A question for the real experts.

I got interested in the electronically mapped controlled cooling system in my Skoda Octavia mk1.

On the net I found two very interesting and informative pdf-files how this system works.

If you're interested you can download a zip-file with the two pdf-files.

Link:

http://www.mediafire...vax201sk3k0lpy9

To be short, the coolant temp is 110° C at so called partial load of the engine and it lowers to 85° at full load thanks to the mapped controlled cooling system.

This is done by a heating element in the thermostate that warms up the wax and can regulate it additionally compared to a conventional wax thermostate that only regulates by the temp of the coolant. The heating element is activated by the mapped controlled system.

By sheer curiosity I have this question.

The coolant temp gauge rises to 90°C and stays there stable.

If the coolant temp varies between 85° and 110° depending on the engine load and other factors why doesn't this show on the gauge?

Shouldn't the gauge also varies between 85° and 110° since it should show the temp of the coolant?

The dash panel shows any coolant temperature between 79°C to 112°C as straight up, which indicates nominal temperature - not 90°C. This is done to stop customers reporting high/low temperature when there is no fault. The CTS and ECU have the correct coolant temperature - it's the dash that processes the values.

The dash panel shows any coolant temperature between 79°C to 112°C as straight up, which indicates nominal temperature - not 90°C. This is done to stop customers reporting high/low temperature when there is no fault. The CTS and ECU have the correct coolant temperature - it's the dash that processes the values.

Thank you for the answer.

Just what I thought..

But why have they numbered the scale like this then?

You think that would be the temp.

It has been smarter with colored fields.

Blue for to cool, green for normal and red for to hot coolant.

Edited 12 August, 201213 yr by rail

Customers expect to see a temperature gauge, but have no idea what is normal (standard map/no fuel quantity uplift --> 7°C above stage 2 fan threshold). Manufacturers fix the display to give customers what they expect to see.

Manufacturers have used colour coded dials in the past but the dealers still got calls from customers saying things like "the needle is at the upper edge of the green" or "shouldn't the needle be in the middle of the green" or "the needle keeps fluctuating".

So where is the heating element and what engine are we talking about

Actually, there are engines that control the engine thermostat. The wax capsule has a heater element embedded in it and that heater is controlled by the ECU.

IIRC, engines AVU and BFQ have this arrangement.

So where is the heating element and what engine are we talking about

Hmmm...

Didn't you read the whole thread from the beginning?

If you download the file I mentioned earlier you can see how it works, including were the heating element is placed on the thermostate housing.

And if the gauge starts moving, it's time to shove the heater on full( and hot) and check the output. Hot engine, hot output, normally no problem. Hot engine, cold output - you've lost coolant. Pull over now and check .It's usually a good cheap check which gets you in before the engine suffers . ( Unless you stick cold water in a very hot engine block)

Couldn't read links i was looking on my phone but i knew the 20v turbo lumps don't have it or at least i haven't come across a heating element anywhere and thermostat is just a standard one

Hmmm...

Didn't you read the whole thread from the beginning?

If you download the file I mentioned earlier you can see how it works, including were the heating element is placed on the thermostate housing.

Must correct myself.

The actual heating element is placed in the wax capsule inside the thermostate housing.

What you see on the outside is the electrical connector to the heating element.

Amazingly good PDFs there rail.  Thanks for pointing these out. 

Really informative thread!

On 12/08/2012 at 15:29, rail said:

Thanks! thanks and again Thanks! This pdf solved all my questions for years!

 

 

 

 

A question for the real experts.

I got interested in the electronically mapped controlled cooling system in my Skoda Octavia mk1.

On the net I found two very interesting and informative pdf-files how this system works.

If you're interested you can download a zip-file with the two pdf-files.

Link:

http://www.mediafire...vax201sk3k0lpy9

To be short, the coolant temp is 110° C at so called partial load of the engine and it lowers to 85° at full load thanks to the mapped controlled cooling system.

This is done by a heating element in the thermostate that warms up the wax and can regulate it additionally compared to a conventional wax thermostate that only regulates by the temp of the coolant. The heating element is activated by the mapped controlled system.

By sheer curiosity I have this question.

The coolant temp gauge rises to 90°C and stays there stable.

If the coolant temp varies between 85° and 110° depending on the engine load and other factors why doesn't this show on the gauge?

Shouldn't the gauge also varies between 85° and 110° since it should show the temp of the coolant?