Pettit AST radiator cap part number?
 

just blew my cap (i hope) after only a couple months of use, its a 13lb kpa90,

but does anyone have the part number so i can pick up a replacement from pep boys on my way home tonight???

radiator caps are pretty similar. They come in a handful of sizes and shapes and a handful of pressures. Just take the cap into a parts shop and they should be able to find a similar one. (dont remove it if it's HOT!)

LOL im no rotary mechanic, but i know all that, just like I dont put the cat in the microwave to dry it off... :lol2:

the rx is now at home (dropped of at lunch, thought i wrote down part number but was pressure rating),

and I kinda wanted to pick up the cap on the way home, rather than go home then back-track to the store....

Anybody got the part number off the top of thier head or close bye?

bump?> anyone before i make an extra 15mi trip? yeah, im that lazy...

Mine says Stant 10329 its 13lb, hope this helps you.

thanks much!! caught your reply on my BBerry about 2 minutes before the exit for the auto parts store, god this thing is handi sometimes, and so are you guys!! lol

Cap Replacements for Pettit AST
 

As I was refreshing the coolant, I noticed the aluminum AST unmarked was a Pettit AST.

So far, no issues except PO had a 16lb cap and SGTBLUE was kind enough to point out wrong pressure cap 16lb.

I found a few posts that indicated the Stant Lev-R-Vent 10329. However, it wasn't as easy to find a cap without safety lever.

This is what I found works for those that still have a Pettit AST and need a replacement:

1) Gates 31527 (better built) without lever cap at independent auto parts store

2) Motorad T-13 without lever cap = BK 7031697 Napa = Murray 7013 Oreilly = Duralast 7013 Autozone. Yes, they were ALL Motorad caps and seemed made of lower gauge metal and spring than Gates. I bought the Gates.

3) Motorad ST-13 with pressure release lever cap

4) Stant Lev-R-Vent 10329 with pressure release lever

5) Prestone RSP-29 with lever cap only found on eBay

Stant 10229 WITHOUT pressure release lever = https://www.rockauto.com/en/moreinfo...=48502&jsn=560

FYI, the Pettit AST is made of flimsy aluminum. The top will eventually warp or lose its shape. At that point it will not seal regardless of what cap you put on it. It is not a good product.

What AST do you recommend?

2 comments
 

I installed my Pettit AST in Dec 2004. It's still working fine. Of course, I have a 13-psi radiator cap and the Miata fan control, so there is less pressure and temperature to warp it.

Also, the lever type caps tend to move the sealing gasket off center if you use the lever to release pressure, so then it doesn't seal properly when you close it again. If you are careful, you can overcome this, but I'd recommend a no-lever cap.

I like the Tri Point AST. I dont know if they are still selling them.

Tri-Point Engineering

There are some other vendors that make a good product too.