AGU overheating

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22irwin.mercure
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AGU overheating

Post by 22irwin.mercure »

Hello everyone

I have a 2000 audi A3 1.8T AGU that heats up only when I am stuck in traffic. However when I continue driving, the heat gauge goes back to 90, but the fan stays on. If I am stuck for more than 10 min, the coolant light comes on.

I have done cambelt and waterpump 10000km ago and never had this issue after the change in waterpump. The waterpump was from goldwagen and had a metal impeller.

1. I have had the car scanned, no codes.
2. Replaced thermostat and engine flush.
3. When doing the engine flush, the coolant colour was normal pink. But I still flushed the system anyway and put in fresh coolant.

Anything else to look at?
Any idea what could be causing this?
Diagnosis picks nothing up.



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Aslam_mk4
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Re: AGU overheating

Post by Aslam_mk4 »

Is both fans working?

Check fan relays also
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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

Yes both fans come on when it gets to operating temp @90 and now stay on. But before it only used to come on when the car was getting hot, then it would go off as per normal. Now it's like always on.
Aslam_MK4 wrote:Is both fans working?

Check fan relays also
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Re: AGU overheating

Post by PapaJo »

Check for airlocks in the cooling system and test the fan temperature switch.
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Re: AGU overheating

Post by panic-mechanic »

Thermostat or even possibly the fan activation relay.
If it overheats with the fans on I suggest you start with a thermostat.
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Re: AGU overheating

Post by Dub rox »

PapaJo wrote:Check for airlocks in the cooling system and test the fan temperature switch.
ImageWhat he sayd. Sounds like the fan swich to me


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Re: AGU overheating

Post by Dub rox »

22irwin.mercure wrote:Hello everyone

I have a 2000 audi A3 1.8T AGU that heats up only when I am stuck in traffic. However when I continue driving, the heat gauge goes back to 90, but the fan stays on. If I am stuck for more than 10 min, the coolant light comes on.

I have done cambelt and waterpump 10000km ago and never had this issue after the change in waterpump. The waterpump was from goldwagen and had a metal impeller.

1. I have had the car scanned, no codes.
2. Replaced thermostat and engine flush.
3. When doing the engine flush, the coolant colour was normal pink. But I still flushed the system anyway and put in fresh coolant.

Anything else to look at?
Any idea what could be causing this?
Diagnosis picks nothing up.



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Did you put the correct temperature thermostat back in?

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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

panic-mechanic wrote:Thermostat or even possibly the fan activation relay.
If it overheats with the fans on I suggest you start with a thermostat.
It overheats with the fans on and I have replaced the thermostat yesterday.

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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

Dub rox wrote:
22irwin.mercure wrote:Hello everyone

I have a 2000 audi A3 1.8T AGU that heats up only when I am stuck in traffic. However when I continue driving, the heat gauge goes back to 90, but the fan stays on. If I am stuck for more than 10 min, the coolant light comes on.

I have done cambelt and waterpump 10000km ago and never had this issue after the change in waterpump. The waterpump was from goldwagen and had a metal impeller.

1. I have had the car scanned, no codes.
2. Replaced thermostat and engine flush.
3. When doing the engine flush, the coolant colour was normal pink. But I still flushed the system anyway and put in fresh coolant.

Anything else to look at?
Any idea what could be causing this?
Diagnosis picks nothing up.



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Did you put the correct temperature thermostat back in?

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I hope so. I bought a replacement from goldwagen. I gave them my engine code and they gave me a replacement, with a new o ring. The new and old thermostat looked identical.

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Re: AGU overheating

Post by panic-mechanic »

show me this thermostat that you replaced. picture or part number.
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Re: AGU overheating

Post by Dub rox »

Not to diss you or anything, but is the thermostat fited the right way round? Common mistake. We're all human after all.
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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

Dub rox wrote:Not to diss you or anything, but is the thermostat fited the right way round? Common mistake. We're all human after all.
It goes in this way Image

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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

panic-mechanic wrote:show me this thermostat that you replaced. picture or part number.
I will take a picture of the box and the old thermostat tomorrow. Image

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Re: AGU overheating

Post by panic-mechanic »

Did you by any chance test the thermostat to see thatbit works before installing?
Are both the radiator hoses hot at that point?
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'09 Touareg 3l TDI
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'05 Touareg v10

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Dub rox
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Re: AGU overheating

Post by Dub rox »

panic-mechanic wrote:Did you by any chance test the thermostat to see thatbit works before installing?
Are both the radiator hoses hot at that point?
Silence is allso an answer..... Image

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22irwin.mercure
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Re: AGU overheating

Post by 22irwin.mercure »

Sorry had some issues with my account... Turned out to be a a faulty fan switch. The 3 pin one. Fan was only working intermittently so the overheating is sorted.

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