I have an 03 Gt and it had an oil leak coming from the front of the engine, it leaked all over the exhaust and smoked quite a bit so I decided to take care of it. I assumed it was the oil pump o-ring or front crank seal, so I replaced them both and resealed the oil pump. I left the timing belt cover off and was checking for leaks after I finished and it was still leaking

 

After drying it off a bunch of times i determined that it was not leaking from the pump, it was leaking just to the left of the pump out of the cylinder or "case half". I took powder (hot coco powder mix to be exact, I ate the left over) and put it in the area too see where it was sticking and washing off and found an extremely tiny pinhole or defect in the cast. It must be in a pressurized oil galley because it leaks alot more at high rpm. I couldn't even see the hole or defect or whatever you want to call it. Either way I cleaned it up, roughed the surface, cleaned it again and got out the JB weld.

 

I assume it has been there since new, Seems to be holding up so far!

 

wow, thats crazy. I would never have found that.

I am surprised it didn't show up sooner; rare for a Subie

I just got the car not too long ago and the dealer threw it up on the lift for me when I bought it and everything was covered with oil, I assumed it was the typical subaru leaks. I hope it holds up

Hm that's pretty weird, but I guess some percent of defects don't get caught. JB Weld works in some pretty interesting situations so hopefully it will last long term. Much faster and less expensive than a new block that's for sure!

I wonder if you could drill/tap and plug it with a small bolt?

 

might not be worth the risk of introducing metal shavings or 'propagating' a crack.

 

how about heli-arc or w'ever welding it over?

I wonder if you could drill/tap and plug it with a small bolt?

 

might not be worth the risk of introducing metal shavings or 'propagating' a crack.

 

how about heli-arc or w'ever welding it over?

 

If the JB weld blows out and I get enough ambition plan b is to weld it shut. My last Legacy had the crank pully come loose and trash the woodruff key slot and end of the crank, I broke out the JB weld and machined it with a file and it shockingly lasted the rest of the time I had the car (about 100,000 Miles). Traded it in with 318k on it.

Yeah the main pressure gallery for the block and passenger head runs right behind there I think. So any where for that oil to go it's going to go with about 40-70 psi behind it.

 

Did the block look corroded at all right there?

Kinda wonder if someone jammed a prybar or screwdriver down there trying to get leverage and cut it just enough to make a weak spot.

Yeah the main pressure gallery for the block and passenger head runs right behind there I think. So any where for that oil to go it's going to go with about 40-70 psi behind it.

 

Did the block look corroded at all right there?

Kinda wonder if someone jammed a prybar or screwdriver down there trying to get leverage and cut it just enough to make a weak spot.

 

No corrosion at all, It was a southern car all of its life and I examined all over for other damage and found nothing. I thought the same thing and figured it was from previous damage, however it looked flawless. I made a decent mound of JB weld over a wide area hoping that it will make it stronger and hold up to the oil Pressure at high rpms.

 

I thought about making a test piece of aluminum with a pin hole and an air chuck on it to test the strength of JB weld in a similar situation. I would drill a hole with the smallest bit possible and prep the area the same as I did on the block, jb weld it and crank up the air pressure until it blows apart or maybe not at all. I only have 130 psi available on my compressor but thats more than an oil galley would see.

i don't mean to be a jerk, but i find this hard to believe.

 

surely it is leaking from somewhere else and just collecting there.

 

but of course i have not seen the block or the oil leak so i will watch and listen.

 

jb weld will work great of you can get it to bond with the surface of the aluminum. maybe rough it up with some coarse sand paper.

I thought about making a test piece of aluminum with a pin hole and an air chuck on it to test the strength of JB weld in a similar situation. I would drill a hole with the smallest bit possible and prep the area the same as I did on the block, jb weld it and crank up the air pressure until it blows apart or maybe not at all. I only have 130 psi available on my compressor but thats more than an oil galley would see.

 

I've done a similar test, and the jbweld worked! Granted this was 2" black iron pipe for compressed air, but it sees 120psig and it has held leak free for a few years.

 

Either way I cleaned it up, roughed the surface, cleaned it again and got out the JB weld.

Yep he's got the roughing of the surface covered!

No corrosion at all, It was a southern car all of its life and I examined all over for other damage and found nothing. I thought the same thing and figured it was from previous damage, however it looked flawless. I made a decent mound of JB weld over a wide area hoping that it will make it stronger and hold up to the oil Pressure at high rpms.

 

I thought about making a test piece of aluminum with a pin hole and an air chuck on it to test the strength of JB weld in a similar situation. I would drill a hole with the smallest bit possible and prep the area the same as I did on the block, jb weld it and crank up the air pressure until it blows apart or maybe not at all. I only have 130 psi available on my compressor but thats more than an oil galley would see.

 

As long as you got the block clean the JB should hold. When you think about it, the JB covering the surface area of that pinhole is only getting a fraction of the pressure from that gallery. PSI Pounds per Square Inch, means that literally. So if the hole is 0.01" square, it only deals with one one hundredth of the pressure.

At warm idle the oil pressure spec is only about 12 psi. At 3000 rpm its something like 35psi or more IIRC.

Probably could have stuck gum on it and it would be fine. :-p

When you think about it, the JB covering the surface area of that pinhole is only getting a fraction of the pressure from that gallery. PSI Pounds per Square Inch, means that literally.

 

Ah, the wit and wisdom of USMB. It's why I enjoy this site so much.

 

Thanks Fairtax for your spot-on logic.

That's actually the exact solution Honda had in a TSB for some of their early v6's. They had porous block castings and would weep oil out. The fix was to clean the block well and butter it with JB.

My last Legacy had the crank pully come loose and trash the woodruff key slot and end of the crank, I broke out the JB weld and machined it with a file and it shockingly lasted the rest of the time I had the car (about 100,000 Miles). Traded it in with 318k on it.

 

 

This story seems SO familiar - have you posted this before under a different user name or on another Forum?

 

anyway, that oil leak is very strange.

Trust me I didn't believe it at first either. That's why I checked it countless times with the powder, and every time it started carrying the powder away right where the dot was. That's the only place I put JB weld and no more leaks. I am on day three and still not a drop under there

 

I roughed it up extremely well and cleaned it twice. Ill keep this updated and let ya know if and when it fails

 

 

i don't mean to be a jerk, but i find this hard to believe.

 

surely it is leaking from somewhere else and just collecting there.

 

but of course i have not seen the block or the oil leak so i will watch and listen.

 

jb weld will work great of you can get it to bond with the surface of the aluminum. maybe rough it up with some coarse sand paper.

This story seems SO familiar - have you posted this before under a different user name or on another Forum?

 

anyway, that oil leak is very strange.

 

I may have, I honestly can't remember. If I did it was about 4 years ago

 

 

 

 

That's actually the exact solution Honda had in a TSB for some of their early v6's. They had porous block castings and would weep oil out. The fix was to clean the block well and butter it with JB.

 

That's good to know! at least my thinking was not too far off.

You may be experiancing porosity which is a casting defect in aluminum and other metals. You see it to some extent in motorcycle engines as well as snowmobile engines. If it is patching generaly does not work due to the fact that the metal has casting defects similar to holes in a sponge.

As long as you got the block clean the JB should hold. When you think about it, the JB covering the surface area of that pinhole is only getting a fraction of the pressure from that gallery. PSI Pounds per Square Inch, means that literally. So if the hole is 0.01" square, it only deals with one one hundredth of the pressure.

At warm idle the oil pressure spec is only about 12 psi. At 3000 rpm its something like 35psi or more IIRC.

Probably could have stuck gum on it and it would be fine. :-p

 

It sees all the pressure, but there is little total force.

 

Call it 35 pounds per square inch, the force on a 0.01 square-inch area plug would be 0.35lbs.

 

Dave

The oil pump relief is around 72 psig on the n/a's and it would see that say at startup or higher rpm operation after warmup.

 

Supposing the hole is 1/64" dia. or 0.0078125" rad. would be

a=pi*r*r=3.14159*0.0078125*0.0078125=.0001917 square inches

So force would be say 72psig*.0001917sq. inch = ~.014 lbs

I think the JB Weld should be able to hold that!

You need a self-sealing stem bolt.

 

Go see Quark.

The oil pump relief is around 72 psig on the n/a's and it would see that say at startup or higher rpm operation after warmup.

 

Supposing the hole is 1/64" dia. or 0.0078125" rad. would be

a=pi*r*r=3.14159*0.0078125*0.0078125=.0001917 square inches

So force would be say 72psig*.0001917sq. inch = ~.014 lbs

I think the JB Weld should be able to hold that!

 

Ha yea I would think so!

You need a self-sealing stem bolt.

 

Go see Quark.

 

I thought you were serious until I googled it and got nothing but star trek stuff haha

I thought you were serious until I googled it and got nothing but star trek stuff haha

 

 

yeah, stupid comment from me.

 

but, that episode is kinda fun - basically about a bunch of trading back and forth and a guy gets stuck with these bolts his nephew bought just because they were cheap or something...until the very end and someone needs them badly and it works out OK. maybe it was in the next episode or... I really don't recall the specifics....just never forgot the 'self-sealing stem bolt' phrase.

 

Sounds like they might actually work! lol!

 

http://www.youtube.com/watch?v=jfqeUq7sZPI

Edited November 4, 201114 yr by 1 Lucky Texan

Still holding strong!