Hello

 

There are some topics covered some issues similar to this, but with different engine and different symptoms. Sorry if it has been exactly covered and I couldn't find it.

 

My  Octavia 2013 1.4 TSI (water pump is on the different side of cambelt) takes a long time / distance (~25 minutes / 5-6 miles) to reach to temperature (90). Also, during cold weather, when the heater is turned on, there is a drop in the temp shown by the gauge. Temp gauge also drops below 90 during winter when driving downhill. The first thing I could think of is the thermostat being always open. To test my hypothesis, started the engine from cold  (morning) and checked the pipe connecting the water pump to the radiator. I noticed that it warms up gradually rather than getting suddenly hot (thermostat opening).

 

1) Is it actually the thermostat failing or could be other things?

 

2) How do I know that my car has map-controlled engine cooling system? Should there be any connector to the water pump housing (other than the one for the pump)? If it is map-controlled, can this issue be fixed with VCDS?

 

3) According to the workshop manual (below image) and Skoda part catalogue (https://skoda.7zap.com/en/cz/octavia/oct/2013-753/1/121-121003/#2), 1.4 TSI engine has two 105 and 87 degree thermostats (2 and 15 in the image). Which one should I replace? should I replace both thermostats?

 

4) Are the Gaskets (6, 9 and 14 in the image) needed to be replaced too?

 

5) Is it advised to change the water pump and/or its belt at the same time?

 

6) Does anyone have any idea how much roughly would be the cost?

  

Sorry for the long post and thanks in advance for your time.

 

Edited 26 September, 20223 yr by Vahids

Doesn't anyone have any experience to help with my issue please? Thanks.

I have an older 1.4tsi so keep an eye on associated topics but cannot remember any previous issue like yours over the last 7 years.

I had a water pump failure after 5 years ownership but even that is relatively rare with this petrol engine.

It does not sound like the water pump to me, in my case the pump failure resulted in rising temperatures and intermittent coolant loss.

Some one with an obd2 reader might be able to find some error codes to be able to better target the issue?

Thanks for your reply. To be clear it does not over heat and there is no coolant loss. The only issue is it takes a lot of time to reaches to 90 degree operating temperature.

There is no error, tested with VCDS.

Sounds like a thermostat stuck open could well be the problem, being a purely mechanical device there will be no diagnostics covering it and hence no fault codes.

Got a quote £264 for the labor for changing the whole water pump. Does it sound reasonable? Also the price for the water pump is £200.

Seems good compared to what I paid my dealer in Australia.

Edited 1 October, 20223 yr by Gerrycan

I agree it does sound like a thermostat issue, you could try covering up the radiator with a bit of cardboard before setting off with a cold engine, if the engine comes up to temperatue  rapidly then it's almost certainly a thermostat, just don't drive for too far/long with no airflow througt the radiator.

When our pump developed a leak I seem to remember that dealer quoted £450 to replace pump and the pump alone was £180 of that.

Aftermarket pumps and thermostats are avaliable cheaper, we bought an FAI one for around £75 and fitted it ourselves, but that was only part 4 from the above diagram, around 2 hours work, probably came to around £120 with new pump, coolant, belt and clips.

You could just replace the thermostat(s) but the waterpump has to come off to replace them anyway, and waterpump reliabilty not a VAG group strong point.

It only needs a small amount of clag or a small foreign body to become pinched in the mouth of the thermostat to give the problem you have, it may not even need the new thermostat.

 

I would whip out both thermostats, inspect and test them before buying any replacement.

Just realised that the thermostat number 15 in the diagram is acessable with out removing the waterpump, so like J.R. says if might be worth testing this one first, this would make it a much cheaper/quicker fix (seem to remember that there are a few topics on here featuring this as failing)

On 01/10/2022 at 19:04, R_U_AFA said:

You could just replace the thermostat(s) but the waterpump has to come off to replace them anyway, and waterpump reliabilty not a VAG group strong point.

Thanks for your reply. Since it has not been replaced from 2013 (presumably), does it make sense to replace the whole unit just in case? Because it is a pain to replace the water pump if it fails in early future.

I would say it depends, do you feel confident working on the car yourself, or would you be paying a mechanic to do it for you?

 

10 hours ago, R_U_AFA said:

I would say it depends, do you feel confident working on the car yourself, or would you be paying a mechanic to do it for you?

 

Thanks @R_U_AFA. I will do it myself, so probably will start with testing trivial things first, like thermostats. I need to buy some essential tools though like a torque wrench.

A bit off-topic question, any recommendation on choosing an affordable (under £100) torque wrench for this job?

1 hour ago, Vahids said:

I need to buy some essential tools though like a torque wrench.

Not essential

 

16 minutes ago, Vahids said:

any recommendation on choosing an affordable (under £100) torque wrench for this job?

See above.

 

I only use mine for cylinder head bolts, big end & main bearing cap bolts, flywheel bolts etc.

 

I know all the manuals give tightening torques for everything but thats to cover their backside from hamfisted Popeyes, I know the Autodoc videos always show a torque wrenh being used on almost every fastener for the same reasons but dont kid yourself that is what professional mechanics do, they rely on their sense of feel.

 

Or  rather they did before they started using battery impact wrenches for everything.

I agree with J.R. For this job a torque wrench isn't essential, especially as seen as all the screws/bolts will be into or bearing against plastic housings, so high torque figures would just end up damaging the plastic.

I would start by testing, and/or mabey replacing the thermostat numbered 15 because I'm pretty sure that this is the one that controls the flow of coolent to the radiator.

It's a very easy job to do, half drain the coolant, move some hoses and pipes to gain access, undo a few trx-star screws, and you've gained access to the thermostat.

The plastic housings usually have hollow steel inserts where the fixings go through, you can pretty much tighten them to what you want within reason and you wont distort the casing.

@R_U_AFA and @J.R. thanks for your help. I will do as recommended, but I think the 103 degree thermostat (#2) is the broken one because I can feel it get warm gradually before the engine gets to the 90 while the 87 degree one (#1) is cold . From the guide below, I think the 87 degree thermostat is for the water returns from the radiator whereas the 103 degree is for flowing to the radiator.