Proper coolant (or newer types that protect iron blocks)???

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keehn
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Proper coolant (or newer types that protect iron blocks)???

Post by keehn » Mon Dec 23, 2019 5:30 pm

Hello everyone!

Because our cars use cast iron blocks, I'm curious what types of coolant everyone runs, and if anyone has issues with their coolant.

I have an RV that uses a 5.9l Cummins cast iron block, and Cummins recommends the following coolant:

https://www.cumminsfiltration.com/organicacidtechnology

Obviously, organic acid technology (OAT) is newer than E12 production, but is a chemistry specifically formulated for cast iron diesel blocks. I'm seriously considering using this in lieu of the BMW coolant for my rebuild.

What say you all?

Mike

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Lock
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Re: Proper coolant (or newer types that protect iron blocks)???

Post by Lock » Tue Dec 24, 2019 2:19 am

I'm not too fussy with brands but I change my fluids fairly regularly. I use Prestone concentrate and mix in distilled water after hosing out the block and radiator. If you haven't done it, definitely remove the drain hole underneath the exhaust manifold because that will fill with sludge.
Anyway I change the coolant out once a year or so and the insides are always coated and clean, and it stays cool even on very hot days. Besides, my current engine has some minor internal damage and is going to be replaced eventually, so I'm not being fastidious.
I was going to add Redline water wetter if needed, but my car never overheats so haven't.
Was also considering ordering some of this because it sounds fairly good: http://www.norosion.com
1979 528i 5-speed conversion G260/6, Motronic 1.3 179
1980 Honda CX-500

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Robert Bondi
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Re: Proper coolant (or newer types that protect iron blocks)???

Post by Robert Bondi » Tue Dec 24, 2019 1:54 pm

I've been running the Prestone long-life orange formula since around 1999. It's also an OAT or HOAT forumulation.
I've been very happy with it and basically run it in all my vehicles. Engine was rebuilt in that span too and everything looked
pretty good on the inside. Since it's free of silicates, you don't get all the crusty white deposit material either. I think the Prestone long-life is also especially nice on aluminum surfaces - rather than the white crusty deposits, the aluminum facing the coolant ends up looking smooth and dark grey and free of any noticeable scale.
Robert
77 530i
77 Euro 528

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keehn
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Re: Proper coolant (or newer types that protect iron blocks)???

Post by keehn » Fri Dec 27, 2019 5:21 pm

Robert, Lock,

Thank you both for your suggestions. It seems that Prestone is a strong contender.

Mike

waltb
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Re: Proper coolant (or newer types that protect iron blocks)???

Post by waltb » Sun Dec 29, 2019 3:16 pm

I would very highly recommend G05 HOAT coolant. It protects iron but more important protects copper and solder. Some of the new OAT coolants like Dexcool and all the other similar OAT coolants protect iron and aluminum great but can be hard on copper and solder. Our E12s have copper and soldered radiators and heater cores (unless you switched to aluminum parts). I believe the blue BMW/Volvo G48 is also perfectly fine but contains some 2EHA which I try to avoid in my old cars. Not sure how the new Prestone with Corguard (OAT + phospates) will work in an old system. The old fashion green IAT coolant would also work fine in our cars.

You should jump over to Bob is the oil guy and search the coolant forum for coolants with compatibility to solder and copper. I have been using G05 or G48 in all my old BMWs for years.

Walt B.
'80 528i
'82 320i
'95 318ti

cory58
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Re: Proper coolant (or newer types that protect iron blocks)???

Post by cory58 » Tue Dec 31, 2019 12:32 pm

waltb wrote:
Sun Dec 29, 2019 3:16 pm
I believe the blue BMW/Volvo G48 is also perfectly fine but contains some 2EHA which I try to avoid in my old cars.
waltb - I use BMW OE coolant in my E12. What is 2EHA and why avoid it in older cars?

Thanks, Cory
1977 530i
1988 320i Touring (euro)
1992 325i Cabrio
2015 328i (wife's car)
2001 325i (R.I.P., still missed)

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