Conventional or Low Silicate " Green" GM '83 2.8

[edge10]

I've got an '83 2.8l HO Pontiac STE that I want to go to the original (or close or better ) the original factory fill. It has Dex in it now - yes I know, I know. No Dex bashing please. No temp problems, but I do notice a few small black particles and some noise in the heater core during cold start when the weather is cool. No problem with the heater though.

Are any significant difference between brands of the conventional silicate green? Peak conventional green is available in my area, I have to mail order others.

What is the best procedure to switch over the coolants. I have read I need less than 10% remaining Dex to switch. My plan was to go through cooling 2 flush cycles with water and maybe a mild flush kit. The thermostat would be removed during the flush just quicken the cool down time between flush cycles if the lower temp does not reduce the flushing effectiveness. I suppose I could try to pump the block dry by not refilling the radiator, being careful not to run the pump too long. Then refill with the conv green and replace the thermostat of course. Then do a drain/replace in a year.

 

[eljefino]

Phosphates are a difference, though you should be fine.

My 95 saturn s-series warned against phosphates, but I put peak conventional in. It's got phosphates. 48 hours later my water pump was leaking.

Either cavitation from the drain and fill got it, or phosphates wrecked the seal, as they are apt to do. Or it was just an old car acting up.

Regardless, I put a new water pump on and all is well.

 

[Donald]

I would go to G-05. Its a better coolant than the old green stuff. I used in in my 93 Suburban with no problems.

I would drain and flush a few times with distilled water. Can you get to the engine block drains?

DEX is fine for vehicles that came with it from the factory. But I would not use it in other vehicles.

 

[jrustles]

Silicate dropout is still a concern for me, as well as it's proposed abrasive properties. That EHA ridden dexcool is always a latent disaster.

+1 on a low-silicate, non-EHA coolant like G-05
Originally Posted By: Donald
I would go to G-05. Its a better coolant than the old green stuff. I used in in my 93 Suburban with no problems.

I would drain and flush a few times with distilled water. Can you get to the engine block drains?

DEX is fine for vehicles that came with it from the factory. But I would not use it in other vehicles.

 

[edge10]

Does Peak have added phosphates compared to other conventional green coolants ?

Both the G-05 and the Con Green meet the 1825M spec in the GM 2.8 manual. Is there a downside to G-05 Phosphate Free if the cooling system the 2.8 was design to run with phosphates? It has a iron block and heads, with a aluminum plastic cap radiator.

I have'nt check the block drains, but good thought. I am just assuming they are rust seized in the block at this point and don't want to chance stripping them - I could be wrong.

 

[Donald]

There is always Peak Global to consider.

Many engines have iron block & heads and aluminum radiator. I think both my vehicles do and both are on G-05. Almost no vehicle has an old brass radiator from the factory. Maybe as a replacement.

My point is, given current coolant technology, I am not sure there is a real need for the old green. If you get the bulk of the old coolant out, the modern coolants will last 2 or 3 times as long as the old green.

The best coolant available is John Deere CG II. But not cheap. $25/gallon.

 

[901Memphis]

Three or more drain, fill, run repeat or more is suggested to get it down to pure water or close. I don't think two will do it.

 

[doitmyself]

If you compare Zerex conventional green to G05 at their website, you will see that they contain about the same amount of silicate (240ppm+/-). So to suggest that G05 is better than conventional regarding silicates makes no sense. All conventional green coolants are now low silicate. Zerex even suggest theirs is good for 100k or 5 years, indicating that it's not the same product of yesteryear.

This older 2004 article by Paul Weisler (coolant guru) suggests that conventional green should have better protective properties for old systems that might have brass/copper/SOLDER:

From page labeled "32" of magazine:
"Conventional American coolant should provide better protection against solder corrosion, which can result in radiator tube restrictions and leaks. But no coolant provides perfect protection."

http://www.gates.com/brochure.cfm?brochure=2822&location_id=2877

Do a bunch of drain and fills. Unless you have pristine tap water, do the last one or two with distilled water.

 

[901Memphis]

I always do three drain and fill with distilled even after I use a hose to clean the radiator and over flow tank if pressurized.

 

[Sayjac]

Originally Posted By: doitmyself
.... All conventional green coolants are now low silicate.....

Can you provide some citing for this? I know Zerex is, and have used low silicate Chevron conventional green, but both say "low silicate" on the jug, and Zerex has lots of info on the wesite.

But, when it comes to Peak Original Green or store brands like Auto Zone, I've seen nothing saying they are low silicate. Just me, but lacking that I'd stick with a conventional that clearly identifies a low silicate formula. Agree though that the low silicate conventional are much improved over the original green conventionals of the past.

I also do a distilled water flush series when changing out the coolant. But, this being an older vehicle with cast iron block, a flushing T could work just fine. Before aluminum blocks and heads specifically recommending distilled water I used a flushing T frequently. If your water is harder, you could use a flushing T and finish with a couple distilled d&f's. Used to use a T with some mild Prestone Super Flush, it's much faster an easier than the distilled flush series I now use.

 

[doitmyself]

No, I cannot provide any citing. My bad. It's just based on my personal observation. Besides Zerek and Peak, the only other conventional greens I have seen at farm stores like Tractor Supply all said low silicate.

ASTM 4985 is a low silicate standard for heavy duty diesel engine use (IF you add a SCA):

http://engineers.ihs.com/document/abstract/UXEPIBAAAAAAAAAA

To my knowledge (someone correct me) you cannot use high silicate coolants in diesel engines.

Every conventional green coolant I have seen over the past 10 years meets the ASTM 4985 standard, as does PEAK - click on the spec link here: http://www.peakauto.com/products/antifreeze-coolants/automotive/conventional-green/

Again, just my observations in the Lake States region. Maybe someone knows the maximum silicate level per ASTM 4985?

 

[Sayjac]

It's cool, not my intention to doubt you, just wondering if you were privy to some information that I could view. Makes sense that all green conventional now meet a low silicate standard, but sometimes trusting without verification doesn't prove out. All makes/models universal coolant being an extreme example.

Based on your ASTM4985 link the fact that Peak Original Green does meet that spec, would seem to indicate it is a low silicate formula. I'd now feel more confident about choosing Peak conventional. Price being the same or close, likely choose Zerex though. Next time I'm in AZ I'll take a closer look at their original green for specs it meets. Afaik doesn't say low silicate on jug. Thanks for the links.

 

[doitmyself]

You are correct to question internet information and I wish to retract my statements about all conventional green coolants!

What's bizarre is that I clicked on my PEAK link above just now and for fun I also checked the pre mixed Peak conventional green and it does NOT include the ASTM4985 standard. Instead, it DOES show a silicate level of 125ppm meeting spec. ASTM D-6130

They're both labeled "conventional green", yet PEAK is publishing different specs. for them.

Good grief.

 

[edge10]

I just received an email from Peak stating the their CG is low silicate, but they did not give the PPM of silicates. The recommend change interval is 2yr/24k miles compared to Zerex CG which is 5 yr/100K miles. Hard to believe there is that much of difference, but maybe the Zerex has much better corrosion inhibitors. Reserve alkinity is about the same, but Zerex spec sheet claims there are other CIs that are not part of the RA spec.