Dexcool vs. other coolants

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There is nothing wrong with Dexcool coolant,the issue first arose with head gasket leaks,the molecules are smaller and will leak whereas the traditional green coolant will not.
Manufactures had to redesign head gaskets and head/engine block finishes to prevent leakage.
They have finally corrected it for the most part.
CC

The traditional green dyed coolant and the newer Dex-Cool are both formulated using an ethylene glycol base. Aside from the dye color, the difference is really more about the corrosion inhibitors. Dex-Cool uses carboxylate corrosion inhibitors and green dyed coolant uses silicate corrosion inhibitors. I don't know about molecule size for the corrosion inhibitors, but ethylene glycol is ethylene glycol and water is water (in these 50/50 mix ratios).

Aside from metal(s) deterioration related to coolant, gasket deterioration is also something to consider. I saw a lot of it in the late 1980s through the 1990s with the 6.2/6.5 diesels that were equipped with the green coolant. Head gaskets for the 6.2/6.5 have definitely improved through the years and for a variety of reasons, but it's the water pump gaskets and other wet gaskets that I saw deteriorate (that had the green coolant) back in the day. I just don't see it with Dex-Cool.
Jim

[sopicki]

I'm very happy to have found this forum. Perhaps I can finally get some answers or at least advice.

I have a vintage 1972 Newell motorhome which was repowered in 1981 with a Detroit 8.2L Fuel Pincher turbo diesel. This is my first diesel engine. As of today this 33 year old engine has about 60,000 miles on it. I've done some research on this engine and it is known for blowing head gaskets. This would be really unfortunate since in the last year I haven't been able to find anyone with the tools to set the mechanical injector heights should we have to pull a head. Many other forums get nasty to people who have questions about this engine so I politely ask that I not be told to dump this engine in a lake....it runs great, has low mileage and with proper care I expect it to continue running for my lifetime since I can't see putting another 50k on a motorhome.

When I purchased it last year it had some very old coolant in it. Everything was rusty so we flushed it and put in some of the pink Diesel coolant we got from Advance Auto Parts. Shortly thereafter the radiator sprung a leak so I had it re-cored, changed all the hoses, new thermostats, flushed and refilled the cooling system with new coolant (again the pink stuff).

I have years of experience using DexCool in my vintage gasoline engines and LOVE it. I change it every 4 years and my cooling systems look like new. I've never discovered any corrosion issues when using DexCool. I'd like to use it in my Detroit, but any Diesel mechanic I talk to (besides telling me to change engines) says to use the pink stuff. I'm not convinced that this coolant is anything but expensive window cleaning solution and I'm worried that additional corrosion will compromise the head gaskets in my engine.

I've contacted Detroit and they sent me to Diamler who in turn sent me to MTU who in turn sent me back to Diamler who said they don't have any engineers left familiar with the 8.2.

Does anyone know if I can I use DexCool as a coolant in my Detroit? What are the risks?

Thank you very much!

Bob Kopicki
1972 Newell Motorhome with 1981 Detroit 8.2L Turbo
1976 GMC C1500
1967 Triumph TR-4a

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I'm very happy to have found this forum. Perhaps I can finally get some answers or at least advice.

...clip....

Does anyone know if I can I use DexCool as a coolant in my Detroit? What are the risks?

Thank you very much!

Bob Kopicki
1972 Newell Motorhome with 1981 Detroit 8.2L Turbo
1976 GMC C1500
1967 Triumph TR-4a

Welcome to The Diesel Page.

Owners of older engines, any engines, can expect to replace some or most of the gaskets due to age and the interaction between the coolants available decades ago and the gasket materials in use during that time.

One of the more notable advancements in engine technology over time is the quality of materials and design of gaskets - both cooling system gaskets and especially head gaskets. We saw this in the 6.2L/6.5L GM diesel engines. Head gasket failures were common during the first 10 years of production - failures in preventing both coolant and compression/combustion leaks (head gaskets). The situation is far-far better now.

I've successfully used Dex-Cool in engines that were originally supplied with the green coolant. Our 6.5L diesel project truck experienced no cooling system problems in more than 250,000 miles - without a routine cooling system flush or any other cooling system service. The water pump seals in this engine never leaked, and lasted beyond the 250K. We sold the truck, and eventually lost contact with its service history.

The key to this success was likely due to the fact that a new copper/brass radiator was installed, and the engine was rebuilt using all current tech gaskets. The original heater core was flushed and all new hoses and clamps were added during the final assembly. Then, a 50/50 mix of Dex-Cool and distilled water was added. So, Dex should work for you.

Unrelated to coolant, the Detroit 8.2L is said to employ just 4 head bolts per cylinder, where most current diesels have 5-6. The high compression and combustion pressures inherent in a diesel engine put more stress on head gaskets than do gas engines. Four bolts per cylinder can be marginal in containing these pressures. Depending on fueling, a turbocharger can add even more stress. Current head gaskets should improve durability, and new head bolts and/or head studs should be installed whenever the head(s) come off. I'd not reuse the old bolts/studs.

Jim

[sopicki]

Jim,

I realize I'm probably in the wrong topic for this thread, but I found it using a search for DexCool and diesel engines.

Thank you for your reply. I've been debating making a routine out of re-torqueing the head bolts to make sure the proper pressure is applied to the head and sealing gaskets. I've run this by a few diesel mechanics and they emphatically say NO - DONT DO IT! If it ain't broke don't fix it, but I worry about the bolts stretching.....and it does have a turbo.

The problem I face right now is if a head gasket does let loose I don't have the injector height tool used to set the injectors. I've searched the internet and old diesel shops but can't locate one. Once a head gasket is replaced the injectors need to be re-set and that can't be done without the height setting tool.

I've not been able to get anything back from Detroit, but I'm still working on finding an engineer who worked on the design and support for this engine.

Thanks again,

[More Power]

Jim,

I realize I'm probably in the wrong topic for this thread, but I found it using a search for DexCool and diesel engines.

Thank you for your reply. I've been debating making a routine out of re-torqueing the head bolts to make sure the proper pressure is applied to the head and sealing gaskets. I've run this by a few diesel mechanics and they emphatically say NO - DONT DO IT! If it ain't broke don't fix it, but I worry about the bolts stretching.....and it does have a turbo.

The problem I face right now is if a head gasket does let loose I don't have the injector height tool used to set the injectors. I've searched the internet and old diesel shops but can't locate one. Once a head gasket is replaced the injectors need to be re-set and that can't be done without the height setting tool.

I've not been able to get anything back from Detroit, but I'm still working on finding an engineer who worked on the design and support for this engine.

Thanks again,

Retorquing head bolts/studs used to be a thing a couple or three decades ago, but the GM 6.2L/6.5L and Duramax engines were (since the early 1990s) factory equipped with TTY (Torque-to-Yield) head bolts, which were designed to maintain a somewhat elastic stretch during the final torque-angle turn during installation. This elastic pre-load can better compensate for thermal expansion and head gasket compression, which allow TTY bolts to provide for a long lasting clamping load over time - most auto engine manufacturers use TTY head bolts. In reality, only the "power players" - those who modify their engines to produce far more than stock power need to consider swapping to head studs. It's my opinion that the unmodified Duramax, with its aluminum heads, are better served with TTY head bolts than with studs.

More discussion concerning the question of whether TTY factory head bolts or head studs are better can be found here.