My wife's 96 A4 Avant 1.8 (manual) has an Oil temperature guage in it. I
was driving it this evening (straight after she had been out in it for about
30 minutes) and I noticed that the Oil temp seemed low....barely 70 degrees
or so. Also the water temp seems low - the "normal" mark on the water temp
is at 90 & it was running at 75-80.
So a couple of questions
Does anyone know what the oil temp should be under normal running? Also,
does this car have an oil cooler & if so is it permanently open or is there
a stat on it - if so could the stat be stuck open?
Are you in the UK, mines doing the same V6, water temp barely moves, and oil
temp less then 80c, if its low its good, just make sure it doesnt go high. I
think its this Cold weather we are having.
Try leaving the car ticking over outside your house, it should then go up to
the middle <90c> water.
Hot or cold weather my water temp is always at 12 o'clock on the gauge which
is 90 degrees. If its not then either the thermostat has failed or the temp
sensor is u/s.
Test the thermostat by starting the engine from cold and feel how quickly
the top hose warms up. It should stay cold until the thermostat opens at +-
87 then it will warm relatively suddenly.
The oil temp varies by how hard you drive. As the oil is water cooled on
some models I would expect a minimum of 80-90.
Agreed, but what if the outside temp is -6 as indicated, and your driving at
60mph, surely the coldness of the air going into the radiator is going to
cool the water and hence keep the temp lower than normal, when I'm at idle
the temp sits nicely around 90c, today the outside temp was +5c and mine sat
at 85-90c all the way.
The engine temp should be the same regardless of the outside temp - that's
what the thermostat is for. When its colder & so the water in the radiator
is getting cooled much more/faster then it just oesn't open as far thereby
restricting the flow out to the rad....
I've recently had the Stat replaced on my Passat because it had got "lazy"
i.e. it was opening & then staying too far open resulting in the engine
running at below normal temp. Better than too high but not good in the long
run none the less.
That said the temperature on that (and the Audi) are not consistent and I
believe probably both need new sensors. Unfortunatly, as I understand it,
the engine water temp senderis located somewhere round the front of the
engine & you have to pull a lot of things apart to get to it....
I agree with this, due to own experience. My water temp is always 90C,
regardless of whether ambient temp is +30C or -17C. OTOH my oil temp varies
between 65C and 100C depending on ambient temp and how hard I'm thrashing the
engine at the time. Car is an A4 Avant 1,8 TS, B5 chassis.
thanks for that - it kind of answers my original question about the oil temp
on my wife's car never getting that high. P'raps I need to take it for a
good thrash up the motorway & see what happens then !
Close, but no cigar ;-) The higher speed on the motorway will get sufficient
air moving past the oil radiator so as to cool the oil. Cooling systems on these
cars are quite effective.
Try a nice summer day, lots of start-stop traffic in town, thus slowish speeds
(which reduces air flow across radiators), and heavy right foot, thus kicking in
the turbo. That'll move the needle up the gauge a bit . . .
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