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Was accelerating very hard yesterday morning, from a standing start onto the M1, up to about 130. My engine was just warmed up but I hadn't gone over about 3000rpm up to that point on the journey. I took it to redline in 2,3 and 4th, and afetr about 130mph I dropped back, however on glancing at my water temp dial noticed that it had dropped back a bit i.e. the temp had actually fallen. Never seen this before, I can only assume that as it was absolutely freezing (at about 7am), the massive acceleration and high speed forced a load of cold air onto the rads - even though the engine must have been hot due to the sudden acceleration - is this likely? Car performs absolutely fine apart from that, generally running cooler at high speed.
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So you are admitting on an open forum that you were doing almost twice the legal speed limit on a motorway but complaining that your temp dial dropped back a bit?
Is there an actual problem with your car or do you just want us to know how fast you were going on a public road?
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Was wondering if it was normal for the temp dial to drop back a bit, as I was thinking that very heavy acceleration would have the opposite effect, thought I'd made that pretty clear
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I should think that air temperatures, such as would be found on a cool autumn morning, would have exactly the effect on a cooling system that you describe. From what you said, you got the car's engine temp up to a point at which the thermostat would just be opening, you sat in traffic for a period of time (presumably with the engine still running) and then blasted the radiator with cold air - hence, coolant temp drops.
The only noticeable temperature increase I would envisage from giving the car the sort of booting you describe would be oil temperature - and that only if you had accelerated hard up to 130+ mph and stayed at that speed (which, ignoring the legal implications, I suspect would be impossible on the M1 most of the time). This is based on how my old Ibiza TDI Sport (the only car I've owned that had an oil temperature gauge) used to behave.
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In reality you weren't accelerating hard for a long period of time. The mass of air going through the radiator would increase with speed, lowering the temperature of the coolant being drawn into the engine. The thermostat will have a temperature differential and would have closed in response to the temperature change, but this would take "some" time. As paulb says the oil will also get hotter at sustained high speed.
Was it a nice, sustained, push back into the seat, and did it bring a wide grin to your face? ie, was it fun?
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You have to be crazy to admit that you drove at 130mph on a public road!
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>>You have to be crazy to admit that you drove at 130mph on a public road!
Not really - how can anyone prove he isn't just boasting? If there were evidence in existence, then he could be "done" regardless of what he writes.
Number_Cruncher
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Crazy to do it and crazy to admit it are two different points united by the fact that the level of crazyness is dependent on the circumstances pertaining at the time.
Dead clear road, no traffic, clear and dry, 130 not to crazy. Busy, dark and wet roads, very crazy.
On an internet forum under a pseudonym not too crazy. In person in front of a police officer, very crazy.
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And now back to the question, rather than further criticism of speeding.
DD.
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Quite normal. The thermal response time of the block mass is far slower then the thermal transfer time of a high revving water pump with an open stat and cold ram air cooling, remember he only gunned it for 15 to 20 seconds so the water temp dropped before the thermal transfer through the block and the oil caught up. If you don't like that explanation try the second one, all the cold heavier water shot to the back due to the acceleration whilst the lighter hotter water moved out of the way so the temp dropped. Only joking. Regards Peter
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Great thanks for the insight, I thought it was something like this, I wasn't massively concerned, just curious as to why it happened & maybe a -little- bit paranoid too (as that car has made me). And it was far more fun than the rest of the day @ work!
Edited by perleman on 06/11/2007 at 21:44
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