Where to find a 10 psi radiator cap?

[Cressida]

I want a 10 psi radiator cap for our 1993 Oldsmobile Ciera. A few decades ago you would go to the parts store and ask for such and buy it. It doesn't work that way today.

Now I go to an O'reilly's and they entered my car info into their computer and it showed a handful of 16 psi caps and they bring me out one and tell me this is the cap for the car. Of course I look at the cap and see the 16 psi and tell them that is the current cap on the car but not the cap that I want. I want that same size (dimension) cap but with 10 psi rating; so the three employees get together and tell me they don't stock any caps like that. I figure AZ will be the same story and I've had no luck during the past week searching RockAuto or Amazon either.

Anyone know how to find a part # or what description to tell these parts store people to find me a 10 psi cap for a 1990's GM car?

 

[AdmiralYoda]

So I went to RockAuto for you and indeed the OEM cap is 16psi. Motorad lists their 16psi version as T16V....for 16psi. Guess what happened when I went to google and searched "Motorad T10V"?????

Rockauto has it. Link here.

And also...you have to be smarter than the parts store computer. If you search "Autozone 10 psi radiator cap" or "Advance Auto 10 psi radiator cap"...you'll see that they have them available, maybe not in store but they exist in their system.

But out of curiosity...why do you want a 10psi cap?

 

[CheezWhiz]

I would look right between the 9 PSI radiator caps and the 11 PSI radiator caps.

 

[Rand]

Anyone know how to find a part # or what description to tell these parts store people to find me a 10 psi cap for a 1990's GM car?

Why would you want to reduce your protection from overheating?

 

[Chris142]

Why would you want to reduce your protection from overheating?

Weak parts in the system. Plus who is going to let an engine get that hot?none of us. stant #10377 .stant 7 lb is much more common.. #10228

 

[daniel327]

I want a 10 psi radiator cap....................

Have you tried searching for a 0.7 bar or 7 kPa radiator cap? This returned a lot of results when I just tried it.

 

[Cressida]

I appreciate the suggestions above, but no you cannot just search "Autozone 10 psi radiator cap". In fact I did just that last week and made a purchase of a Gates cap which appears to be the same as the AZ linked Duralast Heavy Duty Radiator Cap 1006-10. That cap is designed for a much larger radiator opening (think large diesel engines) and much to large to fit.

Likewise, the MOTORAD T10 shows a depth of 1.4". The stock cap for this vehicle is around 0.75" in depth so I suspect that may be too tall of a cap. Radiator necks and openings vary so that is why it has been difficult to find a cap so far.

I had not tried searching for the 0.7 bar so will try more of that. On first pass the results are looking like the smaller caps used by Toyota and other Asian makes so they will not fit either. Never thought I'd spend over a week trying to find a radiator cap.

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[zzyzzx]

Are Motorad caps as bad as their thermostats?

 

[zzyzzx]

According to Google AI:

No, generally speaking, Motorad radiator caps are not considered to be as problematic as their thermostats, with most users reporting better quality and reliability from Motorad caps compared to their thermostats; however, it's important to always check the quality of any individual part before purchase and to consider the specific complaints associated with each product line.

 

[JHZR2]

Weak parts in the system. Plus who is going to let an engine get that hot?none of us. stant #10377 .stant 7 lb is much more common.. #10228

It makes sense until it doesn’t. An underperforming cooling system will then get hit, build pressure, and leak out the weaker cap until it has a lot of gaseous headspace and overheats. I like the idea of lower peak pressure in the system though.

 

[JimPghPA]

Summit Racing. If it exists they probably have it, or can tell you who does.

 

[Tman220]

I like the idea of lower peak pressure in the system though.

Why though? Trying to prolong the life of a weak radiator or heater core?

Part of the reason for pressurized cooling systems is not only for the higher overall boiling point of the coolant but more importantly is to help prevent localized hot spots from boiling and creating voids in the system, usually this would be in/around the heads. Even though coolant might be exiting the block at 190 degrees it doesn't necessarily mean there isn't some spot in the block or heads where flow isn't as quick and has the potential for localized boiling.

Higher pressure will also help prevent cavitation or aeration on the suction side of the water pump where a lack of at least atmospheric pressure will lower the boiling point of the coolant in the system.

 

[zzyzzx]

Why though? Trying to prolong the life of a weak radiator or heater core?

Yes, I've done it, and it worked fine.

 

[JHZR2]

Why though? Trying to prolong the life of a weak radiator or heater core?

Part of the reason for pressurized cooling systems is not only for the higher overall boiling point of the coolant but more importantly is to help prevent localized hot spots from boiling and creating voids in the system, usually this would be in/around the heads. Even though coolant might be exiting the block at 190 degrees it doesn't necessarily mean there isn't some spot in the block or heads where flow isn't as quick and has the potential for localized boiling.

Higher pressure will also help prevent cavitation or aeration on the suction side of the water pump where a lack of at least atmospheric pressure will lower the boiling point of the coolant in the system.

Yes. In some cases. In some scenarios.

And I’m not saying to put it to ambient. I’m saying a slightly lower pressure. Time at heat and pressure weakens stuff. Sure, you could argue that if it’s weak it should be replaced. And you should argue that keeping cavitation and boiling in specific locations is essential. Question really is, how much is enough for that?