M35a2 oils

[Another Ahab]

Yes, its the brand I prefer.

Funny.

I always pictured you more as:

- a Marlboro Man.

(I mean, you know, when you're not wearing your glasses and all)

 

[rustystud]

Rustystud. With the Rotella T Synthetic do you notice more oil leaks. I'm using the regular Rotella T and would like to try the synthetic as long as my weeps don't turn into leaks.

First off I'm sorry I didn't respond to you sooner. I got caught up in all the "Hoopla" going on. There has been a problem in using synthetic over regular oils. If you have been using regular oils for years and then decide to switch to full synthetic you can develop leaks on the engine. This has been debated by mechanics for years now as to what causes it. The fact is synthetic oils have a higher lubricity then regular oils and seem to find the little cracks in seals and gaskets that regular oils do not. I know if you've run synthetic in your engine from the beginning, it will usually not develop leaks. But if your engine has spent most of it's life on regular oils and you switch to full synthetic, you risk developing leaks that you never had . My own truck has started to develop small leaks now, but the benefits of using synthetic oil far out-way the annoying little leaks I have now.

 

[rustystud]

Funny.

I always pictured you more as:

- a Marlboro Man.

(I mean, you know, when you're not wearing your glasses and all)


View attachment 586720

That's closer to what I actually look like then the avator I got from you ! I have a small goatee and mustache, but I have never smoked in my life. I also only use glasses to read now.

 

[jeepsguy]

The yellow metal safe feature is important as most early jeep transmissions have yellow metal parts. In the past, some GL5 rated gear oils were found to attack yellow metal parts (as found in synchronizers).

 

[AZK9]

...
Is ZDDP one of the zinc additives that's been thrown around here?

I probably should have been a bit clearer in my previous post that this link, http://www.ttalk.info/Zddp.htm actually makes
a pretty strong connection to: damage to some older vehicles due to a lack of ZDDP.

... auditing a Chemistry course...

I agree! Almost feels like it might take a 'rocket-scientist' to grasp the complexity of what actions and reactions are actually
happening inside these machines when various metals get lubricated (or not) by certain chemical blends.

What I think I've come to understand is: Due to the older design and construction of components inside M35A2 systems
(ie: cam design), some of the most modern lubricants can ruin some metal surfaces unless a thin film of 'zinc' is present
to provide (an almost molecular level) protection against pounding and wear.

Am I close to being on the right track here?

 

[AZK9]

... There has been a problem in using synthetic over regular oils. If you have been using regular oils for years and then decide to switch to full synthetic you can develop leaks on the engine. This has been debated by mechanics for years now as to what causes it. The fact is synthetic oils have a higher lubricity then regular oils and seem to find the little cracks in seals and gaskets that regular oils do not. I know if you've run synthetic in your engine from the beginning, it will usually not develop leaks. But if your engine has spent most of it's life on regular oils and you switch to full synthetic, you risk developing leaks that you never had . My own truck has started to develop small leaks now, but the benefits of using synthetic oil far out-way the annoying little leaks I have now.

Hi rustystud...

I've just picked up my first M35A2 and have been making my best effort to learn what types of lubrications are best for it.
The previous owner had just done a complete oil and filter change of the crankcase and he stressed that he used synthetic
oil in the process. That was just 40 miles ago. He also said that as far as he knew, all previous oil changes were done with
standard 'Shell' oil products.

Since that recent oil change I have not noticed any leaks, but I have to say that the oil on the dipstick seems to me to be very thin.
My gut (I'm not an experienced mechanic) tells me to drain the system and go back to the 'traditional' oil and zink additive.

Any thoughts or suggestions?

Also, I'm wondering if I should put new filters in even though they are only 40 miles old.

I just want to to the very best for this truck at this point.

Thanks in advance for any help you can offer.

 

[rustystud]

I probably should have been a bit clearer in my previous post that this link, http://www.ttalk.info/Zddp.htm actually makes
a pretty strong connection to: damage to some older vehicles due to a lack of ZDDP.



I agree! Almost feels like it might take a 'rocket-scientist' to grasp the complexity of what actions and reactions are actually
happening inside these machines when various metals get lubricated (or not) by certain chemical blends.

What I think I've come to understand is: Due to the older design and construction of components inside M35A2 systems
(ie: cam design), some of the most modern lubricants can ruin some metal surfaces unless a thin film of 'zinc' is present
to provide (an almost molecular level) protection against pounding and wear.

Am I close to being on the right track here?

Yes you are. This is where I buy my ZDDP additive http://zddplus.com/ .

 

[rustystud]

Hi rustystud...

I've just picked up my first M35A2 and have been making my best effort to learn what types of lubrications are best for it.
The previous owner had just done a complete oil and filter change of the crankcase and he stressed that he used synthetic
oil in the process. That was just 40 miles ago. He also said that as far as he knew, all previous oil changes were done with
standard 'Shell' oil products.

Since that recent oil change I have not noticed any leaks, but I have to say that the oil on the dipstick seems to me to be very thin.
My gut (I'm not an experienced mechanic) tells me to drain the system and go back to the 'traditional' oil and zink additive.

Any thoughts or suggestions?

Also, I'm wondering if I should put new filters in even though they are only 40 miles old.

I just want to to the very best for this truck at this point.

Thanks in advance for any help you can offer.

If the previous owner has already gone to synthetic oil then I would continue since there are no leaks right ? I use the synthetic Shell Rotella T Diesel or Dello Diesel oils. Which ever is cheaper at the time. I also add "ZDDP" additive. As far as the filters go, always change them out on oil changes. Just cheap insurance. Make sure your engine is warm before dumping the oil. This way most of the old oil and crud will come out. I know it's a pain (literally at times ! ) but it's the best way. If the oil is still a good amber color I would keep it. Just make sure at the next oil change to use a 10-40W oil. A good 5-40W is also OK but I would only use this oil in winter.

 

[rustystud]

The yellow metal safe feature is important as most early jeep transmissions have yellow metal parts. In the past, some GL5 rated gear oils were found to attack yellow metal parts (as found in synchronizers).

Most of the "heavy duty" gear oils will be bad for transmissions and transfer-cases. The oils must withstand extreme pressure in the differentials. So always look for a oil that is compatible with yellow metals for your transmissions. They will usually say so on the side of the container.

 

[AZK9]

Rustystud...

Thanks for the helpful, detailed reply. Much appreciated!

If the previous owner has already gone to synthetic oil then I would continue since there are no leaks right ? I use the synthetic Shell Rotella T Diesel or Dello Diesel oils. Which ever is cheaper at the time. I also add "ZDDP" additive. As far as the filters go, always change them out on oil changes. Just cheap insurance. Make sure your engine is warm before dumping the oil. This way most of the old oil and crud will come out. I know it's a pain (literally at times ! ) but it's the best way. ...

As far as I can tell, there does not seem to be any leaking of crankcase oil yet, so that's a good thing. How long does it take for the synthetic oil to find the tiny cracks and show up as leaks? The reason I ask that question is... the synthetic has only been in the truck for 40 miles of driving and a week, or so of time.

... If the oil is still a good amber color I would keep it. Just make sure at the next oil change to use a 10-40W oil. A good 5-40W is also OK but I would only use this oil in winter.

Actually the color of the synthetic oil put in at that most recent oil change (by the previous owner) is 'black' and it seems overly thin. I did check it as directed in a TM (if I recall correctly) just a short period (10 min or so) of time after turning off the engine.

 

[rustystud]

Rustystud...

Thanks for the helpful, detailed reply. Much appreciated!



As far as I can tell, there does not seem to be any leaking of crankcase oil yet, so that's a good thing. How long does it take for the synthetic oil to find the tiny cracks and show up as leaks? The reason I ask that question is... the synthetic has only been in the truck for 40 miles of driving and a week, or so of time.



Actually the color of the synthetic oil put in at that most recent oil change (by the previous owner) is 'black' and it seems overly thin. I did check it as directed in a TM (if I recall correctly) just a short period (10 min or so) of time after turning off the engine.

Check the oil level when the engine is cold. Engine oil when hot is very thin so I wouldn't worry until after you check it cold. After you checked it cold, does the oil still feel thin ? If so does it have a diesel smell to it ? If it does then you have other problems like a leaking injection pump. There are a couple of ways fuel can enter the crankcase. Hopefully this is not an issue. Actually all engine oils will turn black in just a short time, especially diesel engines.
The synthetic oils don't take long to find all the little escape routes out of the engine. So if it hasn't happened yet I wouldn't worry about it.

 

[daytonatrbo]

When synthetic motor oil first became commonplace, the stuff would start to run out of an old engine. The manufacturers discovered that the synthetic oil lacked the properties of regular oil that kept rubber seals swollen. So they added some stuff to the additive package, and this problem was significantly reduced.

If you have an old engine that suddenly starts leaking badly after a change to synthetic oil, its probably because there was some crud or sludge blocking up a potential leak. Synthetic oils have a tendency to dissolve those deposits over time.

 

[Another Ahab]

That's closer to what I actually look like then the avator I got from you ! I have a small goatee and mustache, but I have never smoked in my life. I also only use glasses to read now.

Well of course I KNEW that, and naturally I also knew that THIS is really the hat your normally wear.

I knew all that!

 

[AZK9]

Check the oil level when the engine is cold. Engine oil when hot is very thin so I wouldn't worry until after you check it cold. After you checked it cold, does the oil still feel thin ? If so does it have a diesel smell to it ? If it does then you have other problems like a leaking injection pump. There are a couple of ways fuel can enter the crankcase. Hopefully this is not an issue. Actually all engine oils will turn black in just a short time, especially diesel engines.
The synthetic oils don't take long to find all the little escape routes out of the engine. So if it hasn't happened yet I wouldn't worry about it.

Ok... here's what I found while checking the crankcase oil level once it had cooled down overnight:

[1] The oil color was a very dark black. [2] The oil consistency was very thin. [3] The oil did not smell like diesel at all to me. [4] The oil did, however, have a smell that reminded me of charcoal or soot. [5] Lastly... the oil level was about 1 1/2 inches higher up the dipstick than it had measured while hot the night before.

Thoughts?

 

[AZK9]

... If you have an old engine that suddenly starts leaking badly after a change to synthetic oil, its probably
because there was some crud or sludge blocking up a potential leak. Synthetic oils have a tendency to dissolve those deposits over time.

I can not find any evidence of any oil leaking, but after reading this... I'm wondering if it's possible that the synthetic oil acted to dissolve the
"crud or sludge" deposits that may have built up over the years. Might that crud and sludge have turned the semi-clear, brownish 'new' oil color to a very dark black color?

The black color is as dark as the BLACK INK used to refill computer printer cartridges!

Also, might that crud and sludge smell something like charcoal, or soot?

 

[welldigger]

I can not find any evidence of any oil leaking, but after reading this... I'm wondering if it's possible that the synthetic oil acted to dissolve the
"crud or sludge" deposits that may have built up over the years. Might that crud and sludge have turned the semi-clear, brownish 'new' oil color
to a very dark black color?

The black color is as dark as the BLACK INK used to refill computer printer cartridges!

Also, might that crud and sludge smell something like charcoal, or soot?

All modern high quality oils have a potent detergent package that is intended to break down sludge. Your not going to cause a leak by switching from standard Rotella to Rotella t6 synthetic. Just an example.

If something was leaking oil then chances are it was going to do so regardless of the oil you chose.

As far as the deep black color....well that's actually just a diesel thing due to the increased blowby that all diesels have versus a gas engine.

In fact the black sooty color means the detergent package is doing its job. It's better to have the soot particles in suspension in the oil than building up a sludge inside of your engine.

 

[TB58]

The oil showing higher on the dipstick is just from everything draining into the crankcase overnight. Unless you have the spin on oil filters there is no drain back valve so the filter canisters will drain into the crank case.

 

[welldigger]

The oil showing higher on the dipstick is just from everything draining into the crankcase overnight. Unless you have the spin on oil filters there is no drain back valve so the filter canisters will drain into the crank case.

Not always true. It can also be a sign of fuel or coolant intrusion.

 

[TB58]

I would think if it were a fluid transfer it would show when checking immediately after shutdown rather than as an increase overnight.

 

[welldigger]

I would think if it were a fluid transfer it would show when checking immediately after shutdown rather than as an increase overnight.

Well it would depend on how and when you checked it. But in this case you would be correct that the oil system does drain down.

Now if he runs the truck and it gets even higher than before that would indicate a problem.

If it consistently rises to the same spot then no.