Vauxhall Astra 1.6 Extremely High Temperature. Help Needed!

[Chris86542]

Hello everyone, I have very recently encountered a problem with my 1.6 Vauxhall Astra (S Reg).

For some reason when I am driving around, the temperature gauge will reach extremely high levels (100 Degrees & Red) however if I put the heaters on full the temperature will decline back to a reasonable level.

I would be extremely greatful if someone could offer me there expertise and advise me on what the problem is.

Thank you in advance!

Chris

 

[Burnerman]

Two possibilities at this stage, but there could be others:
1) The thermostat has failed shut, so hot water can't circulate through the main radiator to be cooled;
2) The radiator itself is blocked.
If these prove to be OK, then the water pump may be suspect.
In the meantime, cool the engine down with the heater fans, as you are doing at present.
John

 

[wingcoax]

I had a similar problem with my old "S" plate astra, It was the thermostat stuck.

 

[Stivino]

Is the cooling fan on the radiator kicking in when it should?

 

[Chris86542]

If it is the Thermostat that is stuck or damaged, can any of you roughly explain how I can locate and check that its working?

Stivino, Yes the fan kicks in when it is meant to (at least it seems to). Whenever I finish a journey and get out it is on so im assuming that is correct?

 

[Mursal]

From memory, the top radiator hose where it connects to the engine is where you will find the thermostat.

Remove the casing to see the valve.
If you want to have a look at this vid, but its a 1.8L engine.
http://www.youtube.com/watch?v=EiJUNzK4KlI

Do not keep driving the car as permanent damage will result, leaving the car with only scrap value. As the cost of repair will be excessive.

To test, just take the valve out, replace coolant with water for the test and drive as normal.

 

[wingcoax]

Some of the 'R' reg and the 'S' thermostats are located behind the timing cover. You will need to remove the timing belt and pully to access. It could be a good time to replace the belt as well.

 

[Astra99]

If it is an 8-valve, then the thermostat is definitely located behind the timing cover, making it a real PITA to replace. The timing belt has to be removed which means removing all the belt tensioning system. As previously suggested, replace the belt while everything is in bits, but I would go further and replace the water pump as well. If the bearings are a bit iffy, a new belt could cause failure, whcih could potentially trash the engine. Why they changed the design of the belt cover from the Astra A & B which had a gap to access and replace the thermostat. When the thermostat failed on my Corsa 1.4, I e-mailed Vauxhall and posed that question. The reply I had essentially said that all repairs and maintenance should be carried out by accreded dealers to ensure the quailty of service. I did not even bother to reply, as my reply would have been ..........

 

[Chris86542]

Can any of you give me a rough estimated price as to what it would cost for a mechanics to replace the thermostat and possibly the belt?

 

[Sirbendy]

I had mine done the other week for an almighty £80. That included replacing the aux belt, and fitting a "custom" stat - I bought a new one, cut the middle out of it and had them put that in. Then I put a Renault one in the top hose.

Lets see THAT fail again. Bloody stupid place to put a thermostat, same for all the 8 valvers.

 

[Mikefromlondon]

have you checked youe radiator fan kicks in? if not you will need to look at a new radiator temperature sensor usually mounted on the radiator, often known as fan switch, in some vauxhalls it drives the fan current directly through it and in others it may use a relay, and also worth checking the rad fan fuse of around 30A. This could be mounted in the engine bay in a black box next to rad relay.

 

[stuartturbo]

have you checked youe radiator fan kicks in? if not you will need to look at a new radiator temperature sensor usually mounted on the radiator, often known as fan switch, in some vauxhalls it drives the fan current directly through it and in others it may use a relay, and also worth checking the rad fan fuse of around 30A. This could be mounted in the engine bay in a black box next to rad relay.

If the thermo is stuck shut the rad fan will not come on as the rad remains cold.

 

[Mikefromlondon]

have you checked youe radiator fan kicks in? if not you will need to look at a new radiator temperature sensor usually mounted on the radiator, often known as fan switch, in some vauxhalls it drives the fan current directly through it and in others it may use a relay, and also worth checking the rad fan fuse of around 30A. This could be mounted in the engine bay in a black box next to rad relay.

If the thermo is stuck shut the rad fan will not come on as the rad remains cold.

True, problem is that its not been yet confirmed if it is a stuck thermostat, so before opening a thermostate housing, a quick check first to see if the rad is boiling hot! and the fan has not kicked in, if it is cold, then sure it points to a stuck thermo or even a possible water pump impeller, some of these are made of plastic blades, and they just spin free from the centre shaft.

However, i rule out water pump since he can cool his engine temperature to a reasonable level by using the internal heater fan, which cools it to a reasonable level he said! wouldn't fancy that in the coming summer months!

 

[Postie2003]

Why they changed the design of the belt cover from the Astra A & B which had a gap to access and replace the thermostat. When the thermostat failed on my Corsa 1.4, I e-mailed Vauxhall and posed that question. The reply I had essentially said that all repairs and maintenance should be carried out by accreded dealers to ensure the quailty of service.

I think that was all the answer you needed. Deliberately make things awkward to get more maintenance revenue for their dealers.

Sad to see Vauxhall of all manufacturers have gone down this route though. They used to go out of their way to design their cars to be easy to work on. Cavalier / Astra clutches being a classic example.

 

[wingcoax]

Whilst still on the subject of temperature, how many of you guys have tried changing the fan control resistor( you know the one, that thing stuck up behind the dash)