Homer Posted January 23, 2009 Share Posted January 23, 2009 Ah, is that because of increased circulation in the system? That must be a benefit as far as cylinders 5&6 are concerned? (Sorry for bugging you with these questions at this late hour, and thanks for your help ) The circulation rate doesn't change, the better heat transfer occurs because the water molecules are more compressed at a higher pressure and thus more of them have contact with the surrounding material (the block or turbo) than at a lower pressure. They therefore extract more energy from that material (i.e. take more heat away from the block/turbo). This energy then has to be released by the radiator and combined with the high pressure it's forced to do a LOT more work than it was originally designed. The downside of this is the pressure itself - it puts a higher than designed presure on everything the coolant interacts with: heater matrix, head gasket, raditator, all pipework, etc.... This is why we see an increased failure rate of those compenents on cars with higher than stock pressure rad caps. The fact remains that the stock level of pressure is absolutely perfect as it is, there is no need to raise the coolant pressure provided your stock rad isn't a dud or you're running a seriously high specification engine (massive boost, massive turbo, high combustion temps, etc) Hope that makes sense, it works in my head but I'm not very good at explaining these things. lol, nah, working US hours so it's only evening for me Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted January 23, 2009 Share Posted January 23, 2009 Sounds spot on to me (With what limited knowledge I have of thermodynamics) Looks like i'm shopping for a standard rad cap in the morning. Thanks for your help Quote Link to comment Share on other sites More sharing options...
Homer Posted January 23, 2009 Share Posted January 23, 2009 Sounds spot on to me (With what limited knowledge I have of thermodynamics) Looks like i'm shopping for a standard rad cap in the morning. Thanks for your help Don't take what I posted as gospel, it's only as I understand it so might well have a flaw. Ryan I know agrees with keeping the stock coolant pressure with a stock rad, but its advisable to check with some other more knowledgeable folks before making any changes. Quote Link to comment Share on other sites More sharing options...
j_jza80 Posted January 23, 2009 Share Posted January 23, 2009 I see what you're saying. I think tommorow (When i'm not tired and I can think straight) i'll do a bit more research into this. Quote Link to comment Share on other sites More sharing options...
Stonkin Posted January 23, 2009 Share Posted January 23, 2009 Well done guys, nice to hear First thing Ryan said when the bonnet was opened for mapping at SRR recently was 'mate, you've gotta change that rad cap!' Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 23, 2009 Share Posted January 23, 2009 Stay with 0.8 - 1.1bar caps. Any more pressure and the heater matrix, stock rad and much more will be at risk of cracking espically in these cold nights. Ryan Quote Link to comment Share on other sites More sharing options...
adnanshah247 Posted January 23, 2009 Share Posted January 23, 2009 been reading quite a few sites and i guess the stock cap is the way to go, plenty of people have had issues with after market caps. Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted January 23, 2009 Share Posted January 23, 2009 Your very welcome guys, added to a great evening It is a uprated rad cap at 1.3 bar and it was what I was thinking last night when the hose went, we could see the steam from behind the car even though it was what looked like a small leak it soon went through water I doubt there is any further damage as the temp never got high even though it went through a fair bit of water, Hopefully a simple fix of changing the lower rad hose and putting a stock rad cap on will sort it for you Quote Link to comment Share on other sites More sharing options...
adnanshah247 Posted January 23, 2009 Share Posted January 23, 2009 Your very welcome guys, added to a great evening It is a uprated rad cap at 1.3 bar and it was what I was thinking last night when the hose went, we could see the steam from behind the car even though it was what looked like a small leak it soon went through water I doubt there is any further damage as the temp never got high even though it went through a fair bit of water, Hopefully a simple fix of changing the lower rad hose and putting a stock rad cap on will sort it for you did you just get up? im half asleep at work, walked into a door man, seriously not with it! Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted January 23, 2009 Share Posted January 23, 2009 did you just get up? im half asleep at work, walked into a door man, seriously not with it! LOL no at the clients, only just logged on the forum Once again, thanks so much for the lift it was much appreciated Its well worth being half asleep, the car looked mint! Quote Link to comment Share on other sites More sharing options...
adnanshah247 Posted January 23, 2009 Share Posted January 23, 2009 thanks man, it was a laugh yesterday even the unfortunate break down, funnily you remember what i said about the wipers? as soon as me and Maf got near home they went quite! Quote Link to comment Share on other sites More sharing options...
supra_aero Posted January 23, 2009 Author Share Posted January 23, 2009 Yes I'll be ditching the radiator cap, and its booked into whifbitz on Monday. Thanks again all for your help. Quote Link to comment Share on other sites More sharing options...
T2 MSW Posted January 23, 2009 Share Posted January 23, 2009 Yes I'll be ditching the radiator cap, and its booked into whifbitz on Monday. Thanks again all for your help. thats good to hear, it's in good hands Quote Link to comment Share on other sites More sharing options...
adnanshah247 Posted January 23, 2009 Share Posted January 23, 2009 mike, charles you remember that idiot in the vectra? he came in like a hero, his car was over heating as well but instead of turning his car off he was revving the nuts off it until a big bang and his radiator blew! some people honestly............... Quote Link to comment Share on other sites More sharing options...
supra_aero Posted January 24, 2009 Author Share Posted January 24, 2009 mike, charles you remember that idiot in the vectra? he came in like a hero, his car was over heating as well but instead of turning his car off he was revving the nuts off it until a big bang and his radiator blew! some people honestly............... That was very funny. Quote Link to comment Share on other sites More sharing options...
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