VS-VT Engine Temp

[ORIXVywags]

Hi Guys

Noticed something interesting today,

Mate of Mine and Myself drove home from Canberra today

So we are blasting up the M5, Im in the VS 2 Berlina Wagon, and he is in his VT 1 Accliam Sedan

I checked my gauges thoughout out the trip, and likewise my mate

Fuel Usage was the same, so we were both happy with that, but his Temp gauge was pretty random "up and down and up and down"

The VS was Cool as a cucumber, only quarter temp, all the way,

Question is, is this common, or is this early days to a Cooling system failing and being stranded

Note: VT is a 97 with 115000kms
VS is 96 with 193000kms

Both been looked after since day dot,

[hako]

This is my guess:
Maybe it's because you have a Berlina with climate control (compressor runs all the time and unit mixes cold and hot air) whilst the VT acclaim has plain A/C where the compressor switches in/out.
When the compressor is running it pumps heat into the condenser in front of the radiator.
The Berlina would be constantly pumping heat into the condenser whilst the VT would only pump the heat when the comp was running - which can cycle on/off every minute or so.
The best test on either the VS or VT is after a good drive to pull up, leave engine idling in P with aircon off, and watch the temp gauge rise - it should steadily and fairly rapidly rise to 3/4 when the fan should kick in and temp should creep back to about 1/2 in about 30 seconds. If it performs like this it means the sensors are switching the fan on correctly and the radiator is efficient enough to extract sufficient heat to cool the engine.

[ORIXVywags]

ahhhhhhhh,

I didnt think that the compressor runs all the time, if anything it did more switching in and out then basic A/c system because it detected the hot and cold air before pumping hot and cold air ... effectively climate control being more efficient and economic then basic a/c

Thanks Hako, your a legend, both me and my mate were thinking water pump or temp sensors or heater tap or something might be on it last legs

I will try it though, I will try also with a mates VS Acclaim - if all 3 have a crack at the test it will be interesting to record the results and see what happens

[hako]

Other possibles are that your VS temp gauge needle is a bit sluggish whilst the VT is more responsive, thermostats are different or one is a bit sluggish and no 2 guages will read the same.
This is the way I understand it:
True climate control continuously mixes cold and warm air to the temperature you dial up - to achieve this the compressor must run all the time otherwise it would fluctuate up and down - if you dial 20deg you don't want air going from 15 to 25 deg as the comp cuts in/out.
Straight out A/C as in the Acclaim usually measures the temp of the air just before it goes thru the evaporator (where it cools down).....when this air drops to a certain temp the A/C thermostat will cut the compressor off till the air going into the evaporator warms up again and then repeat this cycle as required. You can manually mix hot air with the cold air.

But like I said - that's just a wild guess. For peace of mind I try to regularly check all hoses and replace any that are swollen or cracked, use the recommended coolant, check the plastic side tanks of the radiator for any signs of weeping and also the heater tap.....all these are critical points.
They also should lose no coolant - you should not have to add any coolant to the overflow tank. If you have to add coolant then it must be leaking somewhere.
Another good test is to get hold of an infra-red thermometer - Dick Smiths have them for about $30, and measure the block and radiator at different points plus the air on both sides of the radiator - they are good toys and you can even measure the exhaust temp as the gas comes out the pipe.
The number one cause of breakdowns on the highways is overheating - the result of lack of maintenance. I'd better get off my soapbox. Have fun.