: GM coolant additive???



supernan1414
01-19-06, 09:41 PM
I have been reading the posts over the past month and want more info about the GM aditive or pellets some here have mentioned nessessary. At 100,000 miles had radiator flush at the dealer I bought the car from and on the bill it says Dexcool Kit and also MOA Additive. At approx 200,000 2 heater hoses were cracked, while I was driving check coolant level came on stopped the car had it towed to the nearest dealer they replaced them and added 3.75 gallons of coolant. There is no mention of a additive on this bill. The next month the water pump went and they added 1.5 coolant, no mention of additive finally a couple months later the radiator developed a crack and that was repaced no mention of adding any coolant on that bill. The water pump and radiator were done at local shops. Should I take it to a dealer and ask them to add this additive or is it something I can buy and put in the tank???? I now have 212,000 on this car ????:hmm:

Night Wolf
01-19-06, 09:54 PM
ah gosh... when you went to the mom and pop shop, are you sure they used Dexcool... the orange stuff?

if they used the old green stuff, then your engine is slowly eating itself from the inside out....

The tabblets are nothing more then crushed ginger, they are the same thing as BARRS leak stop-leak and conditioner, the kind you get in the tubes, its a powder. It is NEEDED for the Northstar and if it wasn't put in, then I would do it ASAP, you don't need to go to the dealer for that as it isn't hard to open the radiator cap and pour the powder into it.

Ranger
01-19-06, 09:56 PM
You can buy the tabs at any GM dealer or go to Walmart or such, and buy Barleaks product "HDC" (tabs) or "G12BP" (powdered version). DO NOT put them in the surge tank. They need to go into a high flow area (radiator hose). If put in the tank, they may clog it as it is a low flow area. They are mandatory on the 4.1 4.5 & 4.9 because a failed head gasket can leak into the oil. The Northstar is designed such that that will not happen as we have been told by a GM engineer. Use of them in the Northstar is just a precaution against porous castings or nuisance gasket leaks. It's a good idea to have them but, don't loose any sleep over it.

Ranger
01-19-06, 09:59 PM
ah gosh... when you went to the mom and pop shop, are you sure they used Dexcool... the orange stuff?

if they used the old green stuff, then your engine is slowly eating itself from the inside out....


Please don't start myths like this. People read this stuff on the internet and take it as gospel. Nothing could be farther from the truth. Green coolant will work as well as Dex. The only difference is that if it is used, you are relegated to 2 year/30K coolant changes instead of 5yr/100K.

Besides, he specifically said he went to the dealer and specifically mentioned Dex-Cool.

Night Wolf
01-19-06, 10:10 PM
Please don't start myths like this. People read this stuff on the internet and take it as gospel. Nothing could be farther from the truth. Green coolant will work as well as Dex. The only difference is that if it is used, you are relegated to 2 year/30K coolant changes instead of 5yr/100K.

Besides, he specifically said he went to the dealer and specifically mentioned Dex-Cool.

myths!?

First, he said he got the w/p done at a local shop as well anti-freeze put in.

I am going to leave my personal thoughs on Dexcool out of this (as I did in the first reply)......

but notice what I said? MIXING Dexcool and normal green stuff.

Meaning, the car origanaly had Dexcool, the dealer put Dexcool in it, if the local shop put the regular stuff in when it was really low and failed to completly flush the system, then that means that Dexcool *MIXED* with the green stuff.

If you don't know what can happen when Dexcool gets mixed with the tradional green stuff, then call any local GM dealer and ask them.

Please, I know what i am talking about, there is no need to make it look like I am going around telling lies, I think everyone here knew me a little better then that.

Night Wolf
01-19-06, 10:12 PM
BTW the last 2 coolant changed I did on my '93 Coupe... the first time using the GM tablets and the 2nd time using Barrs leak powder, I poped the radiator cap and put them in. Over a year and lots of miles later, no clogs. When we first got the tabllets at the GM dealer, I asked if I can put them right in the raditor, the tech said its fine, when it hits water it disolves.

The coolant supplement is required on the Northstar also. It is filled with it when it leaves the assembly line and there is a sticker under the hood as well as being listed in the service manual. Not to mention the dealer even put it in when you took or for a cooalnt change.

It is more then just a "precaution" GM woudln't waste what turns out to be millions of dollars on something (putting this stuff in from the factory) as just a "precaution" It is required.

*BTW if I got a car with Dexcool, and the Dexcool stayed in it (it wouldn't.... but if it did) I would NOT wait 5yrs/100k miles to change it... it would be about half that MAX.

Ranger
01-19-06, 10:21 PM
Sorry, I missed "local shop" on the last line.
Better reread your post. The word "MIXED" was never used. You said "if they used the old green stuff, then your engine is slowly eating itself from the inside out....". Even if you meant mixed, and it was, the engine is not going to self destruct.

Note paragraph 4 in the link below.
http://www.theherd.com/articles/dex_cool.html

Night Wolf
01-19-06, 10:34 PM
it requires a little thought here, but makes perfect sense.... this is what he said:


The next month the water pump went and they added 1.5 coolant, no mention of additive finally a couple months later the radiator developed a crack and that was repaced no mention of adding any coolant on that bill. The water pump and radiator were done at local shops.

So some shop besides the dealer replaced the water pump and the radiator. Nothing wrong with that.

He said they added 1.5 gallons+ of coolant. Nothing wrong with that either.

*both of these were done at the local shop*

This is what I said:


ah gosh... when you went to the mom and pop shop, are you sure they used Dexcool... the orange stuff?

if they used the old green stuff, then your engine is slowly eating itself from the inside out....


*THEY* impling the local shop that did the w/p and rad, and filled it with coolant.

It is very possible they used Dexcool, then there is nothing to worry about... but *IF* they used the green stuff, then that means it *MIXED* It is implied. If you add only 1.5 gallons of coolant, then there is still some left in the engine, not to mention even if ALL the Dexcool drained out from a faulty w/p it is still a danger to use the green stuff, the Dexcool needs to be throughly flushed and completly cleaned out of the system, simply draining all the Dexcool (or it leaking out some how) then filling it with the green stuff (which the shop MAY have done) is no good.

Weather you like Dexcool or not, they should never be mixed. I simply said that because *IF* it was mixed, to take the car ASAP and get the coolant flushed and refilled with Dexcool or whatever, but don't leave a mix of the green stuff and Dexcool in the engine.

But yeah, the engine will kill itself within time if the 2 were mixed. Obvisouly it isn't going to literally blow up at a random time, but with the 2 mixed it will start eating all the gaskets as well as form some really nice and grungy sludge all over the internals of the cooling system, causing blockage of coolant passages, clogged radiator, failed water pump and many other things that will, within time ruin the engine, which is why I said:


if they used the old green stuff, then your engine is slowly eating itself from the inside out....

Night Wolf
01-19-06, 10:38 PM
Sorry, I missed "local shop" on the last line.
Better reread your post. The word "MIXED" was never used. You said "if they used the old green stuff, then your engine is slowly eating itself from the inside out....". Even if you meant mixed, and it was, the engine is not going to self destruct.

Note paragraph 4 in the link below.
http://www.theherd.com/articles/dex_cool.html

Sorry, but I'll take what GM says themself (not to mix the 2) then some random site on the internet...

funny how things work out, on another car forum I am a regular on, we got into the same exact Dexcool debate.....

but even the Dexcool supporters said it is a bad idea to mix the 2.

It comes down to it being your engine. If you think its fine and wont do anything leave it. Otherwise flush it out. (If the 2 were mixed)

looking at the bigger picture with Dexcool vs the green stuff... again, whatever you personally feel, do it. I am happy to say that none of my 3 cars ever even saw that Dexcool stuff, and they never will, and if I buy any 1996+ GM in the future (which I will be) one of the first things I will be doing is throughly flushing out the cooling system and using the green stuff, changing coolant every ~25k miles as I do now.

Ranger
01-19-06, 10:39 PM
BTW the last 2 coolant changed I did on my '93 Coupe... the first time using the GM tablets and the 2nd time using Barrs leak powder, I poped the radiator cap and put them in. Over a year and lots of miles later, no clogs. When we first got the tabllets at the GM dealer, I asked if I can put them right in the raditor, the tech said its fine, when it hits water it disolves.

The coolant supplement is required on the Northstar also. It is filled with it when it leaves the assembly line and there is a sticker under the hood as well as being listed in the service manual. Not to mention the dealer even put it in when you took or for a cooalnt change.

It is more then just a "precaution" GM woudln't waste what turns out to be millions of dollars on something (putting this stuff in from the factory) as just a "precaution" It is required.

*BTW if I got a car with Dexcool, and the Dexcool stayed in it (it wouldn't.... but if it did) I would NOT wait 5yrs/100k miles to change it... it would be about half that MAX.
'93 Coupe? 4.9 right? Yes that had a radiator cap (high flow area). That is where they go. The Northstar does not have a radiator cap. That is why they go in the radiator hose.

Reguarding the "precaution". If you read "The Masters" posts, you would realize that I am quoting him.

Nothing wrong with changing Dex sooner than 5 years. Just qouting what GM says.

Ranger
01-19-06, 10:45 PM
BTW, I never said it was a good idea to mix them, just that the engine will not "eat itself from inside out". I would not mix them, nor would I ever recommend it.

turbojimmy
01-20-06, 10:03 AM
All Dexcool debate aside, it's nice to see a 212k mile Northstar. I think I'll have mine for a long time.

Jim

Ranger
01-20-06, 06:02 PM
Weather you like Dexcool or not, they should never be mixed.

But yeah, the engine will kill itself within time if the 2 were mixed. Obvisouly it isn't going to literally blow up at a random time, but with the 2 mixed it will start eating all the gaskets as well as form some really nice and grungy sludge all over the internals of the cooling system, causing blockage of coolant passages, clogged radiator, failed water pump and many other things that will, within time ruin the engine, which is why I said:

The following link is what GM and Texaco say about it. Note number 7.

Again, I do not condone nor recommend mixing but, the engine will not "eat itself from the inside out".
http://www.imcool.com/articles/antifreeze-coolant/dexcool-macs2001.htm

I rest my case.

supernan1414
01-20-06, 06:27 PM
I feel confident that Dex-cool was used when the water pump was changed. It was done at a NAPA Auto Care Center, two bay, owner operated shop. They were very knowlegable and believe they know not to mix the two differant coolants. ( We were at our campground when this happened) When the radiator was changed, no mention off coolant on the bill, my husband says they must have filled the radiator with dex-cool but I think they often keep what comes out of it and put it back in. Really don't know for sure, this was done at the shop we normally use, buy tires, oil changes, they surely should know not to put the wrong coolant in. Every time they do a oil change they check my coolant levels.

If we pick some of this addditive up and put in the recemmended amount if there is some already in will it hurt the engine. :cookoo: When the heater hose leaked and they put in 3.75 coolant in you would think they would have put the required amount of this additive, but no mention of it on the bill. This was at a Cadillac dealer.
Drove this car 300 miles today and is still a joy.

Night Wolf
01-20-06, 06:28 PM
Keep in mind of course, this was AFTER GM changed the Dexcool formula to help reduce the effects of it, but not get rid of the problem.

200k on a Northstar isn't a rare case... oil and coolant changes and it'll go for alot longer :)

Night Wolf
01-20-06, 06:29 PM
I feel confident that Dex-cool was used when the water pump was changed. It was done at a NAPA Auto Care Center, two bay, owner operated shop. They were very knowlegable and believe they know not to mix the two differant coolants. ( We were at our campground when this happened) When the radiator was changed, no mention off coolant on the bill, my husband says they must have filled the radiator with dex-cool but I think they often keep what comes out of it and put it back in. Really don't know for sure, this was done at the shop we normally use, buy tires, oil changes, they surely should know not to put the wrong coolant in. Every time they do a oil change they check my coolant levels.

If we pick some of this addditive up and put in the recemmended amount if there is some already in will it hurt the engine. :cookoo: When the heater hose leaked and they put in 3.75 coolant in you would think they would have put the required amount of this additive, but no mention of it on the bill. This was at a Cadillac dealer.
Drove this car 300 miles today and is still a joy.

putting in more coolant supplement then required will not hurt anything.

Ranger
01-20-06, 06:41 PM
I agree. You would have to put a LOT in to cause a problem. Just don't put it in the surge tank.

supernan1414
01-21-06, 01:56 PM
OK!!!! Just returned from buying the tablets from a GM dealer, the fellow behind the counter told me to crush them and put them into a hot radiator. We just went out to the car and the only access to the radiator is through the tank. Looked all over the top area of the radiator and DO NOT see a cap????Is it hidden???

C170B
01-21-06, 05:03 PM
Dear Superman

There is no direct access to the radiator.

Standing in front of auto w hood up, look to the L side and about two (2 ft)
from front of engine compartment you will see a small black plastic tank w a metal radiator style cap on it. Don't touch cap while it is still HOT and pressurized. Some owner/operators use a plastic strap "JAR LID" remover since the cap is sometiomes TOO HARD to turn by hand. Added precaution lay a shop cloth or large towel over cap while it is being removed while still Warm. Be cautious, wait 20-25 min after driving bfore removing radiator cap, sometimes mechanics will remove a cap and it will unexpected do an erupting volcano number. Lifetime serious injuries have occurred. This is the reason millions of radiator caps had the message "DO NOT OPEN" printed on
top.

I am sure you probalby already knew the precautionary warning I just felt like I should repeat it when I read your question about location of cap.

Good to hear you have 220K plus miles on N*. Encouragement to many of us.

BTW you have a new radiator, how about the heater core it is a mini radiator. Is yours heater core the original.

supernan1414
01-21-06, 09:18 PM
Thank you for the info, will look you it in the morning. Yes the heater core is origanal, the heated seat still work and has as much power as it did when it was new. My husband is a stickler about changing the oil every 3 to 4 thousand miles. The only other things we have done to this car was a air conditioner compresser at 58,000 and alternator at 140,000.

supernan1414
01-21-06, 09:40 PM
Isn't that the surge tank Ranger said not to put the capsules in???? but it is the only access we see to the radiator. The heater core is the origanal, don't know if it is a mini radiator, its the standard one that came on the '98 Devile


Dear Superman

There is no direct access to the radiator.

Standing in front of auto w hood up, look to the L side and about two (2 ft)
from front of engine compartment you will see a small black plastic tank w a metal radiator style cap on it.

Good to hear you have 220K plus miles on N*. Encouragement to many of us.

BTW you have a new radiator, how about the heater core it is a mini radiator. Is yours heater core the original.

JimHare
01-22-06, 01:46 AM
The additive should be placed in the LOWER radiator hose. When you loosen it, you will loose a bit of coolant, so be prepared. The hose is long enough so that you can pull it upwards and pop the supplement in. It is NOT rocket science, but if neither you nor your husband feels mechanically inclined, any reasonably competant auto shop should be able to to it in about 10 minutes. DO NOT PUT THE TABLETS, CRUSHED OR OTHERWISE, IN THE SURGE TANK. There is not enough flow in the surge tank to carry the stuff back through the cooling system - you'll only clog it up.

Also, save yourself some money and change oil according to GM Oil Life Monitor on the car. It is much smarter than you are, and takes all kinds of engine conditions into considerations.

The old "3K/3Month" oil change habit was started in the 1960s - lubricating oil technology has come a LONG way since then. Your Driver Information Center will tell you when the oil life is around 5% or so - that's the time to change it.

Night Wolf
01-22-06, 02:57 AM
It is much smarter than you are :histeric: :D

Ah sorry, I know what ya ment, but when I read that, I just laughed.

Yeah, change oil according to the life monitor.

and no, the surge tank is not where it goes... it would just stay in there forever never getting into the cooling system.

turbojimmy
01-22-06, 09:24 AM
I don't want to hijack the thread, but I do have a question.....

My water pump cover is leaking on my '01 DTS. I've ordered up the revised cover and gaskets from GM. When I do this, should I pop the sealant in as well? Or won't I lose enough coolant for it to matter?

The car has around 55-60k on it now and since I don't know the maintenance history on the car it's probably prudent to assume the coolant has never been changed.

Thanks,
Jim

Night Wolf
01-22-06, 03:13 PM
I personally would just do a normal coolant drain and refill..... wasn't that car in a flood? you never changed the coolant?

Just replace the coolant and add the supplement, cheap insurance for the future.

turbojimmy
01-22-06, 03:41 PM
I personally would just do a normal coolant drain and refill..... wasn't that car in a flood? you never changed the coolant?
Just replace the coolant and add the supplement, cheap insurance for the future.

Yes it's a flood car. Nope, never changed the coolant. The system is sealed so there was no contamination of the coolant with the flood water. Coolant still looks new.

I'll top it off and add the supplement.

Thanks,
Jim

Ranger
01-23-06, 08:08 PM
An '01 is due for a drain and refill. Now would be the time to do it since you are going to open the system up anyway.

turbojimmy
01-23-06, 10:37 PM
An '01 is due for a drain and refill. Now would be the time to do it since you are going to open the system up anyway.

It definitely can't hurt. When I pull the lower hose to put the supplement in it will puke most of the coolant out anyway. I'll just do a drain and refill.

Jim

SkarTisu
01-27-06, 01:58 AM
Hi everyone,

Since this is a coolant related thread, I'd like to ask my question here, if I may....

93 DeVille, 85k miles, I don't know the service history (or lack thereof) on this car. I've read conflicting information regarding pellets/no pellets for the 4.9s. I'd like to do a coolant drain and refill (no flush if I can help it) and I'm not sure what to do about the pellets. Since I don't know the state of the water jackets, should I avoid putting pellets in? Maybe put half the recommended amount of the pellets in? Put 'em all in and pray?

I'm reasonably sure the cooling system has never been flushed. How much risk do I take in simply doing a drain/refill vs. having a shop perform a flush for me? The countdown clock to blown head gaskets is surely ticking for me.....

Thanks, everyone!

JimHare
01-27-06, 07:33 AM
If I recall, the coolant pellets were absolutely required for the earlier (Pre-Northstar) engines, and highly suggested for the Northstar. The earlier engines could get coolant and oil mixed if a gasket fails dues to the casting of the coolant passages and block. In the Northstar, this will NOT happen.

Thus, the earlier, non-aluminum engines require them for protection, and the aluminum engines find them very useful for 'nuisance' and minor porosity leaks.

Common knowledge here seems to be that a 'flush' can do more harm than good, especially with an older engine. A complete drain and refill is probably the best bet, including tabs.

Don't forget, there is a comprehensive article in the Tech Archives section (link on top of the main page here) addressing all the cooling issues.

Ranger
01-27-06, 12:07 PM
I agree with Jim. Drain, refill and add the sealant tabs. If it has never been service since '93, it is way overdue and you are on borrowed time.

SkarTisu
01-27-06, 01:03 PM
Very good! Thanks for the advice! :thumbsup:

turbojimmy
01-27-06, 03:46 PM
I'm too lazy to look through this whole thread again, but I was going to add 6 pellets to my Northstar until I got to the dealer and noticed that they sold them in packs of 5. The guy behind the counter also said not to put more than 3 in there or I'd be changing my heater core. I didn't react since there's lots of misinformation out there about this stuff.

Anyway, my FSM says to add THREE pellets of the supplement to the lower radiator hose. I know the 4.9 takes 6, but the Northstar evidently gets 3. This is another reason I think this forum needs split up. There are a number of differences between the model years lumped into this category.

Also, I think the LOWER hose is important. I know it's easier to get to the top hose, but the top hose is the return from the engine. The flow of the coolant puts the tabs right to the radiator. If you put them in the lower hose the flow of the coolant will wash it right into the engine where it's needed.

Jim

Ranger
01-27-06, 06:39 PM
The manual said 3, "Rob" said 6. I used 4. I don't think the number is critical. Just put 3-6 in there.

On the 4.9 you put them in the radiator. If the Northstar had a radiator cap, you'd put them in there as well, so I don't think which hose is all that important. Lower hose may be preferable but, I don't think it is critical. They will get circulated through the engine in short order.

SkarTisu
01-28-06, 03:33 AM
Any thoughts on whether to break the pellets up beforehand or not?

turbojimmy
01-28-06, 08:28 AM
Any thoughts on whether to break the pellets up beforehand or not?

I have to admit that I have zero experience with this, but the factory manual served me well during the reconstruction of the car so I'm going to follow it as far as this goes.

That being said, the manual does not say to break up the pellets. Here is the notice in my 2001 manual:

Notice: This engine uses DEX-COOL and GM coolant supplement (sealant) P/N 3634621 specifically designed for use in aluminum engines. Failure to use the engine collant supplement (sealant) and the approved coolant/antifreeze could result in major engine damage. When refilling the cooling system, add three pellets of the engine coolant supplement sealant GM P/N 3634621 to the lower radiator hose.

I'm sure that if previous model years added the stuff to the radiator that it would be fine adding it to the upper hose. Obviously the top hose is MUCH easier and less messy, but there has to be a reason they're specifying the lower hose. Despite the fact that I'll have the upper hose off the car when replacing the water pump cover, I'm going to pull the lower one anyway.

Jim

Spago11
01-28-06, 10:53 AM
Which end of the hose is the best to pull off to add the additives ?? The end attached to the radiator or the end attached to the engine.

In other words which end would produce the least amount of lost coolant.

Ranger
01-28-06, 01:35 PM
The reason for breaking up the tabs is when they are put into the radiator (4.9) there is not enough room to get them all in because of the oil cooler line inside. Otherwise it is irrelavent. They will break apart quite fast when they get wet. If your putting them in the hose (Northstar), just stuff them in whole, it's much easier. The highest hose end will cause the least coolant loss.

turbojimmy
01-28-06, 03:20 PM
I replaced that water pump cover this morning. There was a TSB that affected my car so I put a revised cover on. It was pretty straightforward, but I didn't realize until I got into it that the LOWER hose is connected to it, not the upper. So since I had it off I popped 3 tabs in there.

Only about 6 quarts came out. Per the FSM, I removed the plug from the radiator and pulled the expansion tank. It also puked out a ton of it when I pulled the water pump cover off. The expansion tank was dry so I know it drained. I followed the refill instructions in the manual and it's at the cold fill line like it should be. Capacity is 12.5 quarts so I guess I only really changed about half of it. I don't know where the rest of it was hiding.


Jim

New Caddy Owner
05-09-06, 11:20 PM
I don't mean to hi-jack this thread, but I have a REAL ISSUE that I need help with!!!

I recently bought a '98 Deville (137,000 miles) from an older couple. Just before me buying it, he had a local (shade tree mechanic) change out the upper radiator hose. The car now has 140,000 miles and I figured I would do some preventative maintenance (since I didn't have much info on past work).

I was reading in a repair manual about the Dex-Cool antifreeze and noticed that this car was suppose to have it in it. I bought everything I needed for the preventative maintenance and when I pulled the reservoir cap I noticed that the shop had put the green stuff in, instead of the orange. I've read that you have to flush the system. It says to remove the thermostat and upper hose and flush with water until it turns clear.

My question is this: After I do this, would it be ok to use a cleaner (I.e. Prestone radiator cleaner)? Or should I be safe to just flush the system?

Also, where in the WORLD is the radiator petcock?????? I CANNOT find one ANYWHERE!!!!!

Thanks in advance for any and all help!!!!!

Ranger
05-09-06, 11:25 PM
It's too late. Once the green coolant is in there, it plates the water jacket with silicates. No harm done except that you now are relegated to two year changes, even if you use Dex. The petcock is not the old wing type. It is on the drivers side, either underneath or on the back side facing the engine compartment. It is usually just easier to pull the radiato hose.

New Caddy Owner
05-10-06, 12:19 AM
It's too late. Once the green coolant is in there, it plates the water jacket with silicates. No harm done except that you now are relegated to two year changes, even if you use Dex. The petcock is not the old wing type. It is on the drivers side, either underneath or on the back side facing the engine compartment. It is usually just easier to pull the radiato hose.
So what you're saying is, regardless if I flush the system and put the Dex back in, I'm going to have to change out the fluids every 2 years? I most likely would change the Dex out every 3 anyways. There's something about me that cannot understand leaving the same coolant in a system much longer than 2 years anyways.

Ranger
05-10-06, 12:31 PM
So what you're saying is, regardless if I flush the system and put the Dex back in, I'm going to have to change out the fluids every 2 years?
Correct.

phlipper
07-11-06, 03:58 PM
With my '92 Deville, I purchased the pills, put them in a heavy duty plastic seal type baggie, I crushed them, I put the powder in a jar with a little water and shook it, and poured it into the radiator from the top(while the radiator was cold). Right or wrong, that's the way I did it.