Hi! I bought my 2007 Octavia mk2 2TDI PD a few months ago, and to my disappointment, it had blown head gasket. Week ago, I had my head gasket job done by local garage, changed thermostat, injector seals, gasket, bolts, head resurfaced. Heaters blow heat now and all looks well. But I just remembered that before I got my head gasket fixed, I've never really seen my radiator fans spin at 90c on gauge. Now I checked it multiple times, i still couldn't ever see them spin. As I was worried yesterday I picked up vcds to make a scan to be sure. It threw g83 sensor fault, signal too high. As I've read, it actually controls when fans turn on. I thought I've found the culprit, but decided to clear codes and drive a bit and look at coolant temp in vcds. On idle it didn't exceed 86 ever, when I drove max I've seen it reach is 89 and g83 fault code hasn't appeared yet. When operating fan test with vcds they both spin, so they are good.

 

So my questions are:

1. Could that g83 fault been thrown only maybe because of all that head gasket  fixing and all is well with the sensor since after clearing fault and some driving fault didn't come back? Drove like 30 mins tho.

 

2. Is my coolant temp on 5-7c ambient temp normal on idle, some town driving and fans aren't really supposed to run on this weather? Can't test on normal roads, because of covid we can't leave our city..:')

 

I'm really being paranoid right now, because I soon will have about 700km driving to do and I don't really want to blow new gasket again if it's reading incorrect temperature and because of that fans don't come on when they are supposed to.

 

Sorry for bad sentence formatting, my thoughts are all over the place right now..

1. Possibly.

 

2. Yes.

 

The coolant gauge is notoriously vague.

 

If you run the engine up to temp, switch on all electrical loads but turn off the ventilation fan you'll probably coax the radiator fans into life.  The PD engines are cool runners.

1 hour ago, MicMac said:

1. Possibly.

 

2. Yes.

 

The coolant gauge is notoriously vague.

 

If you run the engine up to temp, switch on all electrical loads but turn off the ventilation fan you'll probably coax the radiator fans into life.  The PD engines are cool runners.

So do you think I should stop being scared and all is well? Because my fear is that if the sensor is faulty it might read normal temperature on vcds and gauge, but in reality engine is hotter and fans should turn on at some point.. But even if that sensor is broken it shouldn't affect vcds readings probably?

You're over thinking it, relax.

 

Do like I said and see what the gauge and real time VCDS reading shows and note when the fans turn on, keep bonnet open as they are hard to hear over the agricultural PD engine.

As long as the coolant temp is being read correctly via VCDS (a max of 89c sounds spot on) and as long as the fans actually work (the fan relay etc is ok) then you shouldn't need to worry.

 

And as long as the fans kick in when you turn the A/C on.

 

The diesels run very cool anyway. You may even see the guage drop while idling and the heater is on and this is normal.

 

Even my 1.4 TSI I've not actually had the fan kick on unless the A/C is running (although it has an uprated radiator apparently due to having a factory tow bar).

When you looked at coolant temperaturewith VCDS was it the G83 sensor reading you were looking at, or G62? I think there are two sensors.

11 hours ago, MicMac said:

You're over thinking it, relax.

 

Do like I said and see what the gauge and real time VCDS reading shows and note when the fans turn on, keep bonnet open as they are hard to hear over the agricultural PD engine.

Will try!

 

6 hours ago, Phil-E said:

As long as the coolant temp is being read correctly via VCDS (a max of 89c sounds spot on) and as long as the fans actually work (the fan relay etc is ok) then you shouldn't need to worry.

 

And as long as the fans kick in when you turn the A/C on.

 

The diesels run very cool anyway. You may even see the guage drop while idling and the heater is on and this is normal.

 

Even my 1.4 TSI I've not actually had the fan kick on unless the A/C is running (although it has an uprated radiator apparently due to having a factory tow bar).

Well, my fans don't spin even with ac on, but it's probably normal since ac doesn't cool and I have compressor and refrigerant fault in vcds. Need to have that checked too.

 

5 hours ago, Wino said:

When you looked at coolant temperaturewith VCDS was it the G83 sensor reading you were looking at, or G62? I think there are two sensors.

Thing is, I couldn't find g83 reading anywhere in vcds, atleast in engine section, every coolant reading was g62 sensor, so that actually confused me.

I guess G83 may be within the HVAC module stuff, rather than engine.