Heza Posted November 8, 2004 Report Share Posted November 8, 2004 well..for one...finally got to my lower intake gasket today after polishing my upper plenum. lemme tell ya what i found. the lower intake gaskets both were shot at the areas for the coolant passages. nearly no rubber and stuff packed between the rubber and plastic. deteriorated gasket in my coolant passages looking like brown boogers. what else...oh yeah...oil all around the intake ports and a fair amount of coolant around the oil distro cover. DEXCOOL sucks...it is true...it does eat gaskets. i will flush it out and run green i think. on a brighter note...my polished intake plenum sure is shiny! Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted November 8, 2004 Report Share Posted November 8, 2004 Dexcool is totally crap. If I ever buy a car that uses it, first thing I'll do is convert to green stuff Quote Link to comment Share on other sites More sharing options...
Brian P Posted November 8, 2004 Report Share Posted November 8, 2004 a lot of people believe Dex cool is good for it's rated 5 years. Total BS. IMO it isn't good for any longer than green is. Quote Link to comment Share on other sites More sharing options...
THe_DeTAiL3R Posted November 8, 2004 Report Share Posted November 8, 2004 My sister's 97 Sunflower had Dexcool so I flushed it out really good and put in Prestone. I don't think my 95 had Dexcool, but it was almost hard to tell cause the coolant was so dirty- I flushed it good and put in the green as well. Quote Link to comment Share on other sites More sharing options...
gp90se Posted November 8, 2004 Report Share Posted November 8, 2004 when dex gets older, it becomes more acidic and damaging to gaskets, change it every 4 years or so, or change the green shit every 2 and you wount have issues. Quote Link to comment Share on other sites More sharing options...
pitzel Posted November 8, 2004 Report Share Posted November 8, 2004 May as well join the others in venting your frustrations with Dexcool, and the 3100/3400 lower intake gasket at http://www.gm-v6lemons.com . Some absolutely gross pictures on that site, you'd be amazed at how bad Dex-Cool can sludge up. Quote Link to comment Share on other sites More sharing options...
Heza Posted November 8, 2004 Author Report Share Posted November 8, 2004 see...here is what the GM guy told me who says GM knows its bad stuff, but wont admit it. he said, "dexcool works just fine in uni-metal engines...but...when it runs in multi-metal engines...problems start up." Quote Link to comment Share on other sites More sharing options...
pitzel Posted November 8, 2004 Report Share Posted November 8, 2004 see...here is what the GM guy told me who says GM knows its bad stuff, but wont admit it. he said, "dexcool works just fine in uni-metal engines...but...when it runs in multi-metal engines...problems start up." Good point, if you want to diagnose bad things happening in your engine, take a voltmeter and measure the voltage from the coolant to a ground source. If you get half a volt or more, your coolant is shot and probably should be changed. Essentially what happens inside a bi-metal engine is that the two dissimilar metals act like a 'battery', with the coolant being an electrolyte. Since the boundary surface between the two metals is at the gasket, this promotes significant gasket corrosion due to localized acidity. It has been said that Dex-Cool just makes the problem worse. Quote Link to comment Share on other sites More sharing options...
Canada Posted November 8, 2004 Report Share Posted November 8, 2004 I've never had any trouble with DexCool. Quote Link to comment Share on other sites More sharing options...
HokemBokem Posted November 8, 2004 Report Share Posted November 8, 2004 I also have Dex-Cool and a coolant leak :x It also looks like my head gasket or water pump I cant really tell :? Im going to flush the radiator soon but I dont know if ill stay will Dex or not? Quote Link to comment Share on other sites More sharing options...
z34_nut Posted November 8, 2004 Report Share Posted November 8, 2004 its suggested that if your car previously had dexcool, not to switch over. they use completely different chemical bases, and cars that came from the factory with dexcool should stick with it. as long as you maintain it, it will be fine. the life expectancy of dexcool is 100,000 miles, but always be sure to flush after about 70k. with regular fluid, it doesn't last as long, but works just as well. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted November 8, 2004 Report Share Posted November 8, 2004 If Dex-cool is so bad, why did my 3.4 intake gaskets leak too? I think it's just a design problem with the rubber+plastic intake gaskets. Also, if the green stuff is so great, why did Prestone green with annual coolant changes gobble up my head gaskets like candy? I have seen a TSB that says some of the sludge attributed to Dex-cool is caused by some anti-leak pellets that GM used to use. I've never seen sludge in any engine I have that uses Dex-cool. Quote Link to comment Share on other sites More sharing options...
z34_nut Posted November 8, 2004 Report Share Posted November 8, 2004 If Dex-cool is so bad, why did my 3.4 intake gaskets leak too?I think it's just a design problem with the rubber+plastic intake gaskets. Also, if the green stuff is so great, why did Prestone green with annual coolant changes gobble up my head gaskets like candy? I have seen a TSB that says some of the sludge attributed to Dex-cool is caused by some anti-leak pellets that GM used to use. I've never seen sludge in any engine I have that uses Dex-cool. exactly its all about the maintence of the car., the faulty gaskets. shit, companies also fucked up other things, but when they were recalled, there was nothing to blame them on. Quote Link to comment Share on other sites More sharing options...
Heza Posted November 8, 2004 Author Report Share Posted November 8, 2004 If Dex-cool is so bad, why did my 3.4 intake gaskets leak too?I think it's just a design problem with the rubber+plastic intake gaskets. Also, if the green stuff is so great, why did Prestone green with annual coolant changes gobble up my head gaskets like candy? I have seen a TSB that says some of the sludge attributed to Dex-cool is caused by some anti-leak pellets that GM used to use. I've never seen sludge in any engine I have that uses Dex-cool. i never put the GM fluid leak pellets in my car, the sludge...still a mystery. ive been told its rotted gasket..which...wouldnt surprise me. i dont have a digi-cam anymore, but when i get one back in my hands...ill take pics of my lower intake gaskets as they need to be a show-n-tell item! Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted November 8, 2004 Report Share Posted November 8, 2004 The brown sludge your refering to is usually a combination of mineral build up, orgaic acid deposits (from coolant breakdown), small amounts of engine oil, etc...It can also be caused by the interaction of blue/green coolant and DEXCool, such as would happen if you swithced coolant types without a good flushing. I did the switch over to DEXCool in my Trofeo when I had it and it wreaked all sorts of havoc on the system. I had buildup everywhere and within months I experienced leaks at the water pump, and two freeze plugs (go figure). As previously noted DEXCool doesn't seem to like multi-metal engines and causes galvanic corrosion at a highly increased rate especially when used in conjunction with tap water. Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted November 8, 2004 Report Share Posted November 8, 2004 I NEVER use tap water in the cooling system. I've always used distilled water and never a problem. I use distilled water even in the cars that I still use green stuff in. Quote Link to comment Share on other sites More sharing options...
Canada Posted November 9, 2004 Report Share Posted November 9, 2004 Intake gaskets.........yes, they are a common problem with orginal gaskets......no just on 3x00s..........or just 660s........or just V6s........they ALL leak. Its what happens when you have an alminum head and an iron block. The new gaskets seal a lot better than the old ones. Remember......these gaskets have to seal A LOT........coolant passages, oil gallery, and intake runners. Quote Link to comment Share on other sites More sharing options...
WhiteOut Posted November 9, 2004 Report Share Posted November 9, 2004 I usually use tap water for flushing simply because its easier and more available. I then use milli q water (HPLC grade stuff, less than 1 ppm of contamination) for the final two flushes and the fill. I figure that should do it. Quote Link to comment Share on other sites More sharing options...
GPdriver1986 Posted November 9, 2004 Report Share Posted November 9, 2004 I believe that Dexcool is good stuff and it doesn't cause any harm to the engine. But what I don't believe is the replacement interval it should be a little bit sooner just to stop the deteroriation. Intake gaskets and headgaskets are the least of your worries as long as the car is well maintained,drives great, and the tranny and major engine components are in good order, think of the gaskets as a way of thanking your car or just a simple maintence expense. Remember you drive a GM not a Honda, parts are cheap and everyone can fix simple GM engines. Quote Link to comment Share on other sites More sharing options...
Heza Posted November 9, 2004 Author Report Share Posted November 9, 2004 The brown sludge your refering to is usually a combination of mineral build up, orgaic acid deposits (from coolant breakdown), small amounts of engine oil, etc...It can also be caused by the interaction of blue/green coolant and DEXCool, such as would happen if you swithced coolant types without a good flushing. I did the switch over to DEXCool in my Trofeo when I had it and it wreaked all sorts of havoc on the system. I had buildup everywhere and within months I experienced leaks at the water pump, and two freeze plugs (go figure). As previously noted DEXCool doesn't seem to like multi-metal engines and causes galvanic corrosion at a highly increased rate especially when used in conjunction with tap water. now that was an interesting read. thank you for that. i didnt mix coolants ever, but im gonna do one hell of a flush on my car with prestone flush and distilled water. then, i will decide from there what coolant i will use. as i said, i got coolant all over the valley of my engine. Quote Link to comment Share on other sites More sharing options...
Brian P Posted November 9, 2004 Report Share Posted November 9, 2004 I believe that Dexcool is good stuff and it doesn't cause any harm to the engine. But what I don't believe is the replacement interval it should be a little bit sooner just to stop the deteroriation. Intake gaskets and headgaskets are the least of your worries as long as the car is well maintained,drives great, and the tranny and major engine components are in good order, think of the gaskets as a way of thanking your car or just a simple maintence expense. Remember you drive a GM not a Honda, parts are cheap and everyone can fix simple GM engines. Exactly. It's not that dex-cool is a problem when compared to green, but dexcool should not be left in for it's "recommended" interval. If it's changed according to green coolant intervals (2 years/24k I believe) there shouldn't be any issues. Quote Link to comment Share on other sites More sharing options...
terryk2003 Posted November 9, 2004 Report Share Posted November 9, 2004 this is good to know...i think i'm gonna flush my coolant VERY SOON... Quote Link to comment Share on other sites More sharing options...
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