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Discussion Starter #1
With all the coolant leak problems I've been having with my V6 one thing my son noticed is the car came with an aftermarket Preston coolant filler tube cap rated at 15psi.
Researching online I found the apparent correct cap is an AC Delco cap rated with a rating of 18psi.
Is this difference in psi enough to have caused any problems?
Am I still in the ballpark running the lesser 15psi cap or should I swap to the greater 18psi cap?
 

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Interesting ------ They show that all models of the G8 use the same cap (# 92205634), an even Amazon sells it. There descriptive wording of that cap says 15psi, but the close up pic of same, shows 8 psi painted on it. So the confusion continues.


My car has just returned, so I decided to have a look at it. So now I can add even more confusion to this. My cap is stamped with the info of 140kpa, an 20 psi. an is the original oem part that came on the car. So it *may* have yet another P/N assigned to it.
 

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Discussion Starter #3
Looked on ebay, the AC Delco they show says 18psi and uses part #92205634.
Wonder if the Amazon pic is just a bad photo but sill the confusion continues.
May just pick one up out of curiousity to see if it may help.
Thank you for your help.
 

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Discussion Starter #4
Interesting ------ They show that all models of the G8 use the same cap (# 92205634), an even Amazon sells it. There descriptive wording of that cap says 15psi, but the close up pic of same, shows 8 psi painted on it. So the confusion continues.


My car has just returned, so I decided to have a look at it. So now I can add even more confusion to this. My cap is stamped with the info of 140kpa, an 20 psi. an is the original oem part that came on the car. So it *may* have yet another P/N assigned to it.
Wondering out loud if it is the difference in climates between California and Ontario that would contribute to yours being 20 psi and mine being 15 or 18 psi.
 

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OK ---- I kept on looking (since this is very interesting). Asked the computer to show 20 psi caps. An son of a gun, Summit shows the 20psi GM part with a P/N of 13502509. An that it fits a ton of GM cars including ALL of the G8 models. Then I tried Amazon, an they sell it also using either P/N 13502509 or as AC Delco # RC115 for about $10


Added---- I'm thinking that when the 09.5 (or MY) cars started coming down the assembly line (all the cars from that point), had the superseded radiator cap #13502509 installed (along with all the other changes specified) on the remaining cars still coming down the line. Also my 2011GMC truck uses that cap, an it shows that the temp runs at 210 deg F (I assume by design)
 

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Aftermarket coolant caps and thermostats are hit-n-miss contingent on both the manufacturer of the vehicle and the replacement part. Can't say whether the 3psi difference between the two radiator caps warrant replacing, however, am more concerned about its ability to hold and release pressure as intended. As stated, the correct part number for the G8 V6 is 92205634.
 

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Discussion Starter #7
Agreed, I stay away from after market parts as much as possible.
Amazon up here doesn't stock this, off to the dealer....
 

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OK ---- I kept on looking (since this is very interesting). Asked the computer to show 20 psi caps. An son of a gun, Summit shows the 20psi GM part with a P/N of 13502509. An that it fits a ton of GM cars including ALL of the G8 models. Then I tried Amazon, an they sell it also using either P/N 13502509 or as AC Delco # RC115 for about $10


Added---- I'm thinking that when the 09.5 (or MY) cars started coming down the assembly line (all the cars from that point), had the superseded radiator cap #13502509 installed (along with all the other changes specified) on the remaining cars still coming down the line. Also my 2011GMC truck uses that cap, an it shows that the temp runs at 210 deg F (I assume by design)
I replaced mine with this cap back in March.

To the OP, pull your existing cap off and see what the part number is on the rubber ring under the cap. Mine listed 13502509.

As GOPHERIT stated, P/N 13502509 is for the MY9.5 break-point.
 
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