gordo9742000 Posted March 17, 2012 Share Posted March 17, 2012 Hello all. Just became the owner of a 1985 r model mack with what I believe to be an em6 300 2 valve. Truck has barely been driven. It only has 110,000 miles on it. Runs like a dream. Only problem is that it drinks coolant. Oil isnt contaminated and doesnt seem to be coming out the stack. Minor seepage coming from the head gasket area. Drinks about three gallons a day when working. Was gonna pull the heads off and send them out to be checked but now I am starting to think about doing the liners too. Looking to see what others have experienced in the past. Thanks in advance Jim Quote Link to comment Share on other sites More sharing options...
Rob Posted March 17, 2012 Share Posted March 17, 2012 You are on the right track. Before pulling the heads drop the oil pan and pressurize the cooling system to about 15psi with air. Look up at the liners and see if coolant is being forced past the sealing rings. If not, go with the cylinder heads and gaskets.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
theakerstwo Posted March 17, 2012 Share Posted March 17, 2012 Or do the water bottle test on the coolant side. Sinple and it will tell you if your getting compression into the coolant and if you are losing water due to a head gasket your getting pressure into the coolant. The compression is what starts the coolant seals to leak in the gasket. Get a pop bottle and fill half full of water then stick the rad over flow hose from the rad filler neck into the bottle. Warm engine as warm as you can get maybe for half hour then watch for bubbles. If so then it will be conmprssion from ahead gasket or crackd head or a air compressor which is rare.Also when the engine cools off stick your finger up in the blow by tubr from the valve cover looking for water dropples. If you find water there and no compression in rad then pull pan and prssure looking for a crack some were of a freeze plug leaking in the heads under the valve covers. glenn Quote glenn akers Link to comment Share on other sites More sharing options...
e9500v8 Posted March 18, 2012 Share Posted March 18, 2012 Those motors have dry sleeves the coolant will not go in the oil pan unless through the head gasket!!! The v8 and all e7 and newer motors are only ones with wet sleeves!!! Does your motor have the cooler box on the side of the left side of the motor? If so does it have water lines going into it? I myself think someone got it hot and cracked the head It is def not a liner they are probly fine. Quote Link to comment Share on other sites More sharing options...
b61mack Posted March 18, 2012 Share Posted March 18, 2012 Those motors have dry sleeves the coolant will not go in the oil pan unless through the head gasket!!! The v8 and all e7 and newer motors are only ones with wet sleeves!!! Does your motor have the cooler box on the side of the left side of the motor? If so does it have water lines going into it? I myself think someone got it hot and cracked the head It is def not a liner they are probly fine. Let it sit overnite and then pull the oil drain plug,( just loosen enought to let some oil out) if there is a decent amount of coolant in there the coolant will come out first. Ron Quote Link to comment Share on other sites More sharing options...
gordo9742000 Posted March 18, 2012 Author Share Posted March 18, 2012 Check the oil yesterday. Wasnt milky or contaminated. Pulled the drain plug. No coolant came out. Pulled the radiator cap off and it seemed to have a lot of pressure in it for being cold and not running. Put the pressure tester on it and it held pressure for several hours without dropping at all. Decided to pull heads. Found a groove in Head gasket from number two cylinder over to a headbolt. Looks like it was burned.Head gasket from number two cylinder over to a headbolt. Looks like it was burned. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted March 18, 2012 Share Posted March 18, 2012 Check the oil yesterday. Wasnt milky or contaminated. Pulled the drain plug. No coolant came out. Pulled the radiator cap off and it seemed to have a lot of pressure in it for being cold and not running. Put the pressure tester on it and it held pressure for several hours without dropping at all. Decided to pull heads. Found a groove in Head gasket from number two cylinder over to a headbolt. Looks like it was burned.Head gasket from number two cylinder over to a headbolt. Looks like it was burned. It would be a good time to send the heads out to be magfluxed and pressure tested.Some times the head can crack from injector bore over to valve seat into the coolant . Quote glenn akers Link to comment Share on other sites More sharing options...
gordo9742000 Posted March 18, 2012 Author Share Posted March 18, 2012 That is a definite. Heads are in the truck headed to the machine shop in the morning. Quote Link to comment Share on other sites More sharing options...
gordo9742000 Posted March 24, 2012 Author Share Posted March 24, 2012 Dropped the heads off at the machine shop and they had their doubts. They said that almost all of these heads they check are cracked. They called me several days later and were amazed that they were not cracked. They ended up going through the valves and cleaning everything up and making good as new or as close to that they could. So now its time to put it all back together.I was wondering if anybody out there have the torque spec for the top end of this engine? I got the spec for the head bolts but I need the specs for the rocker shafts. Thanks Jim Quote Link to comment Share on other sites More sharing options...
miro Posted March 24, 2012 Share Posted March 24, 2012 Put some ultraviolet die in the cooling system, run it for a day and check the engine with a blacklight. Be sure to check the bottom of the air dryer and the intake of the compressor (if it is fed from the engine intake) and the engine oil itself( Not very likely if its not milky) Quote Link to comment Share on other sites More sharing options...
gordo9742000 Posted March 26, 2012 Author Share Posted March 26, 2012 Got the heads on and torque down and most of the accessories put on the outside. Just need to put the rocker shaft and jacobs brake back together. Wondering if anyone has the torque specs for these? Any help would be appreciated. Thanks Jim Quote Link to comment Share on other sites More sharing options...
gordo9742000 Posted March 31, 2012 Author Share Posted March 31, 2012 I guess not. Thanks anyways. Jim Quote Link to comment Share on other sites More sharing options...
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