Radiator Cap question

[WFarm]

My existing radiator cap seal is worn and weeps at pressure. It is an AC Delco RC-36 cap. All the replacements I find are RC-27 caps. Anybody know what cap originally came on a 1987 Sierra Classic 350tbi? Is there any difference between the 36 and 27 caps? Both are 15 psi.

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[MarineOne]

The OE radiator cap is the AC Delco RC36 (GM 6410785) An AC Delco RC27 radiator cap is the GM service replacement starting about 1995. The current version of the redesigned RC27 radiator cap was released by AC Delco in 2009.

 

[WFarm]

Thank you MarineOne!