How quickly should a 1.2 reach operating temp?

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TommyPolo
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How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

Hello, just a quick question.

I was wondering how long a 1.2 should reach operating temp, at the moment starting in the mornings maybe at an ambient air temp of 2 ish deg my car takes around 4 miles to reach operating temp which seems to be bang on 90deg.
Bepis
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Re: How quickly should a 1.2 reach operating temp?

Post by Bepis »

If I remember correctly my old 1.2 being started and driven when it was stone-cold would take about 2 miles to get up to temp driving at 50mph. My current 1.4 takes around 2 miles driving at 30mph.
Johntheo1
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Re: How quickly should a 1.2 reach operating temp?

Post by Johntheo1 »

Thought I had replied to this....

If driving off normally with no stops and blower speed on 2 then it should be well warmed by 4 miles, also remember that once the coolant temperature (in any VW) reaches 75C that it will then read exactly 90C and will only read higher than this if the actual temperature exceeds 107C, if you suspect the thermostat simply feel the radiator top hose (before it reaches "75C") and it should be cold until the thermostat begins to open at I think around 86C for those cars.
Wife has a 2018 65 BHP Polo and its very slow to heat up even with the blower only on speed1 compared with a 2005 Polo also in our family, the only reason I can see for this is that this engine appears to more efficient as it gives ~ 40% better fuel consumption.

I am surprised that a modern 1.4 heats up faster than the older models.
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

Ok I think mine takes longer than 2 miles to warm up to the gauge reading 90deg.

The reason I bring it up is that I am a little disappointed with the fuel economy, I drive carefully with economy in mind and I am only achieving 47mpg, mainly A roads with very few stops and rarely going over 55mph. I had an old 1999 Punto 1.2 for years and always did 50mpg without really trying so when I got the Polo with it being a much more modern design I thought Id crack the magic 60mpg! I can always acheive higher mpg figures than those the manufacturers claim, the Polo is the only car I've ever had that no matter how hard I try I can't do better !

I calculate mpg by brimming the tank, zero the odometer, drive and then at next fill record the amount to brim the tank again and record the mileage. I then dicide litres of fuel by 4.55 to give gallons used.

I'm wondering if the stat is lagging and she's running rich for longer than is necessary, my journey to work is only 11miles so even a few miles running rich will affect mpg.

John would you be able to explain again your knowledge, I didn't quite understand your last message but it would be great to work out if the stat is iffy without having to remove it!
Bepis
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Re: How quickly should a 1.2 reach operating temp?

Post by Bepis »

With 47mpg you're getting the same MPG I got with my 1.2 when it didn't put the CEL on and run very rich. I get around 39-42mpg with my 1.4 with a mix of driving on nationals, motorways, and around town with the occasional bit of spirited back road driving.

The best I have ever gotten from the 1.4 was 48mpg but that was a 250-mile motorway run.

Track your mpg and see what it does when the weather warms up. The free version of fuelly would suffice or you could use a note app on your phone.
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

Cheers Bepis,

it's probably obvious but what is the CEL?
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

CEL - check engine light!

The penny dropped in the end!
Johntheo1
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Re: How quickly should a 1.2 reach operating temp?

Post by Johntheo1 »

Re "iffy" stat, the thermostat should not open until around 86C and allow hot water through the top radiator hose and down though the rad to cool it. This top hose will/should be cold until this temperature is reached so just feel it before the coolant temp reaches this temp but because VW gauges read a constant 90C between 75c and 107C, it's best to feel the hose before it indicates 75C.
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

Ok so up to 75deg on the gauge the hose shoul be cold and soonish after that the hose will get warm/hot.

I suppose VW make the gauge stay still at 90deg to stop it wandering around and freaking owners out, personally I like to see things changing in real time so I can anticipate issues, what's the point of a gauge if it only onforms you of a problem when things have got really bad? It's no more use than a warning light, I really can't stand those!
Johntheo1
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Re: How quickly should a 1.2 reach operating temp?

Post by Johntheo1 »

TommyPolo wrote: Mon Jan 18, 2021 5:35 pm Ok so up to 75deg on the gauge the hose shoul be cold and soonish after that the hose will get warm/hot.

I suppose VW make the gauge stay still at 90deg to stop it wandering around and freaking owners out, personally I like to see things changing in real time so I can anticipate issues, what's the point of a gauge if it only onforms you of a problem when things have got really bad? It's no more use than a warning light, I really can't stand those!
I agree, but under normal driving conditions the normal gauge would scarcely move at all, in traffic then it would rise by around 10C, from 85C to 95C and the coolant fan would cut in, however it is still of some use as it reads accurately up to ~ 75C so you get a good feel for the heat up period and any problems.
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

Ok I see.

Checked the actual coolant today using my hydrometer. The coolant seemed quite gloopy and the reading said it was protected to -60deg+!!!!!!

Judging by the amount I had to dilute the coolant to get it to -25deg protection I think the cooling system is neat coolant!

Doing some research it seems that the higher the concentration the less effient the coolant is a removing heat from the engine ie. it is more difficult to heat the coolant? Adding water improves the ability so maube this could be slowing coolant warm up time?

Maybe I should syringe as much coolant out as I can and add water to dilute the coolant ?
Johntheo1
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Re: How quickly should a 1.2 reach operating temp?

Post by Johntheo1 »

TommyPolo wrote: Tue Jan 19, 2021 7:10 pm Ok I see.

Checked the actual coolant today using my hydrometer. The coolant seemed quite gloopy and the reading said it was protected to -60deg+!!!!!!

Judging by the amount I had to dilute the coolant to get it to -25deg protection I think the cooling system is neat coolant!

Doing some research it seems that the higher the concentration the less effient the coolant is a removing heat from the engine ie. it is more difficult to heat the coolant? Adding water improves the ability so maube this could be slowing coolant warm up time?

Maybe I should syringe as much coolant out as I can and add water to dilute the coolant ?
Ironically, you don't need any heat removed from the engine during heat up, the less heat that's removed, the faster the heat up time, over the years the engine manufacturers have reduced the engine coolant contents to achieve a faster warm up. Also, in older cars, the heater was controlled by the volume of water passing through the heater matrix so if kept shut off, quicker warm up. All modern engines have a continuous flow of water through the heater which results in a slower warm up even with fan speed on 0.
TommyPolo
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Re: How quickly should a 1.2 reach operating temp?

Post by TommyPolo »

I suspected that might be the case but I wasn't sure if the temp sensor was sensing the coolant temp and it was the coolant that was taking longer to heat up as it was pure coolant this was giving misleading information to the ecu and gauge and maybe the fuel injection could be running richer than it need for a mile or two?

What I'm trying to say is yes the engine itself might be warmed up but the coolant is lagging behind more than it needs to due to the having a too rich concentration?
Johntheo1
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Re: How quickly should a 1.2 reach operating temp?

Post by Johntheo1 »

TommyPolo wrote: Wed Jan 20, 2021 7:48 pm I suspected that might be the case but I wasn't sure if the temp sensor was sensing the coolant temp and it was the coolant that was taking longer to heat up as it was pure coolant this was giving misleading information to the ecu and gauge and maybe the fuel injection could be running richer than it need for a mile or two?

What I'm trying to say is yes the engine itself might be warmed up but the coolant is lagging behind more than it needs to due to the having a too rich concentration?
Yes, that's a good point but all those models seem to be a bit fond of petrol, I had a 1.4 Bora that on my regular 18 mile journey to work that would average 46/48 MPG but the 1.2 Polo on the exact same run 40/42 MPG., I have VCDS and the Polo goes into closed running loop at around 30C so, theoretically, can't run with a rich mixture on any sort of run.
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