Modern Engine Swaps: Dexcool or Old School?

[skorpioskorpio]

When doing a swap from an engine originally intended to run Dexcool (orange GM Antifreeze) do you use that or do you use the old green stuff? I'd like to hear what those of you doing modern, especially aluminum head and/or blocks are doing. Also are you using an aluminum radiator or a copper one?

[ChevyCruizer]

I have read that you can run whichever you want as long as you have it completly flushed of the old "new" stuff. Clear as mud?

There are a lot of dexcool haters that have even switched to the old green stuff in there newer GM vehicles with no reported problems.

Just what I have heard/read. I have no experience switching personally.

[MARKDTN]

I would stay Dexcool but really flush your radiator and heater core well.

[skorpioskorpio]

I'll be replacing radiator with aluminum and the heater core with the vintage air system, so there really won't be anything original left, I was more wondering how sour the attitude was on Dexcool and if anyone saw any real advantages to it. I know the engines may have been designed with Dexcool in mind but I'm sure none of the other components, regardless of how modern they are, have been, or for that matter what that even really means. I don't know what type of core the Vintage air unit uses (Al or copper) but I seem to remember that some of the issues with Dexcool had to do with dielectric conductivity that fouled the fluid when run through dissimilar metals.

[SS Tim]

When Saturn started using Dexcool in 97 we were told not to backfit it. Apparently the older hoses were not rated for it and premature failure resulted. Sometimes a car would come in with green coolant that should have Dexcool in it. We always recommended a flush and replacement as the Dexcool is optimized for the alloy engines to reduce galvanic corrosion.

Being as you are using a Dexcool engine and aluminum heat exchangers I would use Dexcool. Keep it properly diluted and change it about every two and a half to three years.

[68 short step]

done lots of these swaps, aluminum heads, all i use is the green stuff, the dexicool leaves a white buildup, thatll potentially lead to a blockage... never had any problem with the green stuff either

[chev3600]

There's a lot of negativity about dexcool, (and alot of crusty blown intake gaskets to prove it) It seems like most of the issues arise from lack of routine maintenance. It does seem to leave a nasty white buildup, and pits aluminum and steel alike after too many years of not changing it. I recommend the new long-life green coolant in everything now.
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[brad_man_72]

After working at a quicklube in the late 90s I wouldn't put dexcool in my lawnmower.
Just use the green the green stuff.
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[WIDESIDE72]

Originally Posted by brad_man_72

After working at a quicklube in the late 90s I wouldn't put dexcool in my lawnmower.
Just use the green the green stuff.
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Dang! I still have an old air cold lawn mower!
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[clinebarger]

Dexcool is a GOOD non-silicate antifreeze & by itself will NOT form any kind build-up, Oxidize, or cause ANY harm to a like-metal or Bi-metal engine using a brass/copper or aluminum radiator.

Non-silicate long-life antifreeze's Like Dexcool WILL leak out of any leak point!.....The Silicate in "Green" antifreeze is what plugs-up all small leak points....But also leads to "build-up" of silicate in the cooling system.

The build-up in early Dexcool GM vehicles was from pure neglect or from people/dealers adding "sealing tabs" to the antifreeze.....Which is silicate (Dirt) to hide gasket defects.

Use ONLY Distilled Water when mixing antifreeze.

[special-K]

My '99 ZR2 that was designed to run Dexcool built up crappy gummy sludge. I had no heat! I don't neglect my vehicles and no one else ever touched it. I flushed that crap out and ran good old green anti-freeze after a serious back flush and that was the end of that truck's cooling system problems. They can take that Dexcool and put it with all the Ethanol as far s I'm concerned. They say Dexcool is fine as long as it doesn't get exposed to oxygen. Hmmm...what planet is it we live on?

[jamesi20]

We call it Dexclog around here...use the green stuff

[skorpioskorpio]

Well, I asked this question also because in the early 60s Buick made the 215 Aluminum V* and Ethyl glycol is what killed that engine (green stuff) or so they say. I know there are many many Aluminum engines these days running green stuff in them and has been for years and years, I just don't know whether provisions have been made to keep them from gumming up or whether Dexcool was GMs way of not having to alter their alloy ratios or coating process or if either of these is done at all and maybe the real issue with Ethyl glycol back in the day was really not about that at all but idiots filling up the radiators with water from the ditch on the side of the road that their car over heated next to.

Anyway, the engine I'm putting in has 10K miles on it, it's barely broken in, I'm keeping nothing else about the cooling system, it'll all be new. Everything that touches coolant will be aluminum or non-metallic with the possible exception of the VintageAir heater coil and that I'm not sure of.

Lucky for me I posted this thread and cleared up the whole green vs. orange debate .

[DnHolland]

Saturn recalled thousands of cars in 1991 and 1992(the pilot run for dex-cool) because they got the mixture wrong and it was to acidic and ate the aluminum away. I hate the stuff. I don't remember replacing as many intake gaskets and water pumps with the green stuff. The green stuff worked fine for almost 100 years. If you can get away from it, I would. However, make sure you flush until you think you have it clean the flush it two more times. You don't want to mix green and dex-cool.

[special-K]

Buick sold that V6 to Rover who used that design for decades. Decades prior to the introduction if Dexcool. I think the coolant story is a myth. I think the market still wanted big fat V8s and the V6 was ahead of it's time,but I have no proof.

I just wouldn't use the Dexcool if it was me. My experience with using it in a vehicle that it was spec'd for was totally negative and no ill effects came from switching to the tried & true. I was advised to do this by my mechanic friend who decided he hated Dexcool after servicing countless vehicles that it caused problems in.

[skorpioskorpio]

Originally Posted by special-K

Buick sold that V6 to Rover who used that design for decades. Decades prior to the introduction if Dexcool. I think the coolant story is a myth. I think the market still wanted big fat V8s and the V6 was ahead of it's time,but I have no proof.

Not to nit pick but the 215 aluminum V8 was sold to Rover, the 225 V6 was sold to AMC and Buick later bought it back. The 215 aluminum V8, the 300 iron V8, and the 225 V6 are all basically the same design except for material and number of cylinders. The 215 became a British Leyland engine after Rover was absorbed and was used in MGs, Triumphs, Jensens, Rovers and Land Rovers. The 225 was reacquired by GM and bumped up to a 231 and then later redesigned with offset crank throws to fire evenly at 120 degree intervals, the original fired 150 degrees then 90 then 150 and so on. The 300 became the Buick 350 eventually but by that time had strayed so much from the original design that it shares almost no parts with the original 215.

The 215 was really pushing the level of technology at the time, well for GM at least, and was a more fragile design than the typical Detroit offering of it's time. I swapped one into a 1976 Skyhawk way back when, which came originally with a 231 V6, was practically a drop in. I used the induction from a Triumph TR8 on it, it was a cool car. I didn't have any issues with it but then again I only had it in that configuration for a short time before the chassis or lack of chassis came apart. That car is basically a Vega, no frame at all, the whole thing is sheet metal.

[special-K]

You're right,I got those engines confused,but whatever. We're talking about the aluminum Buick 215 and my point is Rover/British Leyland didn't have the coolant issues. Using aluminum heads has been done for many years before Dexcool,too.

[motorcritter]

The biggest problem I saw was folks believing Dexcool was 'permanent', and didn't change it regularly, or, after the by-then acidic Dexcool was eating up intake gaskets (3.1/3.4 V6) and 'topping off' the Dexcool with 'green'. Then the overheated, brutalized GM car would end up in our shop, and the sad news was conveyed to the customer, the repair completed- and all that slop got flushed out and replaced with- green! The customer then understood the necessity of regular coolant services. I've run green in just about everything- American, European (older models) and Asian (also older models). The newer ones- I'd go with PE spec stuff, didn't have problems there. Older domestics- a good flush and green!
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[solidaxel]

Well from the sounds I am going with the green stuff!!

What is Embittered on the box mean?

[Hart_Rod]

Good info!

[chev3600]

Embittered. They add a bitterness agent to make the coolant taste REALLY bad. Makes it less appealing to animals and kids.
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[BADPURPLE70CHEVY]

Been in the oil change buisness 16 years. You can't go wrong with the green. Dexcool was a mistake from the start for gm if you ask me. I have seen radiators with dexcool that were solid sludge.

[clinebarger]

Present formulations of Dexcool mixed 50/50 with distilled water WILL NOT cause any issues, Drain & refill every 50,000/5 years.....No flush necessary.

Conventional Green silicate coolant 50/50 with distilled water.....Drain & refill every 24,000/2 years.

[Special-Ed]

Dexcool.
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[ls1nova71]

Unless you have a completely air tight sealed system, Dexcool will turn to mud and clog stuff up. When it comes in contact with air is when it happens, and on older trucks, when the engine cools down, air is pulled back into the radiator, that's why the fill cold level is so low on the radiator. I always use the green stuff now. When I did my first swap, I used Dexcool and regretted it, after about 10k miles, when you opened the cap, it looked like the inside of a diaper on a bad day. Flushed it out and went green, no problems since.