oil leaks

[nickz84]

my 79 gmc the engine is a 72 or 73 400sb i believe engine is leaking oil from 2 places and i havent got any idea where to begin one leak is coming from where the pulley to the belts are in the area right above the frame in the front it leaks right onto the frame and puddles up and the other is farther back closer to the oil pan and transmission pan,it actaully drips off 2 metal tubes that run into something next to the trans pan. i bought the truck from my dad 2 years ago he had oil pan gaskets and front and rear seals changed and someone told me today that they may need to be replaced again is that possible already.any help is appreciated im totally new to the gmc/chevy thing so any help is appreciated..also how do i locate the numbers to identify what year the engine is i dont know where to look or what to look for thanks again

[beaterC10]

The leak in front might be a power steering pump. You might want to steam clean or pressure wash the engine compartment first and then try to find the leak, it might be easier. The leak in the rear could be a valve cover, rear of the intake manifold, or a sender.

[piecesparts]

Did the last replacement of gaskets take place with the motor in the engine bay? If so, then I would venture to say that the work may not have been successful. Also, what required the last gasket replacment? Was there leaks in the same places? If so, then may be the real problem was not fixed then. The oil galleys on the back of the motor could have a leak, as said above the valve cover or intake manifold could be leaking. The front leak could easily be the front timing chain cover seal, no big deal.

I agree ---clean the motor completely and then run the motor and find the area of leakage. Work from there.

[benoit454]

I had a leak on my 86 k10 305 and now 350, that will leak on the pulley and drip on the frame in the middle and onto the front end cover, also mine would only leak if you kicked in the four barrel or passing gear, it ended up being the fuel pump or plate gasket.

I changed both of thoose, used some blue rtv on them, both sides, and made sure the bolts were tight. I torqued them, ran the motor to get it warm then retorqued, that fixed the problem, then we put in a 350, now it does the same, but a bolt is missing from the plate, or broke inside, and it only leaks when you kick it down too.

2 Metal lines, you mean trans. cooler lines? they go from the radiator to the trans.?

My front leak blows back on the lines, they have an oily drip spot or bubble if you will on them, sometimes it drips.

[lurch115]

if the motor was pulled out when they replaced the front and rear main seals there is also a possiblity that the transmission lines(the 2 metal lines you see) could be slightly loose on the tranny.....and another thing to look at for the front leak is that it is possible that the harmonic balancer has grooves worn into it (most factory ones do get them with age) and if it does a new seal wouldn't do any good....either replace the harmonic balancer, or get a sleaving kit for it