Thread: 5.0 L oil leak question

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I have a 5.0 L mustang engine in my 32. It has Trick Flow aluminum heads and ARP studs and nuts instead of headbolts. I bought this engine as a long block and it has been sitting for about a year since being built. I got it running last week but noticed oil leaks coming from between the head and block at the back of the engine. I know it is not the intake leaking.

My question is where could the oil be coming from ? Do I have to pull the heads and re-gasket or is it possible the oil is coming up the threads of the head stud ? To my knowledge there is no oil passages in the head correct ? I thought the head got its lubrication through the pushrod.

Help appreciated.

the oil drainbacks are in the heads, and are you sure its not coming from a valve cover... she'd be running pretty rough if there was any sort of head gasket leak

It is running terrible but I had assumed it was a tuning issue because I have to get the superchip fine tuned on the dyno. It backfires on acceleration. Compression values are within 15 % across the cylinders. The leak is coming out at the very rear of the head between the cylinder head and the block. So what is my fix ?

I assume pull all the ARP head studs and re-seal the threads and new head gaskets ? I didn't build the engine so I don't know if the head studs were sealed

Pull the heads and see if you can determine where the leakage is occuring. There should be some signs there to see.

Are your head studs the proper diameter for the holes in the heads? I would start, before you pull the heads by identifying which holes are the drain back holes (usually in the bottom of the head, for obvious reasons. then when you pull the heads look at the mating surfaces on the head gaskets in that area.

Make sure they put the gaskets on the right way. Ford gaskets are easy to put on backwards, although this usually affects the cooling holes the most.

I really hate dealing with an engine someone else put together, as you indicate yours is. I would suspect whoever put the heads on didn't torque them right, or somehow screwed up the gasket, or it's orientation.

You may want to pull the engine down and check to see what else they may have done wrong. All it wil cost you is a new set of gaskets and some time.

Then you will know where you stand.

Don

I'm an idiot...it was actually a coolant leak. I pulled out the stud and coolant came pouring out. It smells like the kid put the brown gooey permatex on the stud threads. I drained everything and resealed the threads with the ARP pst sealant. I hope that cures it otherwise I'll have to pull the heads and reseal all the studs. When looking at the new head gasket they all have a blue seal imprinted on all the bolt circles except for the bolt hole that is leaking. It makes sense now . Crossing my fingers.

i hope they didn't use sealant on the headgaskets??? that can interfere with head gaskets sealing properly