I do agree with cully, its like those little pressure gauges on the leccy compressors you get from the AA.. goes up to 30-psi with divisions every 20, useless for trying to get 35psi./.
now a 0-3bar one would be a good shout, possibly even a 0-2bar one.. if you can find one
Can't see the point tbh - as already said the rad cap will vent at a set pressure in any case.
Coolant works under pressure as it gets hot.
Not sure how you're gonna see the difference between head pressurising with combustion gas and water pressurising due to operating temps - aside from letting it cool down.
Arbitrary anyway, as will work at diff pressures depending on what ratio of antifreeze / water you run too.
I guess if you know your normal running water pressure then if the head gasket goes - it will rise LOL - so therefore you will have early and definite proof that yer head gasket has gorn !
11-04-2017, 08:14 PM (This post was last modified: 11-04-2017, 08:17 PM by maxaret.)
I dunno - it takes time for the cooling system to warm up - if you saw a pressure rise on a cold engine it would maybe give a warning of impending HG doom.
I have had very subtle HG failures twice where garages could not diagnose it with their normal test gear,but the symptoms were unmistakeable and I got the HG's changed - symptoms then disappeared LOL - funny old thing eh
I also wonder what the actual running pressure is with the coolant at normal temps (circa 82 deg) - I doubt that the cooling system is running at the cap vent/relief pressure all the time - to be sure it will prob vent when you are stuck in traffic on a hot day and also if you come to grinding halt (roadworks etc) after a long fast run on an Mway then the heat soak will bring things nicely to the boil.
It won't prevent a HG failure, in fact, the only action you'd take after noticing HG failure with a pressure gauge (doubtful as others have pointed out), would be to spend money to repair the car.
Therefore, save your money and spend it on fixing and maintaining the car if you do want to keep it for a long time.
This post is an artistic work of fiction and falsehood. Only a fool would take anything posted above as fact.
62k Diablo Phase 1 Gti-6:Project Thread
what symptoms would show for pressure/coolant loss?
(long time ago bruv's Sd1 pissed water from rad leak. spotted when we stopped for a brew. actually pissed thro' the grille without touching the sides :-s)
Both the HG subtle failures I mentioned did not show any temp gauge rise/fluctuations at all - I just noticed evidence of the HG problem via symptoms in the engine bay,as I also previously posted the HG leaks were so small that 2 different garages could not diagnose with their test gear - but I just told them to change the HG anyway. A pressure gauge might give an extra indication of impending HG failure.
Interesting pic Magenta - I was always under the impression that older cars ran at 12-15 psi under normal driving conditions - as I posted on your other thread .
Normal running pressure or vent/relief pressure ?
And I did say I was talking about older cars - hence my question about what is the normal running pressure of (say) an Hdi at approx 82 deg coolant temp.
Pressure will still fluctuate depending on coolant strength. Or run Evans waterless coolant and it won't build pressure at all iirc. Still think you're mixing up water pressure due to temp, and coolant pressure due to combustion gasses leaking into coolant and pressurising the system.