hi all,

i've recently bought a nismo radiator cap which holds up to 1.3Mpa.

before putting it on, i want to ask

- is it suitable to put a higher pressure radiator cap on if all your hoses are still stock, not changed?

because i've read on a few forums and it says that

It has become popular to install high pressure radiator caps in an attempt to lower cooling system temps. While some makes and models come from the factory with and are designed for high pressure caps, raising your radiator cap's pressure above factory specs increases your cooling system's maximum operating pressure above design parameters. While raising your cooling system's maximum operating pressure does raise your cooling system's boiling point and therefore helps to avoid boil-over, it does not lower your operating temperature prior to boil-over, and simply allows your engine to continue to operate at temperatures higher than it is engineered for. Water boils at 212 degrees, and for each pound you raise the system pressure it raises the boiling point 3 degrees - Example: The 1.1 bar (16 pound) cap will have a boiling point of 260 degrees. Operating your engine at higher than acceptable temperatures can destroy your engine. We wish to point out some considerations that should be taken into account before an individual chooses this approach.

There are several possible reasons that you might be experiencing higher than normal cooling system temperatures:

An engine malfunction or cooling system problem - increasing your cooling system pressure will not correct this problem and will quite possibly add to the problem. We recommend correcting the problem instead of using a higher pressure cap.
Engine or body modifications have altered the performance of the cooling system or air flow through the radiator. Again, we recommend correcting the problem instead of using a higher pressure cap.
Engine modifications have increased the HP of the engine - creating more HP means creating more heat. We recommend increasing the heat dissipation capabilities of your cooling system to match the increase in heat generation. The best way to do this is install an All-Aluminum High Performance radiator, increasing the radiator cap pressure will not help dissipate additional heat.
Your car is being driven in a harsh (high heat) environment or is being driven hard for extended periods of time. Again, the best way to solve this problem is install a High Performance radiator, increasing the radiator cap pressure will not help dissipate heat.
Raising your cars cooling system's operating pressure increases the stress on all the other components of your cooling system. Before increasing your cooling system pressure by replacing your radiator cap with a higher rated radiator cap, check to make sure your entire cooling system is in excellent condition and all of the components are capable of handling these higher pressures. These may components include, but are not limited to:

The radiator (all of the All-Aluminum radiators that we sell are rated to handle these higher pressures)
Radiator hoses
Heater hoses
The heater core
The water pump
Freeze plugs
All gaskets that come in contact with the cooling system
Increasing your cooling system pressure by installing a radiator cap that has a pressure rating higher than factory specs increases stress on the entire system. Although some race cars use high pressure caps, their cooling systems are built to handle these higher pressures (All-Aluminum brazed and welded radiators, steel braided hoses, no heater core, high performance water pump, high performance gaskets, etc). We offer high pressure caps because some cars are designed with high pressure cooling systems. We recommend that you only use a cap with the pressure rating that your car was designed for.
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So am i better of using the recommended 0.9mpa radiator cap or is it ok to replace to a 1.3mpa with stock hoses?



thanks

 

if you are that worried about it, don't put it on. problem solved

 

but what i actually want to know the people who are using it or knows about it, does this apply to our Zs too?

Increasing your cooling system pressure by installing a radiator cap that has a pressure rating higher than factory specs increases stress on the entire system. Although some race cars use high pressure caps, their cooling systems are built to handle these higher pressures (All-Aluminum brazed and welded radiators, steel braided hoses, no heater core, high performance water pump, high performance gaskets, etc). We offer high pressure caps because some cars are designed with high pressure cooling systems. We recommend that you only use a cap with the pressure rating that your car was designed for.

 

Quite a detailed explanation about the relationship between pressure and temperature. I think you answered your own question.

 

The safety factors built into the hoses, radiator and other cooling system parts in all likelyhood exceeds the pressure of the 1.3Mpa cap by 10X.

I wouldn't worry about it one bit - I've never heard any evidence or suggestions that higher pressures caused by caps, upgraded water pumps or anything else has resulted in failures of the cooling systems on any cars, not just Zs.

 

ive been sportin it on my z for a few months, no problems

 

few months? I've had mine 6 years - not even noticible.

 

hi Dave,

i've been doing alot of research about this radiator cap thing,

many people have discussed and stated that the higher pressure cap causes wear and tear on their stock hoses, and eventually damaging the stock radiator as well,

but like you said you've run it for 6 years now, and its had no problem, it would still be a possibility chance that if would cause stress to our stock hoses, radiator, etc...

also does the stock radiator need to be upgraded?

here's also a link of people in other forum that has been discussing about this higher pressure cap, and from what i've read there's more negative than positive. and stating that the nismo radiator cap is the cause of the problem if using it.

http://www.b15sentra.net/forums/showthread.php?t=61790


and also this statement

Increasing your cooling system pressure by installing a radiator cap that has a pressure rating higher than factory specs increases stress on the entire system. Although some race cars use high pressure caps, their cooling systems are built to handle these higher pressures (All-Aluminum brazed and welded radiators, steel braided hoses, no heater core, high performance water pump, high performance gaskets, etc). We offer high pressure caps because some cars are designed with high pressure cooling systems. We recommend that you only use a cap with the pressure rating that your car was designed for.

 

ive seen some kill radiators at the crimp seals but that about it.

 

does that mean the whole radiator needs to be replaced or just the seal is able to be replaced?

 

Hey guys, just a quick question. I picked up a Nismo radiator cap to replace my stock one the other day purely for the purpose of looks. However, upon reading the warning sticker that came with the Nismo cap, I found thatNissan does not recommend using the Nismo cap on the street. Can anyone confirm or deny this?
Basically what I'm asking is if the cap can be used safely on a daily driver without fear of damaging the car in any way?

 

Their should be no problem. I've had mine on for years now without a problem. I think they just put that because it's supposedly for "racing purposes only" lol put it on!

 

A quick search yielded the following:

https://my350z.com/forum/engine-and-...ease-help.html

1,000's of us rock the NISMO radiator cap, if you would have searched you would have found no one has ever had issues

 

I tried looking, but I guess not very well. I appreciate the help.

 

why the need for the NISMO radiator cap??? I drive the **** out of my car and it barely sees temperatures over 90*C (yes the metric system is better!!!) and the 90* is when doing uphill runs up the east grade of palamar or sitting in so-cal traffic!!!
yes I have a NISMO radiator cap, and yes I am using coolant... my new motor will have EVANS and a blank cap...

NISMO radiator cap is going to raise your boiling point, yes... if you are having your radiator cap opening and dumping pressure then you have 2 problems
1. the cap you have on now is not working and is not holding the static pressure the system needs to operate correctly
2. you have a larger overheating issue (headgaskets, radiator clogged, or improper coolant mix)

the disclaimer is for dummies

 

Ive had to zs both had after market high pressure caps i don’t remember name brand of first but my current z has z1 Motorsports rad cap on it both caused stock radiator to leak where the plastic meets the coils first z i bought an alluminum performance rad i guess ill do the same to this z just stick with stock cap or upgrade all your cooling hoses and radiator before installing

 

7 year old thread long forgotten.

 

Just hate to see someone have to struggle with the bs i signed up for the forum just to get the message out there. Just lookin out hate to see someone dropping hundreds of dollars for a nifty 20$ cap

 

Fine, appreciated. But honestly, it's a thread that auto shop 101 should have answered 9 years ago.