One cool Citroén!!

Xantia2.0 · Unread post by **Xantia2.0** » 16 Aug 2010, 12:10

Replaced the hose this morning (courier was late), started her up and the temperature gauge stopped at just over the cold mark! Like it used to be! The gauge looks like it's not even working, it's sitting so cold! Ahh, one cool Xantia

andmcit · Unread post by **andmcit** » 16 Aug 2010, 12:28

You have got a thermostat fitted then? When you need that hot air
blasting at your feet or windscreen in February in your northern part
of the world, I'd have thought hot water into the heater matrix may
be desirable!? No?

Andrew

Xaccers · Unread post by **Xaccers** » 16 Aug 2010, 13:11

Surely this should have been an update to http://www.frenchcarforum.co.uk/forum/v ... hp?t=32114 rather than starting a new thread?

Xantia2.0 · Unread post by **Xantia2.0** » 16 Aug 2010, 17:34

The engine is hot enough for the heater to work but still cold enough to make it last for many more years than it would running nice and toasty!

Unread post by **RichardW** » 17 Aug 2010, 08:08

It should run at around 80-90°C. There is a reason Citroen designed it like that.... Too cool is nearly as bad as too hot!

Xantia2.0 · Unread post by **Xantia2.0** » 17 Aug 2010, 08:21

Actually, the colder an engine runs the longer it will last as the bore and pistons have less wear (assuming it has clean synthetic oil). The car did originally run at 80-90 degrees but in 2001 it was reprogrammed to run at the coldest the engine would safely run (don't know the exact degree reading as the gauge isn't the style with numbers on it, it's the "vertical" one with the purple/blue background! But I assume it's running at about 35-40 degrees (emissions papers didn't tell me for some reason, just says "N/A"). My 1.6 Focus is running at 91 degrees according to the emissions papers, but I'm in the process of getting that reduced to 50.

addo · Unread post by **addo** » 17 Aug 2010, 08:39

There's a design range of operating temperatures; part of the principle is correct heat transfer. If you run overcool, the biggest "risk" (as I see it) is poor bore sealing, resulting in crankcase contamination and loss of efficiency - also known as poor fuel economy.

Xantia2.0 · Unread post by **Xantia2.0** » 17 Aug 2010, 09:17

Yep I know, colder the engine runs worse fuel economy I get. But I am willing to sacrifice that in return for the engine to last for the next 20+ years!

I am still getting 30-35MPG anyway!

Unread post by **RichardW** » 17 Aug 2010, 09:33

Cool running = possible bore washing = accelerated wear...

Not sure what gauge you have got in your Xantia - all the factroy fit ones AFAIK were numbered....

Xantia2.0 · Unread post by **Xantia2.0** » 17 Aug 2010, 09:36

Yes, accelerated wear if it is too cold! If you get it just right you have the best of both worlds, average fuel consumption and a long living healthy engine!

Sid_the_Squid · Unread post by **Sid_the_Squid** » 17 Aug 2010, 10:22

I gotta say that sounds wrong Xantia2.0, a cold engine will not only consume more fuel but wear more rapidly, due mostly to oil not operating at the correct temperature, as metal expands when heated I expect this was considered greatly during engine design, running the parts to cold I would have though tolerances would be slightly out.
Drive a car without a thermostat or a thermostat stuck open and feel how rough it runs.

Why you worried about your engine not lasting? keep it serviced nice, and I'm sure it will live far longer than the car bodywork/suspension.
Its not even like its a rare engine, you could always get another one if it breaks.

Feel free to correct me if I'm wrong here Can you provide any information to back up 'the cold running' claim?

Xantia2.0 · Unread post by **Xantia2.0** » 17 Aug 2010, 10:32

I've been working on cars for over 10 years. A colder engine lasts longer than a warm running one. And I plan on keeping the car for over 10 years so I need the engine to last over 300,000 miles! But you would be right if it were regular oil I was using, but I'm using Fully Synthetic oil specifically made for colder-running engines!

Sid_the_Squid · Unread post by **Sid_the_Squid** » 17 Aug 2010, 11:29

Are you citing your own personal experience with engines over the time frame of 10 years as the proof of this statement? Have you conducted an scientific study i.e. two of the same engines equal in all regards except the running temperature, and observed the rate of wear over a 300k mile period?

Whilst its true that synthetics do provide better protection at cold temps than mineral oils, AFAIK they are still designed to operate at 80 to 100 degrees to reach their correct hot VI rating. Are you running a particularly thin oil like a 0w-20?

Over 300k miles would not be unheard of, there are a few on here approaching that figure.

andmcit · Unread post by **andmcit** » 17 Aug 2010, 12:00

You should try a poll on this question rather tyres.

If most of the wear and tear on engines is caused in the first 5 minutes
after start up while it warms up, it never will on your 2.0i 16v and the
engine will be a wreck in no time/miles.

I've come across this idea before as one of my Cx tubos had it's
thermsostat removed and the car would run harder with the fuel
injection effectively running richer ALL THE TIME like it does when
the car is first started - ultimately this did cause issues with the
fuel injection and it would break down and barely idle.

Now I don't even pretend to be an expert in this subject and would
love to see a mechanical engineer weigh into this discussion but looking
extensively through references online, consequences of forced cold
running range from:

• Increased engine wear and corrosion due to a greater concentration
of combustion acids, poorly fitting parts and excess fuel and water
(condensation) in the oil.

• Greatly increased fuel consumption due to car running in cold running
mode with elevated injection phase/pulse width and incorrect operation
of engine management and 02 sensors

• Greatly increased emissions and damage to the catalytic converter
due to the incomplete combustion of fuel

Basically, engines need to be warm so all internal components are expanded
to operational sizes, and combustion takes place properly. Just using more
expensive oil isn't the full remedy to this. You've got to rationalise that the
optimum operating point the engine is designed to run at by Citroen in the
first place is the most efficient - why else would every car manufacturer do
the same? A deliberate ruse for a shorter lifespan on their engines so you'll
be back for another car soon? Come on I don't think so.

There are many cars on this forum with 200-300k miles and going strong
and to a man, everyone will say it's because of regular quality oil changes.
I believe you're putting too much store in synthetic oil to correct a skewed
operating temperature of the engine - if you're doing that you may as well
run the engine normally and change the oil more often for semi/full synthetic
and be done with it. I think you're looking for trouble with a theory that
sounded good over a few pints?

Andrew

Sid_the_Squid · Unread post by **Sid_the_Squid** » 17 Aug 2010, 12:13

Very nicely summarised Andrew