gfromleeds
Well-Known Member
Another thing i noticed but dont know if its relivent the temp guage sits a mm under half way but when i coast down hill it drops quite quickly to just above the blue but almost imidiatly goes back up when i accelerate
Datatek
Well-Known Member
Stat missing or stuck open.
gfromleeds
Well-Known Member
I put a new stat in 2months ago
Tested it bfore fitting too
Tested it bfore fitting too
Datatek
Well-Known Member
The only reason I can think of for the temperature dropping as you describe is the stat not functioning.
gfromleeds
Well-Known Member
Mmm is it possable its gone faulty at only 2 months old?
Datatek
Well-Known Member
Some are duff out of the box these days
Grit Valve
2000 4.6 Vouge
Some are duff out of the box these days
What about an air lock that on the tilt water is not registering on the water sensor due to the lack of water
Datatek
Well-Known Member
Good point
gfromleeds
Well-Known Member
What could cause the presurising?
Last edited:
Datatek
Well-Known Member
An air lock if you are lucky, otherwise HGF or cracked head.
gfromleeds
Well-Known Member
It was a new stat 2 months ago fitted it myself. and tested it first
Would it meen the stats working if the rad in and out pipes were hot (too hot to hold for any lenth of time)
Would it meen the stats working if the rad in and out pipes were hot (too hot to hold for any lenth of time)
Grit Valve
2000 4.6 Vouge
My car would run fine sit half way in temp gauge but as soon as I went up a steep hill it would over heat I tried thermostat no chalnge water pump no change changed the rad and fAn its never happend again.
But I would like to point out if a water pump has failed your car would overheat all the time as there would be no circulation. if your stat wAs stuck closed it would overheat all the time
If if was stuck open it would take longer to warm up than normal and maybe fun colder than normal maybe not depending on how the rest of your system is ie pump circulation. How blocked the rad is and how well the fan works ect ect if stat was removed your car would run cold also depending on what state the other parts of the cooling system are in.
If your radiator is partially blocked from a build up of crud from age your car should run normally depending on how bad and combined with the other parts of the system but at say lights waiting and steep hills where the radiators cooling is at its most denanding it will overheat due to its lack of cooling abilitys same goes for the fan if fan has what's called lock up it can infact over cool the car if on the other hand its hardly working when needed ie motorways steep hills heavy loads your can can overheat you got to remember its not just one factor its all of them combined they all work together if ones getting weak then another fails it all adds up to overheating .
Now I have done a few drains of the cooling system and I tell you this even after checking bleed pipe is ckear filling radiator up as much As you can by yourself and running filling I have myself encounterd overheating due to air locks its a very delicate system do remember in rave it states to turn off allow to cool as soon as the thermostat had opened after a system refill ! Then retop up any water after its cooled if you Still having trouble due to overheating and air locks in the rave trouble shooting page you will see that it requires you to rev the car at 2000 rpm warm car obviously not when it's boiling ! with cap removed to remove any air top up and recheck car.
But I would like to point out if a water pump has failed your car would overheat all the time as there would be no circulation. if your stat wAs stuck closed it would overheat all the time
If if was stuck open it would take longer to warm up than normal and maybe fun colder than normal maybe not depending on how the rest of your system is ie pump circulation. How blocked the rad is and how well the fan works ect ect if stat was removed your car would run cold also depending on what state the other parts of the cooling system are in.
If your radiator is partially blocked from a build up of crud from age your car should run normally depending on how bad and combined with the other parts of the system but at say lights waiting and steep hills where the radiators cooling is at its most denanding it will overheat due to its lack of cooling abilitys same goes for the fan if fan has what's called lock up it can infact over cool the car if on the other hand its hardly working when needed ie motorways steep hills heavy loads your can can overheat you got to remember its not just one factor its all of them combined they all work together if ones getting weak then another fails it all adds up to overheating .
Now I have done a few drains of the cooling system and I tell you this even after checking bleed pipe is ckear filling radiator up as much As you can by yourself and running filling I have myself encounterd overheating due to air locks its a very delicate system do remember in rave it states to turn off allow to cool as soon as the thermostat had opened after a system refill ! Then retop up any water after its cooled if you Still having trouble due to overheating and air locks in the rave trouble shooting page you will see that it requires you to rev the car at 2000 rpm warm car obviously not when it's boiling ! with cap removed to remove any air top up and recheck car.
Grit Valve
2000 4.6 Vouge
As for Pressurising depends what you call pressurising if its boiling up combined with the systems Natural pressure and flowing out if the expansion tank over flow then you have a overheat problem forcing the water out but if its not overheating then the system has pressure in its as that's how it works my top pipes when the car is hot are hot to hold you can't expect the pipes to remain cold as its supposed to run at a certan Temperature.
gfromleeds
Well-Known Member
No i expect the pipes to get hot i mentiond that because it shows the hot water is circulating through the rad so the pump and stat must be ok yes/no??
But the pipes do go harder than i would expect. i just whiped the cap off whilst hot and it dumped about 4-5liters of boiling water out
Im wondering if it is a headgasket problem (although it passed a sniff test) cos ive checked /replaced everything in the cooling system
But the pipes do go harder than i would expect. i just whiped the cap off whilst hot and it dumped about 4-5liters of boiling water out
Im wondering if it is a headgasket problem (although it passed a sniff test) cos ive checked /replaced everything in the cooling system
Grit Valve
2000 4.6 Vouge
If you undo the pressure cap with the engine hot and especially not running it the pressure inside the system will Cause it to overflow you can very gently open a cap if your car is not overheAting and the engine is still running without it overflowing. Although you had a snuff test how many time since have you allowed it to overheat may be now you have a hgf since the test as for top hose going hard cheaper make hoses do that especially if the system has been boiling up as the heat will make the rubber compound go hard.
gfromleeds
Well-Known Member
It hasent overheated since i towed my carsvan in april and ive had the sniff test done since then and changed the stat and rad
Its just pressurising now
Its just pressurising now
Grit Valve
2000 4.6 Vouge
When mine has an air lock it overheats and if you try to take the cap off it will force its way out its acting like steam and also the top hose will feel hot and hard as the boiling water is trying to force its way out .
If I have been on a normal run and up to temputre you can carefully remove cap ease out the little pressure and no over spill if you turn enging of tho and stop every thing circulating then the pressure and heat build up will cause it to over flow no matter how carefully you remove the cap.
If I have been on a normal run and up to temputre you can carefully remove cap ease out the little pressure and no over spill if you turn enging of tho and stop every thing circulating then the pressure and heat build up will cause it to over flow no matter how carefully you remove the cap.
