26 replies to this topic

[PeterFMarham]

I've just been out in my car it normally keeps around 87 but it went well over today oil is at max and fluid in radiator overspill tank. The fan is working and cooled it down after 5 min but it struggled to go bellow 120 when parked up with engine running

[VXBONE]

has thermostat failed to open? thus making no circulation of coolant and then overheated?,At 130 degrees the head may well have warped and failed

Edited by VXBONE, 04 January 2012 - 06:18 PM.

[chris_uk]

does the water in the exp tank ever drop?

[PeterFMarham]

Don't think it's the thermostat as fan kicks in at 100 as per, the fluid does not drop, the problem is that the radiator will not drop it below the recommended 100. O and this is a car which has had a full engine rebuild £4,700 new clutch £380 new gear linkages, new injector coils, wheel bearings, brake pads, new tires, all since being bought in June lol

[The Batman]

take it back to whoever did the work

[techieboy]

Sounds like that's well into potential head damage territory.

[Andrew aka Stuwy]

the sencer might be working but if i'm not mistaken the way it opens is by a heat sensitive spring, so that bit could have failed or broken? i have one from a GM engine in the shed, i'll take some pics and post tonight if you like?

[wantsum]

I remember years ago when the thermostats failed, we used to remove them completely, just took longer for engine to get hot and heater to get warm (not that it matters in a a vx). You could pull it out and see if the problem goes away.

[TheRealVXed]

errr.... and have the car permanently running too cold...there is an optimum operating range. Having the termostat open all the time means it will be below is, possibly meaning it stays in choke territory, furring up injectors, pistons and causing all sorts of other mayhem. Replace the thermostat and see if that helps.

[Winstar]

Sounds like it could also be the water pump, but check the thermostat first as it's alot easier to get to!

[wantsum]

errr.... and have the car permanently running too cold...there is an optimum operating range. Having the termostat open all the time means it will be below is, possibly meaning it stays in choke territory, furring up injectors, pistons and causing all sorts of other mayhem. Replace the thermostat and see if that helps.

I ment a quick way to find out if this is the problem, not to run it forever like it.

[Andrew aka Stuwy]

Sounds like it could also be the water pump, but check the thermostat first as it's alot easier to get to!

If its the water pump the rad wont get warm/hot and the heater matrix wont be supplyed so its fairly easy to check.

[2.2_na]

Sounds like that's well into potential head damage territory.

I wouldn't be leaving the engine running at 120 / 130 C.

[Winstar]

Sounds like it could also be the water pump, but check the thermostat first as it's alot easier to get to!

If its the water pump the rad wont get warm/hot and the heater matrix wont be supplyed so its fairly easy to check.

there will be a small convection driven flow through the circuit due to the diference in hight between the rad and engine

[vocky]

might be the coolant tank cap seal has failed, causing a lack of pressure in the system

[Andrew aka Stuwy]

Sounds like it could also be the water pump, but check the thermostat first as it's alot easier to get to!

If its the water pump the rad wont get warm/hot and the heater matrix wont be supplyed so its fairly easy to check.

there will be a small convection driven flow through the circuit due to the diference in hight between the rad and engine

Tru, but it wil take ages. engine will long overheat before rad gets hot.

I'm placing my money on the thermostat, as its cheap and easy to replace (then the pump)

[Nev]

Blimey 130 degrees C is a lot, I start to panic is mine gets to 97 degrees! I wouldnt run it again until you have isolated the problem. You may have warped your head already, so beware of HGF...

[VXBONE]

in relation to my first post,i was just giving my opinion as ive done quite a few modern engines vaux make like the z16xer,z18xer,and a18xer, and when theyve reached that temp(130),the head warps in centre and water fills bores.but you may be lucky,basically an engine overheating could usually be thermostat stuck closed, water pump(if fins have broken off),an air lock for some reason., a blockage restricting flow?

[VXBONE]

and to make you laugh off topic the above engines have electronically controlled thermostats that regulate between 112 degrees to 118 degrees!and at 130 degrees they overheat!very poor desigh ,espicially when some, ie astra h have no temp gauge for the driver!

[PeterFMarham]

the sencer might be working but if i'm not mistaken the way it opens is by a heat sensitive spring, so that bit could have failed or broken?

i have one from a GM engine in the shed, i'll take some pics and post tonight if you like?