Evening all 

 

our Skoda rapid 1.2 tsi (2015) has started having a niggling issue with the coolant temperature. 

 

ever since the cold snap just before Christmas (in the UK) when we use the A/C (above 3 bars) the coolant temperature gauge drops and the heating starts to blow cooler. 

 

The car seems to get up to temperature ok, especially when no heating on. Before the cold snap it was working fine, although it wasnt used for about a week whilst my wife wasn't too well.

 

Any suggestions? Coolant temperature sensor or thermostat possibly?

 

no error codes etc just the temp guage dropping off.

 

mAny thanks in advance 👍

 

 

 

I'm having my aircon checked soon, when the temperature rises. Same engine as yours but a Toledo.  It's not as efficient as it used to be, well never been regassed in 8 years🤔 and it's the first winter I've had problems clearing the fogged up windows.

For one the aircon will not work at temps below 3°, that's normal according to experts and the handbook, well if I remember below 4° it says there. 

A check with my car suggests the heat is getting through to the inside of the car so have discounted the stat or a sensor at fault, that's without the aircon on.

Have you got a coolant temp reading in the MFD, mine reads ok (around high 80's) warmed up?

7 hours ago, MickA said:

I'm having my aircon checked soon, when the temperature rises. Same engine as yours but a Toledo.  It's not as efficient as it used to be, well never been regassed in 8 years🤔 and it's the first winter I've had problems clearing the fogged up windows.

For one the aircon will not work at temps below 3°, that's normal according to experts and the handbook, well if I remember below 4° it says there. 

A check with my car suggests the heat is getting through to the inside of the car so have discounted the stat or a sensor at fault, that's without the aircon on.

Have you got a coolant temp reading in the MFD, mine reads ok (around high 80's) warmed up?

Morning, thanks for the reply

 

Do you know what? I never thought to check the MFD when it happens. Got to take it out in a bit so will see what it reads and post back. 

 

I initially put it down to being so cold, however even since it's warmed up a bit, it's still doing the same. My Octavia is the same age and, touch wood, hasn't had the same issue, although it's a different engine.

 

The fact that there is heat getting into the car and the engine warming up alright makes me think (or hope!) The thermostat is alright, just seems odd that the temp guage drops..

14 hours ago, MickA said:

I'm having my aircon checked soon, when the temperature rises. Same engine as yours but a Toledo.  It's not as efficient as it used to be, well never been regassed in 8 years🤔 and it's the first winter I've had problems clearing the fogged up windows.

For one the aircon will not work at temps below 3°, that's normal according to experts and the handbook, well if I remember below 4° it says there. 

A check with my car suggests the heat is getting through to the inside of the car so have discounted the stat or a sensor at fault, that's without the aircon on.

Have you got a coolant temp reading in the MFD, mine reads ok (around high 80's) warmed up?

Ok so went out on a trip this morning -0.5 here, and heating was "ok" but not the best. Car warmed up as usual, with heating off no worries. But the same happened when I put the heating on above 3 bars in the AC display, guage drops away from 90 (about 2 sections) and then Aircon, although warm, not as it should. The temp will build back to 90 but then drop again.

 

The only temp in the display I have is if course the oil temp, not water temp, whish was reading about 72 which is about right as it was stop start driving and rather chilly out!

 

I'm wondering if a re-gas will help? Never had it done. 

 

Any other ideas from anyone?

 

Many thanks again 👍

Edited 21 January, 20233 yr by goatus

Is it a short trip like under 10 miles of stop start where the indicated Oil Temp is just getting to 72*oC? 

30 minutes ago, toot said:

Is it a short trip like under 10 miles of stop start where the indicated Oil Temp is just getting to 72*oC? 

Yes only down the road, driving maybe 15-20 mins max, stop start driving only 40mph tops. 

2 hours ago, goatus said:

Ok so went out on a trip this morning -0.5 here, and heating was "ok" but not the best. Car warmed up as usual, with heating off no worries. But the same happened when I put the heating on above 3 bars in the AC display, guage drops away from 90 (about 2 sections) and then Aircon, although warm, not as it should. The temp will build back to 90 but then drop again.

 

The only temp in the display I have is if course the oil temp, not water temp, whish was reading about 72 which is about right as it was stop start driving and rather chilly out!

 

I'm wondering if a re-gas will help? Never had it done. 

 

Any other ideas from anyone?

 

Many thanks again 👍

As my earlier post, I'm going for a regas on mine, having similar problems but the temp gauge seems ok.  It's just when I try to use the aircon in temps lower than around 2°, windows fog up.

Got a local aircon man works the Derby area to contact, pointless ATM as to get the aircon fully checked and regassed the temps aren't ideal.

I'm waiting until at least maybe end of next week, temps supposedly reaching 8° here.

21 minutes ago, MickA said:

It's just when I try to use the aircon in temps lower than around 2°, windows fog up.

Big hint; the A/C will be disabled below 4C.

If it is the 1.2TSI 16V (belt driven camshaft), then you might just be witnessing that these petrol engines are a lot more energy efficient than previous models, and so this can mean, that on a shortish journey, the engine will not be providing enough waste heat to keep the cabin heater hot and also keep the engine coolant sitting at an indicated 90C when the outside temperature is way below 0C.

 

If driving at normal "out of town" speeds for journeys longer than maybe 8 miles, then I would expect that everything would be okay, we were out in my wife's 2015 VW Polo 1.2TSI, and normally I just suffer without the cabin heater on in winter - unless the glass mists up, until the coolant temperature gauge is up to 90C, this morning I chose to not do that so at the end of a 5 mile journey starting from -2C, the indicated coolant temperature never got up to 90C even although the first mile or so was uphill, I'm not worried about that as normally as I said I just let the engine warm up first before demanding a lot of heated air coming into the cabin. That is probably the price to pay when I have 110PS max output that moves the car along very well, and 50>60MPG.

 

Edit:- of course maybe your findings are worse than I'm describing.

Edited 21 January, 20233 yr by rum4mo

1 hour ago, KenONeill said:

Big hint; the A/C will be disabled below 4C.

I did mention that too in my first post 👍

12 hours ago, rum4mo said:

If it is the 1.2TSI 16V (belt driven camshaft), then you might just be witnessing that these petrol engines are a lot more energy efficient than previous models, and so this can mean, that on a shortish journey, the engine will not be providing enough waste heat to keep the cabin heater hot and also keep the engine coolant sitting at an indicated 90C when the outside temperature is way below 0C.

 

If driving at normal "out of town" speeds for journeys longer than maybe 8 miles, then I would expect that everything would be okay, we were out in my wife's 2015 VW Polo 1.2TSI, and normally I just suffer without the cabin heater on in winter - unless the glass mists up, until the coolant temperature gauge is up to 90C, this morning I chose to not do that so at the end of a 5 mile journey starting from -2C, the indicated coolant temperature never got up to 90C even although the first mile or so was uphill, I'm not worried about that as normally as I said I just let the engine warm up first before demanding a lot of heated air coming into the cabin. That is probably the price to pay when I have 110PS max output that moves the car along very well, and 50>60MPG.

 

Edit:- of course maybe your findings are worse than I'm describing.

Yes that had crossed my mind, with the temp being so cold at the time, however I've never noticed this in the time we have owned it (since new). I did try it out when it's been in the plus figures, although not exactly warm, and still the same effect 🤔

 

It's booked in for a cambelt and waterpump change on the 1st, not that I think it'll make much difference to the situation unless the water pumps failing some how but there are no leaks etc I  have...

 

Maybe I'll have to get a video or something when I'm next able too to show exactly how it happens.

 

Many thanks for all of the replies so far 🙂👍

On 22/01/2023 at 06:09, goatus said:

Yes that had crossed my mind, with the temp being so cold at the time, however I've never noticed this in the time we have owned it (since new). I did try it out when it's been in the plus figures, although not exactly warm, and still the same effect 🤔

 

It's booked in for a cambelt and waterpump change on the 1st, not that I think it'll make much difference to the situation unless the water pumps failing some how but there are no leaks etc I  have...

 

Maybe I'll have to get a video or something when I'm next able too to show exactly how it happens.

 

Many thanks for all of the replies so far 🙂👍

 

Went out in mine yesterday (Toledo) and the heating is working fine, gauge soon gets to 90° after around 2 miles approx driving. Toasty warm actually in no time. So definitely having the aircon looked at soon, well it's never been regassed from new, over 8 years.😂

Sorry for the bum info, only oil temp shows in the MFD, we do have a gauge on the dash for water temp😂

 

Just one point does yours have the belt drive or is it still chain on the 2015 1.2TSi? You mention having the belt changed.👍

1 minute ago, MickA said:

 

Went out in mine yesterday (Toledo) and the heating is working fine, gauge soon gets to 90° after around 2 miles approx driving. Toasty warm actually in no time. So definitely having the aircon looked at soon, well it's never been regassed from new, over 8 years.😂

Sorry for the bum info, only oil temp shows in the MFD, we do have a gauge on the dash for water temp😂

 

Just one point does yours have the belt drive or is it still chain on the 2015 1.2TSi? You mention having the belt changed.👍

Good to hear you're nice and warm now! As mentioned before ours has done pretty well warming itself up (considering) it's just keeping warm whilst warming us  that's the issue 🙄😄. 

 

With the MFD, when you mentioned it, I did think to myself it must be something I've missed over the years that's more accurate than the dash guage, I shall bow to superior knowledge 😂

 

Yes as far as I'm aware it's a belt, it's registered 2015 but everyone you put the reg in anywhere it's 2016 model 🤷. May be wrong but wasn't 14 the last chain year?

 

Thanks for the updates!

Normal behaviour during warm up in cold temperatures if you are driving very economically and not going up hills, accelerating to overtake etc, more noticeable on the more thermally efficient diesel engines.

 

A few observations:

 

Your coolant temperature was not at 90°C that is the fiddle factor of the electronics, true temp will have been equal to the oil temperature.

 

At the higher fan speed settings you are pulling more heat from the engine than the excess heat from combustion.

 

With the AC on the air you are heating air that has already been frozen by the AC so you are taking far more heat from the engine cooling system than needed, if you turn the AC off you will not see the guage dip and recover and you will have warmer feet for the first 2 miles of your journey.

Edited 23 January, 20233 yr by J.R.

3 minutes ago, J.R. said:

Normal behaviour during warm up in cold temperatures if you are driving very economically and not going up hills, accelerating to overtake etc, more noticeable on the more thermally efficient diesel engines.

 

A few observations:

 

Your coolant temperature was not at 90°C that is the fiddle factor of the electronics, true temp will have been equal to the oil temperature.

 

At the higher fan speed settings you are pulling more heat from the engine than the excess heat from combustion.

 

With the AC on the air you are heating air that has already been frozen by the AC so you are taking far more heat from the engine cooling system than needed, if you turn the AC off you will not see the guage dip and recover and you will have warmer feet for the first 2 miles of your journey.

Thanks for the detailed reply J.R,

 

I shall try it without ac again next time I take it out (it's my wife's car normally!) Indeed where you are coming from with the behaviour during economical driving in the cold weather. Just after Christmas I drove about 20miles (including motorway driving) whilst the temp was on the plus side, although still single figures and the guage still seemed to dip away, but again that was with the AC active. 

 

Interesting info regarding the coolant temp guage, so in reality even tho the coolant guage is displaying 90⁰c,.you'd be better off keeping an eye on the oil temp in the display?

 

Many thanks again 👍

It will display 90°c for any engine temperature between 70 something and 110 or so, someone did an actual test on here but I cant recall the exact figures.

 

VAG have been doing it for 2 decades now, if they didn't people would be complaining all the time, as it stands it's only in rare circumstances like ours that we see the changes momentarily when the temp falls outside of the fiddle limits and even then the guage does not fall as much as it should.

 

Having the needle sit at a rock steady 90°c creates a false sense of security, when it exceeds it it is in fact by a big amount and will keep climbing.

2 minutes ago, J.R. said:

It will display 90°c for any engine temperature between 70 something and 110 or so, someone did an actual test on here but I cant recall the exact figures.

 

VAG have been doing it for 2 decades now, if they didn't people would be complaining all the time, as it stands it's only in rare circumstances like ours that we see the changes momentarily when the temp falls outside of the fiddle limits and even then the guage does not fall as much as it should.

 

Having the needle sit at a rock steady 90°c creates a false sense of security, when it exceeds it it is in fact by a big amount and will keep climbing.

Excellent, thanks again for the detailed explanation. I shall keep monitoring when the weather improves, and hopefully it'll return to it's usual reliability.

 

Just seemed odd it's been doing it for the best part of a month now and never before, although it has been fairly cold over that time!

 

Many thanks 👍 

I have noticed it several times this winter but only on the coldest of days and when I have been driving very slowly sightseeing or slowly for economy, it will likely happen on the journey I am about to make, it did last time and will go away after climbing the hill on the route or not happen at all if I leave the AC off.

4 minutes ago, goatus said:

Excellent, thanks again for the detailed explanation. I shall keep monitoring when the weather improves, and hopefully it'll return to it's usual reliability.

 

Just seemed odd it's been doing it for the best part of a month now and never before, although it has been fairly cold over that time!

 

Many thanks 👍 

 

Ahh... rather like my oil/coolant gauge in my MX-5 then, just for show, they do jot to warn of any impending oil pressure or coolant temp issues.

 

On 23/01/2023 at 11:42, MickA said:

 

Ahh... rather like my oil/coolant gauge in my MX-5 then, just for show, they do jot to warn of any impending oil pressure or coolant temp issues.

 

Yes, but probably a lot better than not having a coolant gauge - like SEAT seem to omit from lots of their cars at the lower end of the price range, that used to annoy me when I was looking after my daughter's 2009 Ibiza 1.4.

 

I've always had a temperature gauge in my cars or vans, my Anglia van (ex Royal Mail), had one, my Escort MK1 van (ex S&N Breweries) didn't, so I needed to get the dash panel from a similar aged Escort MK1 1300 XL, wiring and sensor were already in that van, from then on always had a coolant temperature gauge! I've even got a "plug in" 12V DC voltmeter in the front power socket - to keep an eye "smart charging" !

 

Edit:- back on topic again, while the coolant temperature was slow to "get up" when the ambient temperature was anywhere between -7C and -2C, after the outside temperature rose up to just above 0C, the engine coolant heated up a lot quicker - surprise surprise - not!  So even when driven moderately and mainly on the flat, at that slightly higher outside temperature, the coolant gauge quickly (<2 miles) got up to an indicated 90C without the cabin heater being on, switching the cabin heater on then had no visible impact on the coolant gauge temperature for the remainder of that 9 mile journey.  I'm just posting this so that you can see that I have noticed a change in "warming up" times ie going by what the coolant temperature gauge is showing over a slight change in coldish outside temperatures - nothing more.

Edited 26 January, 20233 yr by rum4mo

Please note - I am not a mechanic or expert in anything.

 

On 21/01/2023 at 13:38, goatus said:

The only temp in the display I have is if course the oil temp, not water temp, whish was reading about 72 which is about right as it was stop start driving and rather chilly out!

On 21/01/2023 at 14:36, goatus said:

only down the road, driving maybe 15-20 mins max, stop start driving only 40mph tops. 

That doesn't sound right to me, 15 mins stop-start driving not getting above 40mph I'd expect to see more than 72c on the oil temperature of my wife's 2015 1.2 TSI (90), different cars and driving of course but given the heater running cool and even the biased coolant needle not being at 90 the first thought would be that perhaps the thermostat isn't closing or fully closing.

 

Never rely just on error codes and as you've found no errors codes doesn't mean there everything is running as it should.

 

Edited 26 January, 20233 yr by nta16
ETA: Please note - I am not a mechanic or expert in anything.

Please note - I am not a mechanic or expert in anything.

 

IIRC earlier MX-5 models did have a working oil pressure gauge but I'm not sure about the coolant gauge, at the least it's like the coolant gauges in our car and biased to the needle at 90.

 

Gauges that gave true real time readings would probably worry drivers now as they did in the past with first the numbers being left off the gauge then the general markings.  Given the lack of accuracy and very low figures for some cars it was best some drivers didn't know as they'd just worry plus other examples of the same model year and engine may well show different figures so that would worry some.

 

Our cars could do with a gauge for the (12v) battery but only those with EVs would perhaps fully follow what the reading told them at that particular time.

 

 

59 minutes ago, nta16 said:

Given the lack of accuracy and very low figures for some cars

Like my mate's girlfriend's M*n*, where the question following a change of head gasket was "Whereabouts should the temperature gauge on this car be when it's hot?"

 

And the responses included "Above 'cold' and below 'hot'."

Does the swear filter not like Mini now or did you write Minge?

4 hours ago, nta16 said:

Please note - I am not a mechanic or expert in anything.

 

That doesn't sound right to me, 15 mins stop-start driving not getting above 40mph I'd expect to see more than 72c on the oil temperature of my wife's 2015 1.2 TSI (90), different cars and driving of course but given the heater running cool and even the biased coolant needle not being at 90 the first thought would be that perhaps the thermostat isn't closing or fully closing.

 

Never rely just on error codes and as you've found no errors codes doesn't mean there everything is running as it should.

 

Yes I'm still convinced something's not quite right, even now the temp has risen abit outside, I've tried just using the heater (no AC) and whilst it's warming up nice and quick, and getting to 90⁰c on the coolant guage, it's still drops off before picking back up again. The thing never gets a good run out really, I'll have to get it out for a good trip and see what it does on the oil temp figures. 

 

Thanks for the reply and advice 👍