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The Hecat cooling system flush gun

Chick on Tue September 11, 2007 7:44 PM User is offlineView users profile

This is a little late, but I have been busy lately.. Anyway, you all know that I got a 1997 Jimmy that suffered an overheating problem that made the owner junk it.. When it came into the yard, I said I have to have that truck! Almost 200,000 miles, but ran great.. So, I figured if I could solve the overheating problem I am way ahead.. Got it real cheap, well, I didn’t figure everything it would need, but I went for it.. I had to replace the compressor (belly leaking HT6) and bought a “New” Seltec clone from Tim and, along with the accumulator.. Flushed the system, changed the parts, recharged to factory specs and it’s been cooling great even in the 100 degree humid days.. Now the overheating.. Found that the “Orange” antifreeze used by GM had congealed and plugged the overflow tube to the overflow bottle causing a pin hole leak in the radiator when the antifreeze had no where to go. . Just because of the mileage, I changed the water pump, thermostat, and ordered a new radiator.. Now the fun.. I flushed the orange stuff out with water and a hose for an hour. .Looked clean. Put it on the lift and took out a knock sensor and no water came out.. Well, that’s not good.. Should have run out. But, not to worry, this was a chance to use “HECATS” Cooling system flush gun. Put it back together, took out the thermostat and hooked the hose up to the gun.. Rather than take the upper radiator hose off, I just removed it from the radiator (changing the radiator anyway) Took the lower hose off the radiator as per instructions and began.. You had to see the junk that came out that lower hose..(After flushing it before) Only took about fifteen minutes before I felt it was done.. I guess because of all the flushing I did before, but I felt it was done.. Back on the lift, took out the knock sensor and the water poured out.. And it was clean.. I thought the DIY’er pulsator for AC was good, but this tool is great.. I can see why radiator shops use it.. It was so easy even an old guy like me could do it..L So, brought it back to the floor, pulled the old radiator out, put in a new one, new thermostat, and “GREEN” antifreeze. Been running well over an month and a half, in which time it did go over the 200,000 mark, and still runs just fine.. I made a good deal on this Jimmy, and the Hecat cooling system flush gun made fast work of the Orange anti-freeze problem. I don’t expect it to return any time soon. Thanks for making a GREAT product Hecat (Karl)

Email: Chick


Freedoms just another word for nothing left to lose

CorvairGeek on Tue September 11, 2007 9:05 PM User is offline

The 4.3s of that era are known for an issue with sand coming from the castings causing the nasty blockages, which is then attributed (rightly or wrongly) to an issue with the Dexcool . There is a TSB about the sand issue. Don't have any idea what new problem (root cause) GM invented with those particular castings.


HECAT on Wed September 12, 2007 9:51 AM User is offline

Chick, Thank You.

Great success stories not only in flushing your A/C components with the "DIY Pulsator Flush Gun"; but providing an excellent example of "Dex Death" and how effective our "Coolant Pulsator" is on removing such restrictive debris. As you saw by the effectiveness of your hour of flushing with a hose; coolant exchange machines just push in and pull out (why are they called flushers?), and they are not going to clean this "jello" out. Check out the labor time to change the heater core out in that S-10 series. This issue is not limited to GM products; and similar OAT, HOAT, corrosion, gasket failures, casting sand, and sludge issues are occurring in many vehicles.

Short video scenes of both these tools are on the home page of our web site ( Not posted to our web site yet is a current "tool review article" on the "Coolant Pulsator" in the August 07 issue of PTEN (Professional Tool & Equipment News) and a short article "Has Flushing Become a Bad Word?", in the Sep/Oct 07 issue of ACtion.

Please forgive the product "commercial" here on the forum. These tools are available right here ( with pricing that can't be beat. These tools meet the call to "do it right" and purchasing from this forums "online store" helps to keep this online forum operating and this valuable community of knowledge together.

Send me an e-mail ( with your mailing address if you want a CD that has the full detailed videos of these two tools (7 videos covering all HECAT products avalable from ACkits).

Thanks again Chick, validation of these tools by professionals such as yourself, sure does beat having to hire a marketing genius to blow smoke up your...UH...well..ER..anyway, thanks a lot.


HECAT: You support the Forum when you consider for your a/c parts.


GM Tech on Wed September 12, 2007 9:53 AM User is offline

Here is another photo from my collection on the same subject- from a 1996 Blazer 4.3l - that I took in 1999...the good ole "sand in the block" scenario

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

NickD on Wed September 12, 2007 12:34 PM User is offline

It was so easy even an old guy like me could do it..

Yeah, but can a caveman do it? LOL

Remember that tune from the 50's, Mr. Sandman, send me a dream... Sounds like Mr. Sandman sent you a nightmare. Also going back to the 50's, GM use to make the radiators out of brass, not plastic and aluminum foil, think you would have gotten a leak anyway.

Was going to ask you how you and your Jimmy are getting along, sounds like you are still happy with it, that makes me happy as well. Sure your Jimmy likes a concerned and conscientious owner and in turn, will take good care of you.

CorvairGeek on Wed September 12, 2007 2:27 PM User is offline

Anyone know the inside story with the sand in the castings issue? AFAIK, it was only a 4.3L issue, and they didn't have this problem until many years after introduction.


JJM on Wed September 12, 2007 2:56 PM User is offline

That is very encouraging with the advent of Dexcool - or should I say "Destructcool". The Hecat Coolant Pulsator should be standard equipment for any shop (or DIY) doing cooling system work, particularly on neglected vehicles.

GM 3.8 engines also really seem to get trashed by the Dex. It's kind of ironic (or expected) that Toyota uses "red" extended life coolant without any problems. Now GM has come out with a new ATF - Dexron VI and Dexron III will soon disappear. Wonder if Dexron VI will destroy transmissions the way Dexcool does engines. I would imagine so. It seems GM's plans would be complete if they can destroy engines AND transmissions simultaneously.


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