Oil pan leak - wrong pan?

-
U

udlooz

Well-Known Member
Joined
Dec 2, 2012
Messages
63
Reaction score
12
Location
Texas
Have a '73 Duster with a '68 340 block. Have an oil leak at the back of the pan and we cannot get it sealed.:violent1: I originally ordered an oil pan gasket for a '68 340, but did not match what we took out, so ordered one for a '73 and it fit (we thought). Leaked oil even worse. So my mechanic and I are guessing that we need a '68 pan to get this thing fixed. 2 questions:

1) What year and c.i.d. engines would be the same pan as a '68 340?

2) Don't know what a 68 pan looks like....does anyone know if the '68 pan would have any clearance issues with the '73 headers, starter, crossmember etc?
 
X3

318 and 340 pans have the same seal front and rear and should interchange all years. A 360 simply wouldn't fit.Oil pan gaskets can be touchy, but I've had issues mainly with the rear crank seal as well.
 
Engine only has 2000k since rebuild. Mechanic replaced rear main anyway, but it's looking like the '73 pan on the '68 block may be the problem. I originally ordered a 68 pan gasket, but the '68 used holes to align the end gasket Our 73 pan has no holes) so we had to order a 73 gasket kit which used "shoulders" to hold the ends in place. We're wondering if maybe the 68 and 73 are slightly different diameter?
 
a lot of these hard to fix leaks can be traced back to crankcase pressure .check your pcv and any vents for blockage.
 
udlooz said:
Engine only has 2000k since rebuild. Mechanic replaced rear main anyway, but it's looking like the '73 pan on the '68 block may be the problem. I originally ordered a 68 pan gasket, but the '68 used holes to align the end gasket Our 73 pan has no holes) so we had to order a 73 gasket kit which used "shoulders" to hold the ends in place. We're wondering if maybe the 68 and 73 are slightly different diameter?
Click to expand...

When it was rebuilt did he offset the rear main seal so the seams aren't flush with the block? Did he use a little dab of sealant?

Only reason I ask is it can be a problem if installed incorrectly.
 
So is the consensus that the '73 pan should seal up fine to the '68 block?
 
Pics of the pan, the gaskets you used and the rear main cap. I have a pan gasket for an old SB that has ends seals I don't ever recall seeing on anything. I don't remember what year(s) it is supposed to fit though.
 
I suspect the rear main, since working with pan is not helping. The in and out of the seals is important. If one is wrong it could really leak bad. I check myself 3 times, looking up confuses me. Also block and cap edges are sharp. When installing seals care must be used to avoid scraping seal sides.

The Felpro seals are 2 piece, so are not offset. Very little sealer used at ends, dry first with q-tip and acetone. For pan, rubber and cork seals installed on dry surfaces, sealer only at corners where rubber meets cork.
 
maybe the block plug between engine trans behind oil filter?block year makes no difference until magnum for 318-340 any mechanic would know this....
 
KitCarlson said:
I suspect the rear main, since working with pan is not helping. The in and out of the seals is important. If one is wrong it could really leak bad. I check myself 3 times, looking up confuses me. Also block and cap edges are sharp. When installing seals care must be used to avoid scraping seal sides.

The Felpro seals are 2 piece, so are not offset. Very little sealer used at ends, dry first with q-tip and acetone. For pan, rubber and cork seals installed on dry surfaces, sealer only at corners where rubber meets cork.
Click to expand...

Mechanic has verified no oil pushing past the rear main. We have flourescent dye in the oil and checking with ultraviolet light, so getting a really good look.
 
Lonewolf3165 said:
PCV hooked up correctly? Not just breather caps. But something that pulls the crankcase gasses out is a must.
Click to expand...

PCV goes from the base of the Thermoquad to the valve cover. No other vents that I am aware of. Ball rattles freely in PCV valve but may replace. just to be sure.
 
Ok, if not rear main, could it be the the valve covers? If they are not seating, sometimes due to collision with intake, they can drip down and around in hard to see places.
 
KitCarlson said:
Ok, if not rear main, could it be the the valve covers? If they are not seating, sometimes due to collision with intake, they can drip down and around in hard to see places.
Click to expand...

Replaced valve cover gaskets just to be sure. Top and sides are clean and dry....the ultrviolet light clearly showing the leak at the back of the pan and a slight amount at the front of the pan.
 
udlooz said:
PCV goes from the base of the Thermoquad to the valve cover. No other vents that I am aware of. Ball rattles freely in PCV valve but may replace. just to be sure.
Click to expand...

One valve cover has the PCV valve to carb/intake, the other side needs a breather to allow circulation from that valve cover, through the crank case to the valve cover with the PCV.
 

Attachments

  • pcv_valve-scaled500.jpg
    28.1 KB · Views: 225
Sorry...my mistake...it does have breather in the RH valve cover.
 

Attachments

  • Engine right side.jpg
    151.5 KB · Views: 239
Have you verified it's not running down from the oil filter/adapter? I had one do that once and it made a perfect trek down to the rear of the pan making it look like it was the pan leaking.
 
fishy68 said:
Have you verified it's not running down from the oil filter/adapter? I had one do that once and it made a perfect trek down to the rear of the pan making it look like it was the pan leaking.
Click to expand...

Yes...we can actually see the oil seeping at the pan seal using an ultraviolet light.
 
You must log in or register to reply here.
-

Back
Top