got a radiator Q that stumped me

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my hj45 is really giving me the sheites. fixed the fuel injector pump governer, then sprung a pin hole leak in the radiator. now i'll drive it from cold, as soon as the temp gauge gets to where it normally sits, the top pops off the overflow bottle attatched to the radiator, spilling half the radiator water all over the engine bay. if i pull over, re fill it, and drive off, it'll be good till next time it sits long enough to go cold.

apart from an exorcist, what can i do to fix this possessed overflow bottle??? i'm stumped.

only theory i have is that the radiator cap is allowing too much pressure buildup before releasing to the overflow, causing high pressure in the overflow, and thus emptying the contents rapidly. could explain the leak springing up, as the increased pressure found a weak spot. any help or suggestions appreciated :cheers:
 
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but a good rad shop costs $$, which i can't afford for a couple of weeks. just wanted peoples opinions on it, because it stumped me, but got around to thinking up what i typed up there............
 
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clean the crud out of the cap and see if that helps. But most rad shops will pressure test your rad for next to nix just to get the sale of a new core of something, I managed to drive mine for about a month losing 2 litres per hour and just refilling it every time i stopped before i got a new rad (ÄÄ 400) then i lost the overflow bottle and have been using the allmighty coke bottle ever since.

sam
 
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the cap has no crud, was replaced about a year ago. it's managable, i just was interested in opinions on what it was. kind of answered myself when i typed it though :) . ohh and next to nix for me isn't much money, i'm living off 2 minute noodles for 2 weeks.
 
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The thermostat is not opening soon enough so when it opens the water in the jacket has boiled and the build up of pressure causes the rad to overflow.You can test by feeling the bottom rad hose on cold start.The themo should open after 5 mins or so and you will feel warm water flowing into the rad.If not remove the thermostat and temp test.
I dont think rad caps are as good as they used to be and really need to replaced yearly or when ever theyve been subjected to higher than normal pressure.
You will have to give up on the 2 min noodles .I used to share a house with about 6 monash/melbourne uni students and they can eat anything if need be.
 
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not another thermostat!!!!!!!!!!!!!!!!! i replaced this one just over a year ago, after i did the cap.

when the top blows off the water is all fairly hot, so i think it's letting water through.

mmmm stale bread from the dumpster...
 

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Oh...Durka Durka Durka.
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[quote author=bad_religion_au link=board=1;threadid=8794;start=msg76157#msg76157 date=1071531655]


mmmm stale bread from the dumpster...
[/quote]



At least you have your priorities in line.... :D


Good luck!
 
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2 out of 3 mech mates recon it'll be the head gasket. one said possibly the head. so i guess while it's off we may as well test it. no visible cracks in the head, but little to suggest the head gasket, apart from a couple of little dents... heads are expensive
 
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when you pull the head it may become obvoius as to where the problem lies. Typically if the HG is gone you will be able to visually see where the breech is occuring. You can actually see what I call 'tracks" from the combustion chamber over to the water jacket. And definitely have the head magna fluxed/checked for cracks. They will/should also check for warpage.
 
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checked, the water jacket is water tight. replaced the welsh plugs and the head was warped. got it decked, waiting on a gasket then i rebuild it, cross my fingers and fire it up.

any tips on putting the mess back together?
 
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Get a good quality HG, torq in sequence to spec and your GTG. Also, some folks like to use spray on gasket stuff on the HG...personally I stay away from that stuff on HG applications. Some of that crap makes it damn near impossible to take the head back off in the future. Good luck.
 
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cool, gotta pick up the head gasket in a couple of mins, then i gotta wait a day to get a torque wrench, then it goes back together... i just don't want to be the one to crank the starter after it's finished... never put anything this mechanical back together.
 
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Dip the head bolts in motor oil just before you put them back in. May make it easier when, in 100 years or so, your grandchildren need to go back in there.
 
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100 years or so? if it's still running in 100 years, i'l donate a significant amount of my inheritance to getting it professionally done. thanks for the tip
 

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