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Noticed I wasn't building any pressure in the cooling system (engine totally hot, I can whip the surge tank cap off!).

So, picked up a new cap (Delco #RC87). Funny thing though... they must have changed the design over the last dozen years.

Here's the bottoms of them (new on the left) :


Tops still look the same though (except it now calls for an 18 vs 15 psi!) :


(colors are really the same, it was just the angle)

Anyone else run into that?

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Your original (15 PSI) cap is damaged. Compare your cap to the picture of my factory-installed 1998 Seville 15 PSI cap. Your cap has some pieces missing which probably explains why you were not seeing a pressure release with the engine at normal operating temperature. But I would be wondering where the missing pieces are located??

Yes the cap was redesigned and I would "guess" that happened in 2000. Your new (18 PSI) cap might have the ratchet lock feature similar to the gas cap??

As for the difference between 15 and 18 PSI, that is the MAXIMUM pressure allowed in the cooling system; when the rated cap pressure value is exceeded, the cap relieves the excess pressure. And unless you are pulling a loaded trailer across the Mojave at 3:00 PM on an August day at 80+ MPH, you will never see that MAXIMUM pressure value in your cooling system. There is no practical way to know what the operating pressure is in any event.

Happy motoring!!!



Drive your car.

Use your cell phone.


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