antifreeze in cadillacs

[satch4684]

how bad is it if orange/green may have been mixed? apparently the "add coolant" light came on for my father's '02 deville recently, so he threw some 50/50 coolant in there. And the light has still been coming on, think its been going on/off. I know the bottle that was laying around didn't have much, hopefully he didn't add more than that. guess its possible the previous owner(s) changed to regular stuff anyway.

I don't know what coolant type is in my '97 eldorado, but it looks like it could use some more, regardless im just going to flush it and add the green stuff. there is a sticker saying that a leak detection dye was added in 2004, don't know if that makes a difference.

so whats the process here? i've heard things such as keeping it simple, just let everything drain as normal (no spraying with garden hose, detach hoses, etc. although this is probably strictly for flushing, not changing from dexcool to green, right?) to flushing with distilled water, adding pellets, using some kind of powder on the hoses and all that jazz. and should a different process be used on the '02 deville than my '97 eldorado, since it's a lot more likely two different antifreezes have been mixed?

[2002 Caddy]

You should never mix the green and the orange coolants. Almost no one will tell you that this is a good idea. Ya, as soon as possible, you should have the coolant system flushed and refilled with the orange stuff in a proper 50/50 mix with distilled water.

Thats the good news... The bad news is you have to ask... were did the coolant go? I fear that your father is about to join a not very exclusive club of Cadillac NorthStar owners with a failed head gasket.

This is really bad news, and worse, to fix it will require that the car be lifted off of the engine and then all of the head bolts be removed, machined for steel inserts, and then all rebuilt... This will cost AT LEAST $5000 at the dealer. (Less at independent shops.. but make sure you find one that understands the NorthStar engine)

And before he tries, miracles in a can, bars-stop-leak, or what have you WILL NOT save a NorthStar with a head bolt failure since it is the head bolt that has failed in the block... These cans of goo with only plug up your heater core and make things worse.

Good luck.

[sonjaab]

Amen on mixing the coolant types in any vehicle let alone a N-star !
If you only filled the overflow tank and it hasn't seemed to have entered into the cooling system you may be able to get away with just draining the overflow resevoir.

But better safe than sorry and have the system flushed and refilled with the proper antifreeze coolant and water mixture! Check your owners manual for the proper type and also look in the maint. section and see IF your year also requires the GM sealant tabs to be added along with a coolant flush or coolant PM service.

The coolant sealant tabs were required in most newer Cadillac aluminum v-8s from the early 80s till the early 2000s.

And YES 2002 Caddy is correct in warning about the N-stars pulled head bolt issue !

[boston boy]

I heard that 2000 & up maybe less likely to do this. I this true?
Thanks

[2002 Caddy]

I heard that 2000 & up maybe less likely to do this. I this true?
Thanks

Yes, though GM didn't really solve the problem until 2004.

From 1992.5-1999 The NorthStar used the same headbolts as the quad4 engine. you can expect ALL of these engines to fail.

From 2000-2003 The NorthStar used the same fine threaded bolts as the Quad4, but made them almost an inch longer... these still fail, though not as often... If you change you coolant REGULARLY there is a rumor that these engine will last... Though failure are starting to become common in this year range too

From 2004-present GM woke up and switched to bolts very similar to those on the LSx engines, long coarse threads... Problems seem to be resolved.

[boston boy]

Yes, though GM didn't really solve the problem until 2004.

From 1992.5-1999 The NorthStar used the same headbolts as the quad4 engine. you can expect ALL of these engines to fail.

From 2000-2003 The NorthStar used the same fine threaded bolts as the Quad4, but made them almost an inch longer... these still fail, though not as often... If you change you coolant REGULARLY there is a rumor that these engine will last... Though failure are starting to become common in this year range too

From 2004-present GM woke up and switched to bolts very similar to those on the LSx engines, long coarse threads... Problems seem to be resolved.

U the man, thanks.

[Neanderthal]

Yes, though GM didn't really solve the problem until 2004.

From 1992.5-1999 The NorthStar used the same headbolts as the quad4 engine. you can expect ALL of these engines to fail.

From 2000-2003 The NorthStar used the same fine threaded bolts as the Quad4, but made them almost an inch longer... these still fail, though not as often... If you change you coolant REGULARLY there is a rumor that these engine will last... Though failure are starting to become common in this year range too

From 2004-present GM woke up and switched to bolts very similar to those on the LSx engines, long coarse threads... Problems seem to be resolved.

Regular, timely improvements. I like that!

[boston boy]

Regular, timely improvements. I like that!

toyoda does the same, but when the FEDs come & knocking

[Neanderthal]

toyoda does the same, but when the FEDs come & knocking

So did Chrysler with the 2.7.

NO EXCUSE, no matter who continues to sell defective equipment.

[satch4684]

thanks for the replies, someone mentioned a reservoir, there is none and it only has the plastic surge tank. why is there no tag that states "use only silicate free coolant" like on my eldorado?

i can't believe he didn't look in to what he was doing with that one, but i'm wondering about switching over to the regular green with mine. Is it really worth all the trouble of flushing the system thoroughly, and still the possibility of a little leftover so I might damage the engine by mixing them? Is Dex-cool that bad that I should even take this risk to change to green?

[sonjaab]

From Wilki:
Death-cool has been used in GM vehicles since 1996.

There are rumors that mixing DEX-COOL with standard green (non-OAT) coolant causes a chemical reaction that produces sludge in the cooling system. According to the DEX-COOL manufacturer, however, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."[16]

According to internal GM documents, the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.[17]

Typically OAT antifreeze contains an orange dye to differentiate it from the conventional glycol-based coolants (green or yellow). Some of the newer OAT coolants claim to be compatible with all types of OAT and glycol-based coolants; these are typically green or yellow in color (for a table of colors, see [4])

[sonjaab]

Resevoir or surge tank.........same thing.

What year did Cadillac stop requiring the sealant tabs in
the N-star v-8s ?

[satch4684]

interesting, that's the first time i've ever heard mixing standard and dex-cool is not an issue. I don't see why it would be a problem to just do a standard drain and refill with green then. idk, could it really just be a rumor when everyone says mixing is nothing short of disastrous? you sure the manufacturer isn't just bull****ing us on that one?

[dr.gizmo]

GM has told us since the introduction of Dex-cool that mixing the coolants will cause no harm except for the fact that you will now need to change the coolant every two years.

[willix]

GM has told us since the introduction of Dex-cool that mixing the coolants will cause no harm except for the fact that you will now need to change the coolant every two years.

Mixing coolant will not cause harm to the engine other than shorten Dex-cool claimed 5 yr-150,000mi long life service interval.

I would never run any coolant for that long a change interval.

At Wal mart you can get the identical as 50/50 Dex-cool formula 5-year 150,000 mi green coolant made by Prestone under Walmart's store brand name "Supertech". It's just not liciensed for a warranted GM product but the same. It's 30% less per gallon.