Thermostat

[petegardner_901]

Just out of interest what happens if you drive with no thermostat in the system?

 Would this cause damage or just poor running or what?

😬

(GT6 owner!)

[Colin Lindsay]

The thermostat keeps a more or less constant temperature by opening and closing as required; it helps the car get up to operating temperature quickly then keeps it steady as far as possible.

Without one, your car will take longer to reach optimum operating temperature, and you'll be at the mercy of any change in outside temperature without the thermostat to regulate the extremes. A lot of engine damage occurs when the engine is warming up, so this will take longer and cause more wear. Theoretically at speed or when well warmed up the thermostat will be open more or less permanently to allow the radiator to cool the water, so it shouldn't overheat to any dangerous level as long as radiator and cooling fan are up to scratch. However it can run too cool which won't help the running; mixture may be affected, oil will be too thick, and again we're facing engine wear.

[Chris A]

When I got my 13/60 It was quite some weeks before I wanted to check the thermostat condition, lo and behold there wasn't one. No damage done but clearly would have taken longer to get to running temperature 

[Pete Lewis]

add to colins summary  a cold engine needs to run richer that will wash the bores and get worn rings and bore very quickly 

pete

[petegardner_901]

Still having overheating problems here. I drove it for several miles with no thermostat to see if that was causing the trouble but the water was literally boiling in the overflow bottle when I got in.

Head gasket is ok, no thermostat in, no leaks, electric fan working properly….. could a dodgy radiator cap cause this?

[Pete Lewis]

was it actually boiling or just making bubbles   what else make you think its hot   dont rely on the gauge that can have its own problems

how far do you want to experiment

start with how hot was the radiator run your hand across is there hot / cold zones   is the bottom pipe hot   is the radiator tubes blocked 

it should run fine even with the cap not fitted so do check the cap is the correct depth to seat the sealing washer ???  

but caps dont cause boiling   might help expansion water escaping but unlikely the problem you are having 

Pete

 

[NonMember]

As Pete says, the cap won't cause overheating, although a cap that isn't holding any pressure will mean it boils easier.

When you say "literally boiling", do you mean you put a thermometer in the overflow bottle and it was at boiling point? Was there steam pouring out? If not, it was air bubbles, nothing more.

Check the temperature of the radiator, top and bottom. Check the fan belt, make sure the water pump is spinning properly. By far the most common causes of overheating in my experience are blocked radiator cores (rust!) or slipping fan belts. (Or loss of coolant, but you assure us it hasn't lost any)

[petegardner_901]

Paranoia I think is the main problem…

I’ve just fitted a new thermostat, topped up and gone for a run - several miles so up to temp.

All seems good. I’m not yet 100% sure because as I said last time there was a good stream of bubbles in the overflow bottle and it took about 3 or 4 pints.

But this time fine.

I love my car.

😳🔫

 

[NonMember]

41 minutes ago, petegardner_901 said:

I’m not yet 100% sure because as I said last time there was a good stream of bubbles in the overflow bottle and it took about 3 or 4 pints.

Had the system been drained before that? The GT6 cooling system is notorious for being hard to fully fill, partly because of air locks but mostly because the filler cap is not the highest point in the system. When you first drive it after a drain and re-fill, there's nearly always air in there, which is ejected out into the overflow bottle and produces a mass of bubbles. Then when it cools down, the water in the overflow is drawn back in to properly fill the system.

[Iain T]

52 minutes ago, petegardner_901 said:

All seems good. I’m not yet 100% sure because as I said last time there was a good stream of bubbles in the overflow bottle and it took about 3 or 4 pints.

Earlier this year I refilled my Vitesse and on a test drive it was fine until I stopped at traffic lights. The temperature gauge went up to 'I'm gonna explode'. I didn't believe it but was only a minute from home. Waited until it cooled down, put the front on ramps to raise and surprised how much fluid it took. The gauge was measuring compressed steam. All fine there after. 

Iain 

[Pete Lewis]

air locks  very common

i would crack open a high heater hose , loosen clip and allow trapped wind out

raising the front of the car quite high is another method  

do make sure the rim of the thermostat has a jiggle pin to allow air to escape while the stat is closed 

like this  if it does not have one drill a 3mm hole in the rim disc many are sold by reputed with no means of air bleed...thats disaster looming  after refilling