Looks like crack to me.
You have 2 choices, sell the car or drive it until it leaks then you'll be concerned at what to do..
I wouldn't spend a dime on expensive analysis procedures cause you'll need a new engine if it's a crack or pay for the expensive analysis + assembly of the engine.. Either way you're going to spend a small fortune.
What if it's nothing?
Drive it until the oil pressure light goes blink! (if that ever happens)

Good luck.

 

Could this have been caused by raising the car using the crankcase as a jacking point?

H

 

This is a good reason to never clean off or look closely at the bottom of your motor

just kidding. Hope its nothing bad.

 

I hope not! I think most of us jack the car up that way...

 

?!!

 

I have the similar marks on my case. I am curious about how common they are. Does anyone else see them on theirs?

 

Yes, no leaking which is good so far. If the cracks to grow over time I may be tempted to investigate the shallow drilling option.

Thanks for info, have scrubbed fairly well now and still looks similar. Shame the whole engine would need dissasembly for any future repair..

Unfortunately not raised. (shame as then I would have thought casting marks)

I have to say, I'm with you on this. Having just spent a fair amount for a top end rebuild and replacing oil pipes I'm not inclined to spend out for a full rebuild only 1k miles later!! Will monitor the marks over time and see what happens. They may well get me through the next 15 years, 70k miles until next top end then it won't be too much of a stretch to get into the case too. So fingers crossed, use it as it was meant to be used.

Not in my time but I was not the 1st owner and used to run with undertrays so might have never noticed it in the last 14 years!

Yes, very wise words given my 14 years of ignorant bliss....

Are your marks raised or are they cracks too?

 

I'll check tonight... Were those cracks there prior to the top end rebuild? Is it possible that they were caused by the shop that did it?

 

Being an ASNT certified casting inspector of aluminum and magnesium castings with over 25 years experience inspecting castings through penetrant (magnaflux, zyglo as stated elsewhere) radiographic and visual inspection methods . I have to say the photos are inconclusive and far too low resolution to determine if it is a crack.

This could be a surface irregularity since there is a thin surface skin created by the casting process. This could be the result of removing the part too early or not perfectly square with the die while removing it during solidification. Then again it could also be a crack although I highly doubt it. The impact needed to crack a casting like that would be far greater than what we are seeing and if it did crack I would expect to see some oil seepage and far more damage more than likely an indentation deforming the casting from the impact.

If you would like, send me a high res picture and I will take a closer look. Otherwise now that you have thoroughly cleaned it drive it for a while and keep an eye on it. If you notice oil seeping outwards from the crack you have an issue. Although as I said I highly doubt you have a serious issue.

 

Brilliant! Where else but Rennlist could one find an expert in aluminium casting.

 

good question but I don't have any evidence they weren't pre existing.

appreciate the offer thanks. Let me dig up a decent camera and light source and try again with macro.

too true

 

+1 on cobalts comments, I've seen similar looking casting flaws in 911 cases since early motors, and a crack in that location would be leaking like a sieve, the marking on case suggests it got dinged but IMHO its not worth loosing sleep about...I'll bet everyone on the board could go home and find a similar looking flaw on their cases...

 

On a die used for casting,due to the extreme heat involved,over time cracks will appear in the die.These cracks will show up on the casting as raised marks where the alloy has cast into the cracks or sometimes a line of alloy will stick to a overly hot part of the die and cause a small fisure in the casting, so if the line is raised above the surface it's nothing to worry about,if it's into the surface it's still not 100% certain to be a crack.

 

Good point.

Run your fingernail over the surface to see if it is raised material or if it is below grade/surface. If it is raised we have an answer if not we can still try to help although these things are never easy to determine through pictures.

 

I have exactly the same marks on my case without the ding on the bottom so I think we are worring about nothing...