This is a pretty beat up topic but I have a somewhat unique situation. I have a 1984 corvette with an LS1 in it... The BeCool radiator I have has only had the green stuff in it as well as the heating system. The LS1 has only had Dex in it.... what should I use to cool this thing? Dex or green? Help! lol

The heater is not hooked up for now and will not be for a little while so I can flush it or something. My cooling system is not a "closed" system like pretty much all vehicles that use Dex coolant (I have a removable rad. cap). Any thoughts for what I should do? Thanks

Scott

 

You can flush the green stuff out of the rest of the cooling system and then put in the Dexcool. It has different properties than the green stuff and is what needs to be used on the LS series engines. Don't know what you mean about a closed system. All C5s have removable caps on their cooling systems as well. It just isn't located on the radiator its located on the coolant reservoir just like the old C3s.
Bill

 

Dex in the '01...
Green stuff in the '88

 

By "closed" system I mean that there isn't really a way to introduce air into the cooling system like in the traditional radiator with a removable cap... Seems like i recall Dexcool being more reactive to "air" and that was why cooling systems using Dex are filled strictly from an inline fill point or fill tank.

How can I ensure that I have flushed my radiator and heater core etc. good enough? Is there something other than water I should run through them?

 

According to a radiator repair expert I had occasion to deal with, unless the rest of the system is uo to Dex-cool standards, don't use it. It will eat up and destroy anything not designed to be compatible with Dex-cool. I tried it in my street rod and it ruined my radiator. Had to flush everything extremely well and replace with conventional coolant.

 

If your car vents to a tank that has a open to air vent, dex cool will not work....

so , what I have always understood is that the c5 and like cars have a expansion tank, but it is not vented....dex cool works....

on older cars and most street rods, the expansion tank vents to atmospere,,,,so it intruduced o2 and will corrode and gel..

I amy be wrong....i sure know the two get along like KKK and aunt jemima

I like dex cool, but keep it clean and fresh every three years...especially if you have a leak do it sooner.

 

Sorry, can't agree with this statement. There are many papers on this subject written by experts in the field. I converted all of my older "green stuff" cars to Dexcool several years ago, no problems at all, absolutely none. Per the Texaco chemist who was on the development team for Dexcool, 10% green to Dexcool ratio will even work. The biggest problem is when the cooling system is low, and this was shown during a study done three or four years ago. Some of the low coolant issues were the result of the type of radiator cap that was being used. It needs to be a closed system with the proper radiator cap. There was also a training video put together by GM on Dexcool that was released due to bad information, it was available for free at one time.

 

My 99 Regal was factory filled with Dexcool and has a vented expansion tank.

 

On my old 1998 Tahoe, I had the dreaded intake leak supposedly caused by dex cool (as did numerous others). From what I have been told, dex cool is incompatible (corrosive) with the gaskets used on Gen I style intakes, and the LS cooling systems eliminated this problem.

 

I ran Dexcool in my 92 Grand Caravan from the first coolant change at three years old. I sold it about two years ago but it's still running at 210K, with no issues. I did a flush/fill every three years. I never had any leaks and it's still running the original water pump.
In my experience there are no issues as long as the system is properly maintained.

 

1991 Chevy sportside 350SS over 200,000 miles
2002 Gmc Seirra 65,000 miles
2000 Corvette 58,000 miles
2005 Maxima (wife's) 25,000 miles

all have dex cool in it and if they didn't have it before I flushed and cleaned the system and replaced it with the dexcool. Largest change was noticed with the 1991 truck... it dropped 15 degrees in temp!

I have also changed to the dexcool in my parents 2 vehicles also 1995GMC sierra and 2004 chevy SUV...can't remember name of it... but they have done well on the ornage stuff too...

 

I use Prestone 5 year orange stuff, Dex-Cool, in all my vehicles.

 

I heard that dexcool isnt as good for your car. I think it makes your water pump rust and go out quicker.

 

Here are the results of a study that all good service techs should know about. This information has been around for at least 5 years. Funny how some people never get the word and keep repeating myths.

MACS 2001: GM and Texaco “Bare All” about DEX-COOL®
As in the past, the MACS 2001 Convention and Trade Show in Orlando provided some very interesting and helpful air conditioning information. However, the sleeper presentation at this show was not about refrigerant, but—of all things—engine coolant! (Sleeper does not refer to making you sleepy; it was anything but boring.)

Marketing departments of major consumer goods manufacturers are known for their attempt to conceal even a shred of negative publicity about their products. You can’t blame them; you do the same in your business. That’s why it was refreshing to witness a candid GM/Texaco presentation about DEX-COOL coolant and its related field service problems. I give the big guys credit for even bringing up the subject because, well, let’s face it, there are not a lot of kind words being spoken about this coolant at automotive service shops today. (Especially at radiator shops.)

Left: 14-Minute GM Training Video is now available to help technicians service known cooling system contamination problems in specific GM vehicles.

GM’s Jay Dankovich and Equilon Enterprises’ (Texaco) Stede Granger directed a 2-year study of thousands of DEX-COOL cooled vehicles. Armed with the results, they really didn’t have anything bad to say about the coolant. In fact, they strongly defended the product’s reputation. What they revealed to the audience is that specific models of GM vehicles have specific cooling system contamination problems. And essentially, that DEX-COOL is not the culprit!
Their presentation started with a 14-minute video that is now being circulated to technicians at GM dealers nationwide. In the video, GM’s trainers succinctly described the problems that have been found and the corresponding corrective actions to be taken by technicians.

Suggestion. This video is a “must see” for all technicians considering themselves antifreeze/coolant experts. Without this information, your cooling system service knowledge of late model GM vehicles is severely limited. Seriously!
Fortunately, you can buy the video for only $10 (plus S&H). Call MSX International of Auburn Hills, Michigan at 800-393-4831. Ask for the DEX-COOL Video: “Understanding Radiator Cap and Cooling System Contamination.” Part number: RADCAPK. Immediately following this article is a report on this training video by John Brunner, recently retired GM field service representative.

What was said at the presentation? Besides the video, Jay and Stede included their personal observations about the study. At the end, they fielded several questions from the audience. Here’s a recap of their entire presentation.

Keep the cooling system filled. In fact, fill the reservoir bottle to “Hot” level when the system is cold. Problems arise when a system’s coolant level is not maintained. (Fleet vehicles receiving regular maintenance, and with reservoirs kept slightly above normal, do not show signs of contamination. This even applies to the specific “problem” vehicles.)

The coolant problems found in this survey were caused by system contamination, and not due to the breakdown of DEX-COOL.

Check and keep the pressure cap clean and functioning. A contaminated and/or malfunctioning cap causes low coolant levels, which in turn causes overheating and a greater loss of coolant: the notorious vicious cycle. No matter what the vehicle, if the cooling system acts suspiciously, test the pressure cap.

On the ST vehicle models mentioned in the GM DEX-COOL video, you “must” replace all suspect radiator caps, especially those with a Drop-Center design, with a Stant Model 10230 or 11230 (Spring-Center type). (Just do it.)
Make sure that the coolant is at a 50-50 mix. Often, the flush water was not being removed from the engine block. Consequently, when a 50-50 mix is added to the system the resultant mixture could approach 30-70. Like any fluid that has been diluted beyond its recommended levels, the lowered level of inhibitors will not be able to protect the coolant system effectively. Low levels of inhibitors can cause pitting on aluminum surfaces and general corrosion of cooling system metals.

Left: Drop-center, “vented” radiator pressure cap. GM found this cap to be less helpful than a Spring-center cap in controlling the formation of contaminants in the cooling system. If contamination forms, the debris fouls the valve and restricts its ability to seal. In turn, the coolant boils at a lower temperature. Coolant loss is accelerated and so is the accumulation of contaminants.

Left: Spring-center, sealed radiator pressure cap. This is the preferred cap for GM applications that are more prone to accumulating cooling system contaminants.

A safe method of achieving a true 50-50 mix is to first determine the actual capacity of the system (use the owner’s manual). Then add 50% of “that” amount of undiluted DEX-COOL (or any coolant), and top it off with water.

Mixing a “green” coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine. In order to change back to DEX-COOL however, the cooling system must first be thoroughly drained and flushed.
Bacteria cannot live in a hot, Ethylene Glycol environment and is therefore not a threat to DEX-COOL.

While there have been intake gasket failures on CK Series, V8 powered vehicles for various reasons, DEX-COOL has never been found as a cause.

Use a refractometer to check the condition of DEX-COOL. Its inhibitor package is strong enough that if the batch still provides proper freeze protection, it is probably still providing proper corrosion protection as well.
DEX-COOL can handle the minerals in hard water better than silicated conventional chemistry coolants. Drinkable water is suitable for top off.

In ST Blazer applications where the radiator cap is mounted at an angle to the ground, the vehicle is more susceptible to radiator cap contamination and its related problems. The Stant 10230 is a wise choice for these vehicles.

Bill

 

Here is the GM bulletin about Dex-Cool. If you read it you will notice that it specifically says Only virgin DEX-COOL® approved coolants are to be used in vehicles built with DEX-COOL®. DEX-COOL® compatible coolants are not to be used in vehicles built with DEX-COOL®. To me that means no Prestone Orange stuff.

Service InformationDocument ID # 742292

DEX-COOL Engine Coolant Information #00-06-02-006
DEX-COOL® Engine Coolant Information
2001 and Prior Passenger Cars and Trucks
This bulletin is being revised to add updated information. Please discard
Corporate Bulletin Number 73-62-14 (Section 6 -- Engine/Propulsion System).
Coolant Removal Services/Recycling
The following list includes all coolant recycling processes currently approved
by GM. All of these processes are capable of recycling DEX-COOL® or conventional
(green) coolant to a conventional coolant.
Recycling coolant can be accomplished at your facility by a technician using
approved equipment (listed by model number in the following table) or by an
approved coolant recycling service, which may recycle the coolant at your
facility or at an offsite operation. Refer to the table below for GM-approved
coolant recyclers in either of these two categories. Also included is a primary
phone number and demographic information. Should you decide to recycle the
coolant yourself, strict adherence to the operating procedures is imperative.
Use only the inhibitor chemicals supplied by the respective (GM approved)
recycling equipment manufacturer.
Important
Any deviations, in the form of alternate chemicals or alteration of equipment,
will do the following:
Void the GM endorsement
May degrade coolant system integrity
Place the cooling system warranty under jeopardy
Used DEX-COOL® should still be combined with used conventional coolant for
recycling, providing the recycled coolant is designated as a conventional (2
year/30,000 mile (50,000 km)) coolant.
Only virgin DEX-COOL® approved coolants are to be used in vehicles built with
DEX-COOL®. DEX-COOL® compatible coolants are not to be used in vehicles built
with DEX-COOL®. Additional research is being conducted by GM Service Operations
to determine the feasibility of recycling DEX-COOL® to DEX-COOL® with another 5
year/150,00 mile (240,000 km) usability. AT THIS POINT, THERE ARE NOT ANY GM
APPROVED PROCESSES FOR RECYCLING DEX-COOL® TO DEX-COOL®.
Approved Engine Coolant Recycling Services and EquipmentRecycler
Model/Service Demographics Contact
Antifreeze Technologies Systems Service AZ, CA, CO, IL, IN, MA, MD, MI,
NH, NJ, NM, NYC, OR, PA, TX, WA, VA 800-474-4947
Asbury Enviromental Services/Demenno Kerdoon - Trinity Brand Service AZ,
CA, NV, OR, WA 800-974-4495 Ext. 314
Antifreeze Environmental Service Service AZ, CA, NV, OR, WA 650-325-2666
BG Products PF4/Cooler Cleaner US, Canada 800-961-6228
Kleer-Flo AF-250 US, Canada, Mexico 800-328-7942 952-934-2555
Wynn Oil Company (Wynn's) DU-ALL® # 07000, Bulk DU-ALL® # 07400a US,
Canada, Mexico 800-GMTools 800-989-8363
Century Manufacturing Co. TECHGUARD US, Canada, Mexico 800-328-2921

Sealing Tablets
Sealing tablets are not used at the assembly plant for most models. Sealing
tablets are generally not necessary and should not be used as a regular
maintenance item after servicing an engine cooling system. The use of sealing
tablets can, in some cases, produce contamination of the cooling system and/or
severe discoloration of coolant.
Water Quality
Engine coolant is a combination of antifreeze and water. The integrity of any
coolant is dependent upon the quality of both components. For this reason, be
sure to use clean, drinkable water when mixing coolants. If clean, drinkable
water is not available, use de-ionized water available from most grocers.
Pink Colored DEX-COOL®
DEX-COOL® is orange in color to distinguish it from other coolants. Due to
inconsistencies in the mixing of the dyes used with DEX-COOL®, some batches may
appear pink after time. The color shift from orange to pink does not affect the
integrity of the coolant and still maintains the 5 year/150,000 mile (240,000
km) service interval. General Motors is currently pursuing a course of action
which will stabilize the color of DEX-COOL® in the field.
Back Service
Only use DEX-COOL® if the vehicle was originally equipped with DEX-COOL®. The
only exception to this is for 1994 and 1995 models (excluding the 1994 J-body
with 4 cylinder engines), in which case the use of DEX-COOL® is advocated for
enhanced water pump seal durability. If DEX-COOL® is used in 1994 and 1995
models, all "green" coolant must be removed. This can be accomplished by using a
coolant exchanger. Refer to the Equipment section of this bulletin for more
information about coolant exchangers. The service interval for DEX-COOL® in
1994-1995 models is 2 years/30,000 miles (50,000 km).
Contamination
Mixing conventional green coolant with DEX-COOL® will degrade the service
interval from 5 yrs/150,000 miles (240,000 km) to 2yrs/30,000 miles (50,000 km).
If contamination occurs, the cooling system must be flushed twice immediately
and re-filled with a 50/50 mixture of DEX-COOL® and clean water in order to
preserve the enhanced properties and extended service interval of DEX-COOL®.
After 5 years/150,000 miles (240,000 km)
After 5 years/150,000 miles (240,000 km), the coolant should be changed,
preferably using a coolant exchanger. If the vehicle was originally equipped
with DEX-COOL® and has not had problems with contamination from non-DEX-COOL®
coolants, then the service interval remains the same and the coolant does not
need to be changed for another 5 years/150,000 miles (240,000 km).
Equipment (Coolant Exchangers)
General Motors highly recommends use of coolant exchange equipment for
performing coolant service.
GM Dealers in areas where state/local ordinance prohibit unlawful discharge of
coolant must have a coolant exchanger. Use of coolant exchangers drastically
reduces the amount of waste generated by a cooling system flush.
Unit must be "exchange/transfusion" style with vacuum feature, where new
coolant displaces (pushes) the old coolant out of the system. This equipment
has a higher exchange efficiency over other style machines and leaves no
trapped air in the system.
The coolant exchange process delivers a number of benefits over traditional
drain-and-fill techniques.
Proper concentration levels are maintained (refer to the Concentration portion
of bulletin).
Allows safe venting of a hot system to relieve system pressure.
Vacuum feature allows easy "burping" (removal of trapped air) when a cooling
system has been opened for a service repair.
Significant time savings over current methods of repeatedly thermocycling the
engine and topping-off the radiator.
Maintains clean work environment when used to lower coolant level prior to
servicing cooling system components.
Approved coolant exchangers are available through the General Motors Dealer
Equipment Program (1-800-GM-TOOLS).
Concentration
The chemical inhibitors in DEX-COOL® are a critical part of protecting the
cooling system. The inhibitors provide more than just freeze and boil
protection, they are the necessary components for overall corrosion protection
of the cooling system. A proper mix of 50/50 DEX-COOL® and water is essential. A
50/50 mix ensures that the proper amount of chemical inhibitors are in the
coolant.
Important
At low concentrations (less than 30% DEX-COOL® to water), these inhibitors may
not be able to adequately provide corrosions protection and damage may occur to
the cooling system components.
Radiator drain and fills are a major contributor to improper coolant
concentration. Drain and fills only remove about half of a cooling system's
coolant. When the new coolant is added, it combines with the old coolant (with
depleted chemical inhibitors) and the resulting mixture is considerably less
than a 50/50 mix. For this reason, radiator drain and fills are no longer
recommended as a means for a coolant change service (refer to the Equipment
portion of this bulletin).
Low coolant concentration can also result from topping off the cooling system
with water, and improper filling when system components are serviced.
Assuring System Integrity
A properly functioning radiator cap is essential to achieve the intended system
performance. Radiator caps should be tested before reinstalling to assure they
are operating according to their specifications. If any evidence of
contamination is present, or if the cap fails to test to specification, it
should be replaced.
Maintaining a completely full cooling system is likewise critical to its
performance. Whenever cooling systems are flushed or coolant is exchanged, the
possibility of introducing air into the system exists. See applicable Service
Manual and bulletins for procedures. Air pockets in the cooling system can take
as long as 161 km (100 miles) to be completely expelled. For this reason, it is
critical to check the level of both the radiator and coolant recovery bottle 161
km (100 miles) after any cooling system service. Owners should be advised of the
importance of maintaining cooling system at the proper level and referred to
their Owners Manual for information.
© Copyright General Motors Corporation. All Rights Reserved.


Document ID # 742292

 

Actually, the opposite is true. Dexcool has no silicates and will lower wear on the water pump seal. It also is more friendly to aluminum. I have an advantage in that I can borrow a boroscope from work. I went into my motor and radiator and they were as clean as the day they were made running Dexcool. I also did heads this spring, the block passages and heads were like new. Dexcool works very well, just keep it full.

PS: Dexcool also has many of the same properties as Water Wetter, which will lower surface tension and provde better cooling.

 

Interesting info...

 

Thanks to Bill Dearborn. Great info.

 

Well, I really appreciate the input guys! Even though you all pretty much think I should use Dexcool it doesn't look like I'm going to. I will use the green stuff with watter wetter simply because my cooling system vents to atmosphere and I will probably have the car apart in the very near future. I don't have the heater box hooked up right now and I will eventually swap over to using Evans NPG+ coolant with a different water pump as well (just decided that)... Thanks again

Scott

 

Thanks Bill Dearborn. Especially about the part that says to look up the system capacity and install 50 % full strength Dexcool. I've been doing this for years and posting replies to the same whenever someone initiated a thread. Draining the radiator often only gets 1/2 the coolant mix out of the system. Guys that drain the radiator and re-fill with 50-50 coolant mix maintain the proper water/antifreeze ratio, but their coolant is about 50-50 new to old. I think a Vette deserves better. I use city water to completely flush the old coolant out, then pour several gallons of condensed H2O though. If the condensed H2O doesn't completely flush the city water, it should at least dilute it significantly. After shutting the petcock, I make sure that I get 6.25 quarts of Dexcool into my 12.5 quart system.