mxbeaver513 Posted April 3, 2013 Share Posted April 3, 2013 I have a 1980 mack 785LT. what model of motor is in this truck. Its not putting any oil out oil pressure gage line. I need to replace motor maybe Quote Link to comment Share on other sites More sharing options...
BAD DOG Posted April 3, 2013 Share Posted April 3, 2013 Try another Gauge first, seen them go before. A lot easier to change then a motor. Quote Link to comment Share on other sites More sharing options...
j_martell Posted April 3, 2013 Share Posted April 3, 2013 By no means am I an expert on Mack motors, but I have done many engine swaps (mostly jeeps), and my advice is start easy and work towards hard. Quote Lack of planning on your part does not constitute an emergency on my part.... Link to comment Share on other sites More sharing options...
umodelnut Posted April 3, 2013 Share Posted April 3, 2013 Pictures of the motor, truck, and serial number would help. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted April 3, 2013 Share Posted April 3, 2013 Most likely a 237 but things can change over the years... If the engine runs but won't show oil psi on the dash gauge. Pull the gauge remove hose and place it in a empty 2 liter pop bottle or large container with small spout. bump the engine over with the throttle stop out and withing 20 sec of cranking or so you should see oil coming out the hose... Carefully it will come out of that hose kinda fast. If no oil after all that cranking start looking for the problem. Quote Link to comment Share on other sites More sharing options...
mxbeaver513 Posted April 4, 2013 Author Share Posted April 4, 2013 yes thats were Iam right now I take off the line n put a cheap gage on and nothing. then I took off the line n just let it hang n still just a few drops running. the door tag says it is a model RWL785LT vin #RWL785LT51690 what should i do next? Quote Link to comment Share on other sites More sharing options...
Superdog Posted April 4, 2013 Share Posted April 4, 2013 wow,a single axle 237 powered,aluminum framed Superliner,we gotta see pics of this. Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted April 4, 2013 Share Posted April 4, 2013 Ok start from the easy part...does it have oil ...seriously...lol....just asking? If she has oil in the pan Try pulling the turbo drain line off the turbo and bump over to see if you have oil flow there. Put a 5 gallon bucket under that oil drain. It will be gushing if you have any pressure...If not I suspect you either have a clogged pickup tube, bad oil pump. Or you have bearings so warn out that it canT build pressure....the line that feeds the turbo comes right out off the main oil gally so it should really move oil a few sec after cranking....let us know and yea we want some pics of this truck...sounds like a rare dog.. Quote Link to comment Share on other sites More sharing options...
mxbeaver513 Posted April 10, 2013 Author Share Posted April 10, 2013 I took off the line from turbo and it just drips. I found a motor and tranmission for sale. I want to ask you guys how should I remove and install a different motor. should I pull the motor by itself or should I pull motor and tranny togeather. This site is very imformative. Thanks Quote Link to comment Share on other sites More sharing options...
Superdog Posted April 10, 2013 Share Posted April 10, 2013 pull them separate Quote Link to comment Share on other sites More sharing options...
JTFormula Posted April 10, 2013 Share Posted April 10, 2013 I would check the oil pick up and pump first before going through the expense and time of swapping motors. How many miles does your RW have? Quote ~ JT Burkard ~ AKA Sweaty Mackwww.jtresto.com www.wickedreputation.netwww.jonathanthomasmotorcars.com Link to comment Share on other sites More sharing options...
mxbeaver513 Posted April 10, 2013 Author Share Posted April 10, 2013 This 1980 mack was a cement truck. It has a 20 foot grain bed on it now. We had a salvage yard swap motor a few years back. It has the old canister oil filter not the screw on oil filters. It had very low oil pressure and the salvage yard told me the motor came out of a very old truck (maybe 69) and had set for 10 years with out running. It ran good but low oil pressure. we just used it for a summer then parked it. We never use it for 6 years now. Recently I start it up and it runs good. but after driving it the turbo started howling so thats when we determine its not got any oil pressure. So iam thinking its maybe really wore out but still a mack and refused to die. I find a place in kansas city that has several old cement truck he is scraping and has the motors and 6 speed trannys (mid 80)he will sell for $1500. thanks again Quote Link to comment Share on other sites More sharing options...
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