coolant pressure releif #

P

PAwhiteboy

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Dec 2, 2013
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just picked up my pressure relief valve today. Adjustable from 25-175. I was researching the fourms about this and they were from 09 and it was kind of unclear then on what was a good pressure to have them set at.

Is there now a recommend setting?
 
Which valve did you get? I just picked up a watts 530c that only goes as low as 50#. Which from what I've read 50 is just about right. Do you have the part number for your valve?
 
One in the head and one in the block? I was thinking about doing the same since all is have to do is pull a plug out and thread in a pushlok fitting.
 
I went into local plumbing store and gave them watts 530c part number and they cross referenced it. They had this Wilkins in stock. The part number is half missing. But I can give you what I see.

Wilkins
12-P15??
model 1500

I think its their only model in 1/2" that has the 25-175 setting. So it shouldn't be hard to find. Sorry couldn't be more help.
 
I'll have to look into that one. Not enough, how long have you been running your watts valves? I understand their only rated to 180° so I was curious if you've seen any adverse performance from the higher operating temps of our engine coolant.
 
purediesl said:
I'll have to look into that one. Not enough, how long have you been running your watts valves? I understand their only rated to 180° so I was curious if you've seen any adverse performance from the higher operating temps of our engine coolant.
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4 or 5 years never a problem
 
Hey Chase. Educate an ignorant old man. I'm missing the point of a pressure relief valve when the radiator cap releases at 16psi? Is it to bleed off pressure before the thermostat opens, maybe?
 
Sounds like this could be for an electric water pump system rather than the mechanical. Correct?
 
Higher than normal RPM will cause the coolant pressure to be too high because the water pump is driven off the belt.
 
BigPapa said:
Hey Chase. Educate an ignorant old man. I'm missing the point of a pressure relief valve when the radiator cap releases at 16psi? Is it to bleed off pressure before the thermostat opens, maybe?
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Think of your thermostat as a orifice. When it opens it can only flow a certain amount of water. The water pressure inside the block @3500 rpms can be anywhere between 80-90 psi. On a MLS gasket that's no problem, but the I ran fire rings and a 24 valve head gasket. Alot of excess water pressure would be like putting a pressure washer that gasket. So I Setup 2 watts 530c reliefs set at 50 psi and dumped them between the tstat and radiator
One relieved out the back of the block at the rear freeze plug and one in the back of the head
If you remember back when me a Joe was dukin it out at dickson fair thats how my truck stayed cool after 3 hooks back to back
jimbo486 said:
Sounds like this could be for an electric water pump system rather than the mechanical. Correct?
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mechanical
smokin247 said:
Higher than normal RPM will cause the coolant pressure to be too high because the water pump is driven off the belt.
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exactly
 
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I knew there was an issue at higher RPMs. Just never knew the pressure could be so high at a fairly low RPM. Good to know!

Hunted and pecked from a Galaxy S4.
 
Good to know. Thanks Chase. Have you ever put a pressure gauge on it?
 
So at what point does this really become necessary? Hot lapping or just whenever?
 
I noticed when I was running just a s-06 and small turbo it was puckering fluid out of radiator cap, so it is needed when you mod and run the chit out of it...
 
It seems to me that's its rpm related. Higher rpms is what spins the water pump above its intended design limits which increases the cooling system pressure which pops "freeze plugs" (mainly at the back of the block). Yeah its also the time your beating on it, but its mainly rpm related. More rpm= more cooling system pressure. So if you install higher governor springs you should install a coolant bypass kit.
 
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