Keffer inc Posted May 29, 2019 Share Posted May 29, 2019 Hey guys, I have a 2011 Mack CXU613 with a 455 hp MP8 motor. The truck started pushing coolant out of the reservoir tank when climbing up mountains and long hills. The problem seems to be getting worse. I did replace the coolant tank with one of Ebay some time ago, and its maybe possible that I have a higher percentage of water than coolant so that may be boiling over? I plan on draining the coolant and replacing with fresh coolant to see if that's my issue, but else might it be if it's not simply that? What are some test I can do on my own? Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/ Share on other sites More sharing options...
terantrucking93 Posted May 29, 2019 Share Posted May 29, 2019 Have u change the coolant filter?Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423894 Share on other sites More sharing options...
Keffer inc Posted May 29, 2019 Author Share Posted May 29, 2019 A few months ago, I'll change that too. You think that may be all that's wrong? Guess it would make sense. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423895 Share on other sites More sharing options...
terantrucking93 Posted May 29, 2019 Share Posted May 29, 2019 I had the same issue what I did on mine i poor a stop leak from gas station I poor it stop the leak N I clean Raines all and put new antifrezze and I been running 7 months with any issue on my coolant Sent from my iPhone using Tapatalk 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423896 Share on other sites More sharing options...
fjh Posted May 29, 2019 Share Posted May 29, 2019 Remove the egr hose at the front of the cooler and c if it’s wet there! Possibly failure however your symptoms are more similar to injector cup failure 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423898 Share on other sites More sharing options...
Keffer inc Posted May 29, 2019 Author Share Posted May 29, 2019 That's what I'm leaning towards as well. I dont see any "steam" coming from my exhaust or any bad smell from the exhaust pipe. I have noticed my coolant temp is getting hotter, faster than usual. Today I have any empty trailer and in 10 seconds of flooring it uphill, the temp goes 15⁰ hotter and the truck overall is running warmer than usual. Not overheating, but just hotter. The engine fan keeps coming on to. It did cross my mind this could be simply a bad coolant water pump or thermostat? 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423903 Share on other sites More sharing options...
Keffer inc Posted May 29, 2019 Author Share Posted May 29, 2019 Ah hell, I just noticed air bubbles in my fuel filter globe. That's almost a guarantee it's an injector cup isn't it? Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423904 Share on other sites More sharing options...
fjh Posted May 29, 2019 Share Posted May 29, 2019 (edited) If it’s hard to start in the morning it’s a guaranty check egr before getting carried away. The hard pull comment kind of raises my eye brow a bit! Edited May 29, 2019 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423910 Share on other sites More sharing options...
turckster Posted May 30, 2019 Share Posted May 30, 2019 Could possibly be a cracked injector cup at the body to tip area, seen that many times. Could also be a leaking egr cooler, worst case could be cracked head. I don't think a bad water pump would cause pushing coolant unless the engine overheated and cracked the head or damaged the egr cooler. If the upper radiator hose is hot to touch and the lower radiator hose is cold the you may have a water pump issue(vanes spinning on w/p shaft). Even if the water pump is determined to be bad its not the reason for pushing coolant. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423950 Share on other sites More sharing options...
JoeH Posted May 30, 2019 Share Posted May 30, 2019 My cousin had a Pete with a Cat motor, the piston cylinder walls were eaten through and air bubbles were getting into the coolant that way. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423959 Share on other sites More sharing options...
Keffer inc Posted May 30, 2019 Author Share Posted May 30, 2019 Well I took the egr apart at the outlet side, its dry soot inside like it should be. I'm going to buy a cheap harbor freight temp lazer to check the radiator like you suggested, all signs kinda point to something injector related I think. The truck has an appointment with the dealer for tomorrow so tomorrow evening I'll probably have some idea what's going on and how much it will hurt to fix it. Any want to buy a 2011? I'll sell you one half price. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423965 Share on other sites More sharing options...
Keffer inc Posted May 30, 2019 Author Share Posted May 30, 2019 Also I notice the fuel level in the fuel filter is going down all the way out of sight. Fuel is leaking back some where. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-423966 Share on other sites More sharing options...
Keffer inc Posted June 1, 2019 Author Share Posted June 1, 2019 I measured the radiator inlet and outlet with a lazer temp gun and it was a 25⁰ difference between them. I feel like that's kinda lower than it should be. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424122 Share on other sites More sharing options...
fjh Posted June 3, 2019 Share Posted June 3, 2019 So have you got any farther with this problem Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424376 Share on other sites More sharing options...
Keffer inc Posted June 5, 2019 Author Share Posted June 5, 2019 Looks like it was a faulty pressure cap on the over flow side. Seems to be holding coolant now. Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424518 Share on other sites More sharing options...
fjh Posted June 5, 2019 Share Posted June 5, 2019 Good news! 👍 Keep it simple! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424525 Share on other sites More sharing options...
terantrucking93 Posted June 7, 2019 Share Posted June 7, 2019 What do u use to take the coolant filter?Sent from my iPhone using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424667 Share on other sites More sharing options...
Keffer inc Posted June 9, 2019 Author Share Posted June 9, 2019 (edited) My truck uses a normal spin-on style filter, just a filter wrench is all you need on an MP8. Edited June 9, 2019 by Keffer inc Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424905 Share on other sites More sharing options...
Keffer inc Posted June 9, 2019 Author Share Posted June 9, 2019 1 minute ago, Keffer inc said: I ran from Norfolk, VA to Ripley, WV twice since I got the truck back and I haven't had to add any coolant to it. I topped it off this morning after changing the filter but that's to be expected. Everything is looking good for now. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-424906 Share on other sites More sharing options...
Vernon Posted July 15, 2019 Share Posted July 15, 2019 I have 6 Mack engines that I would like to delete the DPF. Any advice?? Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-427966 Share on other sites More sharing options...
Juan Posted August 3, 2021 Share Posted August 3, 2021 Going through the same thing with my 2015 Mack - Sending my EGR cooler to get tested tomorrow, wish I read this first!! To confirm, you switched out the cap on the side of the coolant tank? Thank you so much Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-477883 Share on other sites More sharing options...
RV Hauler Posted June 10, 2022 Share Posted June 10, 2022 I believe he did change the cap on the left side. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-499870 Share on other sites More sharing options...
204 big Mack Posted July 15, 2022 Share Posted July 15, 2022 Very helpful info I am having the same exact issue...have already replaced the waterpump...mine even had a small split were the drain hose reached the cap..going to get a new cap asap!! Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-503118 Share on other sites More sharing options...
Bal Posted September 22, 2022 Share Posted September 22, 2022 I have mp8 engine 2012 , same issues, collant overflow , i changed 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 water pump, thermostat, air compressor, now injector cups ?? What could be next please?? Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-509999 Share on other sites More sharing options...
Mackbaby Posted October 10, 2022 Share Posted October 10, 2022 On 9/21/2022 at 8:04 PM, Bal said: I have mp8 engine 2012 , same issues, collant overflow , i changed 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 water pump, thermostat, air compressor, now injector cups ?? What could be next please?? Did you find out the problem? Quote Link to comment https://www.bigmacktrucks.com/topic/57420-2011-mack-mp8-pushing-coolant-out-of-the-overflow-tank/#findComment-511453 Share on other sites More sharing options...
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