Normal Temperature Of The 2.5.

[rowanmoor]

What is the normal running temp of the 2.5? I think mine is running cold (and I suspect that may be hitting my fuel consumption). I would like to know what it should be before I get the thermostats changed though.

How accurate is the temp guage anyway?

The fans rarely come on except when I have been on the motorway and come to an abrupt halt for a while and it is hot weather.

It usually runs between 70 and 80 (normally closer to 70) no matter what the weather. I can get it to go up to 90 if I am pushing it on a hot day but not moving too fast so the air isn't flowing over the rad.

Cheers,
Rowan.

[Peter.N.]

Hi Rowan

I dont know about the 2.5 specifically, but most engines run at about 88C, much cooler and it will affect fuel consumption. A fairly reliable way to test the theromostat without removing it, is to feel the radiator before the engine gets to normal temperature, it should be cold, if not the thermostat will be faulty. Another thing you will notice if you radiators are in good condition, if the thermostat is not working the temperature will drop as your speed increases.

Peter.N.

[xmexclusive]

Hi Rowan

All my 2.5's when in good order have run consistently at temperatures in the range 87 to 90 on the car gauge. I understand that long heavily loaded runs while towing can take the temperature up to 95/100 range. The car gauge is an indicator not a calibrated instrument so may not be accurate but you can expect it to be consistent in its display. Wide swings in temperature may not be accurate to the degree but they are indicating that the cooling system is not behaving as it was designed to operate. Something that should be sorted incase long term it should prove detrimental to engine life. Similarly significant changes in the typically displayed temperatures over a period of time should be investigated. The fans should cut in about 95 degrees provided your 2.5 does not have aircon which keeps them on most of the time.

Regards

XMexc

This post has been edited by xmexclusive on April 18, 2008 09:46 pm

[rowanmoor]

Thanks. That does confirm a lot of what I thought.

I will have to start it up when I have some time and check when the radiators start to get warm and what the gauge displays when the fans start.

The temp does tend to vary with speed - if I have been on then motorway and then slow down/stop as I come off, the temp rises to more like the 85 (fans still not on if it is just this temp - it has to show higher than that for them to come on). Then when I pick up speed again it drops back down to 70ish.

I expect I will find that one (or both) radiators start to get warm before it gets to normal temp then.

Cheers,
Rowan.

[Peter.N.]

Hi Rowan

Yes, that would indicate a thermostat that is either stuck partly open or is opening to early. If it runs significantly cooler at speed, especially 70ish, assuming that your gauge is something like accurate, that would point to a faulty thermostat.

The thermostat should stay closed until the water reaches the proscribed opening temperature, so the water will circulate around the engine and heater but not the radiator, when it does open it will do so suddenly, so the radiator/s should get hot suddenly, not slowly.

Peter.N.

[Little&Large]

Hi Rowan
Mine runs at 75 ish on a day like today on the motorway.It does go up to 90 ish in traffic when my fans kick in as I don't have the A/Con on.I am pretty sure my thermostat is stuck open permanently as in the cold weather it struggles to reach 60 degrees.My economy suffers in the winter and I really should get it changed but I did a 65 mile trip today with suburban driving both ends of a jaunt on the M25 and averaged 50.4mpg.Somehow I quite like the fact that it doesn't run so hot and presumably the system is not so pressurised.Certainly I can take my filler cap off at most temps without water gushing out.
Regards Rob

[onthecut]

Hi all.

I'm throwing my hat in with XMexc; pretty much spot on mirrors the 2.5s I've had and towing definitely pushes the dial up.
Rob ---- it is worth getting sorted; running consistently cold is likely to do more harm than good. Pretty much all modern oil is designed only to function fully in the design environment and temperature is a key part of the equation. Even antiquated diesels rarely had stats lower than 82deg.
If it's any comfort, I've towed with all the 2.5s I've had; seen the temp up over an indicated 100deg © and never lost a drop of water. Providing the thing is in good order, I think the secret is to use a quality anti freeze at a mix of at least 50%. It really does maintain the waterways in a very clean condition.

Mike.