Xantia Temp 55-65 on long runs

CommY · Unread post by **CommY** » 14 Sep 2004, 23:11

Hi the temp on my new xantia has recently been dropping down to about 55-65 while motorway cruising, is this OK or is the thermostat dubious. Around town it sit's happlily at 90. I know running cold will knack up the mpg.
BTW this si the best car forum I have ever been on 10/10!![:p]

TheWorker · Unread post by **TheWorker** » 15 Sep 2004, 00:08

65 sounds about right, because of the amount of air that gets through the rad to cool it down, then 90 around town when the speed isnt there

JohnD · Unread post by **JohnD** » 15 Sep 2004, 00:41

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by CommY</i>

Around town it sit's happlily at 90.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
My Xantia clocks 90C whether around town or on the motorway. Only does it rise higher when it's towing up inclines in very hot temperatures.

np · Unread post by np » 15 Sep 2004, 00:49

My 1.9td runs about 80c normally.If sitting in traffic for long periods,it will go upto about 90-95c.On the motorway,it stays about 80-90c,unless towing,then its between 85-105c.Depending on hills etc.
What engine do you have?

AndersDK · Unread post by **AndersDK** » 15 Sep 2004, 02:32

It's the engine temp - not the radiator temp - that has to stay in 85-90 ish range for any modern engine.
If the engine runs too cold it will not only suffer poor mileage but also wear more.
Since you can actually see the temp come up to 90, during conditions where any engine would run hot, you may rule out problems with the gauge.
I'd then suspect the thermostat itself. Known to stay more or less full open when they wear out, then causing the engine to heat up too slow and run too cold.

JohnCKL · Unread post by **JohnCKL** » 15 Sep 2004, 08:12

Probably the thermostat jammed in the open position. I've changed the rubber ring around the thermostat as its hardened and it made a difference, engine warmer now. Running temp at about 75-80C, idling 80-85C with a 83C thermostat.

P 2501 · Unread post by **P 2501** » 15 Sep 2004, 13:14

55-65 is definately too cold on this engine. Even on the motorway you should be looking for around 85-90 c. Running at 55-65 will certainly be wearing your engine more.

broomie · Unread post by **broomie** » 15 Sep 2004, 18:18

My Xantia Hdi clocks 90c in most conditions. I'd agree with others that your thermostats is stuck more or less open
PaulB

tomsheppard · Unread post by **tomsheppard** » 15 Sep 2004, 18:47

How nice to have one that isn't overheating for a change! Yes, it is the stat and when replaced it will pay for itself in around 3 tankfuls of fuel.

Panjandrum · Unread post by **Panjandrum** » 15 Sep 2004, 19:08

This is probably an idiot question, but that never stopped me before so I'll ask anyway.
How does 20degrees or so make a big deal of difference to either fuel consumption or engine wear?

AndersDK · Unread post by **AndersDK** » 15 Sep 2004, 20:04

Panjandrum I fully understand the logic of your question -
It has to do with the design of the engine and the combustion of fuel. Try have a look on these pages, where all the basics are explained :
http://auto.howstuffworks.com/
You'll find this library overwhelming on the sheer amount of basic technical descriptions found here.

Panjandrum · Unread post by **Panjandrum** » 15 Sep 2004, 21:32

Thanks Anders ...
"The engine runs best when its coolant is about 200 degrees Fahrenheit (93 degrees Celsius). At this temperature:
The combustion chamber is hot enough to completely vaporize the fuel, providing better combustion and reducing emissions.
The oil used to lubricate the engine has a lower viscosity (it is thinner), so the engine parts move more freely and the engine wastes less power moving its own components around.
Metal parts wear less."
Left me still wondering... But I guess the engine and its lubrication are designed to operate at an engineering compromise temperature that balances friction, viscosity and lubricant performance. In the world of lubrication, 20 degrees off design optimum will make a big difference.
Likewise, 20 degrees difference in and around the boiling point of the fuel makes a big difference.
I got sidetracked into wondering why such a small difference relative to the combustion temperature could make a difference in the power produced.
I guess I should stop confusing myself.
PJ

CommY · Unread post by **CommY** » 16 Sep 2004, 00:31

The only thing that may dismiss the thermostat as a problem is the the heater starts blowing hot air(from sitting overnight) after about 400 yards?? I'm confused.

manic_man · Unread post by **manic_man** » 16 Sep 2004, 00:48

Hi mate, just replace the stat, they r £5 from GSF for the genuine part, and are the easiest stat to replace ive ever come across. very acessible.
Only thing is remember to get a new rubber gasket as it doesnt use paper or anything "normal"

mine used to do exactly as yours did, replaced it and all was well. Just made sure when i topped up the coolant that i stick the fan and heater on full blast and left it running for about 20 mins with the bleed nipple and cooleant cap off, toping up whenever more air was purged.
Now it gets to around 85 doing 90 on the m-way in hot weather, sits at 80 for the most part and occasionally drops to 75 when i first get on the m-way. it used to take ages to rise to 75 and would never EVER go past that point

pwatson · Unread post by **pwatson** » 16 Sep 2004, 04:31

Thermostat on Xantias should start to open at 89 deg (83 for autos) and be fully open at 99. Temp should therefore after warming up never drop below about 90?