Draft—DEX-COOL 2007, Part 1-5.7 Gasket Changeover

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Draft—DEX-COOL 2007, Part 1a:
5.7L V8 Engine Sludge and Gasket Change
by John R. Hess with additions from Mole Snoopster
To appear in March 2007 Cool Profit$ Magazine
© 2007 All Rights Reserved

New! Would you like to respond or add to something mentioned in this article? You can do so now by using our new "Comment" section at the bottom. Feel free to use it, but please keep your remarks relative to the subject. (Vulgarities, spam or libelous, denigrating comments will be deleted.)

We're all aware of the problems with the 3.1, 3.4 and 4.3L IMGs (Intake Manifold Gaskets), what about with the less noticed 5.7L Vortec V8? Did it suffer when GM switched over to DEX? California's John B believes that it did. He became a believer while performing a gasket changeover. Below are the photos. At 100,000 miles, clearly something was not working well inside the engine of his 1999 Chevrolet Suburban K1500.

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Below: While the photos are a little out of focus, the contaminant-sludge in the coolant channels is still recognizable. Plus, it looks like the gaskets had indeed been leaking coolant at certain points around the port.

To lay the groundwork, John stated: "I'm the original owner and did all cooling maintenance myself. I flushed and replaced the DEX-COOL twice since new (about 3 year intervals). I mixed 50/50 with distilled water and never added any other product except Bars Leaks factory sealer (gold powder). The orange sludge is about 1/4 inch thick."

John believes the sludge above came either from the DEX-COOL itself or from other components that were broken down by the antifreeze. He's convinced that this sludge interfered with the cooling of the cylinder heads, causing excessive heat and leading to detonation. The detonation problems occurred mostly in hot weather.

John says: "It's also possible the cheesy plastic intake manifold gasket developed slight air leaks over the years causing the fuel/air mixture to run too lean." He adds, "now when I periodically check under the radiator cap, the coolant level is never low. Fel-Pro actually told me about the special gasket they make called the Problem Solver."

What caused John to finally undertake the arduous repair is when the IMG eventually failed to the point where "coolant was shooting out of top of the engine like a geyser."

Above: Some type of sludge has coated the radiator hoses. If anyone has analyzed this contamination and KNOWS exactly what it is, please call us at 800-883-8929. Or use this email link: Click to email imcool.com.

Above: The "Problem Solver" Fel-Pro PermaDryPlus® gasket that John Bell chose to replace his original part. As seen, this gasket is built around a metal carrier versus nylon used in the original model.

Truly concerned about the future of his "Burb," and wanting it fixed right, John had called me last summer looking for a true expert to guide him through a quality repair. I pointed out several DEX experienced shops who I knew would lead him correctly. John chose to work with Bruce Balfour, owner of Mac's Radiator and Air Conditioning (562-920-1871), Bellflower, California. Bruce provided the Fel-Pro gaskets.

If you have similar stories but maybe with differing details and outcomes, and would like to share them with Cool Profit$ Magazine's readers, please call me at 800-883-8929. Click here to email your story. $$$

Return to DEX-COOL 2007, Part 1
Return to DEX-COOL 2007, Part 2
Return to DEX-COOL 2007, Part 3
© 2007 All Rights Reserved

Leave a Comment

Showing 1-15 of 16 Comments

Kevin – Reno, NV

September 30, 2008 - 11:50

Subject: 5.7 IMG

I have the IMG replaced by the dealer when my 1996 K1500 had 45000 miles in 1999. I did not know what the orange drops on my garage floor was. The dealer service writer took a look at the sample and immediately know it's the IMG.

At 130k miles the IMG failed again. Luckily it only leaked outward and didn't seem to have coolant in the oil or intake track. I tackled the job myself and found it's not too difficult. The front coolant passage did not have significant sludge build-up, but there's quite some sludge in the back, though not as bad as others have had.

Too bad I didn't know there's an improved IMG design so I replaced it with the original style. Looking forward to replace it again a few years down the road.

Bob Hiser – ohio

March 26, 2008 - 13:38

Subject: Dex Cool

Is the aftermarket stuff (Dex Cool) that you can buy in auto stores such as Auto Zone any good.

Reply to Bob Hiser

CPMJohn – Petaluma, CA

March 26, 2008 - 15:05

Subject: Licensing of chemistry and tradename

Bob,
Trust me, if any unlicensed vendor tried to sell GM/Chevron's DEX-COOL trademarked product they'd have enough attorneys gathered over them that would darken the sky.
It's all in the licensing. Auto Zone, Kragen's, etc. aren't going to "knowingly" sell bad stuff. Use it without fear.

Bob Hiser – ohio

March 26, 2008 - 13:34

Subject: Bad Dexcool ???

I have a 99 v-6 Chev. S-10, had intake gasket replaced under warrenty with 20,000 mi.
My son had to replace water pump, rad. and heater core on 96 Impala SS V-8 between 35,000 and 50,000 mi, I just replaced antifreeze on the 99 S-10, 2002 Tracker v-6, and 79 Corvette 350 with 30,000 miles using aftermarket Dex-cool. Now I suppose I will have to dump it for somthing else. I wanted the 5 year protection. Wonder if there is anything else that will work?

Reply to Bob Hiser

CPMJohn – Petaluma, CA

March 26, 2008 - 14:59

Subject: numerous conditions

Hi Bob,

Your '99 S-10 was covered under warranty. Have the Intake Manifold Gaskes and cooling system held up?

Your other vehicles are apparently not covered under this lawsuit. Not sure but I suspect there is no problem with their intake manifold gaskets.

If the jugs are marked DEX-COOL, the product inside is most likely DEX-COOL. (Licensing) See next post.

Reply to Bob Hiser

Bob – ohio

March 26, 2008 - 16:40

Subject: DEX COOL

Since the replacement of the intake gasket on my 99 S-10 I have had no problems. I just replaced the Dex Cool with new. The rad. and cap look like new. No gunk etc. in the neck or under the cap. Total miles on the truck are 31,000. I found the intake leak when recovery tank started to go down and the oil turned white. It would have been a disaster if I hadn't found it. 12,000 miles since repair and no porblems.

Reply to Bob Hiser

CPMJohn – Petaluma, CA

March 26, 2008 - 17:33

Subject: Why oh why did GM wait so long to react?

I still think it would have been "better" all around (cheaper and nicer to their customers) if GM had just recalled the vehicles when they first noticed the degradation of the IMGs. They could have taught their dealers to make fast work of the changeovers to minimize the loss.
Plus, look at the bad name it gave to a well thought out, recognizable tradename. It's really tough to get that back once someone has seen the sludge and has to cough up $1000 to get it fixed.

Kestas – SE Michigan

January 30, 2008 - 06:43

Subject: Deposit analysis

If anyone wants to send me a sample, I can easily do an energy dispersive spectroscopy analysis on the debris. This analysis will show the elemental makeup of the debris, and give a good clue as to what it is.

Reply to Kestas

Hagendoorn – Kentucky

April 19, 2008 - 10:55

Subject: Kestas - SE Michigan

Replaced headgasket at 135000 miles, replaced recently for 2nd time fuel pump (20.000 mile interval) checked recervoir found black deposit inside tank, just below filler cap. Could you possibly get an incling of what is going on from a swipe of debrois from tank wall using spectroscopy analysis ? Car is in garage due to an overheat engine signal after adding water for lack of Dex Cool trying to make it home.

Reply to Kestas

CPMJohn – Petaluma, CA

April 20, 2008 - 16:35

Subject: Cool Profit$ would like to know what's in there as well

Hi Hagendoorn,
We'll hear from Kestas, but if you do find out the contents, please let us know. We'd also like a photo of the residue.
Thanks,
CPM John

Reply to Kestas

Kestas – Motor City

April 21, 2008 - 11:24

Subject: Deposit analysis

The color black would probably indicate organic deposits, such as rubber or oil. I can't analyze for organic deposits because all I would expect is carbon ad oxygen. I can give it a try anyhow. Send the sample to:

K. Smalinskas
31255 Kendall St
Livonia, Michigan 48154-4356

I don't need a lof of sample. Dry the sample as much as possible before mailing.

Charles Heflebower – 10716 Trafton Drive, Upper Marlboro, MD> 20774

January 23, 2008 - 11:08

Subject: Repair Lower Intake Gasket on 1997 5.7 V8

To make this repair is it normal or the suggested method to Loosen or remove the Sepertine Belt Tensioner, or is it common to not touch it ? Can this repair be made by leaving previous Alternator Serpentine settings Un changed?

Reply to Charles Heflebower

CPMJohn – Petaluma, CA

January 23, 2008 - 15:15

Subject: remove the Sepertine Belt Tensioner?

Charles,
I'm not enough of a technician to answer your question. I am researching it now, however.

Charles Heflebower – Largo, Maryland

December 06, 2007 - 08:58

Subject: 5.7 V8 / Dexcool 1997 Silver ado, purchased new October 24, 1997

I just turned 40,000 miles, yes,this is the true mileage. For quite sometime I would see a small coolant spot on my carport floor. It would appear at various intervals. I changed the Dexcool twice at 5 year intervals regardless of the low mileage. Finally in my attempt to determine where the Dexcool was leaking from, I was advised by my Mechanic that the Lower Intake gasket was leaking.

Do you know of any assistance by GM for the repair? Thank you.

Reply to Charles Heflebower

CPMJohn – Petaluma, CA

December 06, 2007 - 09:42

Subject: DEX-GM Clas Action Tentative Settlement

Charles,
Take a look at this page I posted yesterday; you might qualify. It announces a tentative settlement between the law firms and GM over the DEX Class Action Lawsuits:

www.gohtsn.com