# High pressure radator cap



## taskcds (Jun 22, 2009)

Has anyone changed there radiator cap to one the high ressure caps. A local atv echanic told me that it helps the brutes out to change from a 1.1 to between a 1.4 to 1.6

If some what brand did you get and part number with website f possible


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## Polaris425 (Dec 16, 2004)

I can tell you which one cross-refferences when I get home tonight... Not sure of the pressure on it though I'll have to look...


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## taskcds (Jun 22, 2009)

thanks


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## phreebsd (Dec 16, 2004)

what is the benefit of a higher pressure cap?


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## taskcds (Jun 22, 2009)

i was told my the mechanic that if you replace the stock cap with a high pressure one ten the motor will run a little cooler because it will take more pressure to build up before it starts burning coolant out. He actually said most people dont know if they replace with one of these high pressure caps that they probably would not have to relocate the radiator


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## phreebsd (Dec 16, 2004)

oh.
shoot i dont think there's a cure for a fully packed with mud radiator except moving it to keep it from getting muddy in the first place.


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## taskcds (Jun 22, 2009)

i agree he just told me it would have saved alot of bikes he has worked on especially the brutes since most still have to travel to a water hole or somewhere to spray it down to try to clean it when a light comes on


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## Yesterday (Jan 2, 2009)

that guy's crazy for thinkin a cap will help temperatures..


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## outskirtsdweller (Jul 6, 2009)

taskcds said:


> i was told my the mechanic that if you replace the stock cap with a high pressure one ten the motor will run a little cooler because it will take more pressure to build up before it starts burning coolant out. He actually said most people dont know if they replace with one of these high pressure caps that they probably would not have to relocate the radiator


 
Not sure if it'll run cooler, but the higher pressure in the system, the higher the boiling point of the coolant....


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## Polaris425 (Dec 16, 2004)

^^^^^ Thats what I was thinking... A cap that will let the pressure build up too much is dangerous, b/c the coolant will look for somewhere else to come out... like, gaskets... and thats a BIG problem... If it were me, Id stick w/ a plain ole cap. 

I can tell you this, I lost mine, and replaced it w/ a general one form automotive store, since I was out on a ride when it happened.... And since them, my bike overheats more often... not less. but I was going to give u (and everyone) the part ## for emergencies, like, losing one in the woods.. haha..


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## taskcds (Jun 22, 2009)

cool i was just curious from people who own brutes because i am new to the brute and was just going off what the mechanic said. I have stuck with my stock cap and just relocated the radiator


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## phreebsd (Dec 16, 2004)

you'll never overheat now


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## Roboquad (Sep 8, 2009)

I have not gone with the high pressure cap, I have to agree with polaris:agreed:. But changed rad cap and thermostat at the same time, drilled the pilot hole in the thermostat to one size larger bit.(have to go check)... Seemed to keep th bruit a ferw degrees cooler by allowing for a bit more flow.


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## oilfield_trash21 (Aug 27, 2009)

Believe it or not the higher pressure cap does help the temps with a highly modded engine. Its not gonna do anything with a mud clogged radiator though. When I had my turbo nissan 240sx, nismo offered a rad cap with a higher pressure for them. Nismo, TRD and a few other imports offer them.


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## hondarecoveryman (Feb 28, 2009)

IMO the stock system is designed with the factory set pressure in mind , if you start changing pressure you are askin for probs. Also pressure= heat , not the other way around . the mechanic only was slowing the boil over not the overheating by switching to a high pressure cap , If I had any suggestion it would be to replace the thermostat with a flow restrictor(basically a large flat washer) to get more flow but not to much(see the high flow water pump thread) ,I used theese when building Drag strip engines years ago


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## oilfield_trash21 (Aug 27, 2009)

Its really not raising the pressure but a pound or so or sometimes even less. The one i got from nismo raised it 2 psi and I never had anymore boilovers. Even running 30 psi of boost, she stayed cool. You would be surprised how much it raises the boiling pint of water by increase the pressure on it.


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## hondarecoveryman (Feb 28, 2009)

the reason you needed a higher pressure cap was because of the increase of pressure in your system as compared to a slow revving stock motor . the increase in pressure on your cap allowed you to keep the water in the rad. not blow it into the overflow tank. the turbo was spooling so fast (at 30 psi)it caused a spike in pressure in your system. and BTW high school physics taught me that the boiling point of water does not change with pressure .


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## oilfield_trash21 (Aug 27, 2009)

Well I'm not trying to start an arguement here but yes the pressure on water does affect its boiling and freezing points. We deal with this everyday here at work. We use turbine exhaust to heat water in order to use in our heat exchangers. The water is at 410 degrees and doesnt boil because the system is under 230 psi. And on the flip side of that, if you raise the pressure on water then you also raise the freezing point. We have flowlines from wellheads in 6000' of water and have to inject glycol in them because of the posibility of forming hydrates(ice plugs). When the water coming from the well is under 1000 psi, it raises the freezing point to around 55-60 degrees and the ocean temp at that depth is about 35 degrees.


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## qwackhead (Jun 25, 2009)

you run a higher presure cap to raise the boiling point of the water in the system with high perf. engines you can get the evaporation of water next to the cylinder walls and these bubbles will explode erroding the cylinder wall their is a name for it but i cant recall it at the moment. it dose not drop the engine temp. now on an atv a higher presure cap can cause head gaskets to leak radiator cores to leak hoses to leak and a number of other problems. all in all bad idea unless you have a modified engine that has a need to raise the boiling point of the water.


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## hondarecoveryman (Feb 28, 2009)

those are extreme pressure changes compared to atmospheric pressure(We didnt cover anything like that in high school), also the fact that the water is moving and not exposed to outside air has a lot to do with that too..., the rad. cap in question is 0.5 psi higher than stock , not enough to change anything at all , you do understand my point correct???


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## oilfield_trash21 (Aug 27, 2009)

I completely understand your point. I was just clearing up the fact about "high school physics", I thought the same thing until I seen it for myself out here. I'm trying to find the table of pressures that we have that shows the increased boiling point temps vs pressures. And you are also correct in the change being small with diff rad cap pressures. The dont work miracles but the do have an effect on modded engines.


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## hondarecoveryman (Feb 28, 2009)

o.k. cool just didnt want you to get me all wrong, not disputing you , just the guy that fed the line of crap to him about .5 psi making a diff.


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## oilfield_trash21 (Aug 27, 2009)

I smell what you steppin' in, we on the same page. I dont see .5 psi making a difference at all either. Best thing to do is put the rad on the rack and let her rock. Solved my overheating problems.


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## hondarecoveryman (Feb 28, 2009)

I am going to leave the P650 rad. in its stock loc. and buy a brute rad. to mount on the rack ....think i will have any problems then?


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## oilfield_trash21 (Aug 27, 2009)

You mean running them in a series?


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## hondarecoveryman (Feb 28, 2009)

yep going thru the stock then to the rack mount then back to the block


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## qwackhead (Jun 25, 2009)

my point was changing the cap will not make it run cooler


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## oilfield_trash21 (Aug 27, 2009)

I think there was somebody on here or HL that was doing that. Looked cool for sure. Def would cure any over heating probs.


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## hondarecoveryman (Feb 28, 2009)

our point too qwackhead .. we just went around the world to make the same point!! LOL


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## hondarecoveryman (Feb 28, 2009)

oilfield_trash21 said:


> I think there was somebody on here or HL that was doing that. Looked cool for sure. Def would cure any over heating probs.


 Dont know if he is on HL or not but Camo650 has his done like that too thats where I got the idea


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## oilfield_trash21 (Aug 27, 2009)

qwackhead said:


> my point was changing the cap will not make it run cooler


You are correct, it doesnt make it run any cooler. Just raises the boiling point of the water in the cooling system. The fan and thermostat is gonna regulate the cooling system temps, that is IF everything is in working condition(I.E. rad not clogged with mud). A modded engine is really the only one that will benefit from it because of the added stresses thats being put on it from the mods.


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## Polaris425 (Dec 16, 2004)

Ok I don't know about any of that, but if you lose one and have to have a replacement and kawi isn't around a carquest brand cap #33028 will fit perfect. You can probably cross reference that # w/ other brands to find ones that would also ft :rockn: 
Only problem here is that its a 13lbs cap.......


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## hondarecoveryman (Feb 28, 2009)

I will never forget spending the first 30 min at the M&G lookin for a rad. cap on the ground :haha:


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## Polaris425 (Dec 16, 2004)

Lol... Yeah :-(


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## hondarecoveryman (Feb 28, 2009)

dude I would have gave you mine , before I let you sit at base camp while we rode . and would have thought nothing of it


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## Polaris425 (Dec 16, 2004)

Well I was going to have to ride B* w/ someone if those boys couldnt find one. I'd have probably just rode in Phenix's Hoe wagon w/ the... well... girls that were driving it


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## hondarecoveryman (Feb 28, 2009)

ha ha , maybe they shouldnt have found one then .....LOL


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## Roboquad (Sep 8, 2009)

*OK Class*, now the *"Boiling point"* of an element or substance is the temperature at which a vapor pressure of the liquid equals the environmental pressure surrounding the liquid .A liquid in a vacuum environment has a lower boiling point than when that liquid is at atmospheric pressure. A liquid in a high pressure environment has a higher boiling point the liquid is at atmospheric pressure. In other words, the boiling point of liquid varies with and depends apon the surrounding environmental pressures.The people at Kawasaki have given good measure to the cap beast suited for stock needs. And you guys have given me a headache....LOL...good luck with your decision.


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