Electric cooling fans

fastRob · **Posted:** Thu Apr 03, 2008 8:37 am

Reflex wrote:

I don't consider myself an oil expert, I just disliked the snake oil sales technique some were using in a previous thread. The thing is that any decent quality oil will do just fine in standard driving, especially in a diesel when changed on a reasonable interval schedule(I do 6250 miles on mine). Right now I just use whatever Chrysler reccomends at the dealer, once I'm out of warranty I'll use whatever the local Jiffy Lube or whatever uses. I have never had a engine failure that was traced to oil problems or wear, and that was driving gassers which break down oil much worse than diesel.

The supposed benefits of synthetics to my mind wouldn't come into play during the usable lifespan of the engine, which makes them a waste of money. Even if they are theoretically 'better', what does that mean if the benefits won't start showing up until a million miles plus? Is anyone really planning to drive it for two million miles? And wouldn't it be just as good or better to change twice as frequently with an oil half the price, especially if as TurboTim states they actually help cool the engine better(heat is an enemy of mechanical devices)?

I'd like to see what TT has to say about it.

Please tell me what Chrysler recommends, it is mentioned in your owners manual.
This is important to the life of your engine.
Glad to hear we all have both fans.

R

Joe Romas · **Posted:** Thu Apr 03, 2008 10:16 am

fastRob wrote:

Reflex wrote:

I don't consider myself an oil expert, once I'm out of warranty I'll use whatever the local Jiffy Lube or whatever uses. I have never had a engine failure that was traced to oil problems or wear, and that was driving gassers which break down oil much worse than diesel.

I'd like to see what TT has to say about it.

Please tell me what Chrysler recommends, it is mentioned in your owners manual.
This is important to the life of your engine.
Glad to hear we all have both fans.

R

And I'll give you 5 to 1 odds that "jiffy lube or whatever" dosen't use the right oil and strips the drain plug :lol:

Turbo Tim · **Posted:** Thu Apr 03, 2008 10:30 am

Back in my “Good Old Days” when we were running the VW’s in the dunes, we would monitor engine oil temps and head temps. At that time (and still now) the big debate was which weight oil to run, multi grade like Castrol GTX 20-50, or the straight weights, like 40W or 50W. Now understand that at this time, I had designed a fuel injection system for VW’s and we would take these little girly VW Type 1 1600cc engines and pump them up to 2276cc or 2332cc. Add a turbo, 25 PSI of boost, and found out real quick why carbs don’t work well with Turbos. Thus the fuel injection. We also would run 9 fuel injectors on these engines (one for each cylinder for gas, one for each cylinder for methanol, and one methanol injector on the output of the turbo to act as an intercooler).
At this time, watching the temps, someone tried synthetic oils and thought that this is much better as my engine oil temps are way down (like around 125* F instead of close to 220* F). This stuff works great, not realizing that the head temps are now 150 to 250 degrees hotter! (Normal is around 200* F to 300* F, with synthetic oil, head temps got up to 550* F). This is when we would lose valves and other valuable engine parts.

These air cooled engines will glow in the dark if cooling isn’t maximized. The point is if your engine is water cooled (like the CRD), that is a good 85% (or more) of your heat removal. Adding oil cooling protects the oil from breaking down but also aids in removing heat too. If it makes a big difference on your water temp gauge by adding oil cooling, your main cooling system is way under sized! (On a water cooled engine).

We found that synthetic oil would not transfer the heat nearly as fast as Dino oil would.
Maybe someone can build a little test fixture to prove this and do a side-by-side comparison test? I would like to see……

gmctd · **Posted:** Thu Apr 03, 2008 11:36 am

Ummm.........need to back the turbocharged train up a bit, here folks - Diesel-rated oils are formulated for greater temperatures and pressures than gassers (patooie!) ever even dreamed of - even at idle, the oil is subject to more abuse than in those other engines, because the crankshaft is constantly working against high cylinder pressures on the compression stroke, not even to mention the attainable pressures on the power stroke - at 30psig Boost your 2.8L air pump is effectively displacing ~7-8liters at wot - can any of those other 2.4L\3.7L engines even come close to that?

I think not.

Then there's the concept of Boost: where do we get that elevated Barometric pressure that effectively doubles\triples displacement? Enter the turbine-motor driven air compressor = average EGT's 650degF in the turbine - no 2.8L spark-infested engine ever even hoped for bearing stresses like your Diesel 2.8, much less those elevated oil temperatures in the oil-lubricated and -cooled turbine cartridge center section - I mentioned average EGT temps - how does 1200degF at 20psi Boost, full load, strike ya? Talk about yer excessive crankcase vapors as yer wimpy gasser-rated oils boil off at them temperatures.

And, how much of the inherent lubricating quality does that wussy oil retain at 1200degF?

I think none.

Yer limp-wristed pansy gasser (patooie!) motor might run with sewing machine oil or WD-40 in the crankcase, but not that Diesel powerhouse under your KJ hood - increased bearing loading + 1200degF oil temperatures: those are the reasons for the API CI-4 Plus, SJ, SL, SM ratings.

As a side note - the new breed of turbocharger cartridges are water-cooled to reduce thermal loading into the oil, resulting in reduced molecular breakdown - way extends oil life - the big Garrett HE551VGT for the 15L Cummins and the HE351VGT for the 6.7L Cummins are notable examples of efforts to reduce thermal loading on engine oils.

Somewhat related, but still not good enuff: due to the proliferation of factory-installed turbochargers, oils for those other engines were also-uprated, out of necessity - again, not even good enuff for Diesel engines.

Syn oils have one really big advantage over dino stuff - syns do not break down under high loading and high temps like dino oil - because of that, the effective viscosity can be lowered, which results in reduced operational resistance, which equals greater efficiency and fuel economy

And, BTW - wanna talk about yer engine oil cooler? We already got one - which is another reason your coolant temps continue to climb under continual loading.....................

Anyone out there still considering removing the engine-driven fan?

Anyone still considering using one of them wimpy almost-a-oils in their CRD engine?

fastRob · **Posted:** Thu Apr 03, 2008 11:46 am

Gmctd,
Sometimes you can lead a horse to oil but you cannot make him refine.
Thanks for your input.
I am a fan.
R

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

Good stuff from both TurboTim and Gmctd. Much appreciated!

Turbo Tim · **Posted:** Thu Apr 03, 2008 12:16 pm

My point about adding the turbo to the VW's was that with boost the combustion temperatures are now exceeding that of a normally aspirated engine. If all you have is air cooling, you have exceeded the thermal limits of the engine if it was never designed for boost.
Yes we way exceeded the limits of the engine with boost, air, temperature, fuel, fun and alcohol. (These engines only lived a very short time, but it was fun!).

The other point is synthetic oil will not move heat from one point to another nearly as well as dino oil does in comparison. (We are not talking about oil breaking down, just thermal transfer ability).
Pure water moves heat much better than 50/50 water-antifreeze solution does, but then other factors come in like corrosion, etc…

chadhargis · **Posted:** Thu Apr 03, 2008 12:25 pm

GMCTD is right. Synthetic oil is superior.

I have spent a lot of time at the racetrack and around racers. Of course, this on motorcycles where piston speeds are astronomical. A little 600cc engine will spin up around 14,000rpm and make 110hp or so. Yep...that's .6 liters. Not only does the engine oil lubricate and cool, it also lubricates the transmission and bathes the clutch.

I don't know a single racer or track day rider that doesn't run synthetic oil....AND.....changes it often. I typically dump my oil in my track bike after 3 or 4 track days. That amounts to about 200 to 250 miles....maybe. Depends on the track.

Am I wasting oil? Probably. But I've torn down my engine and it was clean inside. No metal shavings (just clutch dust) suspended in the oil. It takes about 2.5 to 3 quarts to fill up my bike. So at $8 a quart, that's $24 in oil about 3 times a year just for one bike. So I'm spending ~$100 (by the time you factor in filters and shop supplies) per year changing the oil in a bike that I ride maybe 1000 miles. To me, that's darn cheap insurance.

Combine that with the fact that my average ownership period for a motorcycle is about 18 months, and I'm sure I'm wasting money. But when you're running 140mph coming into a tight turn and you're hard on the front brake with the rear wheel barely skimming the pavement, it's the wrong time to be wondering, "Is my oil going to fail me today?".

So, I run synthetic in my CRD (as specified by the manual). It's pretty cheap at Wal-Mart or my local auto parts store. I run an expensive oil (Redline) in my motorcycles, one of which is air-cooled and I've never had it overheat on me.

UFO · **Posted:** Thu Apr 03, 2008 12:33 pm

I am skeptical about the claim synthetics don't transfer heat as well as conventional oils. Synthetics claim they lower friction and reduce foaming; both of those will reduce total heat generated. This link to an air-cooled site also contradicts the claim synthetics won't transfer heat as well...

Quote:

ADVANTAGES OF RUNNING SYNTHETIC OIL in AIRCOOLED ENGINES
So if you are asking yourself "What's the point of running synthetic oil, if you can't change it less often?" Here's your answer in a nutshell.

Since synthetic oil has better heat transfer qualities than dino oil, your internal engine temperatures will be lower. Things like bearings, especially, will not operate at as high of a temperature as a result. The wider range of temperatures that synthetic oil can withstand is well suited for the air-cooled VW engine. With head temperatures normally between 300-350 degrees, synthetic will not breakdown while lubricating the valvetrain components at the heads. The better lubricating properties of synthetic in general will lead to a longer engine life as well. On average, when synthetic oil is run in an air-cooled VW engine, head temperatures stay the same, but engine oil temps reduce by anywhere from 10 to 15 degrees. This is in engines that have all the correct cooling tin in place, and are not suffering from overheating to begin with. Important note: Do not run synthetic to fix a hot running engine. Find the real reason it's running hot, and fix it!

http://www.aircooled.net/gnrlsite/resource/articles/synthoil.htm

Turbo Tim · **Posted:** Thu Apr 03, 2008 3:40 pm

Not to start something here, but I wouldn’t believe that an ice cube is cold coming from that web site. (Everybody gets to have an opinion here).

I will say (like Reflex would), show me the test data. I have personally seen temperatures change dramatically on air cooled turbo charged 350+ HP engines just by changing the oil. Now for whatever reasons, excuses, causes or what have you, this particular instance dino oil had lower engine temps. Same day, air temps, most of the variables stayed the same. Back to back comparison.

An easy test is someone get a thermometer, two pans, put them on the stove, and cook up some oil. See how fast one heats up and cools down….

UFO · **Posted:** Thu Apr 03, 2008 4:23 pm

I'm just curious myself, having no stake in this discussion. I use synthetic in the CRD like the manual recommends. I also cannot testify to the veracity of any of these claims I've read regarding synthetic vs. conventional motor oils. However, I found this quote at grassroots motorsport. They maintain synthetics transfer heat up to 10% more effectively than conventional oils.

Quote:

Oils also have a heat capacity, which is the amount of heat the oil can absorb before a change in overall oil temperature occurs. Much of this has to do with the polarity of the oil. Polarity is a characteristic of the individual molecules that make up an element; it helps determine the stability of those molecules, and therefore that element. Synthetic oils are more stable than conventional petroleum oils under high temperatures; this enables synthetics to outperform their petroleum counterparts by approximately 10 percent in the area of heat transfer. Furthermore, it means synthetics will absorb 5 to 10 percent more heat before a change in oil temperature occurs.

Petroleum oils are not only less efficient at removing heat, they also begin to break down significantly above 275 degrees F. Unfortunately, temperatures at high stress areas within the engine-like cam and follower contact areas, pistons, etc. can routinely exceed 400 degrees F. Petroleum oils may boil away or vaporize, at these temperatures, leaving high stress areas without adequate protection.

http://grassrootsmotorsports.com/news/012005/beat-the-heat.php

Also, Amsoil makes the same sort of claims (of course, synthetics are their business...) http://www.searchforparts.com/important_articles/rx_for_long_engine_life.php

Just posting what I've seen, I'm sure there are lots of variables and special circumstances...

tjkj2002 · **Posted:** Thu Apr 03, 2008 5:07 pm

gmctd wrote:

Ummm.........need to back the turbocharged train up a bit, here folks - Diesel-rated oils are formulated for greater temperatures and pressures than gassers (patooie!) ever even dreamed of - even at idle, the oil is subject to more abuse than in those other engines, because the crankshaft is constantly working against high cylinder pressures on the compression stroke, not even to mention the attainable pressures on the power stroke - at 30psig Boost your 2.8L air pump is effectively displacing ~7-8liters at wot - can any of those other 2.4L\3.7L engines even come close to that?

I think not.

Then there's the concept of Boost: where do we get that elevated Barometric pressure that effectively doubles\triples displacement? Enter the turbine-motor driven air compressor = average EGT's 650degF in the turbine - no 2.8L spark-infested engine ever even hoped for bearing stresses like your Diesel 2.8, much less those elevated oil temperatures in the oil-lubricated and -cooled turbine cartridge center section - I mentioned average EGT temps - how does 1200degF at 20psi Boost, full load, strike ya? Talk about yer excessive crankcase vapors as yer wimpy gasser-rated oils boil off at them temperatures.

And, how much of the inherent lubricating quality does that wussy oil retain at 1200degF?

I think none.

Yer limp-wristed pansy gasser (patooie!) motor might run with sewing machine oil or WD-40 in the crankcase, but not that Diesel powerhouse under your KJ hood - increased bearing loading + 1200degF oil temperatures: those are the reasons for the API CI-4 Plus, SJ, SL, SM ratings.

As a side note - the new breed of turbocharger cartridges are water-cooled to reduce thermal loading into the oil, resulting in reduced molecular breakdown - way extends oil life - the big Garrett HE551VGT for the 15L Cummins and the HE351VGT for the 6.7L Cummins are notable examples of efforts to reduce thermal loading on engine oils.

Somewhat related, but still not good enuff: due to the proliferation of factory-installed turbochargers, oils for those other engines were also-uprated, out of necessity - again, not even good enuff for Diesel engines.

Syn oils have one really big advantage over dino stuff - syns do not break down under high loading and high temps like dino oil - because of that, the effective viscosity can be lowered, which results in reduced operational resistance, which equals greater efficiency and fuel economy

And, BTW - wanna talk about yer engine oil cooler? We already got one - which is another reason your coolant temps continue to climb under continual loading.....................

Anyone out there still considering removing the engine-driven fan?

Anyone still considering using one of them wimpy almost-a-oils in their CRD engine?

The only difference in the oil for deisels is the additive package added to the oil,that's it,and mostly to aid in the suspension of your very dirty engines.Again there is no difference between deisel 15w40 and regular 15w40 besides some extra additives have been added to hold the soot better,which a cleaner gas engine does not need.

Oh and I guess turbo gas engines never see 1200 degrees EGT's,but wait they do.My '75 Cutlass had more compression then your CRD does and plan old Valvoline 20w50 oil did just fine.

Turbo Tim · **Posted:** Thu Apr 03, 2008 5:37 pm

These are great discussions and I for one will agree it won't be the first time I've gone down a rabbit trail for all the wrong reasons.
If anybody does find a reputable outfit that had empirical data on the thermal transfer abilities between the two, please post.

Back to the fan issue, if more air is needed to flow to get rid of heat, I will add another electric fan to help move more air (after I make sure that there is nothing wrong with the mechanical one first as it will do most of the work).
My first choice is to increase the capacity of the radiator first (2-row to a 3 or 4 row if possible), then maybe a larger tranny cooler or two tranny coolers, and then a larger engine oil cooler (or two with electric fans).

I just don’t want to give up any and all AC comforts when towing just because I happen to live in the desert. (Insert insane reason for living in hell here).

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

On the initial topic, I think its fairly clear that removing the mechanical fan would be suicidal for the engine over the long term...

Sir Sam · **Posted:** Thu Apr 03, 2008 6:30 pm

Reflex wrote:

On the initial topic, I think its fairly clear that removing the mechanical fan would be suicidal for the engine over the long term...

Agreed.

UFO · **Posted:** Thu Apr 03, 2008 6:45 pm

Reflex wrote:

On the initial topic, I think its fairly clear that removing the mechanical fan would be suicidal for the engine over the long term...

I totally agree with that. My only issue with the mechanical fan is it doesn't move enough air at low engine speeds, at least from what I've seen driving over the Colorado mountains. I can easily maintain the speed limit up the hills, but if I leave the transmission in O/D, the temperature gauge will quickly leave the center. Take it out of O/D, the RPM rises to 3k or so, and the needle never budges off center. Same road speed, different engine rpm. I may not be taking the boost required to maintain speed into account, and there may be a significant heat contribution from the turbo at lower rpm and higher boost. The IC may be getting heat soaked, and the higher fan speed may be pulling the air through necessary to cool.

It's be nice if the electric kicked on before the temperature gauge rises. Maybe it's not up to the task...

Sir Sam · **Posted:** Thu Apr 03, 2008 6:51 pm

UFO wrote:

Reflex wrote:

On the initial topic, I think its fairly clear that removing the mechanical fan would be suicidal for the engine over the long term...

I totally agree with that. My only issue with the mechanical fan is it doesn't move enough air at low engine speeds, at least from what I've seen driving over the Colorado mountains. I can easily maintain the speed limit up the hills, but if I leave the transmission in O/D, the temperature gauge will quickly leave the center. Take it out of O/D, the RPM rises to 3k or so, and the needle never budges off center. Same road speed, different engine rpm. I may not be taking the boost required to maintain speed into account, and there may be a significant heat contribution from the turbo at lower rpm and higher boost. The IC may be getting heat soaked, and the higher fan speed may be pulling the air through necessary to cool.

It's be nice if the electric kicked on before the temperature gauge rises. Maybe it's not up to the task...

Another possiblity, and one I always liked, was having a manual switch for my electric cooling fan, for example, if you knew you were about to start climbing a hill, just go ahead and kick it in before you start up. Pretty simple to do and its nice to have for people who actually drive their cars, not just control them.

UFO · **Posted:** Thu Apr 03, 2008 6:55 pm

The manual ON switch is a good idea.....

05infernoCRDL · **Posted:** Thu Apr 03, 2008 6:59 pm

Sir Sam wrote:

Another possiblity, and one I always liked, was having a manual switch for my electric cooling fan, for example, if you knew you were about to start climbing a hill, just go ahead and kick it in before you start up. Pretty simple to do and its nice to have for people who actually drive their cars, not just control them.

is there a way to do this and still have the auto kick in when needed? so that under
normal conditions it will turn on by it's self and when you want it on you can do it manually?

Sir Sam · **Posted:** Thu Apr 03, 2008 7:02 pm

05infernoCRDL wrote:

Sir Sam wrote:

Another possiblity, and one I always liked, was having a manual switch for my electric cooling fan, for example, if you knew you were about to start climbing a hill, just go ahead and kick it in before you start up. Pretty simple to do and its nice to have for people who actually drive their cars, not just control them.

is there a way to do this and still have the auto kick in when needed? so that under
normal conditions it will turn on by it's self and when you want it on you can do it manually?

Yes, all you need to do is have a switch that provides power to the fan or to the fan relay. This would not negate the factory controls for the cooling fan.

Electric cooling fans

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