Thread: Red VS Green Coolant again!!!

Originally Posted by Hoges

FWIW The OAT coolant is especially effective in all-alloy engines. that's why it was developed. I personally wouldn't use it in engines with ally heads and iron blocks or engines with iron blocks and heads. Different chemistry re. galvanic action. For them I'd use the green ethylene glycol -based formulation.

Don't know much about CAT engines...are they iron or alloy?

For the past 10 years i've used the GMH OAT red stuff recommended for the LS1 engine in my V8 Commodore. 5yrs replacement 50/50 mix. Not a sceric of scale anywhere in 130,000km.

When I bought the P38 a few yrs ago I drained the coolant put in the GMH stuff as well...134,000km now and clean as a whistle. All done always with either distilled or demineralised water.

The Honda Jazz example earlier is getting to be par for the course... I'd expect a thermally stable OAT formulation to last 10 yrs in a properly serviced alloy engine...

CAT engines are all cast iron.
It's the way in which OAT does it's thing that's different to green.
Why you can't use OAT in a standard green glycol system is due to the different seal materials used in the system.
OAT in a non OAT system will eat out waterpump seals and some other rubber components.
Whether it's used in cast or ally really makes no difference, however as previously stated, it's purpose designed for ally radiator cores but is still equally as good on cast iron and far better than non OAT for protection and life.
The best result I have ever seen from a coolant was the Toyota coolant. 1975 Corolla with 300 odd thou on the clock. Showroom condition owned by an old guy at a workshop. Used it from day dot and still had the original thermostat housing and on it's second thermostat!! Opened up it looked like a brand new inside, not one hint of cavitation or corrosion in it.

Have contemplated using it in both my LR's but just can't get past putting a Toyota product in my Landies.......
It's kinda like ****ing in your own nest......

I have just finished doing an engine change on a 1996 Jeep Grand Cherokee Laredo (4 litre in line 6, pushrod, cast iron block and head). The engine had overheated and was then driven to destruction. The reason it had overheated was that the pressed steel impeller on the water pump had corrroded off the shaft ! There was very little water left in the block/radiator as the head and block were cracked big time. The alloy waterpump housing had serious pitting on the machined impeller face. The alloy thermosat housing was fine.
What I found most interesting was on flushing the radiator (copper/plastic tanks) prior to re-fitting was that the flush water came out dark blood red. Even after flushing for half an hour the water was still coming out a pink colour. Have never seen anything like it before. There was obviously a dark red residue of some kind in the radiator. Could this have been due to incorrect coolant ? Anyone seen this before ?
As far as the thrust of this thread goes it seems to me that Glycol based doesn't give problems but needs more frequent replacement than the OAT stuff which can give major problems and needs less frequent replacement. Think I'll stick with the Glycol based stuff.

Deano

Dean, use whatever type is spec'd from factory.
There is no upgrading from green to OAT, its one or the other.
Like any other coolant it needs changing. The fact that an engine fails and it has gobs of red stuff flowing out of the block while flushing is more than likely to do with a lack of maintenance than a bad product. Mixing different types of coolant will also result in a similar situation although IIRC, GM Dexcool based coolants were the OE fluid and Dexcool has a history of similar results. Google it.

There are differing OAT's around with different SCA's added, and different blends of green coolants. Nulon for example do a green coolant that is totally glycol free and works exceptionally well. Add to or alternatively use Water Wetter from Redline.

In the Disco I run Caterpillar ELC. Comes from the same pot as Genuine LR OAT but has additional SCA's for cavitation and electrolysis protection amongst other things.

Green glycol is OK but the added benefits of the OAT arent there.
I would however tread carefully around any Dexcool product (GM OAT) as it has had a reasonably bad reputation over the years with its dislike of mixing with oxygen causing it to coagulate and block everything. GM do say that this issue has been fixed.
From lots of years of experience, I also spruke Toyota coolant in place of green. Expensive, but well worth it.

Another option I am investigating is the Cummins PGXL. PGXL is a polypropylene glycol based coolant, newish and pretty much proprietary to Cummins, but has excelent reports so far.
As I have a minor affiliation with Cummins/Fleetguard, I are looking at the option of PGXL and its suitability for Mercedes Benz, Detroit and Cat applications. At present, I need to carry about 1000-1200L of each type to cover service refills for our Merc, Cat, Detroit and Cummins powered engines.
Mercedes Benz use Castrol NF but coolant changes are 4-5 times higher in time/mileage than Cat or Detroit engines.

But as said, go with the factory recomendation, and look for improved types within the spec.

Cheers

Andrew

In the 36 years since my Rover was built, the radiator has been replaced every 10 years or so (new core,..same end tanks)..so say every 100,000km. I used SQ36 (a corrosion inhibitor) until 2007 and now run Penrite AF/AB @ 33% in my 4.6. My radiator is brass as it always has been,..the end tanks are the originals form 1974.

The only areas of corrosion that I have noted is on the outside of the aluminium alloy water pump,..the fittings that accept the three hoses does illustrate pit corrosion where the rubber hoses cover the pipes. The original water pump lasted for 16 years and even then the degree of corrosion as mentioned was not beyond repair.

Inside the inlet manifold where the thermostat resides, there is also a small amount of corrosion occuring to the steel insert into which the thermostat sits.

So pretty good I would say for 36 years.

Ron.

Pulled this from a 2008 US Grassroots Motorsports Forum.

.........................................Dexcool ate gaskets on land Rovers when they switched...but they were Land Rovers so instead of leaking at the first service they leaked ON THE SHOWROOM FLOOR! I'm a 10 year LR tech and I saw it happen more than once. Rover changed the gasket coatings and they leak normally again If I weren't worried about the seals in my older stuff not liking it I'd switch to it. As discussed when it hits air it goops up, making leak diagnosis a snap. If it goops up IN your engine its because you have other problems-Dexcool is only the messenger......................

Wasn't one of GM'sgreatest products. Being the US, lots of litigation.

Reading online I reckon what happened to my ex-engine was it had a mixture of glycol and OAT coolant. On flushing the radiator it was like it was full of red dye. Not dirty brown rust colour or red as in Pilbara soil but red as in Dexron ATF. Amazing. As I said after half an hour of flushing still running pink.

Deano

Originally Posted by Fluids

No Robbo ... just boring old tap water. Our water here seems to be pretty good ... so far. It's pretty close to pH neutral last time I checked it (years ago).

I think frequent changes go along way to preventing issues.

Kev..

Mate i worked with water, and i have never seen tap water PH neutral. but having said that you don’t want tap water PH neutral, if it was it would drop all the minerals out of solution and block up all the water mains etc etc.

The only solution is to have water with no minerals in solution at all, and then you can drop the PH to neutral. tap water is usually about Ph 7.2-7.4 and up to 2000 ppm in solution ( sea water is about 24 000 ppm)

Here is another thing, adding CO2 to water to manage the Ph will also push the alkalinity up over time which will have the effect of pushing up alkali and that’s not a good thing.

Not all OAT's are red, not all reds are OAT's. Some reds are neither.

I'm using, since fitting a new 4.6, so there's no mixture a red OAT plus redline water wetter. There's no sign (yet) of sludging, residueor any particulates.

Have to agree with the comments on the Toyota coolant, on the 7M (and iron/ally engines of the same era) use anything else and the heads will rot out.

Just bringing and old thread back to life. I just had the heads re-conditioned, with porting and new cam, followers and timing gear. British Offroad used green coolant. They said they dont like red - too corrosive to hoses and everything else. Having said that my water pump only just failed at 200,000 - had the vehicle since new.

So i looks like now I will keep green coolant. They know their stuff.

Cheers