Bubba Rick Posted December 17, 2020 Share Posted December 17, 2020 New to forum, new to Mack. I just bought this truck, cheap & available. 5k service; tech said I've got cross contamination of fuel & coolant. Fuel in water filter in frame & coolant in Fuel separator. HELP!!! Quote Link to comment Share on other sites More sharing options...
mrgumby Posted December 17, 2020 Share Posted December 17, 2020 Sounds like injector cups Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted December 17, 2020 Share Posted December 17, 2020 I guess you didnt notice an engine miss or rough running. Injector cups on a legacy Mack was not very common. More than likely it's the fuel water separator. If the the injector cup splits then coolant would leak out the fuel line due to capillary action. Hope its the fuel water separatorthat's otherwise it could get expensive. Let us know what you find. 1 Quote Link to comment Share on other sites More sharing options...
Bubba Rick Posted December 17, 2020 Author Share Posted December 17, 2020 Before the service ran fine, maybe loaded up a bit more if allowed to idle 15+ minutes. AFTER the service? #3 injector sensor shows on the dash, rough idle & miss. Seems little bit better shortly after fueling, or when running Lucas injector cleaner, but I'm now hyper sensitive! Oil is still black, and I'm not making oil. Hoping for a quick and easy fix, but all too. Often I get what I paid for! LOL SIGH Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 18, 2020 Share Posted December 18, 2020 (edited) Just curious... "V".. are you suggesting there is a Davco filter on the truck and it failed?? I'm trying to think how this could happen on a Legacy engine... sounds like an 8-3 code... i dont think he has an MP ...I pay attention to to what you write. I worked in mack dealerships for 9 years.. i left 2 years ago... Glad youre here, Jojo Edited December 18, 2020 by Joey Mack Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 18, 2020 Share Posted December 18, 2020 Just curious.... does the truck have an A.P.U.? Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted December 18, 2020 Share Posted December 18, 2020 Thats what I'm thinking JoJo. I've seen these fail several times before. I have seen only 1 injector cup that split on an 03' ETech. Its worth a try to bypass the dayco filter if it has one. Coolant pressure would naturally go to the suction side of the fuel system to create equilibrium. When the engine is shut off, as the coolant cools it contracts it will draw the fuel with it. I hope I'm right for the original posters sake because its a simple fix. As for the EUP codes, remember that service bulletin that a datafiile update would correct this? These were very typical EUP codes at idle FMI8 mechanical system not responding. Its probably because the fuel is contaminated and sticking the poppet valve in the solenoid. I'm glad I'm here. Its an excellent forum. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 18, 2020 Share Posted December 18, 2020 Yes I remember E.U.P. issues, what do you think about the A.P.U. causing this issue, provided the truck has one.... I have done the simple fix of replaceing the Davco 382 filter assembly, to stop contamination, however in N.C. i dont see too many with coolant connected to them. When I lived in Maine, I saw plenty.. I have also only replaced 1 cup in an E-Tech, Glad youre here, Jojo Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted December 18, 2020 Share Posted December 18, 2020 JoJo are you talking about one of those Rig Masters that sit on the back of the truck and has a small Perkins diesel or one of those espar heaters? You would be correct. I think it's possible, because coolant and fuel do meet through a heat exchanger. If the heat exchanger is cracked then absolutely. Up in the northern states and into Canada those Davcos or Raycors are fitted with coolant supply lines. The plastic ring that secures the filter assembly was always chewed because techs did not have the proper davco wrench. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 18, 2020 Share Posted December 18, 2020 Yes sir I am,,, yes and the Davco filters have a coil inside that coolant can flow through if the fuel heater option is used.. Jojo Quote Link to comment Share on other sites More sharing options...
Bubba Rick Posted December 18, 2020 Author Share Posted December 18, 2020 Sorry guys, not good with computers! Yes truck has a fuel fired bunk heater (Webasto?), but I THINK water is shut off to that, cuz I've got zero heat in bunk. (Truck running or off..) I've also got Devco filter with coolant going to it, but no shut-off valves. I can't tell if I've got in-tank heaters as well (belly's to big!) But ALL that's getting disconnected this weekend. And YES, I am losing coolant, 1 gallon per 1500 miles. Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted December 18, 2020 Share Posted December 18, 2020 By pass the coolant lines at the Davco and drain the Davco filter housing in a bucket. If you not sure there is a valve on the bottom. Drain it until clear fuel comes out. Don't drain it completely. Drain 250ml (sorry for the units of measurement I'm Canadian). Run the truck and recheck it. You may have to do this several times depending how much coolant contamination there is. As for the EUP codes hopefully they will clear up. Finger crossed. Let us know what you find. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 18, 2020 Share Posted December 18, 2020 Hey Bubba, we'll get to the bottom of this... Jojo 1 Quote Link to comment Share on other sites More sharing options...
Bubba Rick Posted December 30, 2020 Author Share Posted December 30, 2020 Davco coolant lines disconnected. Water filter replaced. Bad lines replaced. (Bunk hard lines on order) . NO MORE COOLANT LOSS! NO MORE CONTAMINATION! Bunch of little things added up... Bad connection to VGT took care of that issue too. Still misses occasionally and code for #3 injector, but with 890k, probably could use a set. THANK YOU! Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted December 30, 2020 Share Posted December 30, 2020 Glad we could help. V Quote Link to comment Share on other sites More sharing options...
OldRedMack Posted December 31, 2020 Share Posted December 31, 2020 On 12/30/2020 at 6:18 AM, Bubba Rick said: Davco coolant lines disconnected. Water filter replaced. Bad lines replaced. (Bunk hard lines on order) . NO MORE COOLANT LOSS! NO MORE CONTAMINATION! Bunch of little things added up... Bad connection to VGT took care of that issue too. Still misses occasionally and code for #3 injector, but with 890k, probably could use a set. THANK YOU! The injectors really aren't that expensive, but where they get you is with eups. When/if you change injectors be prepared for some weak unit pumps. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.