Sealing the dipstick

[nrramse]

Has anyone figured out how to seal an OEM dipstick? I don't mean where the tube inserts into the pan, but where the stick inserts into the tube. A lot of the newer vehicles have a little o-ring built into the dipstick - I'd like to do something like that.

 

[broncodriver99]

For what purpose? There really shouldn't be a need to have a seal there. With newer vehicles it is more a function of emissions standards than a contamination prevention measure.

 

[Steve83]

Swap in a newer dipstick. ;D



But be prepared for more PCV sludge...

 

[nrramse]

For what purpose? There really shouldn't be a need to have a seal there. With newer vehicles it is more a function of emissions standards than a contamination prevention measure.

There's a little vacuum in the crankcase, because of PCV system - right? Sealing the dipstick would improve the vacuum and keep the dirt out. That's my line of thought, anyway.

 

[nrramse]

Swap in a newer dipstick. ;D



But be prepared for more PCV sludge...

I've thought about putting in a newer dipstick, but if there's an easy way to keep the OEM I'd like that better.

How would a sealed dipstick cause more sludge? In my mind, it seems more like the opposite.

 

[ntsqd]

I did this on my old '84 Xcab when the engine was rebuilt. Used a compression union between the tube and a tube brazed to the dip-stick. Bottom nut left tight, top nut tightened up, then loosened to finger tight.

 

[broncodriver99]

There's a little vacuum in the crankcase, because of PCV system - right? Sealing the dipstick would improve the vacuum and keep the dirt out. That's my line of thought, anyway.

If you look at the old dipstick vs a new one they are made differently. The old one has a sort of shield that slips over the tube and acts as a dust shield the new one doesn't have that but uses an o-ring instead. I doubt much if any fresh air enters the crankcase through the dipstick tube when there is a dipstick in place. You could just find an o-ring that fits the diameter of the inner part of the dipstick handle and roll it onto the stem of the handle.

The PCV is metered so the vacuum won't change. The orifice in the valve is the same no matter where the fresh air comes from.

 

[Steve83]

How would a sealed dipstick cause more sludge? In my mind, it seems more like the opposite.

Right now, there's a fresh-air leak around the dipstick. When you seal it, the PCV will get a more-concentrated load of vapor from the crankcase, which will condense in the intake to a thicker layer of sludge.

 

[ntsqd]

oh please!
The volume of air that can leak there is so tiny as to be insignificant to anything that isn't EFI. Even then it's probably not a big deal.

 

[Steve83]

I didn't say it would be 100x as much sludge - do I have to specify every little detail for you? ;D

The change will depend on how much sludge there is now, and how much air was leaking in OR OUT of the old dipstick. If you have a lot of blowby now, and it's venting out the dipstick, and you seal the dipstick, guess where all the blowby has to go now. Some will blow out the crankcase vent (air filter housing), and some will go through the PCV into the intake, increasing the sludge.

If you have very little blowby, the change won't be as noticeable. But either way, it will increase, which is all I said originally.

 

[ntsqd]

You hold me to it, so turn-about is fair play.

I maintain that the volume of leaking air is insignificant to anything except an EFI system, and maybe not to it as well. However, even that little air volume could have dirt in it and that isn't acceptable. Which is why I sealed it with the method described in my first post in this thread.

 

[broncodriver99]

Any microscopic contamination that could possibly make it's way down the dipstick tube would be immediately caught in the oil and filtered out before it ever made it's way to any moving parts.

 

[ntsqd]

One would hope you're correct. For so little effort involved I'd rather not take the chance.

 

[nrramse]

Right now, there's a fresh-air leak around the dipstick. When you seal it, the PCV will get a more-concentrated load of vapor from the crankcase, which will condense in the intake to a thicker layer of sludge.

Respectfully, I disagree. The PCV system also pulls filtered air from the air breather. The whole system is essentially a "controlled vacuum leak" to suck out engine vapor. A sealed dipstick shouldn't change the amount of fresh air available to it, unless the air filter is horribly clogged.

Anyhow, I guess I don't have as much faith in the OEM dipstick as you guys do. It seems like fine dirt can get in there pretty easily, though I admit the problem is kind of low on my priority list.

Thanks for sharing your thoughts guys. I'll post back if I come up with a solution. Also, ntsqd, can we see a pic of the compression nut you put on?

 

[ntsqd]

You could have if you'd asked last week. After 18 years of owning it, the truck went to it's new owner last Saturday. Sorry.
It is just a compression union fitting with the ferrules crimped to the tube on one side and to a short section of tube that was silver-soldered to the dip-stick on the other.