I have been good about using Mercedes brand coolant for the om603.

The only other consideration was Getex G5 or something like that, when I was last looking.

But it's been a few years, and I see this on the market, an aftermarket (Canadian Tire selling "OEM Premium") brand that is advertising car-specific applications.

This is what they have to say:

Designed for use in specific vehicle-makes
Recommended for BMW, Jaguar, Mercedes-Benz, Mini, Smart and Volvo vehicles
Low silicate OAT formulation
Nitrite, amine and phosphate free
Recommended change interval: Up to 250,000 km or 5 years service protection
50/50 pre-mixed, ready-to-use coolant
May also be used in gasoline or diesel engines




They also have this diesel specific kind but does not list any brands of engines:

Low silicate, phosphate and amine free
Performance rated at 6 years or 960,000 km
For use in light- and heavy-duty diesel applications where an extended service interval is required
For all on-road trucks, marine and industrial stationary and mobile farm equipment
Meets performance specifications of ASTM D-3306, D6210, JIS K-2234 and TMC RP 329


What's the current thinking on coolant religion?

Any opinions on whether either of these are OK for my om603?

And what is "low silicate OAT" anyway? I guess I'll google that.

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Cheers!
Scott McPhee

1987 300D

I would be looking for the phrase "meets MB 325.0". That ensures you are giving the engine what it needs.

Zerex G05 can be found online and on sale at most of the big name auto parts stores.
The genuine MB part number is BQ 1 03 0002.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Here is the Zerex G-05 Spec sheet:
http://content.valvoline.com/pdf/zerex_g05.pdf

None of the specifications match the Zerex-G-05; however, that does not necessarily mean it is unsuitable for an 87 300D.

I would wait for more knowledgeable feedback.

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Nosce Te Ipsum "Know thyself"

A 617 would probably tolerate just about anything, but in an engine with aluminum head, to go with all the aluminum bits in the cooling system, I wouldn't deviate from MBZ approvals.

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1995 E300 Diesel
~300k

Zerex, yes, thanks, that's the name.

Zerex PDF is right up front and "proud"? to says this, "Zerex G 05 is a nitrite containing coolant designed to protect diesel engine cylinder liners from cavitation"

Whereas the aftermarket brand claiming Mercedes and diesel compatibility, description I posted says this: Nitrite, amine and phosphate free

So that's an imbalance right there.

And the aftermarket brand claiming just diesel specific compatibility, does not say nitrite free. Soo... of the two that one is sounding maybe more applicable. I just wish I knew if any of these specs "ASTM D-3306, D6210, JIS K-2234 and TMC RP 329" came close to the MB 325.0 as you have pointed out (thank you!).

__________________
Cheers!
Scott McPhee

1987 300D

Pretty sure you need nitrites for a diesel engine to prevent cavitation damage.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

A very accurate point indeed. The 617 is entirely built with copper, cast iron and some rubber/plastic in regards to cooling components.

__________________
Nosce Te Ipsum "Know thyself"

om603... aluminum head

less tolerant

I know when I was shopping around to acquire more 87 300D as a runner or for engine parts, I'd do a quick coolant inspection. If I saw GREEN liquid in there, ask the previous owner 'what kind of coolant you using'... and got a shrug or a 'Prestone'... I'd walk away from the deal

__________________
Cheers!
Scott McPhee

1987 300D

zerex G05 is probably your safest bet, or if you want to go all the way to the top then buy a gallon of final charge truck coolant, It will be fill for life in your case.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

What is / where do I get "final charge truck coolant" ?

__________________
Cheers!
Scott McPhee

1987 300D

The Mercedes coolant is not OAT, but HOAT (Hybrid Organic ...). Not the same.

As far as nitrites (SCAs) to prevent cavitation damage, this is true for all engines, Mercedes makes a point of it in their literature showing the damage to a water pump impeller from cavitation. In the block however, this is more of a concern with wet-sleeve diesel engines where cavitation pitting will create holes through to the combustion chamber, in these Mercedes dry-sleeve engines it is not a risk to the block and sleeves.

So, ... I prefer Mercedes coolant or ZEREX G-05, in all of my Mercedes cars, replace regularly unless you have purchased a newer coolant tank with the SCA block in the bottom (or test your coolant annually as I do and top-up your SCAs as needed).

I would not run away from a green-coolant Mercedes, it is a small oversight if a car is otherwise well maintained IMO.

__________________

Gone to the dark side

- Jeff

In my parts its sold at Walmart and NAPA. slightly pricey than regular stuff though. Its made by Old World Industries and its brand is "PEAK"

usual GM diesel truck buyers (lots upon lots of them in Texas), the first thing they do after taking delivery from the dealer is to flush the transmission of Dex VI and fill with Transynd ATF and then flush the cooling system of dexcool and fill with Final charge.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

I use Evans Waterless Coolant in both my 300D's, just because I abhor corrosion. But, recently removed it in my 1985 while chasing a strange apparent overheating issue all last winter. Usually ran ~100C, creeping up at long red lights, and IR gun confirmed. Unlikely it is due to Evans since I ran at least one summer with it. Changing water pump, T-stat (again), etc. Hope not a crack in the head, and if it is unlikely would be due to Evans. My 1984 runs a stable 82 C even on the hottest days and use Evans in my 2002 T&C minivan.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I buy truck coolant (different than Mercedes) at my CAT dealer for my CAT engine, have used Detroit Diesel for my DD engines, put the pre-charged stuff from Tractor Supply in my loader, each has its specific needs. For older stuff the Penray SCA from my local fleet supply has worked well to top up SCAs annually as indicated by the test-strips.

I would not consider any truck coolant (PEAK or otherwise) to be "fill for life", especially if it does not have Mercedes' approval.

__________________

Gone to the dark side

- Jeff

MB 325.0 - Anticorrosion/antifreeze agents (Specification 325.0) - Mercedes-Benz Specifications for Operating Fluids

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Marshall Welch
Seattle, WA
1982 300D-T