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Hi all.

Since the weather warmed up a bit a I've noticed my omega not only running hotter but also the needle seems to jump around a bit.

Whereas before the highest I'd seen it get was 96-97ish, it now quite often goes to 100. If I am idling lights and I notice this then give it some revs the temperature drops rapidly to 93-95ish.

As a non scientific test I decided to boot it to work today in sports mode.
11.5 Outside temp. First two miles temp gradually rose to 99 -100, next three sat at 99-100, last two dropped to 95-96.

There was no real diference in my driving on on last two than the three before.

Searched some posts and noted many people with hot running had a cold blowing heater. Mine does blow hot and does take the temp down if left on.

Obviously if there is a problem I would like to get it sorted before the summer.

How hot is too hot ? Is it really safe to drive the car until it hits the red line or should I be pulling over and letting the car cool at some point before this ?

To anyone that remembers my post about coolant loss worries. The level in the header tank has stayed the same for over a week now. So I'm either not losing coolant (where did the last lot go ?) or its not being drawn into the cooling system (how to check?)

Apologies if i've rambled
 

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My 2.6 is running 95-100 in traffic/idle, and 85 on motorway. The reason for the hunting between 95-100 when in traffic/idle is the elctical fans cutting in and out, while on motorway the cooling is steady and provided by airstream on the rad.

I don't really see a problem with yours...
 

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robs omega said:
its important you have a good 50/50 mixture of antifreeze in these engines, it also helps keep hot running engines run cooler?
will have to disagree with the ' engine runs cooler' because the less antifreeze you have in the mixture the better cooling you get as the water has better thermal conductivity. 50/50 is good mixture but it is a bit conservative i run with distilled water 70% and mobil longlife antifreeze 30% changing it once a year.
 

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Yesssshhhh... But Ethylene Glycol has higher boiling temprature then water which is important for modern pressurised cooling systems where tempratures can go higher than 100 degrees.

If the old days (now how many times did I say this already..?) we use to do something similar to waht you did, i.e. take distiled water (the type you use for batteries), add Ethylene Glycol and drop a bottle of Holts rust inhibitors. You can also add blue dye for good measure (Ethylene Glycol is green), this makes the coolant look light-blue and fresh... But we did it 50/50 not 70/30.

Keep in mind that Ethylene Glycol is not corrosive while water is, the less water you have in the coolant system the better though you still need it for the thermal transfer (otherwise you'l run the engine on 100% Ethylene Glycol...). So having more water may increase the efficiency of the coolant BUT will not do any favours to the alloy heads.

Also, the Ethylene Glycol is thicker and lubricates the water pump.

As for the changing every year - this is good!

My t***ence.
 
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I see an interesting debate coming.... ;)

Gripped, your engine is running too hot for my taste at this time of year.

Flush out your coolant and refill with a 50/50 mix (ideally distilled water) and see if operating temp changes.

Ps. When was oil last changed?
 

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Am I right in thinking that the Merlin engine in the WW2 Spitfire was cooled with 100% ethylene glycol?

If its good enough for the Merlin engine its good enough for the Omega but obviously very expensive. This would also give frost protection down to a very low level. We do not live in Siberia at the moment but are the winters getting colder?
 

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Looking it up on the Internet, it seems that the Rolls Royce Merlin engine was the first to use Ethylene Glycol as coolant, but it was mixed with water and not 100% pure - apparently pure Ethylene Glycol if flammable so was not suitable for a warplane that was prone to getting shot in the rad (the rad was used for low-speed flying and taxing).

...and did you know that Ethylene glycol was first prepared in 1859 by the French chemist Charles Wurtz? Fascinating stuff, the Internet.
 

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....and by pressurising the water and Ethylene Glycol cooling system, they were able to increase it's efficiency to a point where they could do away with the low-speed radiators all together and reduce both drag and vulnerability to enemy gunfire. I am beginning to sound like BBC2 TV at 9pm….
 

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markjay said:
Yesssshhhh... But Ethylene Glycol has higher boiling temprature then water which is important for modern pressurised cooling systems where tempratures can go higher than 100 degrees.

If the old days (now how many times did I say this already..?) we use to do something similar to waht you did, i.e. take distiled water (the type you use for batteries), add Ethylene Glycol and drop a bottle of Holts rust inhibitors. You can also add blue dye for good measure (Ethylene Glycol is green), this makes the coolant look light-blue and fresh... But we did it 50/50 not 70/30.

Keep in mind that Ethylene Glycol is not corrosive while water is, the less water you have in the coolant system the better though you still need it for the thermal transfer (otherwise you'l run the engine on 100% Ethylene Glycol...). So having more water may increase the efficiency of the coolant BUT will not do any favours to the alloy heads.

Also, the Ethylene Glycol is thicker and lubricates the water pump.

As for the changing every year - this is good!

My t***ence.
My point was that the (which i have nothing against to)50/50 is a conservative measure that covers the a** of the manufacturer. If you want the most of your cooling system performance then you have to reduse the % antifreeze which is suficient enough to protect the surfaces if you change it every year. Regarding to boiling points i assume that we all know that in a closed cirquit the water doesn't boil but it increases its pressure almost relatively to temperature, e.g at 100degrees you get 1 bar.
 

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OmegaV6CD said:
Regarding to boiling points i assume that we all know that in a closed cirquit the water doesn't boil but it increases its pressure almost relatively to temperature, e.g at 100degrees you get 1 bar.

BUT........... The cooling system is not a closed circuit because it has a pressure relieve valve, so the pressure will only rise that much, after which the water WILL boil. I have seen this happen….
 

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markjay said:
BUT........... The cooling system is not a closed circuit because it has a pressure relieve valve, so the pressure will only rise that much, after which the water WILL boil. I have seen this happen….
This is when you exceed by far the limits at extreme situations also i don't seem to recall the existance of that 'valve' (i think you mean the pressure rated radiator cap)on the omega. The cooling system is a closed cirquit under pressure and the coolant doesn't boil but as you warm it up the pressure raises.
I have seen too the scenario that you predescribed but this occurs only when something goes wrong on the cooling system.
 

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Marks DTM Calib said:
Electronic Eng. Beg (hons) MIEE (although not renewing it as it offers nowt!)
Smartarse ;)

I got a CSE in French at school, does that count?
 

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Marks DTM Calib said:
Electronic Eng. Beg (hons) MIEE (although not renewing it as it offers nowt!)
Hey mate much the same as you... now doing my doctorate :)

I'm also MIEE and MIEEE, I agree they offer little but as I'm a student membership is cheap and I don't pay it anyway :cool:. Besides usually the discount when attending a single conference more than pays the membership (I go to 3 or 4 a year, free holiday effectively). :Cool2:
 

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markjay said:
That's the one.

Err... any engineers out there? Proper engineers that is, i.e. chemical engineers, physics engineers... :)
Mechanical Engineer BEng(hons) AMImechE currently doing part time MSc in automotive engineering.
 
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