: Double Flush?



lry99eldo
10-02-05, 10:51 AM
Here's one for yall. I plan on flushing my cooling system soon. I have a '99 Eldo, with 48K on the odo. The coolant looks good at this point and not showing any signs of problems other that it is past the 5 year replace schedule.
My plan is to double flush it. I have purchased two gallons of Dexcool and four tubes of Bars Gold as supplement. My thought here is to get as much of the exisiting coolant out seeing as how there are no block drains and I don't want to disturb any of the heater system stuff. That normally requires a back flush, which I'm trying to avoid.
So, one week, I'll drain and refill with 50/50 Dex and distilled water with two tubes of supplement. Run it for a week, with heater sometimes also to exchange coolant in that circuit. The next week I'll perform the same procedure. As I read it, all I'll get out of it will be less that the two gallons I've mixed but more than one gallon total resulting from the drain only. I've done this on my '86 Olds several times and the results are always great. Seems as though all the components stay cleaner and here in Phx., Az., I have never had an overheating problem.
So, the question is, is this overkill with the N*? I should be good for another 100K or so if all is true to manual recommendations, right?
Well, thanks in advance for all that chime in on this!
lry99eldo

speedyman_2
10-02-05, 12:11 PM
I've never performed a flush on my STS but I have on a few other cars. I would say there's really no problem with this. Kinda like washing your car twice. You're always bound to get some more dirt on the second attempt. Plus, I always like to get something as clean as I possibly can. I remember flushing my '65 Mustang once. Very old coolant systems and I stopped and was about to fill it up with fluid. I poured some more water after the previous flush had already went through. Quite a few pieces of crap came out. So, at least a followup flush of some sort wasn't a bad idea. :)


Here's one for yall. I plan on flushing my cooling system soon. I have a '99 Eldo, with 48K on the odo. The coolant looks good at this point and not showing any signs of problems other that it is past the 5 year replace schedule.
My plan is to double flush it. I have purchased two gallons of Dexcool and four tubes of Bars Gold as supplement. My thought here is to get as much of the exisiting coolant out seeing as how there are no block drains and I don't want to disturb any of the heater system stuff. That normally requires a back flush, which I'm trying to avoid.
So, one week, I'll drain and refill with 50/50 Dex and distilled water with two tubes of supplement. Run it for a week, with heater sometimes also to exchange coolant in that circuit. The next week I'll perform the same procedure. As I read it, all I'll get out of it will be less that the two gallons I've mixed but more than one gallon total resulting from the drain only. I've done this on my '86 Olds several times and the results are always great. Seems as though all the components stay cleaner and here in Phx., Az., I have never had an overheating problem.
So, the question is, is this overkill with the N*? I should be good for another 100K or so if all is true to manual recommendations, right?
Well, thanks in advance for all that chime in on this!
lry99eldo

mcowden
10-02-05, 01:35 PM
Here's one for yall. I plan on flushing my cooling system soon. I have a '99 Eldo, with 48K on the odo. The coolant looks good at this point and not showing any signs of problems other that it is past the 5 year replace schedule.
My plan is to double flush it. I have purchased two gallons of Dexcool and four tubes of Bars Gold as supplement. My thought here is to get as much of the exisiting coolant out seeing as how there are no block drains and I don't want to disturb any of the heater system stuff. That normally requires a back flush, which I'm trying to avoid.
So, one week, I'll drain and refill with 50/50 Dex and distilled water with two tubes of supplement. Run it for a week, with heater sometimes also to exchange coolant in that circuit. The next week I'll perform the same procedure. As I read it, all I'll get out of it will be less that the two gallons I've mixed but more than one gallon total resulting from the drain only. I've done this on my '86 Olds several times and the results are always great. Seems as though all the components stay cleaner and here in Phx., Az., I have never had an overheating problem.
So, the question is, is this overkill with the N*? I should be good for another 100K or so if all is true to manual recommendations, right?
Well, thanks in advance for all that chime in on this!
lry99eldo


Your plan is just fine. As long as you're not dumping any flushing chemicals in there or tap water, I think you will have good results. It may technically not be necessary, but I do agree that the cooling systems on Northstars can be fickle at times, and it's probably better to be safe than sorry. I asked our old friend about this once and he said just drain, refill, and drive it, but on this particular issue, I think I'd rather do what you're planning, just for that extra measure of protection. Be sure to use distilled water.

You might think about flexing the water pump belt tensioner while you're looking at cooling system maintenance, and putting a few drops of oil on the spring just to keep it limber and rust-free. How is the thermostat? Do you think it would be worth replacing it while you have the system drained?

Let us know how this works out for you, especially how the first and second coolant drainings look. Good luck!

97STS4ME
10-03-05, 11:19 PM
All of my older cars id stick a hose in the upper radiator opening and let it run full blast with the engine running and heater wide open. It would flush the radiator, engine, heater and everything else along the line. But the Caddy wasnt that simple. I had to flush the radiator seperate from the block and it almost seems like it only flushed half of the block because all the water was pouring out of the lower hose inlet on the water pump. And when I stuck the water hose in the upper hose outlet it still came pouring out the lower hose outlet. Im not sure how much of the engine actualy got flushed when I did it. So I kinda wonder whats the proper way to flush the N*?
I gotta replace the alternator soon (sometimes only charges at 12.5V when hot) And that requires removal of the radiator so I figure ill flush the cooling system again then.

(sorry to steal the thread, but the manual I have doesnt help much)

mcowden
10-04-05, 12:00 AM
All of my older cars id stick a hose in the upper radiator opening and let it run full blast with the engine running and heater wide open. It would flush the radiator, engine, heater and everything else along the line. But the Caddy wasnt that simple. I had to flush the radiator seperate from the block and it almost seems like it only flushed half of the block because all the water was pouring out of the lower hose inlet on the water pump. And when I stuck the water hose in the upper hose outlet it still came pouring out the lower hose outlet. Im not sure how much of the engine actualy got flushed when I did it. So I kinda wonder whats the proper way to flush the N*?
I gotta replace the alternator soon (sometimes only charges at 12.5V when hot) And that requires removal of the radiator so I figure ill flush the cooling system again then.

(sorry to steal the thread, but the manual I have doesnt help much)

Because the cooling system isn't the same as cars used to be in simpler times, I would definitely not recommend doing any kind of flush procedure on the system. Just drain it and refill it. It's too easy to harm the system by flushing it.

You do not have to remove the radiator to replace the alternator. It takes some maneuvering, profanity, and about a 6-pack to wrestle it out of there, but you can get it out without removing much other than the torque strut and the electric radiator fan. I had to replace mine after, like an idiot, I drove through a pool of water that was much deeper than I thought it was. When I got back to the garage and turned it off, I could still hear arcing sounds coming from the alternator. It wasn't right after that, so I replaced it with one from a 2000 that matched up perfectly. It was a little frustrating, but I got it done in a lot less time and effort than if I had removed the radiator.

If you do want to disconnect the radiator and run some distilled water through it, by all means, do that, but use distilled water. If you want to try and replace more of the coolant, I've heard people say to use the blower side of a shop vac to blow air through the system and empty more out of the block. Whatever you do, don't put any tap or hose water in the system at all, and don't use any flush chemicals.

That's just my opinion. Someone else may have a better technical reason why it's OK. Hope it helps in some way anyway. Let us know what you do and how it works out.

krimson_cardnal
10-04-05, 10:53 AM
While we're on the subject, how would I go about getting the orange stuff in my engine that has the green stuff in it. Just had the rad replaced [a GM dealer job] and was assured that the green was, indeed, okay [it was in there already]. Dude said he put the tabs in.

Would sure like to get to spec on the coolant, but hearing the horors of flushing - tap water - and all I'm at a loss??

I'm a believer in picking your battles and the better of two evils, but for sure, unless I can get ALL the green stuff out it's probably not worth it.

:confused: (http://misc.php?do=getsmilies&wysiwyg=1&forumid=23#) So how do you change out the coolant in a NorthStar [green for orange].

mcowden
10-04-05, 10:58 AM
While we're on the subject, how would I go about getting the orange stuff in my engine that has the green stuff in it. Just had the rad replaced [a GM dealer job] and was assured that the green was, indeed, okay [it was in there already]. Dude said he put the tabs in.

Would sure like to get to spec on the coolant, but hearing the horors of flushing - tap water - and all I'm at a loss??

I'm a believer in picking your battles and the better of two evils, but for sure, unless I can get ALL the green stuff out it's probably not worth it.

:confused: (http://misc.php?do=getsmilies&wysiwyg=1&forumid=23#) So how do you change out the coolant in a NorthStar [green for orange].

Don't waste your time. Once the green stuff is in there, you will not get the benefits of the DexCool again, even if you get all the green stuff out of there. The green stuff contains silicates, and they plate the interior surfaces of the cooling system. Once they're on there, it's difficult or impossible to get rid of them. DexCool will work fine with silicates, but you will still have to change it at the 2 year or 30k mile interval that the green coolant requires. If I was you, I'd just leave it alone and remember to change the coolant at 2 years or 30k miles. All you've lost is the long-life characteristics of DexCool. The engine and cooling system will work just fine with the green stuff.

krimson_cardnal
10-04-05, 11:45 AM
Thanks mcowden - I bought this car off Ebay - great deal, but it came w/ the green. You cleared up an issue that's been on my mind, hopefully it will help others in the same situation. Techie said that once the green goes in you'll never get it all out and you've explaind the silicate thing.


_thanks