Skoda Octavia Starting Problems: Troubleshooting Guide

Hello.

I'm brand new here and I stumbled upon this community while "googling."
Now, I hope you can help me a little.

I own a Skoda Octavia 1.9 TDI (77 kW), manufactured in 1999. This car has the unpleasant characteristic of being very difficult to start when warm (the engine is at its normal operating temperature). I had this problem about 1.5 years ago as well, and took it to a specialized workshop. However, the problem is that the car is only connected to the diagnostic computer, and the results always show 0 errors. This meant the workshop was unable to find a solution. As a precaution, the temperature sensor was replaced, but it didn't really help.
A new problem has emerged, specifically during the winter (temperatures below 0°C), where the coolant warning light illuminates after the engine has been started. My initial suspicion was that the coolant was freezing, but that's not the case, as the coolant is frost-resistant down to -30°C. I also had it checked by a workshop. After the engine has been running for a few minutes and has warmed up somewhat, the warning light goes out. Starting the engine in freezing temperatures is possible, but not ideal, even with the glow plugs.
However, as described, the problems only occur at the engine's normal operating temperature, as well as at temperatures below 0°C.
There are no problems when the outside temperature is normal. In that case, the engine starts normally during cold starts. However, the problem with warm starts persists.

Okay, here's my question. Is there a connection between the two problems? Could they have the same cause? What could it be? I'm asking for your help because I'm not sure what to do next, and the mechanics aren't really helping either. I'm seriously considering selling the car because it's really frustrating.

Thank you in advance for your help!

northernlights81

Hello,

You can fix the problem with the coolant warning light by cleaning the level sensor in the expansion tank with a toothbrush or similar. It works based on a resistance measurement, but it tends to get dirty.

The starting problems can have several causes. It's best to consult the relevant technical article.

Hello Roger,

Thank you for the quick response.
As described, the warning light only comes on when the temperature is below 0°C. I haven't experienced the problem when the temperature is above 0°C. If the sensors are dirty, shouldn't the warning light come on at all temperatures? Or am I mistaken?

nordlicht81 wrote:

Is there a connection between the two errors? Could they have only one cause?

Hi,

It's likely that there are two different errors, see also Roger's response.

To troubleshoot warm start problems, next time try disconnecting the water temperature sensor (but don't ask me where it is on your car).
If it starts immediately, then it's likely another case of "warm-start reluctance" software, which is probably necessary to meet emissions standards. This is quite common, for example, in AFN engines.

If, after reconnecting the connector, the warning light stays on for a longer period, you may need to have the memory erased.

If it still doesn't start with the connector unplugged, then the problem is likely something else, possibly a loose connection related to the crankshaft position sensor that only occurs when the engine is warm.

Quote:

If the sensors are dirty, shouldn't the warning light come on at every temperature?

IMO yes, unless you really have very little water, and the alarm happens to trigger exactly at 0°C because the level in the container drops far enough.
While spinning water sensors are not the main topic here, perhaps someone else will have an insight.

nordlicht81 wrote:

Hello Roger, Thank you for the quick response. As described, the warning light only comes on when the temperature is below 0°C. I don't have the problem when the temperature is above 0°C. If the sensors are dirty, shouldn't the warning light come on at every temperature? Or am I mistaken?

You are mistaken; Roger is right. If you have a connector plugged into the expansion tank, use an old toothbrush to verschandeln the two sensors (metal tubes INSIDE the expansion tank) as best you can.

Optional: Afterwards, you can drain the coolant, rinse the container with verschandeln water, and then refill it with fresh G12 plus mixture. This should solve your problem with the light bulb. I experienced the same thing on an A3, but only in cold temperatures. Believe me, it's like that! I don't fully understand it either, but it probably has something to do with the conductivity.

Cold water is less conductive than warm water.

@Rainer:

Extreme dependence... I wasn't aware of that.

Hi,

The diagram suggests that charge transport at low temperatures is a diffusion current, not a field-induced current.

According to that, the diagram would look different if the conductivity were measured using high voltages. Any volunteers?

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

But wait... Rainer has corrected it, and the diagram applies to distilled water, which is essentially free of free ions for charge exchange, and therefore not conductive. If there wasn't the antifreeze coolant providing a large amount of ions to compensate, this filling would likely trigger the coolant alarm permanently even at +20 degrees Celsius.

@ nordlicht81

Perhaps I am a little late with this now (last entry 02.2007 ).

The issue with the coolant warning light is a well-known problem with Skoda cars, and it has been discussed extensively in the Octavia forum.

The quickest and easiest solution, without requiring any modifications, would be to ensure the coolant level in the expansion tank is at its maximum when the engine is cold.

It helped me too. (Same problem since I bought the vehicle). My fluid level was always somewhere between the "Min" and "Max" marks. Below 6°C, the warning light would always come on during cold starts.

During a cold start, the water level in the expansion tank temporarily drops, briefly falling below the "Min" mark, which consequently triggers the "Alarm."


Best regards, Benny.

Hey, it's been a really long time... The problem is long resolved. It's been so long that I don't even remember what it was about anymore .

By the way, the warm start problem has also been resolved. It turned out to be a defect in the starter motor. It was drawing too much power from the other components, especially when starting the engine when it was warm, which meant it couldn't provide the necessary power for the start "in time." A new workshop and a clever mechanic identified the problem. After replacing the starter motor, there are no more starting problems.

Nevertheless, thank you to everyone .