Blueline 1.6 petrol cooling stytem, various faults and symptoms

[Octandy]

Hi all.

 

Im new to this forum and it looks great for the knowledge factor so ill jump straight in with a problem. i am pulling ones hair out so any help or guidence would be greatly appreciated.

 

Car is a MK1 Octavia Blueline 1.6 petrol 2003.

 

Firstly im not sure how to read codes as of yet as my code reader wont work on the port as perhaps the protocol is wrong i dont know.

 

I have whats becoming a major cooling system issue. Maybe its common to these engines i dont know. Wish i had bought i diesel.

 

Symptom 1. The temperature gauge on the dash works at random times, sometimes when the revs are higher it will register but at lower revs it wont read at all even after a long run.

Symptom 2. The heater is not producing the correct amount of heat into the car and only luke warm heat comes out at randoms times.

Symptom 3. The engine takes a while to rev when stationary and splutters a bit then revs all of a sudden. Driving condtions puts the engine into limp mode sometimes!

Symptom 4. The cooling fans stay on all the time shortly after starting the car and if left to their own devices flattens the battery when engine is off as they wont stop running.

 

Things that i have done and my mechainc has done so far:

 

New electronic thermostat (including plastic pipe manifold assembly as well).

New water temp sensor.

New water pump.

Coolant flush.

Limp mode resets etc.

 

As i understand it the cooling system on these 1.6 enignes are electronically controlled via two sensors which tells the ECU to open or close the thermostat. My mechanic has told me that one was reading 98 degress and the othert was reading 35 degrees so he changed the sensors but the problem(s) are still here haunting me.

 

Can anyone help me ?

 

Thanks guys.

 

Andy.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[georged30]

Symptom 1. with the temp sensor pump and thermostat replaced the problem is with your instrument cluster or the wiring.

Symptom 2. blocked heater matrix or pipes.

Symptom 3. post fault codes in order to help you.

Symptom 4. under the battery tray is the controler for the fans tell your mechanic or better take it to an electrician to check it.

[Octandy]

Hello sorry for late reply. Here are some updates for you as I've found them.

I plugged in VCDS and got several fault codes:

Coolant Temp. Sensor(G62)

The others were a load of central locking faults because I had been previously looking at the doors silly me.

I've bought a whole new thermostat sensor plastic housing to go on when I have time, which includes a thermostat. This brings me on to my next question.

I did an instrumentation output test and made sure all the dials were working and that's all fine. This included the coolant gauge also. I cleared the codes and started the engine and allowed it to get to temperature which was around 90 indicated. The fans cut in when they were needed. Great everything appears to work but we know the fault is still there somewhere so I went for a drive....

Straight away after about 5 mins driving the temp gauge starts to drop and it continued to drop all the way to 50 which is the lowest reading on the gauge physically. I pulled over before it went into limp mode again and waiting for engine temperature to increase once more then I drove it back home.

I did a live reading whilst driving too of the rad outlet temp and engine outlet temp. Nothing went above 95 degrees. I also had the duty cycle of the thermostat. This stayed at 0%. I assume the thermostat operates at a higher temp somewhere and fluctuates between 0 and 100% as specified by VCDS.

I've concluded the stat must be partially open as it's pumping through the rad all the time. Theach thermostat housing to fit has all the bits in one lump so I'm hoping this will cure it

Thoughts?

Edited 14 April, 2016 by Octandy

[Octandy]

Sorry I made an error in the above post but im unable to edit it for some reason so ill post here:

 

Whie i was driving and the instrument gauge was dropping, the live data also dropped on the coolant temps so i know the sensor was working and tallying up with the indicated gauge. Assuming the ECU is seeing all this thats why it goes into limp mode because the engine is getting too cold thus causing the map to changing the fueling.

 

I have also flushed out the heater matrix and now i have heat coming through the vents which is nice. the was gunk within the matrix.

 

I do have a LOG report from VCDS on my laptop if you want a full report on what it picked up

[georged30]

The top hose which goes to the radiator should be cold when you start the car and should get hot when the engine temp is 100-105c ,if it gets hot gradualy the thermostat is stuck open.

[Octandy]

All sorted. Turns out it was a dodgy thermostat failed open. Wide open actually. Thanks for all the help guys. On to the next problem now gear change notchy....

[Normski55]

Hi Octandy,

 

I read your post with interest as it mentions the problems you had with the heater. Guess what, I have the same issue. You mentioned you flushed out the matrix. can you explain how you did it please?

 

Thanks.