Cooling system issues

[AAH!]

Currently having a few problems with the cooling system.

Just done a quick fix (whilst wait for the samco's) to deal with a leak in the top rad hose where it attaches to the water rail by cutting the hose back by 20mm to the split, which has done the trick.

I hoped it might cure a problem I thought might be caused by the leak dripping onto the MFTS and as a result the leaking water being cooled by the airflow at motorway cruising speed the the water temp gauge dropped to about 2.5 lines above 50º. It didn't help.

After a bit of searching on the forum I found that the new 3 pin MFTS (like mine) can indeed suffer from wind chill which causes the water temp gauge to show low temps at motorway speeds and as a possible cure I will construct a baffle to try and protect it from the cool air.

The search results also suggest that the thermostat could be ******ed which can also cause the water temp gauge to show low temps and also high fuel consumption, which I suffer from. Will replace the thermostat. How tricky is this?

Should I be looking at anything else?

Lastly whilst out on the track at castle coombe the above mentioned leak caused the car to loose 3 litres of coolant, but what was a real worry was that the low coolant warning light did not come on! I have checked and cleaned the connections to the sensor at the bottom of the tank and they appear to be ok and the sensor itself rattles within the tank when shaken. when pressing the warning light system check button on the instrument cluster the low water light does come on.

Any ideas on this?

Thanks ... Angus

p.s. I have replaced the expansion tank filler cap as the old one's pressure relief valve was siezed up indicated by a lack of a rattle when shaken (thanks robo).

[Doug_RS2]

If you lost 3 litres I would get it fixed asap - are you definitely leaving a puddle. change the short hoses for the turbo coolant feed and the heater feed coming off the thermostat housing. Bleed it properly - it takes a while to bleed them!!

[S2central.net]

Changing the stat is like many jobs on the s2 - not technically complex in itself - its just the amount of graft and stuff you have to move outta the way first that will grind you down.

You need to drain down the coolant and hydraulic systems for this... Because the hydraulic pump needs removed to get access to the thermostat housing. As Doug says - it takes a while to bleed the system.

[Greg_S]

you can also do it by removing the rad to get access too, i think thats the case anyway.

[Mikes2]

That's how I changed mine by removing the rad with fan attached. Makes it easier to reach the short hose to the thermostat. If doing the other short water hose to the turbo, you will need to lift the hydraulic pump out of the way.

[AAH!]

With fixing the leak in the top hose the coolant level seems to be holding at the moment. There was never a puddle under the car as the coolant seemed to only escape when the car was on the move and the system was up to pressure, occasionally there would be the tell tail puff of steam coming out from under the bonnet when I would come to a stop. What probably didn't help was that the expansion tanks filler cap pressure release valve was not working, so the build up in pressure may have forced the coolant out of the split in the top hose.

I think I might wait until the samco coolant hoses to arrive (how's it looking Paul?) and then tackle the thermostat and the hoses all in one go.

What does the bleeding procedure entail for the coolant system and the hydraulic system?

Thanks for the replies ... Angus