6

I'm more specifically interested in performance vehicles.

My current car has gauges for coolant temperature, oil temperature and oil pressure. The coolant temperature gauge is there so you can tell whether coolant temperature is too high so you know whether you should cease driving. In some modern cars, this is simply replaced with a warning message when the temperature gets too high telling you to pull over. This makes sense for regular vehicles, and also performance derivations.

On a performance vehicle oil temperature is a better guide for deciding whether the car is ready to be driven enthusiastically. Even without the oil temperature display, this can be estimated by waiting for the coolant to reach normal level and then leaving it a few more minutes, the amount of time depending on current weather conditions.

However, some modern performance vehicles have neither a coolant display nor an oil temperature display. This is obviously a deliberate design decision. Are manufacturers of performance vehicles confident that their engines will not suffer permanent damage being driven on cold oil? What is the rationale behind this decision?

My guess is that modern engines and modern oils can much better cope with cold conditions, that this is no longer an issue.

  • Which performance vehicles are you talking about? I know most American (all I can think of) have the gauges you talk about, so very curious as to "which ones"? – Pᴀᴜʟsᴛᴇʀ2 Apr 17 '16 at 10:44
  • Eg BMW M135i doesn't have either. – SilverlightFox Apr 17 '16 at 10:44
  • I started to try and answer your question but became stuck on what 'cold oil' is. It's quite a broad range. Certainly at -20F the oil will be considerably thicker than 75F. Can you wrap a descriptor attribute around the cold object? :-) Cheers! – DucatiKiller Apr 17 '16 at 17:16
  • @DucatiKiller: Good question. I guess on my current car I usually wait until the oil temperature is above the first marker (75C or 167F), because the oil pressure at idle appears to drop around then. Therefore my definition of "cold oil" is any temperature below 75C/167F, with the minimum being the ambient temperature in the current climate. I large range I know, but without any vehicle instrumentation the driver is left guessing, which leads to my question - are vehicle manufacturers confident enough of their engines to allow any throttle and rev input anywhere in this range without damage? – SilverlightFox Apr 18 '16 at 9:27
4

Your sample may just be non-representative.

All the ones I know (I'm mostly into Japanese performance cars) have oil temps. Even many non-performance cars have an indicator that goes out once the engine is up to temperature (such as my wife's Honda Jazz)

I think cars like the M135i have some cost based design decisions in order to meet their price point - it's only an entry level performance car. But for a car like that it doesn't really matter - the ECU will control attempts to push too far out of standard envelope.

  • That's my point really, many of the Japanese performance cars are entry level yet have the gauges. – SilverlightFox Apr 17 '16 at 14:28
  • That's the difference though - with a Japanese car you aren't paying the "fashion" premium that you have to pay for a BMW – Rory Alsop Apr 17 '16 at 14:31
  • Is installing a coolant/oil temperature gauge that costly? – I have no idea what I'm doing Apr 18 '16 at 7:09
  • @IhavenoideawhatI'mdoing Anything is costly when you're producing hundreds of thousands of them.. – Trotski94 Apr 18 '16 at 14:18
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    @iha Yes, I'm not convinced it's a money saving thing on a car like that. It's not entry level in the grand scheme of things, maybe only in bmw world. Especially looking at the standard equipment levels with gadgets such as electronic dip sticks, pollutant sensors, sat nav etc which the average consumer might not be bothered about too. A temp gauge isn't going to break the bank, especially when the sensor is there already. – SilverlightFox May 4 '16 at 21:57

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