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I own a '68 M715 Cargo, all stock. Saturday I spent quite a bit of time trying to get the truck started. Ended up having to use a charger on the batteries. The truck started up and was running fine. Was letting it idel and went inside. 10 minutes later when I walk out I have oil spraying out from under the intake manifold. I shut everything down. No radiator fluid. I add oil and the truck starts right up. Oil begins spraying out again from under the intake manifold.
I'm thinking headgasket needs replaced. Would appreciate any thoughts, comments, or guidance for my next step.
Thanks, Howard
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Is the leak from under the intake right up next to the firewall? If so, it could be the oil feed line for the head. The line runs from the exhaust side of the block, off of the oil psi sender by the flywheel, up between the engine and firewall to the back of the head. It is a hard rubber line with coiled steel wrapped around it. Mine broke last summer, sprayed oil everywhere.
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Diamond or Stockton?
They are a son of a gun to get to also, I'd suggest removing the factory crimped collar from the ends and just replace the hose and use hose clamps to secure it. I did this this on one of mine and it held up just fine.
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Besides the head gasket....you probably checked this stuff but....the dipstick and breather are in the area....if you verified, best as is possible, that it wasnt one of those, the head gasket is pretty much all that is left.
As far as tips....
If the rubber hose from the oil sending unit to the back of the head has any leakage, now is the time to do it....putting in a braided steel line like I did is a great way to fix it for the foreseeable future.
The timing chain and gear can be a real pain....might want to look at a new chain and the adjuster while your in there...
If you really want to clean the motor up inside a bit....pain as it is....pull the cam and cam deck. There is a puddle of oil under there that always have some settled out nasty stuff. Also drain the cam of the oil thats in it and clean out the lube holes in the lobes as best as you can. The oil path from the rear of the head up through the rear cam bearing is difficult to clean, but it is very important that this not have any residue that would reduce flow.
Other than that, its pretty much like other motors...torque specs and procedures are in the online manuals, if you need something thats not there, let me know.
brute4c
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All,
Greatly appreciate all the input. Will start with the oil feed line. As I recall, the one on my engine may have been replaced once before, as there is a brass fitting at the back of the head. Will check out this weekend.
When I purchased the motor I had everything outside, clutch, pressure plate, head gasket, throw out bearing, fuel pump, valve cover gasket and all radiator hoses replaced. When the valves were adjusted the mechanic told me the inside of the engine was very clean and it did not appear anything else needed replaced. He confirmed the engine appeared to only have 5,200 miles on it. Could not perform the service myself, due to disabilities. I'm hoping this will be something I can do myself.
Will keep you all posted. Thank you all again.
Thank you, Howard
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In the head, under the cam deck, there is a 'reservoir' that holds a cup or 2 of oil...this area does not drain back to the oil pan after the motor is shut off. There is supposed to be an antidrainback valve in the back of the head to prevent it from returning to the pan that way. This oil is there so that when the motor is started, there is a pool to fill the cam out of and lube the bearings...no actually lubing takes place until the cam and this area are full.
It goes something like this:
Oil enters the rear of the head and goes to the rear cam bearing. The cam has a hole in it here, that when it spins and lines up, gets a shot of oil into the cam, which when the cam is full, comes out of a small hole in each lobe to lube the rocker tips. The oil that doesnt go into the cam, goes into the void under the cam deck. Once this area is full, due to there being little tubes to guide it, the oil makes its way to the forward cam bearings. Any extra that gets down in there, will overflow and come out of the void under the cam deck, where it can run down the oil returns. The heavy stuff that gets down in there, never leaves...and there is a ditch down in there where the stuff accumulates.
I had mine off a few years back, after FE99, and there was almost solid stuff in the bottom of there.
IF you have to pull the head to do a head gasket anyway, it would be worth the time to clean this area up...it really is an unfortunate part of the design.
brute4c
