M38 oil pan gasket

[horse]

Hi, I would like to change the oil pan gasket we call it a sump gasket all the same I think.

The gasket has arrived and is made of cork, looking through some of the posts some use sealants as well.

Also noted was not to tighten the bolts up very much, just snug as not to deform the gasket.

So sealant yes or know, if yes the best places, also is there a tightening order on the bolts.

Thanks for any advice.

[wesk]

It helps you receive more accurate answers if you identify the make/model of the vehicle you are asking about. This is easily done automatically by simply adding that information to your signature element at the end of your post.

Using the correct service pubs and parts listing is very important as is occasionally referring to the civilian jeep manually that is most equivalent to your make/model jeep. Often times the civilian manual which is meant for use by both mechanics and owners will have more detail on certain procedures.

1 - And as is the norm all surfaces need to start out clean & dry.

2 - Make sure you pean the existing bolt holes in your pan back outward so the edge of the pan is perfectly even/flat.

3 - Follow directions in service manual for installation If sealant is required it will be mentioned. It is seldom used by pro's unless the manufacturer's data specifies a need for it. It makes the seal to pan surface slippery allowing the seal to migrate outward or inward during tightening which leads to unwanted leaks. Sometimes there will be light damage to either of the metal surfaces that will not clean up smooth. It is common practice to use a drying sealant or epoxy to smooth those out.

4 - Bolt tightening sequences if critical are usually published in the service manual. If nothing is published then the industry standard is to insert and snug the bolts in a diagonal crisscross then go back and torque them in a similar crisscross.

[horse]

Thank you for the tips, in my ignorance I thought the oil pans on the L Head are the same.

I have seen some posts from people that put sealant on the pan side to hold the gasket in place then offer it up an hour or so later to try and stop any slip when tightening.

I will follow 1 - 4.

Signature sorted.



Thanks.

[wesk]

Differences in equipment are one reason it's a good thing to ID the vehicle you are discussing. Another thing is to help folks offer you the appropriate manual selections that may help.

The main problem with the old Army manuals is they are written on the assumption that they will be used by trained motor pool technicians. To get why and how answers from them is virtually impossible. One would have to review a motor pool technician's technical training course text books for these answers.

With the M38 the appropriate manual selections for this issue are the TM 9-1804A


This is all the Army thinks it needs to tell you.


Then you go to the index and look up "Torque Specs" Ahhh Page 121 Par 148 & 149, great.


Page 121 has NO TORQUE SPECS nor are any torque charts found anywhere in this manual!

Let's take a look at the Civilian Jeep service manual for the CJ series early (Up to 1964):


Voila, they even give the torque specs here. A note of caution here. This paragraph assumes the engine is on an engine stand and inverted so all you need do is lie the oil pan on the bottom of the block.


This chart is in Chapter "U" of this CJ manual.

The advice to use grease to hold the gasket in place is very poor advice. If you cannot keep your gasket still during installation then use a very light amount of drying gasket cement not RTV or other pasty sealants. Gasket cement is very tacky and thin and is usually applied with a very thin brush or special applicator. Usually this Hi Tac cement is a very thin dark brown fluid.
https://www.summitracing.com/parts/ptx- ... 60QAvD_BwE

Do not use silicon based sealants like RTV.

Watch this https://www.youtube.com/watch?v=eHEcf0itBuE

[horse]

Good information thanks, I have found a lot of assumed knowledge with the T.M. I have seen on U Tube the sealant, thanks for giving the make.

Which is the best book to buy to give you more information as you have shown?

[wesk]

For the CJV35, M38, M606: http://www.willysmjeeps.com/v2/modules. ... _album.php



For the M38A1, M170, M606A1 A2: http://www.willysmjeeps.com/v2/modules. ... _album.php



I have a large part of these manuals loaded in my photo album page 3.

[horse]

Thank you, I will have a good study.

[horse]

Amazing bought the Permatex 80062 in the U.K, postage more than the product,least it is the correct product.

[horse]

I have removed the oil pan and cleaned all areas.

I have noticed two small holes which have some type of fibre in them.

If you look at Wes photo album, L134 engine photo 116, they are at the back of the engine next to the two oil pan fixings.

Should they be open or filled?

My leak is from this area and just thought they might be connected.

[horse]

Think I have found it.

TM9-1804A page 87 Installing rear -bearing cap packing.

I suppose the gasket should cover it anyway.

[wesk]

[horse]

Thanks for the clear photos. I see the cork gasket cuts around this packing.
Do they ever leak down the packing and do they need to breath for any reason?

[wesk]

The two rubber tubular seals are cut after installation in their grooves so a 1/4" pertrudes from the block. The pan and gasket will then compress this so the tubular seal expands tightly in it's grooves.



No sure what you meant by cuts the pan gasket but yes the tubular seal leaves a light indentation in the pan gasket.

[horse]

Thanks for the explanation.

My gasket has two cutouts in this area and the two tubular seals are a type of fabric on mine which will give no upward pressure.

I will have another look tomorrow.

[wesk]

If there is any evidence of oil leaking on the rear face of the block under the flywheel you should pull that main bearing cap and replace the entire seal set. The pan gasket is not suppose to have any cutout for those two tubular seals.