SRT-10 Coolant - What Do I Use?

ejholt

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I need to change the coolant in my truck. I noticed the coolant cap said it takes special coolant. Does anyone know what is the best coolant for the trucks? Thanks!
 
Factory fill is Dexcool. Its one of several extended life coolants on the market. Lots of very bad history with Dexcool particularly with GM products from back when they began using it as factory fill back in 1996. Originally it was developed and first used in Sweden due to environmental concerns of regular green coolant. Seems there is a chemical reaction when exposed to oxygen resulting in "sludge" build up to the point of reduced flow (clogged radiator and worse case engine block) and eventual overheating problems.

I personally don't have an issue with Dexcool after a bit of research on this subject. I my opinion its fine however don't let it go the 5yr/100K life the manufacture states. If you do switch to regular type coolant (green) be sure and do a thorough flush. I'm about due for my second flush. I will continue with factory fill Dexcool type coolant.

Other info if you are interested:

How to test coolant? Sure everyone knows how to test to see if your coolant still offers freeze protection but remember when you have dissimilar metals in an acidic liquid you have a chemical reaction. Guess what? If the coolant is acidic you now have a battery! Coolant is normally around 7.5 ph which is not acidic but overtime it becomes acidic and thats when the chemical reaction begins.

Electrolysis is a process of chemical changes in the cooling system that allows electrical current to pass through the engine coolant. This is from dissimilar metals in contact with the coolant (much like a battery) and/or electrical current is passed through, because the engine serves as a pathway to ground between the battery negative cable and the negative terminals of various electrical components. Dirty or loose ground connections can increase voltage flow through the cooling system. Remember, electricity takes the path of least resistance and your coolant can become an the "alternative" ground for your trucks electrical system.

Your coolant has additives to protect your engine. Overtime these additives are removed/lost due to exposure, heat and electrolysis. Maintaining good coolant with the proper amount of corrosion inhibitors to protect against rust, oxidation and electrolysis is critical to long life of your pride and joy.

So how do you know the condition of your coolant if electrolysis is occurring? My personal opinion is if your coolant is two years old its PAST time to flush and replace. Particularly when the vehicle contains high amounts of aluminum and other dissimilar metals your coolant has rapidly deteriorated by year two.

To check for electrolysis is quite simple. First step is to bring the engine up to normal operating temps. Next, using a digital voltmeter place the negative lead to the battery negative post and the positive lead into the coolant. A voltage reading above .300 V can cause severe corrosion and damage to metal surfaces.
 
Damn...good info. I was unsure what to use either so i called the dealer and was told not to use Drexcool. WTF?:confused: So i uset the yellow stuff from prestone. It was not a total flush, just a top off.

So is it safe to use Drexcool?
 
includemeout said:

One thing that my local trusted mechanic noted about Dex-cool and issues was the common use of Brass within the system. Generally found with the added option of heated engine block. Brass and Dexcool apparently does not do well together. As your article stated my research also found no real problem with Dexcool itself. Most all were related to outside conditions/issues. Interesting that they stated no issues going from Dexcool to regular though problems going the other way. My research showed this was apotential issue going either to or from Dexcool.

Regular maintenance goes a long ways....:rock:

As for which water to use I found quite a few interesting articles that stated that distilled water was NOT ideal. I grew up that distilled water was the way to go. Two types of water that worked well in all types of coolant....Reverse Osmosis or softened water. Soft water being the number one choice.
 
Last edited:
I pulled this from the service manual...

The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection. Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769), or the equivalent ethylene-glycol base coolant with organic corrosion inhibitors (called HOAT, for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without corrosion when mixed with 50% ethylene-glycol and 50% distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.

CAUTION: Mopar® Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any other type of antifreeze. Mixing of coolants other than specified (non-HOAT or other HOAT) may result in engine damage that may not be covered under the new vehicle warranty, and decreased corrosion protection.
 
Chuck B said:
One thing that my local trusted mechanic noted about Dex-cool and issues was the common use of Brass within the system. Generally found with the added option of heated engine block. Brass and Dexcool apparently does not do well together. As your article stated my research also found no real problem with Dexcool itself. Most all were related to outside conditions/issues. Interesting that they stated no issues going from Dexcool to regular though problems going the other way. My research showed this was apotential issue going either to or from Dexcool.

Regular maintenance goes a long ways....:rock:

As for which water to use I found quite a few interesting articles that stated that distilled water was NOT ideal. I grew up that distilled water was the way to go. Two types of water that worked well in all types of coolant....Reverse Osmosis or softened water. Soft water being the number one choice.
This applies to most any engine, that is why I use these in my engines:D
http://www.westmarine.com/webapp/wc...=true&storeNum=5000&subdeptNum=4&classNum=317


Sacrificial Zincs
by Don Casey
Any time you have two different metals that are physically or electrically connected and immersed in seawater, they become a battery. Some amount of current flows between the two metals. The electrons that make up that current are supplied by one of the metals giving up bits of itself-in the form of metal ions-to the seawater. This is called galvanic corrosion and, left unchecked, it quickly destroys underwater metals.

The most common casualty of galvanic corrosion is a bronze or aluminum propeller on a stainless steel shaft, but metal struts, rudders, rudder fittings, outboards, and stern drives are also at risk. The way we counteract galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. This piece of metal is called a sacrificial anode, and most often it is zinc. In fact, most boaters refer to sacrificial anodes simply as zincs.

It would be hard to overstate the importance of maintaining the zinc anodes on your boat. When a zinc is gone, the metal component it was installed to protect begins to dissolve-guaranteed.

How much zinc
The amount of protection a zinc anode provides depends on its surface area. The zinc surface area needed varies with the kind of metal being protected and with the chemical make-up of the water, but you can use 1% of the surface area of the protected metal as a starting point. Check the protected metal frequently. If it shows signs of corrosion despite the zinc, you need more surface area.

Zincs should be replaced when about half of the anode has been lost to corrosion. Ideally we want that to occur not more frequently than annually. The longevity of a sacrificial zinc anode is a function of its weight. When a zinc lasts less than a year, you need one with more weight.

Normally, however, you are not faced with determining the appropriate anode size (other than diameter for a zinc shaft collar). Rather, you are simply replacing depleted zincs with new ones of the same size. Check all zincs at least annually and replace all that are half depleted. Here are some replacement guidelines.

Electrical contact is essential
There is an unfortunate misconception that a sacrificial anode can be mounted anywhere, even hung over the side on a string, and it will still perform its appointed duty. That is dead wrong!

For a zinc anode to provide any protection, it must be in electrical contact with the metal being protected. The conductivity of the water is not adequate. We need low-resistance, metal-to-metal contact-either by mounting the zinc directly to the metal being protected or by con- necting the two with a wire. A hanging anode can provide protection if it is connected by a wire to the metal being protected.

Where the zinc is mounted directly to the protected metal-bolted to the side of a metal rudder, for example-it is essential to make sure the surface under the zinc is bare and bright before the anode is installed. This is to ensure good electrical contact.

No paint
Zinc anodes cannot perform their function unless they are exposed. Putting paint on a zinc smothers it, rendering it useless. Never coat zinc anodes with bottom paint, or anything else.

Props and rudders
Propellers are normally protected by a zinc collar fashioned in two pieces and bolted together around the shaft forward of the propeller. It is essential to make sure the shaft is clean and bright before clamping the collar to it. Corrosion protection for outboard and outdrive propellers is typically provided by a bolt-in-place zinc ring or a zinc prop nut.

Metal rudders and struts are most easily protected with zinc disks bolted directly to the metal. Rudder zincs have a shallow dome shape to streamline them and minimize their drag and turbulence.

Hull plates
Bonding is a different subject altogether, but boats with all underwater fittings bonded together electrically are typically fitted with one or more zinc plates bolted to the hull. The mounting bolts for these anodes are connected by heavy-gauge electrical cable to the bonding circuit. If these anodes are allowed to deplete or if the electrical connection deteriorates, other underwater metal, such as bronze through-hull fittings, will begin to corrode.

Zinc hull plates are also fitted to metal boats to protect the hull. Needless to say, such anodes must be carefully monitored.

Outdrives
The mix of immersed metals makes stern drives and outboards particularly prone to galvanic corrosion. Many are fitted with multiple anodes. Typically, these include at a minimum a sacrificial trim tab (intended to warn you of depletion by a change in steering), a zinc plate or two attached to the gear case or the anti-ventilation plate, and perhaps anodes in the exhaust cavity and in the cooling-water jacket. It is a good idea to consult your engine manual to be sure you know where every anode is located. Then check all of them and renew any that are more than half depleted.

Zinc pencils
Heat exchangers, because they are typically a copper alloy, are at risk of galvanic corrosion. To combat this, most heat exchangers are fitted with a zinc "pencil" anode. You will find it (or not) under a brass plug in the exchanger. The pencil is unscrewed from the plug for replacement. Some engines have a similar zinc pencil inside the cooling-water jacket to protect dissimilar metals in the engine. Determine if your engine and heat exchanger are fitted with internal anodes, and if so, check them at least annually. If they are half depleted. . .well, you know.
 
Please do NOT remove the radiator cap when the vehicle has reached operating temperature!!!! You will be burned!!
 
Hucksrt10 said:
Please do NOT remove the radiator cap when the vehicle has reached operating temperature!!!! You will be burned!!
Got that right.:rock: :rock: :rock: :rock: :rock:
 
Looking to flush coolant and refill since I don't know when the last time this was done. Talking with a buddy here at work he suggested draining the coolant filling with distilled water and running the motor a little to flush the system then fill back with coolant. Any suggestions? And im thinking about going to dealer and getting the recommended Mopar coolant or should I try something else? Thanks for any help
 
Looking to flush coolant and refill since I don't know when the last time this was done. Talking with a buddy here at work he suggested draining the coolant filling with distilled water and running the motor a little to flush the system then fill back with coolant. Any suggestions? And im thinking about going to dealer and getting the recommended Mopar coolant or should I try something else? Thanks for any help

That is exactly what i did a month or so ago to mine. Bought 2 gallons of the premixed mopar fluid and 4 gallons of distilled water.
 

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