Mk6 overheating

[james15678]

Hi,

I have done a search but can not find the answers.

I have a 2005 fwd and when driving it slowly starts to over heat. I have read about water pumps failures are common but I'm not sure it is that.

I have checked a few things
Heaters blows hot and cold same as it always has
Disconnected cylinder head stat, as i read on here it will put the fan on but it didn't, just made glow plug light flash and temp gauge not work
Rad hoses are warm but not red hot, unlike heater matrixs hose that are red hot,
Checked fuses for fan in engine bay
When gauge is near the red the fan still does not kick in.
Reason I doubt it's water pump is it does not over heat just ticking over.

Any advice appreicieated as I don't want to just throw parts at it

Thanks all

[scas]

did you look and see if the thermostats working

[james15678]

No, can it be checked without removing it? I can squeeze the big hose to thermostat and feel the water moving on the other 2 pipes from stat if that makes a difference.

Can you tell me if the water is always circulating around the head/ engine or does the stat have to be open for it to circulate around engine? If it only circulates when stat is open then I guess it's that that's failed

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[wojciech]

Disconnected cylinder head stat, as i read on here it will put the fan on but it didn't, just made glow plug light flash and temp gauge not work

It works like that in TDCI models. I don't know is it similar in TDDI. But maybe your funs are broken... Try check funs, throw current pins No 3 and 5 (pins for switching contacts) in R12 relay socket (using a short wire). They should begin work with smaller power.

Can you tell me if the water is always circulating around the head/ engine or does the stat have to be open for it to circulate around engine?

Yes, water is always circulating around whole engine. If engine is cold - it works in "small circuit" excluding cooler. If termostat temperature is close 90 C deg - termostat opens "big circuit" with cooler. If temperature still rises, PCM turns cooler fun on.

1. If you have any doubts about water pomp, check heating system, take heater fun on for full speed - if internal air intake is warm long time, water pomp works ok.
2. If you have any doubts about termostat - first check (by hand) how long time is cold pipe connected to the top of cooler after cold morning start. It should be cold long, long time, even if air from heater is becoming warm. If pipe between termostat and cooler is becoming warm from the begining of engine work - termostat is broken (still opened).
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All what you said - if funs are ok, it looks for me as broken CHT sensor.

[Mad Husky]

Tddi is viscous fan not electronic so always turning. Just realised yours is front wheel lol so probably is electronic.

[james15678]

It is electric, took thermostat out and tested it I think it's that that has failed, won't know till I take it on a run tomorrow now

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[knobby1]

Tddi is viscous fan not electronic so always turning. Just realised yours is front wheel lol so probably is electronic.

FWD has electric fans....RWD has viscous fan.

Lord Knobrot

[wojciech]

Tddi is viscous fan not electronic so always turning. Just realised yours is front wheel lol so probably is electronic.

FWD has electric fans....RWD has viscous fan.

Lord Knobrot

In 2,4l models with AC is one extra electric fun. Maybe because it's not responding for overhiting (disconnected CHT sensor - for PCM it should be temperature = 120 C deg).

[james15678]

I don't know why fan was not coming on, but it was thermostat, thanks for everyone's help

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[wojciech]

I don't know why fan was not coming on, but it was thermostat, thanks for everyone's help

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Apparently electric fun works only for AC, viscous fan respond by itself for temperature rise or overhiting - because of work principle.