2.1 DJ not hot enough then too hot

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axeman
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Re: 2.1 DJ not hot enough then too hot

Post by axeman »

have you cheaked that the temp gauge sender is working correctly? it is located on the thermostat housing. i don't now what the resistance readings you should get from it. but the test is quite straight forward with a multi meter,

and flushing the system, changing the stat and fresh G12+ wont do any harm. when changing the stat it may well be worth ordering an new thermostat housing cap thingy. (the plastic top half that houses the thermostat) that baxter sells them as they go brittle over time and may well break when you disturb it.to change the stat.


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PetenAli
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Re: 2.1 DJ not hot enough then too hot

Post by PetenAli »

Thanks Neil. Will check the sender and add the stat housing to Brickwerks order.

Pete
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..lee..
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Re: 2.1 DJ not hot enough then too hot

Post by ..lee.. »

you state it takes a long time to get up to temp but then state that it goes to the red light too quickly for your liking.

i think you are going the correct way about fixing it but does it overheat. try and borrow a lazer thermometer for a min or two and check all over the rad for cold spots in case you have a blockage.

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Re: 2.1 DJ not hot enough then too hot

Post by PetenAli »

i think you are going the correct way about fixing it but does it overheat. try and borrow a lazer thermometer for a min or two and check all over the rad for cold spots in case you have a blockage.

Thanks Lee. Will try the lazer thermometer if I can find someone who's got one.
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1664
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Re: 2.1 DJ not hot enough then too hot

Post by 1664 »

PetenAli wrote:It takes maybe ten miles for the engine to fully warm up as indicated by the temp guage (more in the recent cold weather). This can't be good as it means an unnecessarily rich mixture that will cause premature wear. Once warmed up it then runs with the needle just on the hot side of the red light on the temp guage. If I put the heater on the needle drops quickly (within 30 seconds) to between normal and cold. In traffic or just left ticking over on the drive the temp rises until the fan cuts in. This seems to happen very quickly even at this time of year.
Er, sounds 'normal' to me. The fan NEVER kicks in unless your're running in a traffic jam - if you're moving at any kind of appreciable speed the air movement will be enough to cool the rad. Putting the heater on has much the same effect. The gauge will just pass the RHS of the red light before the fan kicks in - it won't bother before. If I start my van and just leave the van stationary with the engine running things heat up surprisingly quickly, the gauge goes a 'little' past the red light, then the fan kicks in. As far as I know, that sounds about right. You're obviously worrying because this is all new to you..........................heat that is
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Re: 2.1 DJ not hot enough then too hot

Post by PetenAli »

You're obviously worrying because this is all new to you..........................heat that is

Nice one 1664! Heat can be a bit of a novelty when you've driven air cooled for 35 years!!
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kevtherev
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Re: 2.1 DJ not hot enough then too hot

Post by kevtherev »

PetenAli wrote:Hi All,


The Problem
It takes maybe ten miles for the engine to fully warm up as indicated by the temp guage (more in the recent cold weather). This can't be good as it means an unnecessarily rich mixture that will cause premature wear. Once warmed up it then runs with the needle just on the hot side of the red light on the temp guage. If I put the heater on the needle drops quickly (within 30 seconds) to between normal and cold. In traffic or just left ticking over on the drive the temp rises until the fan cuts in. This seems to happen very quickly even at this time of year.


yes that's all perfectly acceptable and "normal" is any where between either end of the gauge. your cooling system is in good shape.
The mixture ratio's are progressive as the engine warms, and the ratios are not that far off working temps even at low temps.
Only initial start up is where the ratio is close to over fuelling.

What basis do you think that a rich mixture causes mechanical damage?
AGG 2.0L 8V. (Golf GTi MkIII)

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Re: 2.1 DJ not hot enough then too hot

Post by PetenAli »

yes that's all perfectly acceptable and "normal" is any where between either end of the gauge. your cooling system is in good shape.
The mixture ratio's are progressive as the engine warms, and the ratios are not that far off working temps even at low temps.
Only initial start up is where the ratio is close to over fuelling.

What basis do you think that a rich mixture causes mechanical damage?

Well thanks. The concensus seems to be that I'm worrying about nothing. I don't however know when the anti freeze was last changed and it looks blue to me so I'm probably going to still drain, flush and refill. Very grateful for everyone's advice.

Just on the rich mixture / engine wear point - I always understood that if a fuel injected (or auto choke) engine stayed cold for too long it would mean that the management system - however basic - would run rich thereby putting unnecassary fuel into the combustion chamber thus undoing the good work of the oil. See John Muir page 133. Is this just an old air cooled thing or does it stil have currency?

Would just like to say thanks to everyone for the advice - this is just such a useful forum.

Pete
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kevtherev
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Re: 2.1 DJ not hot enough then too hot

Post by kevtherev »

PetenAli wrote: Just on the rich mixture / engine wear point - I always understood that if a fuel injected (or auto choke) engine stayed cold for too long it would mean that the management system - however basic - would run rich thereby putting unnecassary fuel into the combustion chamber thus undoing the good work of the oil. See John Muir page 133. Is this just an old air cooled thing or does it stil have currency?
Pete

Ah I see... (John Muir?)
Personally I think there should be no oil in the "combustion chamber"
But fuel injected engines receive a far more precise amount of fuel for any given situation than a carburettor.
The amount of fuel delivered by the management system will rapidly respond to any change in it's environment due to the amount of sensors involved.

your temp 2 sensor is an important component in this chain of command.... not your temp gauge
AGG 2.0L 8V. (Golf GTi MkIII)

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