Hello, so my engine runs a little too cold. The coolant temeperature gauge climbs up to only 1/4 instead of 1/2 and doesn't go higher. From what I've heard it could be a permanently opened thermostat, but the cabin heater works just fine. Could it be just a faulty sensor? Or is it really the thermostat?

2 minutes ago, pixelovski said:

From what I've heard it could be a permanently opened thermostat, but the cabin heater works just fine. Could it be just a faulty sensor? Or is it really the thermostat?

Yes and Yes. Does the top hose pressurise before the temperature gauge moves? Suspect open or broken thermostat. What temperature do you get from an independent source like VCDS?

If the cabin heat seems unchanged and reasonable compared to other heaters then it is almost certainly the coolant temperature sensor (CTS), like so many new posters asking for help you have not stated what engine your vehicle has, certainly on the diesels the CTS is a common failure and also affects the idle speed.

 

Many say to steer clear of pattern part sensors, the VAG ones changed colour from or to green, its the later updated one that you need, I think the green one but please check.

@pixelovski Your engine uses (grey) coolant temperature sensor part number 06A 919 501A, same as all other mk1 Fabias.

I would be tempted to just chuck a new one in to see if it changes matters.

 

 

 

Edited 23 January, 20224 yr by john999boy
Quoted post removed

Alright, seems like most of you agrees on the CTS failure so I'm gonna buy it and we'll see, it's just few bucks anyway. I also already bought the thermostat but haven't changed it yet so I took the opportunity to ask just to be sure... Guess I'm gonna replace both to be 100 % sure haha. I'll let you all know once I do it. Thanks!

1 hour ago, pixelovski said:

Guess I'm gonna replace both to be 100 % sure haha. I'll let you all know once I do it. Thanks!

If it is a diesel engine and your cabin heater works heater fine why change a working thermostat just change the sensor, do you really want to be messing about too much with coolant in winter.  Buy a good quality sensor, cheap can be rubbish so expensive.  And you might swap out a working thermostat for a new one that fails sooner.

 

Alright, so I changed the coolant temperature sensor and now it's starting so smooth. With the old sensor it took much more effort to start the car. So I guess the sensor was faulty. However, the engine is still runing a little too cold... 😕 Any other suggestions?

Thoughts.

 

What makes you say the engine is still running a little too cold, are you going by the dash gauge reading, the heat in the coolant hoses and radiator, or other.

 

More info helps, how long has it been since you fitted the sensor, have you used the vehicle much since, did you do anything else when fitting the sensor.

 

What's your history with the vehicle, what servicing and maintenance has been done before or since this problem arose, apart from the sensor what other work or new parts have been recently fitted or before the problem started.

 

Do you fit a good quality sensor or just go with what was low priced.

 

On 23/01/2022 at 21:27, nta16 said:

  And you might swap out a working thermostat for a new one that fails sooner.

 

 You have no way of knowing if it is a working stat unless you remove and try in a pan of water or view temperatures in a way that allows tracking fluctuations. 

Cannot remember what readings the gauge gives on a Mk1 as a while since my previous 2 Mk1 TDI's - is it actually calibrated in degrees C or just in 1/4, 1/2, 3/4 as your initial post suggests . What make you say  heater cabin is fine, is this based on another Fabia TDI or just a gut feeling. A bluetooth OBD2 and Torque App on a phone or tablet will give actual values - as accurate as the sender allows - but will allow you to track temps - does it ever give a basically stable reading or does it rise/fall over a large range. My Mk.2 Greenline only has a blue light that extinguishes at 45 deg.C but using the Torque method showed that I never reached 90 deg.C until I fitted a new stat.

 

12 hours ago, pixelovski said:

Alright, so I changed the coolant temperature sensor and now it's starting so smooth. With the old sensor it took much more effort to start the car. So I guess the sensor was faulty. However, the engine is still runing a little too cold... 😕 Any other suggestions?

I had the same issue a couple years ago with a 1.9TDi PD engine in a 2004 Seat Toledo though mine failed all together so the dash board temperature dial wasn't working at all and was struggling to start from cold. This sensor doesn't just feed the temperature dial it's also used by the cold start circuit to make the engine run rich at start up from cold. IIRC there are 3 or 4 wires that connect to the temperature sensor. I just bought a cheap pattern sensor off Ebay and the temperature dial then read slightly less than before. I put this down to using a cheap poorly calibrated part? I had no further problem for about 3 years before I scrapped the car with over 300,000 miles on the clock!

Edited 31 January, 20224 yr by Derbyshirebod

7 hours ago, nta16 said:

Thoughts.

 

What makes you say the engine is still running a little too cold, are you going by the dash gauge reading, the heat in the coolant hoses and radiator, or other.

 

More info helps, how long has it been since you fitted the sensor, have you used the vehicle much since, did you do anything else when fitting the sensor.

 

What's your history with the vehicle, what servicing and maintenance has been done before or since this problem arose, apart from the sensor what other work or new parts have been recently fitted or before the problem started.

 

Do you fit a good quality sensor or just go with what was low priced.

 

 

Okay, so I got the car used pretty recently (like a month ago) but due to exams, I had to postpone all the maintenance. So this weekend I changed the oil, filters and the CTS, but no other electrical device. I followed your advice and bought one from Hella (it was still fairly cheap, but Hella makes good quality parts, right?). So after changing oil, I removed the air filter housing, removed the old sensor and plucked in the new one with a new O-ring - and removed the old one obviously. I then gave it test ride, the dash gauge climbed up to 1/4 - as before. Didn't really think anything of it, since it was pretty short ride. But yesterday I rode for hour and a half and it still climbed only to around 1/4... I haven't checked any reading from the OBD2 (although I have one, but I cannot get it until friday), but now I feel kinda stupid doing this whole thread based on a gauge on a dashboard haha.

 

2 hours ago, KeithCheetham said:

 You have no way of knowing if it is a working stat unless you remove and try in a pan of water or view temperatures in a way that allows tracking fluctuations. 

Cannot remember what readings the gauge gives on a Mk1 as a while since my previous 2 Mk1 TDI's - is it actually calibrated in degrees C or just in 1/4, 1/2, 3/4 as your initial post suggests . What make you say  heater cabin is fine, is this based on another Fabia TDI or just a gut feeling. A bluetooth OBD2 and Torque App on a phone or tablet will give actual values - as accurate as the sender allows - but will allow you to track temps - does it ever give a basically stable reading or does it rise/fall over a large range. My Mk.2 Greenline only has a blue light that extinguishes at 45 deg.C but using the Torque method showed that I never reached 90 deg.C until I fitted a new stat.

 

Yeah, I should probably check the OBD and get back to you all...

 

 

P.S. This is my first car and I don't know - at least I didn't until like last week - much about car maintenance, but I just wanted to take on the challenge and do as much of the stuff as possible myself, so I'm sorry if I sound like a moron to you...  

23 minutes ago, pixelovski said:

P.S. This is my first car and I don't know - at least I didn't until like last week - much about car maintenance, but I just wanted to take on the challenge and do as much of the stuff as possible myself, so I'm sorry if I sound like a moron to you...  

 

We all start somewhere! Mine is my first car too, and have been learning quite a bit thanks to the wealth of knowledge of this forum and through working on the car, obviously.

1 hour ago, pixelovski said:

Hella makes good quality parts, right?

Sorry I don't know,  Hella to me are lights, if it's working then that a good start, never just go by brand name even ones you think might be good or often fitted to the car and it might just be a label on a product made elsewhere, you can ask on here before buying.  Always buy from a reputable source though unless you like gambling.  Don't worry I'm sure someone will say Hella is fine.

 

Possibly you might need to clear error codes or drive the car more for it to settle or it might just be the gauge, if the cabin is getting hot that is a good sign and probably a sign that the thermostat isn't at least stuck open at least, there are other ways to check the thermostat without removing it but as you have a scan tool you might as well wait for that.

 

With scan tools do bear in mind the error codes often only give you a starting place for further diagnostics not the solution and immediately which part to change to resolve the issue.  Also readings on the scan tool can be off sensors which may or may not be fully functioning and accurate, and it's just computer programs, you can know more than it and sooner often.  The car may not show error codes but still be faulty and you realise this, we have senses, 7 (apparently), and a brain, often these are needed in conjunction with a scan tool or can be better or detect better/sooner than a scan tool.

 

As the car is new to you take the time to not only change things like filters but to also do, if required, a bit of clearing out and/or cleaning inside the housing and inlet (outlet probably a waste of time on a diesel).  Always allow plenty of time and don't be in a rush, best to do the jobs when the shops and motor factors are still open.

 

Great that you are taking on servicing but do bear in mind the engine is one of the less important components on the car more priority should be given to checking, and if required servicing/maintaining/repair, the important component/parts/systems like brakes, steering, suspension, (all three include tyres) lights and visibility and safety electrics.

 

As has been put no one is born knowing, we all had to learn for a first time even those that now know a lot.  That doesn't included me, I am not a mechanic or expert in anything, what very little I might have known I forgot or repeatedly forget but I do have decades of experience of car ownership (and the English motor trade).

 

Giving as much information as you can, especially with your opening thread, which may mean repeating some stuff from previous threads, helps those that respond.  Good clear photos can often help no end - (plea from me, please hold the phone horizontally where  appropriate as this gets more into the photo frame generally).

 

If you are going to do a lot of short journeys (not a good ideal for a car and particularly modern diesels) keep a check on the car battery and how much charge it has, starting the car is just one of its jobs.

 

I much prefer prevention to cure and unusually for someone on a car forum I loathe doing anything but driving a car so I think it is a good idea to put a bit more effort in at the start of ownership and during regular servicing and maintenance to avoid doing more work later when it's less convenient or takes you away anything more enjoyable.

 

Let us know how you get on.

 

Edited 31 January, 20224 yr by nta16
spelling

11 hours ago, nta16 said:

 Great that you are taking on servicing but do bear in mind the engine is one of the less important components

 

 The engine is what make the object a motor car, otherwise it would be a roadside shed that doesn't require the other components.

 Use your OBD2 with Torque or similar to give you a visible baseline of what is actually happening - this is what is call Root Cause Analysis and will give a good starting point which has allowed people to proved invaluable in many cases such as temperature issues, turbo boost issues, charging/voltage issues without the cost of purchasing a programme such as VCDS which is dedicated to the VAG group where many others do not cover all the modules in these vehicles. This is not to say that you cannot use one for generic code reading/clearing codes as a starting point. Lack of factual information can result in guessed or irrelevant suggestions being replied.

1 hour ago, KeithCheetham said:

 The engine is what make the object a motor car, otherwise it would be a roadside shed that doesn't require the other components.

I did put less important, it's a matter of priorities.

 

I know all about cars that become static roadside ornaments, I've not only got the t-shirt I paid for the design and manufacturer of it, which is why I believe in preventative checking and timely regular servicing, maintenance and repairs to the whole vehicle, most important with a car that is new and unknown to you. 

 

The engine is lower down the priority list of checking and servicing, maintenance and repairs particularly on a vehicle new to you.  Many of the checks can initially be visual, you don't strip down a loan, hire or courtesy vehicle before you drive it but as you are responsible as the driver you would check it over (if only to save hassle and arguments later about its condition).

 

As many prove by doing so, you can drive a vehicle with an engine that isn't running fully well or maintained well, it will get you there and back again many times and with safety.

 

When you go to get in or check a vehicle your first thoughts should not be I must check the engine (oil) it should be brakes then steering, etc., stopping and controlling the vehicle is more important than starting and running.  If the car won't start generally you and others are safer than if it won't stop.

 

And yes the engine has effect on control of the vehicle but it's a matter of priority in the checks, if the brakes, steering, suspension (all three include tyres) are faulty then you may not be driving the vehicle so the engine condition is of little importance, a matter of priority.

 

You want the car to brake, steer, handle well and have all necessary safety eclectic items working well before having the engine running in best condition, it's a matter of priority - the engine is important just less so than other things with the car .

 

Edited 1 February, 20224 yr by nta16
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