What effect do solvents have?

[expat]

I'm just asking as many people poo-poo additives that contain solvents (Stoddard solvent) What is the risk? How long will the solvent content last in an engine? (I would think it would flash off at close to normal operating temperature)
What residue would stoddard solvent leave behind?

 

[addyguy]

Like fuel, they thin and 'weaken' the oil in the engine (I think).

I've read that solvents are bad b/c they don't 'bind' to the dirt they loosen - they dislodge it, and then it simply circulates around the engine and re-deposits elsewhere.

 

[MolaKule]

Oil or fuel?

It's not so much the cleaing effect that I have a problem with it's the viscosity reduction from these thin compounds.

I mean fuel dilution these days is bad enough without adding thin solvents to the oil.

In winter I doubt engine temps get high enough to burn them off, but if you drain as much oil as possible, very little solvent should be left.

If solvents do burn off, they leave very ittle residue in the form of an ash. They usualy leve as gasses.

 

[PT1]

Like watering down your Sam Adams brew....no good can come from it.

Unless...you have a really dirty engine. In the fuel system I think they do a nice job of cleaning a dirty fuel system or better keeping a clean one in good shape.

 

[demarpaint]

IMO it depends on the solvent and the % of it in the additive, and how long you plan on running it. Quick flushes probably have a high concentration of solvents and are to be used for a very short time period. My understanding is when used as directed they work fairly well.

 

[bepperb]

Around here the gas is all E10. Ethanol is a very strong solvent, and you can see it's negative effects in both fuel economy (it doesn't have as much energy per unit volume as gas) but also in fuel system components that weren't designed for it (or adequately for it). I doubt there is a big enough problem with either of these with the ratio people use around here. But.... There's also the law of unintended consequences. GM/Ford/Honda whatever test your engine for a bazillion miles during the design testing. At no point do they run MMO at 128:1 for 200,000 miles to see what effects that has on the cat, or exhaust valves, or O2 sensors, or who knows. Really. Nobody.

Solvents in oil? No thanks. The ideal situation is an engine kept clean enough to not need them. Not a witch's brew of stuff designed to clean (not lubricate).

 

[expat]

I would think lower viscosity could be compensated.
Don't engines reach operating temperature in the winter?

I always think of two cycle engines running on 98% diluted oil

with no real harm!

 

[demarpaint]

Originally Posted By: expat
I would think lower viscosity could be compensated.
Don't engines reach operating temperature in the winter?

I always think of two cycle engines running on 98% diluted oil

with no real harm!


Depends on how cold it gets, and how long the engine is running. I would imagine many engines don't reach operating temps depending on location and run time. In my neck of the woods they do if they are run long enough.

As far as adding a straight solvent to oil I would imagine for a few minutes it would be fine. That is one of the nice things about MMO it is not a solvent in the traditional sense, it has lubricating oils in it along with anti-wear ingredients. The ingredients were posted in another thread, along with what they do.

 

[mechanicx]

Originally Posted By: expat
I would think lower viscosity could be compensated.
Don't engines reach operating temperature in the winter?

I always think of two cycle engines running on 98% diluted oil

with no real harm!


This is a good point in that 2-stroke oil most likely doesn't have VII and so an oil that has little VII probably isn't near as sensitive to fuel dilution.

 

[expat]

Originally Posted By: addyguy


I've read that solvents are bad b/c they don't 'bind' to the dirt they loosen - they dislodge it, and then it simply circulates around the engine and re-deposits elsewhere.


I have used solvents in my parts washer, and that was NOT the case.
The solvent tended to dissolve the 'crud' at the crud's surface, reducing it's size until it was gone.

What is the flash point of stoddard solvent?
I would think it quite low. Even if your engine reached 170F I would think you would quickly remove a lot of the solvent content of your additive.

 

[MolaKule]

Quote:
If solvents do burn off, they leave very ittle residue in the form of an ash. They usualy leve as gasses.


Most engines will get up to or near operating temp in the wintertime if driven far enough.

You have to realize that engine cleaners have more than just stoddard solvents, and they may or MAY not contain stoddard solvents. They usually have a higher viscosity naphthenic oil component and some XXX-tri-chloro-dichloro benzene compounds as well.

The higher viscosity naphthenic components would probably not evaporate in the winter.

Many newer adds also contain vegetable-derived esters (oleoesters) which would certainly not evaporate in cold weather.

As I said, if you use a solvent flush, fast idle or run at 1500 rpm, and drain as much of the old oil as possible and sleep well.

 

[expat]

Originally Posted By: MolaKule


As I said, if you use a solvent flush, fast idle or run at 1500 rpm, and drain as much of the old oil as possible and sleep well.


Which has been some manufacturers recommendation for some time.
What I wonder is, What could be the long term effects if a solvent containing additive is left in an engine for an extended time, or even a full OCI?

What I imagine might happen is:
The stoddard solvent would soon evaporate (after some initial cleaning, leaving the grime dispersed in the remaining oil) The remaining oil would regain some viscosity due to the removal of the stoddard.
The remaining solvents, and perhaps detergents/dispersant's will continue to have some effect while they last.
Could wear rates increase due to the dilution of the host oil?
Has this been shown?

 

[labman]

Originally Posted By: bepperb
Around here the gas is all E10. Ethanol is a very strong solvent,


Not really, but blended with the aliphatic and aromatic components it becomes a very strong solvent.

 

[MolaKule]

I guess I don't understand the basis of your question. Are you trying to rationalize the keeping of a solvent type cleaner mixed with the oil for the duration of the OCI?

With the current detergent and dispersant additives in modern engine oils, I see no reason for keeping it in there, and really see no reason to use it all unless you know of some performance problem, or are trying to improve performance in the short term, say for a beater, until you can have the engine repaired or junk it.


Quote:
What I imagine might happen is:
The stoddard solvent would soon evaporate (after some initial cleaning, leaving the grime dispersed in the remaining oil) The remaining oil would regain some viscosity due to the removal of the stoddard.
The remaining solvents, and perhaps detergents/dispersant's will continue to have some effect while they last.
Could wear rates increase due to the dilution of the host oil?
Has this been shown?


If the cleaner does reduce the viscosity of the oil below a certain point, then yes wear rates would increase. Any time you reduce the HT/HS numbers of the oil, wear will increase.

This has been shown with various UOA's in which fuel dilution showed increased wear.

My concern with the short-term cleaners being kept in the oil longer than say a 10 minute (or whatever) dwell time, is what affects do they have on the oil film and what effects do they have on the chemicals in the additive package.

Apparently, the third party or OTC engine flush marketers and formulators have made the recommendation for short dwell times for a reason.

 

[expat]

Originally Posted By: MolaKule
I guess I don't understand the basis of your question. Are you trying to rationalize the keeping of a solvent type cleaner mixed with the oil for the duration of the OCI?

With the current detergent and dispersant additives in modern engine oils, I see no reason for keeping it in there, and really see no reason to use it all unless you know of some performance problem, or are trying to improve performance in the short term, say for a beater, until you can have the engine repaired or junk it.


Quote:
What I imagine might happen is:
The stoddard solvent would soon evaporate (after some initial cleaning, leaving the grime dispersed in the remaining oil) The remaining oil would regain some viscosity due to the removal of the stoddard.
The remaining solvents, and perhaps detergents/dispersant's will continue to have some effect while they last.
Could wear rates increase due to the dilution of the host oil?
Has this been shown?


If the cleaner does reduce the viscosity of the oil below a certain point, then yes wear rates would increase. Any time you reduce the HT/HS numbers of the oil, wear will increase.

This has been shown with various UOA's in which fuel dilution showed increased wear.

My concern with the short-term cleaners being kept in the oil longer than say a 10 minute (or whatever) dwell time, is what affects do they have on the oil film and what effects do they have on the chemicals in the additive package.

Apparently, the third party or OTC engine flush marketers and formulators have made the recommendation for short dwell times for a reason.


Thank you, that basically answered my question.
I was not trying to rationalise ANY procedure, But I have noted some members posting that they were leaving (for instance) MMO in their oil pan for extended periods.
In this case, I could see the reduced viscosity (lower than the host oil) could well reduce fuel consumption and/or increase performance slightly, But I was concerned about the potential increase in wear.
On the other hand, I remember Frank (the Arx guy) in his day, saying that "You could never, fully remove solvent from your engine once you put it in, despite changing the oil"
That to me seemed a bit of a stretch of credibility

I was looking to find out if solvents themselves effected the host oil, other than by inherently reducing their viscosity and HTHS abilities so some degree.

 

[demarpaint]

Frank was wrong, with regard to MMO, sorry. In all the years been using it [35+], I've never seen a report about it ruining an engine. There are several other long time user/members reporting the same thing. In fact for a product that has that a tremendous life span [87 or so years] I really haven't seen to much negativity. The only negative things I've seen posted about it were here, more in the form of bashing and probably by people who: A. Never used it, but have an adgenda, or B. someone who had a mechanical problem that actually needed a wrench and some parts to fix.

As far as increasing wear, we have a few UOA's showing nice reports, and a member posted recently a breakdown of what is in it and its purpose. Seems it would help oil to cling (polar), and has AW additives. Plus it does a bang up job cleaning, sludge, varnish, ring packs, and splash fed areas. I think you'll be just fine using it. Again JMO based on 35+ years of use. HTH

 

[MolaKule]

Quote:
On the other hand, I remember Frank (the Arx guy) in his day, saying that "You could never, fully remove solvent from your engine once you put it in, despite changing the oil"


I don't know the context of that conversation but you can get most of the solvent out after the first oil change as it mixes with the oil and is part of the oil when drained.

One has to be careful not to take statements out of context.

MMO has a viscosity of about 3.5 cSt (this varies depending on the lab and the batch at the time and there is a clean oil sample here somewhere), and most other flushes are down around 0.5 to 2.0 cSt, about that of gasoline.

In addition to the solvency of flushes, the low viscosity of those flushes is what helps them to wash away carbonaceous material and get into tight clearances. I think the reason that engine flush manf. recommend the fast-idle, short term dwell time is to allow the flush to work at the highest temp possible and get the crud out as soon as possible. In addition, since the oil thins out, they don't want it in the engine too long since the host oil's viscosity is thinned and the wear could increse.

Now LC20, while not a flush, has a viscosity of about a 20 to 30 weight and is closer in viscosity to the host oil.

ARX is a totally different chemistry than either MMO or thin flushes, or LC20.

So the choice is up to the owner as to whether to use a quick solvent and its environmental and wear risks, or use an ester-based cleaner with it's slightly more complex (and longer dwell time) cleaning procedure.

In between these cleaners is something like MMO which is suggested by the manf. to be added to the host oil. My suggestion is, if you think you just HAVE to use it or something like it, use 1/2 of the suggested dose so as not to thin the host oil.

As I stated before, modern oils have great detergent/dispersant packages, so if you use a quality oil coupled with UOA trending data, you won't need this stuff. Just my HO.

 

[c3po]

Originally Posted By: demarpaint
Frank was wrong, with regard to MMO, sorry. In all the years been using it [35+], I've never seen a report about it ruining an engine. There are several other long time user/members reporting the same thing. In fact for a product that has that a tremendous life span [87 or so years] I really haven't seen to much negativity. The only negative things I've seen posted about it were here, more in the form of bashing and probably by people who: A. Never used it, but have an adgenda, or B. someone who had a mechanical problem that actually needed a wrench and some parts to fix.

As far as increasing wear, we have a few UOA's showing nice reports, and a member posted recently a breakdown of what is in it and its purpose. Seems it would help oil to cling (polar), and has AW additives. Plus it does a bang up job cleaning, sludge, varnish, ring packs, and splash fed areas. I think you'll be just fine using it. Again JMO based on 35+ years of use. HTH






Registered: 01/24/08
Posts: 2422
Loc: Maryland
Re: Auto-Rx Illustrated Field Test Results
Frank


Registered: 05/28/02
Posts: 2164
Loc: Jacksonville Beach Fl Auto-Rx photos quite clear from e-mails received from others, all Auto-Rx tests are third party verified.

I think Demarpaint makes a good argument about arx being wrong about MMO and other oil additives since there are no tests that arx did on these products, meaning nothing was sent to an independent lab. I take arx's stance on solvents to be an opinion and not a fact.

 

[mechtech2]

Methanol is the parts killer.
Ethanol is rather benign.

 

[MolaKule]

Quote:
Demarpaint said:Seems it would help oil to cling (polar), and has AW additives.


OK Demar, we got the idea; you and some others don't like Frank and you don't like ARX and now MMO is your current choice.

What additives are in MMO to promote polarity?

It does have some phosphorous but how do you know its the AW kind and not the cleaning kind?