# OEM or aftermarket radiator cap? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet, blazer\ **Created:** [November 23, 2016, 12:10am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626 "2016-11-23T00:10:39Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![tardrex](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@tardrex](https://community.cartalk.com/u/tardrex)\ **Post date:** [November 23, 2016, 12:10am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/1 "2016-11-23T00:10:39Z")
1998 blazer 4.3L I think i need a new radiator cap. The overflow tank is full and overflowing. a couple of days ago i cleaned the overflow tank and then filled it halfway with antifreeze,everyday since then i`ve had to add 1-2 cups of water to the radiator because it was low. I haven`t seen any water on the engine or on the [ground.It](http://ground.It) seemed like the water was just disappearing. Today i checked the overflow tank and now it is completely full is completely full up to the overflow tube [now.at](http://now.at) least now i know where all that water went. anyhow i`m going to get a new cap because i think this one is kaput,i`m leaning towards getting an aftermarket cap.The cap that is on there now doesn`t look like any cap i`ve ever seen i`m not sure how it`s even suppose to work. It`s a thin 1/2 inch thick plain plastic cap with no spring on it. can I get any old aftermarket cap or are aftermarket caps vehicle specific? ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [November 23, 2016, 12:15am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/2 "2016-11-23T00:15:20Z")
If the resivour tank is filling up I do not think the radiator cap is the problem. Easy check when cool remove the radiator cap and see if the radiator is full. A failing radiator cap will in my experience allow fluid to escape via the cap and never make it to the resivour. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 23, 2016, 12:16am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/3 "2016-11-23T00:16:06Z")
When GM built your vehicle, they didn’t make the cooling system pressure cap. It was purchased from a vendor/supplier. So if you buy it from the dealer/parts store, you’re probably getting the same part. One major supplier to the auto industry for pressure caps is Stant. Tester ---
**Author:** ![tardrex](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@tardrex](https://community.cartalk.com/u/tardrex)\ **Post date:** [November 23, 2016, 12:18am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/4 "2016-11-23T00:18:35Z")
no it`s not full, i have to add 1-2 cups of water everyday. i only filled the overflow tank halfway and now it`s full, water is going in to it from the radiator but not going back out to the radiator. ---
**Author:** ![tardrex](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@tardrex](https://community.cartalk.com/u/tardrex)\ **Post date:** [November 23, 2016, 12:24am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/5 "2016-11-23T00:24:08Z")
That`s what i was going to replace the plastic cap with, a metal stant cap. maybe the plastic cap is suppose to have a spring or did have a spring but it doesn`t have one now. This cap has a 15psi pressure release but all the stant ones that the local parts stoer has are 16 psi pressure release, will that be ok? ---
**Author:** ![tardrex](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@tardrex](https://community.cartalk.com/u/tardrex)\ **Post date:** [November 23, 2016, 12:29am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/7 "2016-11-23T00:29:38Z")
The radiator has just a plastic screw on cap too.like i said it doesn`t even a spring on it so i don`t know how it releases pressure, that`s why i want to get a new cap. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 23, 2016, 12:30am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/8 "2016-11-23T00:30:48Z")
It’ll be okay. All 1 PSI will do is just slightly raise the boiling point of the coolant. Tester ---
**Author:** ![tardrex](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@tardrex](https://community.cartalk.com/u/tardrex)\ **Post date:** [November 23, 2016, 12:36am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/9 "2016-11-23T00:36:53Z")
this is what it has now: ![](https://global.discourse-cdn.com/cartalk/original/2X/7/7429a73faebd91690431891bc9995ee6ff05f8d1.jpg) I want to get one of these: ![](https://global.discourse-cdn.com/cartalk/original/2X/7/7323562d0021a245bdf0d3807b1aaebbe5e95deb.jpg) ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [November 23, 2016, 12:39am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/10 "2016-11-23T00:39:55Z")
If it screws onto the radiator, it should work. Tester ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [November 23, 2016, 3:33am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/11 "2016-11-23T03:33:46Z")
Replace it with exactly what came off. Don’t try to force that different cap on it. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [November 23, 2016, 3:47am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/12 "2016-11-23T03:47:03Z")
The cap’s design depends on the dimensions of the place where it screws on. The cap has to match up with those. Especially important is the distance between the top surface (on the Stant photo above, the surface corresonding to the bottom of the red lever to the lower rubber washer.) The spring force acts on that distance, so it has to be correct for it to open & close at the correct psi. And of course the diameter of the sealing surface where that washer seats has to match up so it makes a water-tight seal. Make sure to compare the old cap to the new one, make sure those dimensions match. You don’t show the underside of the black cap, so hard to say if the Stant cap would work or not. Me, I’d only replace it with a cap the parts store had verified was OEM or an an aftermarket OEM equivalent. ---
**Author:** ![cyberbabe](https://avatars.discourse-cdn.com/v4/letter/c/b9e5f3/32.png) [@cyberbabe](https://community.cartalk.com/u/cyberbabe)\ **Post date:** [November 23, 2016, 4:11am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/13 "2016-11-23T04:11:37Z")
Try: [http://www.oreillyauto.com/site/c/search/Radiator/01386/C0331.oap?year=1998&make=Chevrolet&model=Blazer&vi=1314133](http://www.oreillyauto.com/site/c/search/Radiator/01386/C0331.oap?year=1998&make=Chevrolet&model=Blazer&vi=1314133) [www.rockauto.com/](http://www.rockauto.com/) [www.autopartswarehouse.com/](http://www.autopartswarehouse.com/) ---
**Author:** ![bloody\_knuckles](https://avatars.discourse-cdn.com/v4/letter/b/ee7513/32.png) [@bloody\_knuckles](https://community.cartalk.com/u/bloody_knuckles)\ **Post date:** [November 23, 2016, 10:58am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/14 "2016-11-23T10:58:41Z")
Some parts I buy OEM and some I buy aftermarket OEM equivalents. If the price difference is small then I usually buy OEM from the dealer. This is one of those situations. How much more can an OEM radiator cap be than an aftermarket? I found an OEM cap for your vehicle online for less than $12. You have spent a lot of time on this to save maybe $6. Time is money. You’ve already lost. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [November 23, 2016, 2:33pm UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/15 "2016-11-23T14:33:55Z")
Its a Chevrolet arent they basically disposable cars? drive em till they stop running then throw them away,no maintanence required. 👿 ---
**Author:** ![monkarl](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@monkarl](https://community.cartalk.com/u/monkarl)\ **Post date:** [November 24, 2016, 3:20am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/16 "2016-11-24T03:20:09Z")
Another vote on Stant cap particularly their lever vent radiator cap. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [November 24, 2016, 6:17am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/17 "2016-11-24T06:17:02Z")
I don’t think those 2 cap types you show in the picture will interchange on any type of vehicle. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [November 24, 2016, 2:43pm UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/18 "2016-11-24T14:43:40Z")
> [@circuitsmith](#): > > Its a Chevrolet arent they basically disposable cars? drive em till they stop running then throw them away,no maintanence required Touche! As the old saying goes, _Turnabout is fair play_… 🕶 ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [November 24, 2016, 2:58pm UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/19 "2016-11-24T14:58:29Z")
> [@tardrex](#): > > I want to get one of these: Why ? It seems that when replacing parts you should get what came on the vehicle to start with. The people who made the vehicle just might know what works. ---
**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\ **Post date:** [November 25, 2016, 5:27am UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/20 "2016-11-25T05:27:12Z")
> [@circuitsmith](#): > > Its a Chevrolet arent they basically disposable cars? drive em till they stop running then throw them away,no maintanence required. A radiator cap is not as serious as an engine replacement. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [November 25, 2016, 7:57pm UTC](https://community.cartalk.com/t/oem-or-aftermarket-radiator-cap/96626/21 "2016-11-25T19:57:38Z")
> [@Engine replaced on a 2007 Kia Optima, check engine light still on](https://community.cartalk.com/t/engine-replaced-on-a-2007-kia-optima-check-engine-light-still-on/96625/4): > > Its a KIA arent they basically disposable cars? drive em till they stop running then throw them away,no maintanence required.