landbdevelopers Posted June 28, 2015 Share Posted June 28, 2015 I have 1996 mack ch600 all mack drive train that builds preasure in the coolant system. When running truck under a load it begins to push coolant out the over flow tank. Once it pushes out a gallon or so it seems to stop coming out but you can look in the cap of the over flow tank and see small air bubbles coming out the hose running into the bottem off the over flow tank and out of the top tank by the fill cap. Also a electronic malfunction light comes on and off time to time. When the light is on the tac begins to jump around . When the light goes out the tac goes back to normal. Do not know if the light has anything to do with the coolant problem. Quote Link to comment https://www.bigmacktrucks.com/topic/40684-building-preasure-in-coolant-system/ Share on other sites More sharing options...
TRH Posted June 28, 2015 Share Posted June 28, 2015 Pull codes with the cruise switch when the light is on. Just for giggles.There has been a lot of hoo-da for coolant push on that era engine, including an updated waterpump and filter arrgt., they would suck air past the seal and cause the system to bubble and fart. Removing the drivebelt would be the way to isolate the waterpump as the source of air. If it's elsewhere, there isn't a lot of places, mostly expensive ones, for air to get into the system. Quote Link to comment https://www.bigmacktrucks.com/topic/40684-building-preasure-in-coolant-system/#findComment-294886 Share on other sites More sharing options...
landbdevelopers Posted June 28, 2015 Author Share Posted June 28, 2015 How do i pull the codes . Would i do it while the light is on and truck running? Quote Link to comment https://www.bigmacktrucks.com/topic/40684-building-preasure-in-coolant-system/#findComment-294893 Share on other sites More sharing options...
TRH Posted July 5, 2015 Share Posted July 5, 2015 You can. Leave the cruise control toggle in the off position and hold the cruise switch in "SET" until the light blinks off. It'll flash x number of times, pause, and then flash y number of times, so your blink code looks like x-y - then you just need to look it up in the VMAC book and follow the troubleshooting. So say it blinks four times, pauses, then four more. That's 4-4. You can find that, and a lot more, on the Mack eMedia portal. Search for "V-MAC" Quote Link to comment https://www.bigmacktrucks.com/topic/40684-building-preasure-in-coolant-system/#findComment-295584 Share on other sites More sharing options...
turckster Posted July 9, 2015 Share Posted July 9, 2015 The fault you get is most likely a 1-7 (low coolant). It's pushing coolant because of one of two reasons (or could be both)-blown head gasket/cracked head or blown air compressor head gasket. Sounds more like a blown head gasket/cracked head since its pushing coolant under a heavy load/pull. The best way to tell is to isolate the air compressor from the engine cooling system, run the engine and see if it still pushes coolant. If one head is cracked it would be best to replace both heads, in my opinion. Excessive heat is probably the reason this has happened. Quote Link to comment https://www.bigmacktrucks.com/topic/40684-building-preasure-in-coolant-system/#findComment-296179 Share on other sites More sharing options...
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