All,
Still a bit stuck on ym heaters and water temp ont he car and worried that the cold weather is masking an issue that will become apprent when the
weather warms up.
Fitted a new stat to my 1.9TDi A4 the other weekend. Before the water temp was only getting as far as 70 deg max (90 deg is normal middle temp)
Now the car will eventually get to 90 deg and stay at it for a whole drive (motorway) I did over 300 miles and the temp stayed at a constant 90.
However, around town, if I blast the heaters, it significantly reduces the water temp on the guage.
Hoping this is an airlock but would like to know the signs of the more scary stuff like a broken/bust water pump etc?
As said, the stat is new, alognw ith the water temp sender unit, its performing better with the new stat according to the engine water temp climbing
to 90 degree, just thinking I have cocked up the coolant fill.
Couldn't it just be normal? Running the heater will take a fair bit of heat out of the coolant therefore dropping temperatures. I seem to recall it's a good trick to use if the radiator fan stops working.
Blank off part of the radiator air flow in really cold weather, 60 to 70% usuually works. The ideal is just to stop cold air blasting directly on
to the core but still allow to draw air in so the engine won't over heat in traffic.
On my own car I have neatly fitted black plastic (translate a heavy duty bin bag) behind the grill.
What is the operating temp of your engine ? as per VW
My Saab runs anywhere between 78 & 86c - And varies up and down during a journey.
I would expect the heater on full tilt to drop the temps as it is a radiator, as previously pointed out.
Since I have had the Saab front end off, and the radiator flushed, new hoses etc my car runs hotter than it used too, It did have me flapping for a
while, but all seems well.
It is pretty normal on the older tdi engines, I have exactly the same issues on mk3 tdi golfs, I did 250,000 miles on the first one like this.
The reason is that they are that efficient that they take an age to warm up and with the heater on it will drop the temp.
on ocasions when doors have been frozen solid I have clambered in and turned the blower and heater to max at the end of a journey so I can open the
door. after 10 min of full heat and blower driving at 30 mph it will bring the temp needle nearly to the rest.
I have driven VAG tdi's in winter without the engine undertray on and that makes a huge difference to the temp gauge.
I currently have a golf mk3 estate, at -9 on the motorway at 70 ish it can start to feel chilly inside with the heater on full bore.
I do recall in the VAG ETKA parts book they did sell radiator covers for cold climates
quote:
Originally posted by BenB
Couldn't it just be normal? Running the heater will take a fair bit of heat out of the coolant therefore dropping temperatures. I seem to recall it's a good trick to use if the radiator fan stops working.
I run about 70C in winter unless I'm running it pretty hard.
My old astra never used to move from the bottom of the gauge during the winter even with hard driving.
so, its there the potential then that I have fucked something?
The old stat was not stuck oen when removed, however the new one has given me significant improved (higher) water temps on back to back tests with no
more than a couple of degrees change in outside temp.
I just assumed the old stat was opening too quickly due to age? (up to 7 years old)
Sounds fairly normal. a lot of cars will drop the temperature a bit with heater on full because your basically added another radiator to the system
and blasting air through it....
Years ago we had an old transit and if you sat in traffic with the heaters on you'd eventually find it would be blowing cold because the
temperature had dropped so much.