Impossible Oil Leak?

[Captain Obvious]

On 4/18/2023 at 11:06 AM, chaseincats said:

I'll get a flat head and hammer and try to bash it out or something tonight then.  Could I just go to home depot and grab a thick oring if they have it in its stead? 

Well "hammer" and "bash" aren't the words that come to my mind... I was thinking "gently pry" with a "small screwdriver" or "pointy pick" to identify where the seams are.    But whatever works!

And since the cross section of the original isn't round, I'm not sure sticking an O-ring in there is going to work. It it were me, first thing I would do is clean the coating off the valve cover and use a flat file to dress the surface where the cap is supposed to seal. I don't know if it's a trick of the light, but in the pic you posted, that sealing surface looks to have imperfections on the one side.

Pitting or other imperfections on the valve cover? At eight and nine-oclock in your pic?  :

[chaseincats]

36 minutes ago, Captain Obvious said:

Well "hammer" and "bash" aren't the words that come to my mind... I was thinking "gently pry" with a "small screwdriver" or "pointy pick" to identify where the seams are.    But whatever works!

And since the cross section of the original isn't round, I'm not sure sticking an O-ring in there is going to work. It it were me, first thing I would do is clean the coating off the valve cover and use a flat file to dress the surface where the cap is supposed to seal. I don't know if it's a trick of the light, but in the pic you posted, that sealing surface looks to have imperfections on the one side.

Pitting or other imperfections on the valve cover? At eight and nine-oclock in your pic?  :

Good catch on the pitting but luckily that's just oil that had a couple of small bubbles in it from when I took the cap off (but you definitely did make me look twice haha).  Since the car got a well needed oil change tonight, and in the interest of keeping as much of that oil in the engine as possible, I came up with an interim solution which I think should work:

I grabbed some thick gasket paper and made a ring seal, placing it basically on top of the old rock hard one and being sandwiched between the oil cap and valve cover until I can find a replacement.

[SteveJ]

Just because I like resurrecting old threads every now and again, I wanted to add a product review.

I put the gasket @Zed Head linked in post #26 in this thread on my ebay watchlist. A couple of weeks ago, I got a "special offer" that knocked $2 off the price. I figured I could spend the roughly $6 to get one of these printed gaskets, and it arrived today.

It is much more pliable than the old gasket.

The reproduction is 2mm smaller diameter than the gasket on my spare oil cap.

It's also not quite as thick.

Does it matter? Probably not. It will mate to the sealing surface of the valve cover, and I don't think there would be any gaps. The cap with the new gasket is on the left.

[chaseincats]

1 hour ago, SteveJ said:

Just because I like resurrecting old threads every now and again, I wanted to add a product review.

I put the gasket @Zed Head linked in post #26 in this thread on my ebay watchlist. A couple of weeks ago, I got a "special offer" that knocked $2 off the price. I figured I could spend the roughly $6 to get one of these printed gaskets, and it arrived today.

It is much more pliable than the old gasket.

The reproduction is 2mm smaller diameter than the gasket on my spare oil cap.

It's also not quite as thick.

Does it matter? Probably not. It will mate to the sealing surface of the valve cover, and I don't think there would be any gaps. The cap with the new gasket is on the left.

Just bought it, thanks for the reminder

[Zed Head]

Looks like an interesting experiment.  There is a ton of different grades of TPU out there.  The Overture site does not tell much.  I linked to one of the big TPU suppliers for example, at the bottom.  Click the Products heading to see more.

Still weird that the guy made it look like a Nissan product, even down to the Japanese text.  Almost like it's not meant for actual use.  Good luck!

 

https://overture3d.com/blogs/news/tds-overture

https://cdn.shopify.com/s/files/1/0207/3624/5824/files/OVERTURE_TPU_TDS_EN.pdf?v=1706141279

https://overture3d.com/blogs/news/sds-1

 

https://www.lubrizol.com/Engineered-Polymers/Products/Estane-TPU

https://www.lubrizol.com/Engineered-Polymers/About/What-is-TPU

Edited May 7, 2024 by Zed Head
Oops.

[zKars]

My collection of caps (4 kinds), indicates that all the ones that say simple “OIL” require no gasket on the cap, and fit valve covers that require O-rings in the provided groove around the fill opening on the cover. 

All others, Elephant or otherwise, use the stepped flat o-ring gasket discussed above. A few of mine had that gasket inverted. One had two gaskets, all had at least one. Most were quite hard, though none were rock hard. None were dry split or deteriorated to the point of obvious leakyness. 

I only included pictures of OIL cap and it’s back side showing no groove like all the others that take the step gasket.

[zKars]

O-ring groove in the early 2400 cover

[chaseincats]

Got mine today and while you can pop it on so that it fits tightly to the valve cover, screwing it fully down isn’t possible…

[Captain Obvious]

On 5/7/2024 at 12:07 PM, zKars said:

O-ring groove in the early 2400 cover

So the O-ring for the early 2400 valve covers. Anyone got a source for those?

Fits in this groove as pictured above:

I assume it would be easy to measure the size and find a suitable replacement, but I also assume someone has already done that work so I don't have to do it again?

[chaseincats]

5 minutes ago, Captain Obvious said:

So the O-ring for the early 2400 valve covers. Anyone got a source for those?

Fits in this groove as pictured above:

I assume it would be easy to measure the size and find a suitable replacement, but I also assume someone has already done that work so I don't have to do it again?

I just don't understand how the pressure in the valve cover is so great that it is able to push oil vapor out of the cap.  I checked my PCV valve the other day as well as the hose and everything is clear/working properly.

[Zed Head]

Blowby from combustion can create pressure.  But there is also just general leakage and surface coverage from the oil vapor and oil splashed on to the bottom of the cap and cover.  Oil tends to spread and cover whatever surface it contacts.

[chaseincats]

39 minutes ago, Zed Head said:

Blowby from combustion can create pressure.  But there is also just general leakage and surface coverage from the oil vapor and oil splashed on to the bottom of the cap and cover.  Oil tends to spread and cover whatever surface it contacts.

Fair enough - so all Z's have oil vapor stains on their valve covers?