I have had the oil temp dipstick on two previous bikes and my current one. Always thought it was fairly accurate. Just installed the HD oil temp gauge last week and took a long ride today. Air temp 71F, Dash Oil Temp reads 190-210, oil dipstick reads 260, head temp must be hot because rear cylinder wants to go into heat management when activated. Which is closer to the right temp and does all this really matter?

 

well they are getting readings from 2 different locations so I would say they are both right , or atleast close , I put a gauge in the fairing on mine so I can watch it but what I do with mine is just learn what is normal 225 -230 then if it gets hotter I know to do something , stop move or what ever , but I don't go down the road stairing at it , these motors are pretty tough

 

I have both. I have found that it takes the oil a long time to reach a consistent temperature throughout the pan. Most of the time, I get readings such as you describe. However, on a long trip, they do tend to get really close, and sometimes read the same.

 

The dash gauge sender is in the front of the pan at the pick-up port, about 4" upstream from where your dipstick contacts the oil, they should be within 1-2 degees. I'm inclined to believe the dipstick is probably right. My experience is the dash gauge scale is deceptive, it "reads" low, but supposedly it was corrected a couple years back. You can double check with a turkey fryin' thermometer in the pan. There's no predictable relationship between OT and CHT, don't waste any effort trying to find one. It only "matters", if it matters to you; you've added two oil temp gauges to your bike, so does it matter to you?

 

Am I missing something here? My dash has a oil pressure gauge, not a temp gauge; this is the reason I purchased the dipstick that gives a temp and level reading... Is there a dash oil temp gauge I don't know or remember?

 

Yes, there's an HD accessory OT gauge for the fairing that replaces the stock AT gauge.

I've checked the OT gauge (fairing mount) in my '07 (installed in late '06) and it is within a few degrees of both an infrared and a meat thermometer. The IR is guaranteed ±4°F (IIRC) and I assume a meat thermometer is very close since it is used in food preparation. OTOH a friend installed one on his '10 SG and it reads ~15-20° lower than mine even though IR readings of his oil pan surfaces are a bit higher. Both senders are installed in the oil pan. I've heard that some gauges, perhaps those made in recent years, fudge toward lower readings to keep customers from complaining, thus reducing warranty claims. I can't say for sure if there's such a pattern, but I would do some measurements of the actual oil draining from your oil pan with a known good thermometer and compare that with what you see on the HD gauge.

I see these gauges as references that show when OT goes outside the norm, and if you're 20° high or low I figure you can just make adjustments in your mind while viewing. The idea is to inform, so as long as you know the error, the gauge is giving you the information you need. That's not to say that I wouldn't rather have an accurate gauge, of course.

 

Dip sticks. My new readable dipstick is longer. Does that matter?

 

Just put me in the who cares list...

 

I am in the "who cares" side since there is little that can be done to CONTROL the oil temp by the rider. If you are stuck in stop and go traffic, you already know the engine and the oil are above normal temp. Gauges are nice for things you can control, otherwise they are just distractions. For a while, it bothered me that my Road King didn't have a tach, especially during break in. Finally realized it has a rev limiter so I can't over rev the engine by accident. or by intention. Tach irrelevant.. Still sort of miss the volt meter, but every start tells me what I need to know.

 

I have checked my dash oil temperature gauge with a laser thermometer. It's right on. It let me know the oil in the tank was running 130 in the winter. Too cool so now i disconnect the cooler lines in the winter and its ok. It is Harley cooler with thermostat but on certain engines they don't work as they should and let oil go to the cooler in spurts. Found this out with the laser thermometer Without the gauge i would not have known this so they are handy to have.