What is the "normal" reading?

 

I have the McEwan gauge on an '08 FLHTC in Victoria, Canada (NW).Here in April it is reading 230F... and got real close to 300F during slow speed manoevers in an advanced rider course yesterday. 200-230F seems to be the norm.

 

First, the reading you get off the filter (the OP's configuration) compared to the pan temperature shouldn't be that far off. The oil goes from the engine to the pan, so that oil should be hot in both locations. The HD-prescribed sender location to me isn't best because it probably starts reading only after the thermostat opens, if you have a cooler, and involves much more plumbing in an area that doesn't need it--i.e., near the oil filter, making it more difficult to remove. The pan location to me is more elegant, with no negatives that I can think of other than the remote possibility that a heavy object could theoretically strike and break the adapter, but since it is mounted high with frame and oil pan surrounding it, that possibility seems remote. I've never heard of it happening.

Next, the OP's high oil temperature. Yes, 250° would alarm the hell out of me, especially in San Bernardino for this time of year. When it gets into the high-90's in July and August, I can imagine your oil temp climbing way above a safe level. In about 16 months I have seen 230° three times, all in heavy traffic in hot weather. Normally oil temps run 180-205° for me while moving, even in summer, and I'm running the PCIII quite lean in the cruise range. I do have a cooler with thermostat (HD Premium), and I consider this essential for all TC engines. It will lower peak oil temps 20-30°, and synthetic oil will add another 5° or more to that. Another good option is the Jagg 10-row, either low- or side-mount, with a thermostat. What PCIII map are you running? Almost any map available should lower head temps and thus keep oil temps at a safe level, as they tend to be rather rich overall.

To those of you considering the HD dipstick gauge, I'd advise you to reconsider. It is not particularly robust, and to get a safe reading you must not be moving. For RK, Dyna, etc., there isn't much choice, but for EG, RG, and SG the fairing-mounted gauge is much better once you get it installed. It takes an hour or two and requires a modicum of mechanical knowledge, but once installed is a much better alternative, IMO. There are more than one tutorials here on the install procedure. I've had two dipstick gauges, one lasting one week and the other three years, and I don't recommend them unless you have no other choice. Once they break, either from inevitable water leakage or other reason, you throw them away. I've never been able to fix them once broken.

 

HD says 230° is "normal," which I assume means while moving, not peaking in traffic. If so, that's too high for me, and hotter oil taxes the oil's ability to resist oxidation, even synthetic--not to mention other side-effects. I'm not surprised they run that hot in stock form as lean as they're set at the factory in closed-loop mode (14.7:1). I consider my normals (200-205° in summer while moving) to be high enough, so that's my benchmark. If they get higher I will take measures to lower them.

On a trip to TX recently I saw up to 200° oil temps, usually 180-190°, in weather as hot as 85°, which I'm happy with. They creeped higher on occasion in traffic, but not much.

 

I had an issue with 2 gauges. The first worked great until I was ina heavy rain. Then it fogged over and went dead. The repacement (under warranty) never worked right so I returned it to Chicago HD. The parts guy told me after the 2nd one that they have had a lot of issues with them.

 

The second one I had on my old RK also died by water seapage. Upon disassembly the problem was easy to see. The gauge is sealed with a very thin o-ring, and in time it shrinks and/or hardens and it loses its sealing ability. Once the water gets in the gauge is history. I tried to revive mine but failed, and I didn't replace it. Since the warranty is 90 days, IIRC, you may be continually replacing these things at $100+ a pop, rewarding HD each time for giving you a mediocre product. Not me, as I won't buy another. The fairing gauge has been fine in 16 months and is far superior, sealed from the weather and can be seen while riding the bike without risking life and limb.

 

I have the same oil temp gauge. I saw the same temps you are experiencing. I tried the digital dip stick also. Worked OK until it got wet (barely). I had my trike tuned about 6 months ago and the temps now on my trike are around 180-190 degrees F. When sitting in traffic or at long periods of idling I used to see hotter temps (some unbearable), but since the tune it hasn't experienced any high temps.

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