96bulldogpower Posted Thursday at 09:39 PM Share Posted Thursday at 09:39 PM hey guys looking for some help on this one. I’ve got a 12’ Mack granite with an mp7 that’s making oil. Oil level rises about a gallon every two weeks. I’ve put UV dye in the filter and checked to see if I could find the leak, I found nothing around the injectors or galley plugs. I then added another ounce of dye directly into the fuel gallery through one of the plugs and still nothing. I can’t find the leak even after hours of looking. Anyone have any ideas on where else these engines can pass fuel into the crankcase? Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/ Share on other sites More sharing options...
Joey Mack Posted Thursday at 10:08 PM Share Posted Thursday at 10:08 PM Tandem pump ? Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582109 Share on other sites More sharing options...
96bulldogpower Posted Thursday at 10:18 PM Author Share Posted Thursday at 10:18 PM Do you mean the fuel pump that mounts behind the power steering pump? I thought about that but fuel isn’t mixing with the power steering fluid, which I assumed was the first thing that would happen if the fuel pump seal went out. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582110 Share on other sites More sharing options...
Joey Mack Posted Thursday at 10:39 PM Share Posted Thursday at 10:39 PM Fair thinking, im grabbing at straws after reading the post. Is there raw fuel smoke? Bad injector ?? Low power/missfire, stuck piston rings Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582111 Share on other sites More sharing options...
96bulldogpower Posted Thursday at 10:56 PM Author Share Posted Thursday at 10:56 PM 17 minutes ago, Joey Mack said: Fair thinking, im grabbing at straws after reading the post. Is there raw fuel smoke? Bad injector ?? Low power/missfire, stuck piston rings No other concerns besides the rising oil unfortunately 😞. Truck starts and runs great. No misfires or smoke. I’d hate to throw parts at it and I don’t have much time to work on it before it has to go back into service in a week and a half. If I can’t find anything else tomorrow then I may just have to put it back together and order a set of injectors to throw at it next time it come back to the shop and hope it fixes it. Meanwhile we’re changing the oil once a month Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582113 Share on other sites More sharing options...
Joey Mack Posted Thursday at 10:58 PM Share Posted Thursday at 10:58 PM You are sure its fuel ? Did you do a halo test or oil sample test? Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582114 Share on other sites More sharing options...
96bulldogpower Posted Thursday at 11:07 PM Author Share Posted Thursday at 11:07 PM It’s for sure fuel, I haven’t got an oil sample yet (going to send some off though) but I’m certain it’s fuel. Put a drop on cardboard and it leaches out. Smells like fuel too. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582115 Share on other sites More sharing options...
Joey Mack Posted Thursday at 11:16 PM Share Posted Thursday at 11:16 PM Ok Good enough.. just save the sample money. I am probably not going to help much at this point, but Mackpro may see this and chime in, and a few others. I will watch this thread.. Jojo, Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582119 Share on other sites More sharing options...
Popular Post Mark T Posted Friday at 12:01 AM Popular Post Share Posted Friday at 12:01 AM Probably injectors. Have they been changed ? Remans often are less than perfect. Leak around the pushrod and adds up after a short time. 3 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582128 Share on other sites More sharing options...
Joey Mack Posted Friday at 12:02 AM Share Posted Friday at 12:02 AM Glad you're here Mark.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582129 Share on other sites More sharing options...
96bulldogpower Posted Friday at 01:09 AM Author Share Posted Friday at 01:09 AM 1 hour ago, Mark T said: Probably injectors. Have they been changed ? Remans often are less than perfect. Leak around the pushrod and adds up after a short time. I’ve got a feeling you’re right about that. After inspecting it further tonight I can the the FAINTEST uv dye glow on the injector springs. I will look for new injectors at this point, looks like this is probably my best bet. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582131 Share on other sites More sharing options...
96bulldogpower Posted Friday at 01:10 AM Author Share Posted Friday at 01:10 AM 1 hour ago, Mark T said: Probably injectors. Have they been changed ? Remans often are less than perfect. Leak around the pushrod and adds up after a short time. The truck has about 280k miles and about 20k hours. It’s got the original injectors as far as I can tell Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582132 Share on other sites More sharing options...
fjh Posted Friday at 01:39 AM Share Posted Friday at 01:39 AM 13 hours ago, Mark T said: Probably injectors. Have they been changed ? Remans often are less than perfect. Leak around the pushrod and adds up after a short time. Fairly common you need to put some dye in the fuel filter and run and check with a black light to confirm! As mentioned better than throwing injectors at it a bit of expensive amo for the parts canon on a guess! Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582135 Share on other sites More sharing options...
Mark T Posted Friday at 08:47 AM Share Posted Friday at 08:47 AM IDK that I'd be just running out replacing injectors, but it'd be a likely spot to get more involved with looking for the problem. Then there's the wiring harness, that sometimes doesn't live through it all. Like F said, it can get expensive. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582141 Share on other sites More sharing options...
Joey Mack Posted Friday at 09:14 AM Share Posted Friday at 09:14 AM What about the cups? Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582142 Share on other sites More sharing options...
Mark T Posted Friday at 11:05 AM Share Posted Friday at 11:05 AM 1 hour ago, Joey Mack said: What about the cups? Probably conicals in it. Just a guess. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582144 Share on other sites More sharing options...
The Heinz Posted Friday at 01:49 PM Share Posted Friday at 01:49 PM 4 hours ago, Joey Mack said: What about the cups? They would be the conical style that started in '07. Mack sells a Six-Pack of injectors that includes the cups, orings, and hold-down screws. They're usually priced to be cheaper than all six individually too. Part number for an EPA10 MP7 should be 85143381. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582147 Share on other sites More sharing options...
96bulldogpower Posted Friday at 02:06 PM Author Share Posted Friday at 02:06 PM Okay guys, update this morning I’ve exhausted all my UV dye, I’ve never used this much dye trying to find a leak. I’ve checked meticulously around each and every injector, plunger, and both gallery plugs. I still cannot pinpoint a leak. I have a suspicion of a faint uv glow from the injector plunger springs but I’m not sure it’s even that, at this point even the oil pooled up on the head seems to glow 🤣 it’s driving me crazy.. I could be wrong, but I don’t suspect cups just because the engine starts and runs perfectly with no performance issues, no air blowing into the fuel system either. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582150 Share on other sites More sharing options...
The Heinz Posted Friday at 02:08 PM Share Posted Friday at 02:08 PM Just now, 96bulldogpower said: Okay guys, update this morning I’ve exhausted all my UV dye, I’ve never used this much dye trying to find a leak. I’ve checked meticulously around each and every injector, plunger, and both gallery plugs. I still cannot pinpoint a leak. I have a suspicion of a faint uv glow from the injector plunger springs but I’m not sure it’s even that, at this point even the oil pooled up on the head seems to glow 🤣 it’s driving me crazy.. I could be wrong, but I don’t suspect cups just because the engine starts and runs perfectly with no performance issues, no air blowing into the fuel system either. We've had trucks create oil before, and 9 times out of 10 it's the injectors overfueling. I can't confirm that's your issue 100%, but it sounds like that's your issue. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582151 Share on other sites More sharing options...
96bulldogpower Posted Friday at 02:09 PM Author Share Posted Friday at 02:09 PM 17 minutes ago, The Heinz said: They would be the conical style that started in '07. Mack sells a Six-Pack of injectors that includes the cups, orings, and hold-down screws. They're usually priced to be cheaper than all six individually too. Part number for an EPA10 MP7 should be 85143381. Currently the engine has all Volvo injectors with part number 22479123, I figured these were original to the truck? Would the six pack part number you referenced interchange with the ones I currently have? Vin: 1M2AX04C5CM011802 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582152 Share on other sites More sharing options...
96bulldogpower Posted Friday at 02:11 PM Author Share Posted Friday at 02:11 PM 2 minutes ago, The Heinz said: We've had trucks create oil before, and 9 times out of 10 it's the injectors overfueling. I can't confirm that's your issue 100%, but it sounds like that's your issue. Would this cause the truck to be horrendous on fuel economy? We have a mix of 18 speeds and Allison’s. We’ve always known our Allison trucks to be bad on fuel economy but this one seems to be the worst, and this one is also an Allison truck. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582153 Share on other sites More sharing options...
The Heinz Posted Friday at 02:18 PM Share Posted Friday at 02:18 PM 7 minutes ago, 96bulldogpower said: Currently the engine has all Volvo injectors with part number 22479123, I figured these were original to the truck? Would the six pack part number you referenced interchange with the ones I currently have? Vin: 1M2AX04C5CM011802 Interesting, the number you gave me is for EPA14 injectors, yet the VIN is an EPA10 engine. Per your VIN, the Six-Pack number I gave is accurate. I'm starting to think someone put the wrong injectors in and caused the issues you're having. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582154 Share on other sites More sharing options...
The Heinz Posted Friday at 02:25 PM Share Posted Friday at 02:25 PM 12 minutes ago, 96bulldogpower said: Would this cause the truck to be horrendous on fuel economy? We have a mix of 18 speeds and Allison’s. We’ve always known our Allison trucks to be bad on fuel economy but this one seems to be the worst, and this one is also an Allison truck. That tracks, you're dumping more fuel than needed into the crankcase, so you'd be "using" more fuel than other trucks. Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582156 Share on other sites More sharing options...
Popular Post 96bulldogpower Posted Friday at 02:33 PM Author Popular Post Share Posted Friday at 02:33 PM 7 minutes ago, The Heinz said: That tracks, you're dumping more fuel than needed into the crankcase, so you'd be "using" more fuel than other trucks. Oh man 😓. You’re a lifesaver! I just went ahead and placed my order on a six pack using the p/n you provided. It ships out today, I’ll get them installed as soon as they arrive and I’ll keep you guys updated on the results after a while of working the truck 3 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582157 Share on other sites More sharing options...
Popular Post Joey Mack Posted Friday at 02:49 PM Popular Post Share Posted Friday at 02:49 PM Heinzy strikes again.. 🍻 1 1 3 Quote Link to comment https://www.bigmacktrucks.com/topic/75926-2012-gu713-mp7-making-oil/#findComment-582158 Share on other sites More sharing options...
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