Would synthetic have made a difference?

[Eccool]

I was on a 9 day trip south, temps were around 95 every day.  Within 1 minute of starting out on day three, two warning lights come on:  The check engine light and the coolant temp light ('14 Ultra Limited).  I quickly determined the coolant pump had stopped working (2d time since I've had the bike). 

The Harley dealer I stopped at didn't have one in stock.  He told me that as long as I keep the vents open and keep moving I should be okay.  That's what I decided to do.

  Everything was more or less fine until day 7 and I'm headed home.  I had been riding for about an hour at about 70 mph, when traffic up ahead starts to back up a little.  I squeezed the clutch in to downshift and the lever had no resistance at all.  I pumped it a few times and it worked.  I went straight to the nearest Harley dealer.  They told me the clutch issue is due to the excess heat; fix the coolant pump and you won't have an issue.  Thankfully, they had one in stock.

  Here's the question:  If I had of used synthetic (like I started to do for the trip), do you think the bike still would have gotten hot enough to cause the clutch issue?

[kd]

Yes, it would still get hot if a comparable weight of oil.  A good syn oil will however survive up to higher temps and do what it's intended to do better under the excessive heat.  My experience is it will not normally influence the heat unless it is a different viscosity.

[Hossamania]

How much difference would a higher viscosity really make? If in heavy traffic in high temperatures, what would the temp difference be between a 20w-50 and a straight 60w?

[boooby1744]

I thought the heavier the oil the more it retains heat.  A 1970's myth?

[Sycho01]

I won't comment on the oil viscosity but if the bike does not have a oil cooler with a thermostatic fan and I was traveling or in city stop and go traffic I would install one if it were my bike. Just a thought.

[Rockout Rocker Products]

I always wonder about the "just ride it, it's fine" line from the dealers. I mean.... what else are they going to say.... "sorry brother, you're going to have to find a motel for 3 weeks until I can get a new one in"? How would that be for sales?

I can tell you that when mine went out is was NOT OK to just keep riding. Engine temp well into the 300s, it even smelled like it was baking and power was way down.

Side note...

I broke down 2 or 3 exits from my selling dealer. HOG towing would have towed it there for free.... I paid $300+ to have it towed home instead. Yes, their service dept. is that bad. 

[Deye76]

"Engine temp well into the 300s"
If the coolant system isn't working, won't it be like a air cooled one? In 90 deg temps my head temperature on my Evo, TC, and M8 are all in the mid 200 degree range measured with a infrared thermometer. And the primary being a separate case from the motor, how much does engine heat influence the clutch?

[Rockout Rocker Products]

With no coolant it leaves pockets with nothing drawing the heat out, air cooled engines have solid aluminum there to act as a heat sink.

[Ohio HD]

With no coolant it leaves pockets with nothing drawing the heat out, air cooled engines have solid aluminum there to act as a heat sink.

[Ken R]

I've heard that the coolant pump can be made to work in the field by disassembly, cleaning, and reassembly.  The impeller is spun with a magnetic coupling; so it isn't really strong.  A little gummed up and they quit. 
Anyone know for sure? 

If the pump isn't running, I think that the water in the head passages will boil and become empty.  That doesn't seem good to me.

[PoorUB]

Engine temp in the 300's wouldn't bother me. With a TTS I recorded engine temps of 425F on my 2010 Ultra when I got stuck on 110F temps and slow traffic for a couple miles. That did make me nervous, but I can't say it caused any damage either. I was more worried about the inside of my thighs getting broiled!

[Deye76]

With no coolant it leaves pockets with nothing drawing the heat out, air cooled engines have solid aluminum there to act as a heat sink.

Thank You. Never paid much attention to the cooled motors, learning everyday.

[smoserx1]

Here's the question:  If I had of used synthetic (like I started to do for the trip), do you think the bike still would have gotten hot enough to cause the clutch issue?

I doubt it would make any difference you would notice.  If it lubricated better there would be a slight heat reduction from lower engine friction but most of the heat is from combustion.  They say that oil helps cool an air cooled engine but IMO it is very much a secondary function.  Most of the heat originates in the heads and cylinders and most air cooled engines don't have coolant jackets where oil circulates for cooling like liquid cooled engines do.  These engines rely on fins to carry this heat away.  Finally there is the property of specific heat which is sort of a measure of how well or rapidly a material gains/looses heat.  Materials like copper and aluminum with low values transfer heat better/quicker.  For the synthetic to do better in this regard it would need a different specific heat and I doubt it is enough to make much difference, if any.

[Deye76]

Still with "pockets" in the heads, how does that affect the clutch? More than one problem IMO.

[ultrafxr]

Your clutch problem is due to moisture in the hydraulic fluid in the clutch lines.  Can't stop it. Moisture will get in and that's why H-D STRONGLY recommends a complete flush of hydraulic fluid in clutch and brake systems every two years.  Look at how close your clutch line (and rear brake lines also) is to the super hot exhaust. Heat builds and boils the water in the clutch line.  Air won't compress like hydraulic fluid so bingo no clutch until everything cools down.

[Moparnut72]

I was wondering what a hot engine had to do with the clutch but you explained it. Makes perfect sense.  However your last sentence should probably say that air will compress unlike brake fluid hence the loss of of clutch function. Not criticizing just clarifying, you hit the nail on the head.
kk

[roadkingdresser]

Wasin sturgis a few yrs. ago setting waiting to get thru a tunnel and a friend came up with a heat gun. They were running syn 3 and i run 20/50 dino and my bike was cooler than theirs.
Also out there last yr. buddys water pump went out, he got one at the harley shop and we changed it in the trailer. This yr. another guys pump went out took it to the harley shop $900 to change it.