Hello folks I have a superb Cbgb 2.0 cr tdi. I am having issues with the car cooling down when doing a constant 100kmh. I changed the stat on the block ( which was a pig to get to) but the issue remains. I have a hand held diagnostic tool and the coolant temp and radiator exit temp nearly rise at the same rate. The cooling fans aren't on when I experience the problem. I was looking at the cooling circuit and found an electric pump for the egr valve ( I think) what turns this pump on is their a sensor or stat somewhere or does it always run? Is their meant to be a check valve in this? This seems to take from the bottom of the rad and then put back in on the block side of the stat. Or does anyone else have any ideas? Any help greatly appreciated as my head is wrecked. It's a dsg if that makes a difference.

I also forgot to say I takes any age to heat up and not all the time

EGR is exhaust gas recirculation - this sends some exhaust gas back to the engine with the intake air to reduce combustion temperatures and NOx formation. This should definitely not be connected to the coolant lines.

 

It sounds like the thermostat is stuck in the open position all the time, so coolant is running through the engine from the radiator at all the time, especially if it's really slow to heat up. This will hit your fuel economy and give the oil/engine bearings harder time too. Back in the day this was a matter of getting the thermostat out, sticking it in boiling water to see if it operated correctly and replacing it if it didn't. It's probably electrically controlled at this stage, so testing the valve should be a matter of taking it out and powering it up to see if it responds.

Thanks for the reply, on the engine I have their is an egr cooler this use the engine coolant and Is circulated by an electric pump I think this reduces the temps of the recirculated exhaust gas before putting it into the inlet side ( I think). I think I found the problem the egr temperatures father the cooler is reading -270 I know is getting cooler but not this cold! Just as a matter of interest there is no faults stored in the car.

The temperature sensor seems to be faulty. The car won't give an error code because it's getting a temperature even though it makes no sense. 

EGR, in my opinion, should be disabled on any car. It will do more harm than good. EU "invented" it to make NOx emissions look better, by taking a small portion of the exhaust gas and recirculating it into the air intake. 

 

Any tuner should be able to disable the system via the OBD. It might cost a little, but it's worth it. 

It doesn't just make the NOx emission look better, they are actually better as the lower combustion temperature EGR creates means the nitrogen the car takes in (78% of air) remains nitrogen rather than reacting during combustion and becoming NOx.

Thanks for the help lads, If I disconnect the electric cooling pump (v178) the car will temp up normally. By this I mean the engine temp climbs but the rad exit temp stays low until the mechanical stat opens. Does any one know should this pump be running all the time if not what turns it on?

I think I found the problem the egt temperature ( temp sensor 1 g235) was reading 20 deg when I left the car over night the the other exhaust sensors were reading 8deg or so. The other sensor jumped in temp when I stated the car it took about 60 seconds for g235 to read and then it was jumping around by a couple of hundred degrees 180deg to 700deg with a second. So I ordered sensor will change it when I get it here's hoping. I think the other sensor in the first post aren't in my car that's why they giving funky readings. I only have a hand held scanner not vcds.

Well all after much head scratching and cursing I fixed the issue with slow heat up and cooling down on the motorway. It was the coolant stat for the dsg gearbox, my local skoda garage has never sold one of these before it's easy to fit but can't be bought without the hoses. See photo. Anyway hopefully no more issues with this beast

Hi,

I'm having the same issues that you're having, low temperature and slow heating. I have the webasto heater that's working all the time. I've changed the engine thermostat without any change (4h in the shop for they to find the fault), that wasn't any fault. A real hassle to change.

 

I also have the DSG gearbox and I've found out that the part number for the Coolant stat for the DSG is 1K0121113A and you can purchase it on ebay separetely from Mahle.

 

I just want to make sure that we're talking about the same part #15 on the following exploded view:

Thx in advance!

 

 

Edited 30 November, 201411 yr by Maxizor

I've now changed the DSG Stat but no change :(

I'll try and disconnect the EGR Cooling Pump and plug the wire.

//Erik