Vmac3

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.

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.

I used 2 or 3 9/16" bolts and cut the threaded portion of the bolt in the center. Then I would use an 1/2" extension and slide bolt into the inspection cover then onto the clutch brake. I would use my impact gun to spin off the clutch brake. No torch or air hammer. Usually 2 bolts would do the trick.

Those old 237s were an excellent engine.

The fuel system has changed to Electronic Unit Pumps (EUP). Your dealer will help you determine if the engine can be bumped up to that horsepower. It can be just a software update, or sometimes engine components will have to be changed.

They updated those oil pumps to a high volume type. This was to correct the poor jake brake performance. That humming noise you are taking about is normal.

The fuel system has changed to Electronic Unit Pumps (EUP). Your dealer will help you determine if the engine can be bumped up to that horsepower. It can be just a software update, or sometimes engine components will have to be changed.

I remember there was a lot of screwing around with the engine brakes on these jake heads. The problem was when the engine oil reached operating temperature the oil pressure dropped just enough to not engage the pistons on the engine brake. The cure was to install a high volume oil pump and retro fit these jake heads to top oil feed. Here is the service bulletin. Happy drilling! sb266015.pdf

The Egr system can be deleted, but the engine ECU has to reprogrammed to ignore the EGR. If you go ahead and do the delete, the engine ECU will not see EGR flow when the EGR is commanded on. Then the check engine light will come on and de-rate the engine. I have found plugs on the EGR cooler to block the EGR flow on several trucks but they all had the check engine light on and de-rated engine power. I understand your frustration but its illegal to attempt this.

It doesn't look good. But I would of deleted the coolant lines from the air compressor first then run the truck. Just to be sure. If its the same then.......Hope the counter bores will be okay.

Thank you

I have also seen the square plugs on top of the cylinder heads leaks coolant as well. For the time it takes pull the rocker covers off and pressure test the cooling system to about 20 psi. Also if you have the oil pan off check to see if coolant is coming out from the oil pump pick-up. Should be an indication of a bad oil cooler. Hope its nothing major.

What year are the trucks?

Joey Mack is correct. Those EGR coolers were bad for leaking. If a head gasket is going to fail then combustion gases will push coolant out the coolant overflow. On a side note, if you have a Bendix air compressor, the intake was on the suction side of the turbo and would draw oil out of the compressor. There were plenty of service bulletins that addressed this issue as well. Did you notice your engine oil level dropping? You mentioned that you found heavy oil in the exhaust.

Hello everyone, Glad to be part of the team. I've been a service technician for 20 years. 14 years working on Mack trucks and of course Volvo. I was a shop supervisor for 14 years at a Mack dealer in Canada. I have since retired as a technician and now teach apprenticeship at a community college in Toronto, Canada. I will try and help out in any way. Thanks