purple Ice compatible with Dexcool?

TIA

[R Dubya]

unwise to convert unless you can actually turn that engine upside down.  there will always be remnants of it in the cooling system, so stick with dex IMO.  

remove the thermostat housing and the lower radiator hose and attach a garden hose to it and wash it through, i did this on my 4.3 blazer and it worked well, removed a lot of shit from the block, it looked like brown flood water it was so bad.  then take the return hose for the heater core and wash it back through, then wash it forward again, then wash it back again.  

I would say used deionized water but its hard to get that pressurized and use it to wash, you can always add it later though.

Also might consider putting in some prestone coolant system cleaner a few days before you decide to flush, maybe even a week or two.  The shit i used was in a yellow cardboard tube and it was a powder.  Most reviews I heard were good.

[TurboSedan]

thanks Ryan  i'm going to go get that Prestone cleaner today and do what you suggested.  one question - which hose for the heater core is the return?  i want to start out by flushing it backwards.

[R Dubya]

definetely flush backwards first.  i would say run let it run through the system for day at least before you drain it, and try to drain it as hot as you can before all the shit settles again

you are working on an engine that i do not know as well as the 3.1 or the 4.3, so I don't know which one is the pressure or return.  my guess is however that the pressure line will be close if not right off the top of the w/p, and the return will be the other one.  follow the smallest hoses back to the firewall and see if you can spot them.  the core outlets might even be stacked vertically, top is usually the in line.

[TurboSedan]

the core outlets might even be stacked vertically, top is usually the in line.

yeah i'm pretty sure that's how it is.  thanks again Ryan.

[99RegalGS]

I believe that the knock sensors are in coolant passages. you can try to remove one of those to get more of the coolant out of the block.

[TurboSedan]

thanks for the tip Sean.  i tried to find that Prestone cleaner stuff at NAPA and Checker but they didn't have it.

[R Dubya]

what i used might have been an old product.. I don't know for sure.  they were upstairs on the shelf and weren't used very often because they had BG products that they pushed, mainly for the kickbacks, I don't think that shit was worth the money.  There has got to be some sort of substitute cleaner you can use.  What are you eyeing?

[sl3196]

thanks for the tip Sean.  i tried to find that Prestone cleaner stuff at NAPA and Checker but they didn't have it.

They have it at wal-mart.  Oh and I plan on using the yellow compatible with any coolant shit next time I change it on the gtp.

[Invasion1]

I wanna do the ZR2 and i have never delt with that DEX COOL shit before......

Would like to convert it to the universal stuff prestone makes but im not sure as i hear DEX is really fussy what it mixes with and such..

[sl3196]

But that stuff says it goes with anything haha.  Dexcool has always turned to shit in my cars.

[Dstanic]

I would play it safe and buy AC Delco brand Dexcool, but that's just me (plus I get discount at work..lol).

[R Dubya]

no matter what you do, unless you turn your car upside down you will have a hell of a time converting away from Dex.  It's really not a bad coolant to use,  just people always say 100k, I would never let a car go 30k without a change, in fact I've put 4k on my TGP since I last changed the coolant, its been in there 2 full years and some change, time to change it this spring.  

By yellow prestone stuff I meant a powder cleaner and not the mix all coolant that I think you guys are talking about.  The cleaner is in a yellow tube, kind of looks like a pringles or tennis ball container.  worked good for me, but I would let it run in the system at least a day.

[R Dubya]

http://www.prestone.com/products/coolingSystemTreatments.php

looks to be an antirust treatment, as well as a cleaner.  I think the shit I used was old, it was on the upstairs shelf in the dealership i worked at, it was probably illegal or something, phosphates and whatnot.  Who knows.  I trust the powder more than the liquid.. up to you guys though.

i think these products are the same thing just liquid form, and I was pleased with the product.  The anti rust might be what the Dex guys want, who knows, if you've got the time drain some then add it, use it for a day or two, then do the swap, but make sure the coolant is as hot as you can get it when it comes out, without melting your skin.

[TurboSedan]

what iWhat are you eyeing?

the stuff i was looking at was a NAPA brand and it came in powder form in a ~16oz bottle.  the directions said to drain the radiator, premix the powder in one gallon of water, then refill the radiator to the top with the premixed stuff and the rest with water.  then run the engine for 6-8 hours of normal driving, dump the radiator, fill it with water, run the engine to operating temp, then dump it again and add 50/50 coolant and bleed the system.

i'm definately not going to convert to the green stuff, not until the day comes i need the motor rebuilt or something.  i plan on using the NAPA brand Dexcool.