Astra Coolant Temperature gauge

Hi,

I have an R-Reg Astra (older shape). The engine temperature gauge never
seems to move much above cold, unless I'm sitting in traffic or somthing in
which case it will creep up the scale, however, as soon as I'm moving freely
again, it slowly drops back down to Cold again.

Anyone got an idea what the problem could be? I've checked my cooland level
and that's fine. Someone said it could be a faulty thermostat(?) If this is
the case, how expensive would it be to get it replaced. Is it somthing that
a somewhat mechicanically-challenged person such as me could attempt?
Does it matter? what if I don't bother doing anything at all, car seems to
be working just fine (except for the temperature).

Thanks,

Chris.

 

I had the same issue with my Astra (jesus this car has had a lot of
niggles!). It was a very easy job to do, and if I can do it, ANYONE can do
it

 

Excellent! How exactly would I go about doing this then? A good start would
be whereabouts is the thermostat on this engine (oh, it's a 1.6 8v by the
way)

Cheers,

Chris.

 

Mine was at the front of the engine, and I followed Mr Haynes every step of
the way I`d scan it in for you, but my scanners gone a bit mental, and
thinks that the world is pure white

 

For what its worth, if the engine is running cool all the time due to a
faulty thermostat
then the ecu will have the fuel mixture permanantly too rich, so it will be
using extra fuel as well.

Mike

 

Ahh, that's not good...

Could anybody give me a rough idea of the steps involved in replacing the
thermostat then?
Just to repeat, R-Reg Astra (older shape) 1.6 8v engine.

Thanks,

Chris.

 

Lets just back up two paces. Is the car heater getting warm even when the
gauge says cold?

Cheers

D

 

In message ,

Yes, heater does get warm. though arguably not as warm as it used to (missus
says so...)

What are you thinking...(Coolant header tank is still full)

Cheers,

Chris.

 

In message ,

.... oh, and gauge DOES move up if I'm sitting in a queue for a few minues...

 

and when it does, does the heater seem to blow a bit hotter?

Mike

 

In message vkAhh.12404$,

Haven't really noticed. Will try and check next time I'm in a traffic jam...

What could it mean if it does or if it doesn't??

 

If it gets warmer then the fault is electrical. probably sender or
connections to it. Unusual for the guage to go bad.

If it doesnt get warmer then it is likely a fualty thermostat. Coolant
should circulate between the block and the
heater core (essentially a small radiator) without passing through the
thermostat. This is so the heater can deliver
maximum heat from the coolant as soon as it is available, when the engine is
warming up. When coolant reaches optimum
temperature the thermostat opens to divert coolant to the radiator.
Temperature out of the block depends on two factors,
coolant temp in and how hard the engine is working. In colder weather the
thermostat diverts less coolant to the radiator
because it is cooled to a greater extent before re-entering the block. a
faulty thermostat that is stuck open will divert
too much coolant to the radiator and hence back to the block, giving
excessive cooling (engine running cool) and poor heating.

Mike

 

In message C1_hh.13808$,

Mike,
Thanks for such a comprehensive reply. I shall see what happens to the
heater temp if the gauge goes up when sitting stationary.
One last question, what is involved in changing the sender or the
thermostat? I'm not mechanically minded, so will probably get my local
dealer/garage to do it. How much should I expect to pay to get either job
done(including parts and labour)?

 

It should be at a high point in the cooling system. Find the top radiator
hose, and follow it back to the engine.
Usually the bit that the hose plugs onto is the thermostat housing. You
would need to remove the hose, and usually
2 bolts to remove the housing. Dont know about your specific engine, but
either you replace the thermostat (cheap)
or if its like our 1.8 zaf I did a while back you have to buy the whole
bastich housing from Vx, and as it is specific
for a Vx engine, no pattern parts available, hence not cheap. Visit your
local motor factors and see if they list one for your car.

If its the sender, look for a wire that plugs in very close to the
thermostat. thats the sender. simply unplug, unscrew and replace.

BTW, all better with a cold engine, and no pressure in the coolant (just
remove the pressure cap).

A sender should be a 5 minute job. Thermostat should be up to 1/2 hour
allowing for some buggeration factor, like cant find a socket,
or might have to remove something else to get at it.

Price of parts? dunno. think of a number. Then shop around if it seems
expensive.

Mike

 

To get to the thermostat on the 1.6 8V engines you have to remover the cam
belt to remove the rear section of the belt cover to expose the thermostat
housing.

 

In message 45a4fae5$0$4839$,

Yuk, don't like the sound of that... I can make a bit of the mess if I cock
anything up with the cam belt can I not...?
Or is removing it and replacing it very simple(and I mean VERY- I can just
about tell the difference between a hammer and a screwdriver!)
Maybe I'll just take it down the local workshop...

 

Its not that difficult, get yourself a Haynes book, When I changed my stat I
also changed the cam belt so it involved a little bit more work but it only
took about 45 mins to do it from start to finish.