This photo gives the telltale signs of oil leakage at the rear of the gasket...
Oil leak! In addition to my oil pump rebuild that we did a few posts back I knew that there would be a day I would need to address the issue with a pesky leak at the rear of the block. For the longest time I have had very few issues with oil leaks on this 292 Y Block. Even at Fast Fords in June with all of the hard pulls and the time in the staging lanes things were just fine. Over the past couple of months though I have noticed that when the coolant temperature got up to 200 degrees there was an occasional drip out the back end. Now granted, the rear main seals on Y Blocks are notorious for leaking. Most of that reason is given over to the old rope-style seals or just lack of expertise on the installation of the better neoprene-lipped version.
Oil leaks at the rear of the block can be hard to ascertain. Most often, people think that any leak at the rear of the block just has to be the rear main seal. If you want to see the video version of this post on assessment, then scroll down to the bottom of the post and click the links to part 1 and part 2 of this repair work. Included in the videos are shots of the gasket set, tools you will need, and even references to the shop manual. The videos take quite a bit of work to produce but from the feedback I receive each week through my website and through my YouTube account it seems that many subscribers jump to that version of events rather quickly.
Beyond the obvious tips of using secure jack stands, draining your oil, purchasing a quality gasket set, etc, let me cover a few items that will relieve some frustration if you attempt to pull your oil pan while the engine is still in the vehicle.
Finding the Source of the Leak
A clean undercarriage will help you with locating the source of any leak.
It should go without saying - make sure your engine block and other undercarriage components are clean before you run the engine to find the source of the leak. I can remember years ago at Brenner's Advanced Automotive that one of my jobs was to clean up the engine bay if the mechanics were trying to find the source of the leak. Often this would mean I got to use the steam powered "Jenny" to blast all of the crud, road grime, and oily deposits on the block and the frame and the running gear. Nasty work indeed but I loved it! Sometimes the fellas would call the owner after I cleaned up the car and have them drive it for a few days so that the leaks would have time to come back and the source could be easily recognized.
Make sure the engine is at operating temperature and running when you examine the block for oil. At times, the area will be obvious because there will be a drip, drip, drip coming from a part of the engine that is exposed to oil pressure/presence. For example, I have had several conversations with subscribers this summer concerning the crankcase breather tube on the driver's side of the block. Not only is the location of the puddle on the floor a good indicator of this source, but checking the area where the assembly mates to the block or the outside of the down pipe itself will help pinpoint the problem.
For my Y Block, I certainly knew the location but did not know if the leak was from the rear main seal, the side seals of the rear main, or the oil pan gasket itself. (On rare occasions there could be a leak at the rear camshaft plug as well.) It was not until I removed the flywheel cover to find a dry flywheel, and felt the back of the rear main seal cap, that I ruled out the rear main as a source. Once I removed the oil pan and discovered a very wet gasket from the inside of the pan towards the outside, then I knew it had to be the pan gasket.
Y Block Specifics
Y Blocks have a separate rear main seal retainer from the rear main cap.
Y Blocks do have some peculiarities that make them unique when it comes to dealing with the oil pan and sealing up the block. I go through some of these things in my videos below, but suffice to say most would already know about the rear main seal cap. The seal for the crankshaft is a two-piece affair, the side seals of the cap need to be sealed from top to bottom, and most forget that the studs are open to oil so the threads do need to be sealed as well.
Along with the rear cap would be the front timing cover. Y Block timing covers are notoriously heavy, and the bottom of each one provides a mating surface for the front oil pan rails. It should be obvious that the oil pan mating surface of the block and the lower surface of the timing cover must be lined up on a flat plane or there will be trouble in sealing up the oil pan gasket. (Again, this is also referenced in the videos below.)
Next would be the oil pump pick up tube. I get a lot of questions about where the washers should go on the pick up tube when it mates to the side of the oil pan. (note the picture below)
Oil pan gasket sets come with more than you need. Beyond the main gasket that will seal the oil pan rails to the bottom of the block you will find several washers and maybe other gaskets. Ford had different versions of oil pans so it is always best to check your shop manual diagrams to ensure you place the correct washers in the right positions. The 55 Ford shop manual even calls for sealer at the large nut that retains the pick up tube to the block. Your gasket set will also include a new tubular seal that will slide onto the pick up tube where it mates to the oil pump. This is a critical component to keep unwanted air out of the oil delivery. If you do not have a good seal here at the oil pump then you will have oil pressure loss, I guarantee it.
Another nuance of Y Blocks in mid-50s Fords would be that you need to bring #1 cylinder to TDC in order to remove the oil pan from the car. Trucks would be a different matter altogether as the oil pan is a rear sump, clearance is plenteous, etc. The 55 Ford shop manual mentions this of course, and most of the idea has to do with aligning the crankshaft throws up into the block so that you can slide the oil pan forward. The passenger cars all had front sump pans because of the crossmember that was in the way of removal.
Check Your Oil Pan!
It did not take long to find out why there was a leak at the rear!
When you remove the oil pan it is always best to check your pick up screen and to give everything a good cleaning. This will make the process of inspection much more thorough and less of a mess as you work to install new gaskets and seals.
The oil pick up tube screen was in very good shape.
I even take a wire wheel to the rails to ensure that all of the old gasket material has been removed and that the mating surfaces are very clean. DO NOT LEAVE ANY BITS OF MATERIAL BEHIND! You want that pan as spotless as can be - remember that all of your oil will pass this way and will carry any small objects in suspension right towards that pick up tube screen.
If you look three pictures above you can tell that the oil pan had serious issues with what I call "dimpling". For all practical purposes over an engine's lifespan as the oil pan is removed and re-installed the rails can have dimples because of the over-tightening of bolts/nuts. I can recall a very long time ago when I installed this oil pan I was in a hurry and did not take the precautions necessary to torque things down correctly. While some may decide a hammer and a flat surface to the best means of attack, I decided to be a little bit more gentle and use the bolt/socket method to bring things back to 180 degrees and flat! You can witness this process in the videos but for now we will just leave a picture to show the setup. If you turn wrenches at all you can understand the process.
A simple bolt, socket, washers, and a nut are all you need to take out the dimples.
I made a final check of the alignment by placing the oil pan on a spare block I have. (Actually, this C2AE block is being prepped for a 312 build in the near future - hopefully anyway.) Use a straight edge, feeler gauges, an engine block, or whatever you have so that you can be sure your rails are flat and that the oil pan mating surfaces are square. This will give you the best seal possible.
Ensure the oil pan rails are flat and ready to be mated to the block.
Sealer and Other Controversial Topics
I almost hesitate to include this section because these days the topic of sealer is getting very close to asking what brand or what viscosity of oil to use in an engine. Some people fight and argue over these things. Most Y Block gasket sets readily available are made of cork, and cork is meant to be the material that actually seals out the oil by taking up any variances between the mating surfaces. It is interesting that the FoMoCo shop manual actually calls for using sealer on both sides of the gasket before installation. You may be wondering what I did and what I use for such things. For the gasket I used the Copper Coat in a spray can on both sides. For the mating surfaces where there is a parting line (rear main seal cap and the timing cover) I used the Permatex gray rtv made for gear oil. One handy tip on this would be to use thread to secure the gasket to the oil pan before you lift it into position. I used 8 or 9 strands of thread of a contrasting color from the pan (so I could see each thread for removal after installation) in various holes along the rails. Tying off the gasket this way made it stay in place for alignment to the holes in the block. I highly recommend the idea. Lastly would be the use of a torque wrench. The shop manual will give the specs on torque values, but I do recommend going lightly on cinching down the bolts and the nuts on the studs. If you go through all of the work to straighten your pan you really don't want to revisit the issue next week!
Enjoy the videos below and until next time - keep those Y Blocks on the road!
and part 2...
The Hot Rod Reverend
aka Daniel Jessup