911porschefan

Some know my story, but here is the short version. Took my car to a reputable indy to have my oil leak addressed. Car was there about 2-3 weeks, didn't care about time frame as I couldn't drive it anyways. Was told that they needed to borrow a special tool from Porsche to diagnose whether I have a crack in my case or source the location of the leak. Was told that I had a crack in the passenger side of my case where it seals together. After excessively cleaning and tearing apart most of my engine, I still have yet to see the crack. I did notice leaking from the valve and timing chain covers, but nothing from the case.

1. Does anyone know what type of special tool this is? What it does? Is it real?
2. Have not taken off the heater exchangers yet as the engine is on a cart, not a stand. Could the case be cracked somewhere that the exchangers are hiding it?

I want to believe the indy since I have known him for a long time and his reputation is outstanding, but having some doubts my case is cracked.

Makmov

Well since you cannot magnaflux an alumium case there is probably a special tool to do it. Seems that I recall something about sonic testing a case. I guess they also can use some photo developer stuff which is a three part process, however, you need the case split, cleaned and dry to do that.

ThomasC2

The O-seal where the camshaft enters the chain housing is a common leak. I have it but still not much to bother with. Are you sure you have a crack and why do you think you have one? A cracked case is not very common failure.

Thomas

mojorizing

Take photos of the general area to your mechanic to point to the crack.

You can use penetrating dye to see the crack once you know generally where it is - it's a 3 step processes. Cleaner, dye pen, developer - highlights the crack. Don't get confused by casting lines etc.

Indycam

Indycam

http://www.lightplane-maintenance.com/LPM_LPM_0605.html
"Crack Finding
Since the beginning of time, the FAA, and the aviation industry as a whole, have used dye-penetrant testing procedures to find cracks in aluminum castings-including those found in crankcases. Fact is, crankcases are required to pass a Zyglo check before a serviceable tag is issued to the part."

cobalt

I can assure you that every you tube post is an epic fail in one way or another and stay away from visible dye testing. (the red stuff) Magnaflux, zyglo are just trade names for liquid Penetrant testing.

Not sure what line your mechanic is using but if they are not certified to do this type of work I wouldn't trust the results.

Proper surface preparation, application of penetrant, dwell time, rinsing including type and temperature, developing and viewing conditions are critical to determine the test results. If a crack is present it would need to be determined if it is surface or through wall (harder to do than you might think). Sensitivity of the penetrant is critical and verification of the effectiveness of the test is helpful to determine if the penetrant will penetrate the indication.

In either case the cost to break down the entire engine clean it properly and do the test will be very costly. Before they start to take anything apart i would consider getting a second opinion.

Black light viewing should be done in a room without background light and have a minimum of 1200uw at 15inches to properly determine what you are seeing. Your eyes need 5 minutes to acclimate before inspection and unless you have some understanding of what your looking at all sorts of indications can appear to be something they are not. Any indication should be swab tested using a dampened swab with alcohol and redeveloped to determine if it is a relevant indication.

Yes it can be done but I wouldn't trust my mechanics word especially if he needs to buy a "Special tool" from Porsche to test.

For your edification penetrant inspection can pick up porosity or cracks of very small size. The photos i am attaching show a surface that the naked eye detects as being perfect. After failing penetrant inspection the area was cut and polished and a photo was taken at 500x magnification as you can see there is a rather porous surface even though they eye cannot detect it. BTW the section in black box is smaller than 1/8" actual size.

911porschefan

The indy that I went to told me that there is a crack in my case

911porschefan

Cobalt - thanks for the detailed procedure. I am sure they did not break down any part of the engine to determine that my case was cracked. I was told they borrowed a tool from Porsche that would determine whether it was cracked. Sounds like the dye penetrate process in a way. I was told they needed to put something in the motor and then the cracks would show through.

KaiB

meh...harrumph.

My GM dealer just told me my Duramax fuel filter was in the tank and didn't need replacing during my 36K service.

Blown Away

As has been said, a cracked case is fairly rare and your photos look fairly free from oil.

I'd suggest you check what your indi meant. Does he mean that one of the aluminium casings has cracked or does he mean the two sections are separating?

If they are separating, that could be more common as the through bolts can fail.

You are already a long way down the slippery slope - if you have a leak between the two sections the through bolts could have failed, I'd say get the through bolts redone. Upgrading with ARP bolts is common.

If you are going in there, take a good look at the crank, bearings etc.

You don't want to be doing the job twice IMHO.

cobalt

i would request a more detailed explanation. Sounds like some kind of dye they are adding to the oil and then looking with a black light to see where it shows up on the outside of the case. Although if it is apparent enough i doubt you need to go that far.

Assuming there is a product that Porsche makes that can be added to the oil it is possible. this would be similar to what they use for A/C systems. However a simple can of gunk and pressure washing of the engine and watching where the oil comes from would do just as well IMO.

Odds of cracking the engine case is rare, heads more likely but without the motor ceasing I doubt it is cracked.

I know my mechanic personally and still question what he tells me, I never trust anyone when it comes to things this extreme especially if it is the first time using them.

August West

Yo Porschefan, I've been following your posts regarding your oil leak woes...my sympathies as I went through all this last year to the tune of $20k dollars but now have no leaks (my story is detailed elsewhere on this forum).

My thoughts pertaining to your situation are the following:

With a leak of 4-5 inch puddle per day and leading up to a two foot puddle over a couple of days, I'd find it hard to believe it would be coming from a crack in the case that noone can seem to be able to find.

Occam's Razor and my own personal experiences with all things mechanical and electrical point to something much simpler than what your expecting.

Hang in there and keep your father-in-law on a leash!

Metal Guru

The possibility of a crack in the case from normal usage is almost zero. It would take an impact to do that kind of damage.
If it were a leak from porosity, chances are that the first owner would have detected it and Porsche would have given him another engine.
The most likely areas for a leak to occur from are the thermostat body on top of the engine or the power steering drive take off on the right front side of the engine. Inspect those areas first.

Indycam

http://www.lightplane-maintenance.com/LPM_LPM_0605.html
"While we will agree some cases seem more crack-prone than others, no engine is immune. Both Lycoming and Continental discuss crankcase cracking at length in service literature, understanding that it can happen and with some frequency.

Both publish guidelines for inspecting cases and offer advice on what is considered airworthy and what isn't. Some publications provide repair criteria to be used during overhaul that severely restrict where welding and re-machining of the case may be accomplished."

"Crankcases crack because aluminum castings do not like to flex and air-cooled engines equipped with opposing cylinders flex as a matter of operational functioning. The result is predictable as the case relieves normal and abnormal stresses."

My father was a prototype machinist for Hughes Aircraft , he tells me that every piece of metal is flawed from the get go and more so after it has been machined as most machining rips metal from metal . Every cut surface has micro cracks resulting from the cutting . He has told me that if you look close enough at any part you will find flaws , that the trick is knowing what flaws are acceptable and what flaws are not .