VW Golf 1.6 TDI Mark 6 2009 Overheating

[worldbackpacker]

Hello Guys,

First of all thanks for allowing me to join and apologies that I am starting by asking a question! I hope this is in the correct place.

I have a VW Golf 1.6 TDI, Mark 6 2009

I have an overheating issue. The temperature went up as high as 120-130 Degrees C.

So far we replaced water pump, thermostat, two temperature sensors and head gasket. The issue persists.We have checked the actual engine temperature with a infrared heat gun which showed all components inclusive of the actual coolant to be below 100 Degrees C so below what the dial on the dash showed.

Symptoms:

-Overheating after driving for roughly 10-20 miles
-It goes up to 120-130 Degrees C and then drops back down and goes back up.
-I noticed twice that when it reached 120 Degrees C I lost accelaration
-Can run on a short journey in town and be fine, longer journey or higher speed and the issues start.
-No issue when idling
-No loss of coolant/ Changes to the colour


If anyone has faced this issue and has any idea what it could be causing this I would really appreciate some support with this.

Thank you all!

[Jim the Sunderer]

Maybe the fan not kicking in or blockage in the radiator.

[GreenV8S]

worldbackpacker said:

We have checked the actual engine temperature with a infrared heat gun

...

-It goes up to 120-130 Degrees C and then drops back down and goes back up.

Engines generally don't change temperature that quickly and you seem to have proved the gauge is inaccurate but are still taking the reading at face value.

I suggest you stop trying to fix it by trial and error and concentrate on identifying the problem. The easiest way to do that is by measuring the actual coolant temperature. One way to do that is to attach a remote wired thermometer to the outside of the top hose or similar where it thermally well connected to the coolant at the hottest point in the circuit. If possible insulate around the position of the sensor so that it reads close to the actual coolant temperature. Another option taking slightly more effort but giving a more accurate reading is to insert a thermal probe under the end of a hose - there are tapered rubber inserts available to maintain the seal.

It may be that you have an electrical problem, or an air lock, or a genuine overheating problem. You need to know which, before you can fix it.

[catman]

If it's overheating at higher speed, then the radiator could be blocked, or the fins on the outside could be clogged, preventing any airflow. The fan should come on though, so you should check that it's working too.

Tim

[E-bmw]

For it to change that rapidly, I would be expecting an air lock in the coolant system somewhere.

Look around, there is probably a recognised model specific method of bleeding but in the absence of that get your bleed point as high as possible on ramps/stands/etc run with the bleed/tank cap etc off & filled up, the heating on full heat & full blower and run it up to temperature.

As the thermostat opens all hoses should warm up & HOPEFULLY that could be the issue.

Some cars (old Rover 2 series were one of the worst) are REALLY difficult to bleed having no natural high/bleed point.

[usmanzar]

Hi. I fixed the same problem by bypassing the internal heater matrix. Sounds bizarre but it works. Its apparently a common thing with 1.6 tdi CYAC engine. Due to the way water flows through the cooling system. It has to also flow through the heating matrix to cool the engine down. So before you change anything it will be worth bypassing the heater matrix to make sure its not blocked.

[kylos27]

Is the gauge on the dash telling porkies?

[Petervtec]

Hello! You managed to solve the Golf’s overheating problem. Thank you.

I have the same problem with my Golf as well.