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14th April 2020, 08:43 | #1 |
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Dashboard Temperature Gauge
I've been reading the current thread (started 24th December 2019) about an overheating KV6 engined car.
Embedded in one of the responses (number 12) is a reference to being able to "adjust" the temperature window, at which the gauge stays at a constant 9.00 pm. The term used was "Buffer zone" Could this be used to other peoples advantage, to make the gauge more useful, I wonder? I have pasted below the relevant response. Regards Mike Originally Posted by T-Cut View Post I guess by 'over half way', you mean the gauge needle was above the '9 o'clock' i.e. the 'normal' position. If so, then it has somehow lost its calibration. The gauge is calibrated such that at 75C, the needle just hits the 'normal' mark. It will then stay in that position (the 'buffered zone') until it reaches 115C. At 116C the needle will begin moving up and rapidly hits the red light at around 120C. It seems your gauge is over-reading, so it reports an overheat when the temperature is in the normal running area. Perhaps a T4 specialist can adjust the calibration? I know it is possible to alter the settings of the 75-115C buffered zone, so it might be possible to fix it. TC
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14th April 2020, 08:49 | #2 |
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Hi Mike,
Phil T4 replied to that thread to inform us that, alas, T4 cannot overwrite the temperature gauge programming so I think that idea will remain wishful thinking. Simon
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14th April 2020, 13:43 | #3 |
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That thread might have been me with my project ZT v6.
I think its possible that I got my facts wrong when I said temp gauge was over half way at what ever low temp I had said. |
8th September 2020, 00:24 | #4 |
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Bit of a thread revival...
Yes, It is possible to adjust the temperature gauge scale. I have been test driving some revised values in my car recently, and am now confident to be able to say that it is all working as I intend The standard gauge is not much use, as pointed out previously, the dash has the following standard values Start moving (bottom of Blue) = 15 End of Blue (Cold) = 52 1/4 Mark = 64 Arrive at halfway (start of buffer) = 75 leave halfway (End of buffer) = 115 3/4 Mark = 120 Red (overheat) = 125 When looking in to the fan behaviour on the different engine variants I have found the following information: (edit - Updated with the information SD1Too Supplied in post 6) 1.8 Low speed: on 104, off 98 High speed: on 112, off 106 KV6 Low speed: on 100, off 96 Medium speed: on 106, off 102 (not used on 2 speed systems) High speed: on 112, off 108 Diesel Low speed: on 100, off 98 Medium speed: on 106, off 102 (not used on 2 speed systems) High speed: on 112, off 110 This means that on all engine variants the cooling fan is running at high speed before the temperature gauge has even moved above the half way point (ie things are getting really out of hand already). so I have changed the following values on my car : start of buffer = 80, end of the buffer = 95 3/4 = 110 This means that the gauge starts to move above 'normal' before the fans come on, and is at nearly 3/4 before the high speed fan comes on. With a petrol I would be tempted to apply lower values to the end of buffer & 3/4 point to better reflect the actual fan behaviour (possibly starting with end of buffer = 90, and 3/4 = 105). I could do with some details regarding 'normal' temperatures seen when driving on a 1.8 & V6 to see if these values make sense - edging slightly above 'normal' in stop start traffic is fine, but there is no point going above 'normal' for normal driving (the risk is the driver ignores the gauge as 'it always goes above half now') I have now driven for a month with my settings, and have seen the gauge rise above the halfway point when in stop start traffic towing a caravan, but usually it stays in the 'normal' position. (Testing has also involved writing lower values across the range to force the gauge to declare an overheat condition, as I don't think I can achieve those temperatures on a diesel without doing silly things that might actually damage the engine). If anybody local wants their gauge modifying, contact me - As pointed out previously this is not something the standard T4 can do (and I don't believe this is something that TOAF can do either), Chris
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Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics. Last edited by cb750chris; 8th September 2020 at 20:24.. Reason: Cleared up Fan temperatures in line with SD1Too post #6 |
8th September 2020, 02:21 | #5 |
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This sounds interesting.
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8th September 2020, 07:49 | #6 | ||
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Radiator fan switching points
Quote:
Where did you obtain the figures in this format? I'm afraid that they are inaccurate and misleading. The fan does not operate in the manner suggested. Here is the official RAVE data: 1.8 Low speed: on 104, off 98 High speed: on 112, off 106 KV6 Low speed: on 100, off 96 Medium speed: on 106, off 102 (not used on 2 speed systems) High speed: on 112, off 108 Diesel Low speed: on 100, off 98 Medium speed: on 106, off 102 (not used on 2 speed systems) High speed: on 112, off 110 As you can see, the greater of the two values is the temperature at which the fan switches on and the lower value is when it switches off. The author of the figures you've posted has got it the wrong way around (as well as quoting some incorrect values)! However, making the range of "normal" temperature readings on the gauge more practical is a very interesting modification! Quote:
Simon
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"Whatever is rightly done, however humble, is noble." Sir Henry Royce. Last edited by SD1too; 8th September 2020 at 08:31.. |
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8th September 2020, 09:46 | #7 |
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Hi Simon,
Thanks for clarifying the fan behaviour - you have explained them clearly. Where I found them there was just the ranges quoted (eg for 1.8 low = 98 --> 104, high =106 --> 112, which left a bit of a gap at 105, and above 112 - where the fans were not in either of the valid states, so I took a guess what the actual behaviour would be). Thanks for the information about your normal running temperatures - that is useful information. Rover decided that overheat was appropriate at 125 so all we are doing is increasing the amount of headroom between the gauge leaving 'normal', and reaching 'overheat'. From the figures you have quoted I think 115 for 3/4 is the right value - The high speed fans are on, and the cooling system is doing everything it can - it now needs the driver to help get the temperature down - with 10 degrees headroom left before the temperature gauge reaches 'Red' (Which I suspect Rover specified slightly lower than engine damage but probably not much) The point at which to leave the buffer zone is perhaps slightly more difficult to judge. I agree with it being after the low speed fan has come on (as that is 'acceptable' behaviour) but whether it should be as high as the medium speed fan starting is questionable - If in slow moving traffic I could accept medium speed fan being on, but If I am driving normally I would be concerned if the medium speed fan was enabled. So I would possibly err to wards leaving the buffer zone before the medium speed fan is enabled. Regards Chris
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Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics. |
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