c-mac Posted February 7, 2019 Share Posted February 7, 2019 (edited) I’ve got Mack chi 613 with an mp8 that’s blowing coolant out the overflow hose of the coolant tank mounted above the radiator. I’ve already pinched off the coolant lines to the compressor and it builds up to 15 psi in the tank. Is there anything other than a head or head gasket problem that will cause this? Edited February 7, 2019 by c-mac Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/ Share on other sites More sharing options...
Mackpro Posted February 7, 2019 Share Posted February 7, 2019 Injector cup can cause the issue. If a worn tool is used to install the cup, then compression can come between the cup and head and cause is issue. But being a 2018 it’s unlikely Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415125 Share on other sites More sharing options...
c-mac Posted February 7, 2019 Author Share Posted February 7, 2019 I edited my post. It’s a 12 model and I have an 08 with the same problem. I’m not sure if either has had the cups and injectors replaced. I work on a large fleet and they don’t keep good records..(oilfield). My self I write on the date and hours on the valve cover. I thought I had seen all the symptoms til now. Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415131 Share on other sites More sharing options...
turckster Posted February 8, 2019 Share Posted February 8, 2019 Some coolant reservoirs have a burn hole in the pressure cap/overflow side that can cause coolant loss. Pushing coolant can also be caused from a bad air compressor head, leaking egr cooler, bad injector cup and cracked head. Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415177 Share on other sites More sharing options...
fjh Posted February 8, 2019 Share Posted February 8, 2019 The two most common as mentioned are the cups and egr cooler! Start at the cooler and work back remove the outlet of the egr hose lower front and check for dampness in the cooler! check the surge tank as mentioned however that should have showed up before now! Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415210 Share on other sites More sharing options...
c-mac Posted February 11, 2019 Author Share Posted February 11, 2019 (edited) Ok I pulled the cooler because I seen what looks like tiny red droplets of coolant and the inside of the housing is damp and sooty. I’m not sure if what appears to be red droplets is coolant. What do y’all think? You may need to blow up the pic to see Edited February 11, 2019 by c-mac Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415442 Share on other sites More sharing options...
fjh Posted February 11, 2019 Share Posted February 11, 2019 (edited) Sorry bud you need a cooler! Keep this site on speed dial you will likely need encouragement as you go along!😡 Edited February 11, 2019 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415458 Share on other sites More sharing options...
c-mac Posted February 14, 2019 Author Share Posted February 14, 2019 On 2/7/2019 at 11:03 AM, Mackpro said: Injector cup can cause the issue. If a worn tool is used to install the cup, then compression can come between the cup and head and cause is issue. But being a 2018 it’s unlikely ok the cooler took care of the one I posed the pick of. The next one has a new cooler and compressor. I guess someone else has been chasing this problem too. I checked the newish cooler, it was clean and dry. I clamped pinch off the coolant line to the compress and ran the engine at 1000rpm. The cooling system got up to 13psi. I left the system a little low of coolant so as not to blow it back out. I pulled the overflow hose up and stuck it down a bottle of water and light bubbles were present and the coolant tube from the back of the thermostat housing to the coolant tank was jumping. I cant thing of any other way of determining if it is cups or a head problem. This one is an 08 model built date is 11/07. Not sure if it has copper or stainless cups of if they have been changed Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415742 Share on other sites More sharing options...
fjh Posted February 14, 2019 Share Posted February 14, 2019 Your only choice is to lift an injector to see what cups are in there in my opinion! Assuming it is cup issue Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415749 Share on other sites More sharing options...
Mackpro Posted February 15, 2019 Share Posted February 15, 2019 There is a service bulletin on coolant push on early MP engines. It might take me a day to find it though Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415754 Share on other sites More sharing options...
Mackpro Posted February 15, 2019 Share Posted February 15, 2019 Quick question, on the expansion tank on top of your radiator. On the drivers side of it, is the pressure cap on it blue or black? The problems ones were blue, the updated ones are black. I got the service bulletin but I cant post it here due to size but will PM you . 1 Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415795 Share on other sites More sharing options...
c-mac Posted February 17, 2019 Author Share Posted February 17, 2019 On 2/15/2019 at 9:00 AM, Mackpro said: Quick question, on the expansion tank on top of your radiator. On the drivers side of it, is the pressure cap on it blue or black? The problems ones were blue, the updated ones are black. I got the service bulletin but I cant post it here due to size but will PM you . It’s black and the tank is new Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415899 Share on other sites More sharing options...
c-mac Posted February 17, 2019 Author Share Posted February 17, 2019 On 2/14/2019 at 5:37 PM, fjh said: Your only choice is to lift an injector to see what cups are in there in my opinion! Assuming it is cup issue Gonna pull the injectors Monday. I guess if it has stainless, I’ll change just the cups. If there copper I’ll put in a six pack. The engine runs fine other than on cold start it has a little rough idle for about three seconds which my be a little coolant in the suspect cylinder Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-415902 Share on other sites More sharing options...
c-mac Posted February 25, 2019 Author Share Posted February 25, 2019 Pulled the injectors and the original copper cups. Didn't see anything out of the ordinary with the cups, all looked about the same. I'm going to go back with new injectors and cups. Hope this takes care of it, I dont want the boss to loose faith. Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-416614 Share on other sites More sharing options...
Bal Posted September 21, 2022 Share Posted September 21, 2022 (edited) I have same issues, collant overflow , my mechanic change the injector cup ( they are leaking) but still have same issues . Now It very low amount collant overflowing. But could be another reason for loosing power and coolant overflow?? I have changed the water pump , thermostat, air compressor, now changed injector cup , still have same Problem overflow but low amount collant?? What could be next please?? Edited September 21, 2022 by Bal Forget to add something Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-509998 Share on other sites More sharing options...
Onyx610 Posted September 22, 2022 Share Posted September 22, 2022 Id suggest starting your own thread on this, however there is more than enough information on this topic. For now you may want to do a combustion gas test on the cooling system to verify and what direction next. It could be cups if not installed correctly, it could be egr cooler, or head gasket. Keep in mind that correctly refilling these newer trucks with coolant is very important, not to have any air pockets. They create hot spots and can burn out egr coolers very quickly. Quote Link to comment https://www.bigmacktrucks.com/topic/55519-2012-mp8-pressuring-up-cooling-system/#findComment-510009 Share on other sites More sharing options...
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