Where to get right rad cap?

[James Morse]

For the '97, I got the RS90 from R.A. It's the wrong one, it's too big. Tried to give it away, nobody wants it.
What's the right one for my engine (preferably Motorcraft)?
Not sure why RA says RS90 fits my engine becaise it doesn't. There must have been variations in the rads. Anyway, if somebody can point me in the right direction, I'll get it.
Shop manual just says 8100 is the rad cap I can't find any other part#.
One on there now is 18 lbs and manual says it should be 16 lbs.
Edit: I gather 8100 just means rad cap, there should be more number/letters in front of it to know the right one.

 

[franklin2]

They call for a rs62 for the 4 cylinder trucks. It looks a little smaller if you look up rs62 on Amazon and then rs90 on Amazon. Don't know if it will fit or not. Do you have the wrong radiator? The Ford Parts site calls for a rs90 also for your truck with a 4.0.

 

[James Morse]

I have replacement radiator but cap came off original radiator. I remember someone else went through this same issue.
It's the '97, dual core radiator. I believe it's the correct radiator, everything fit exactly to it, while that doesn't prove it's right, it sure implies it.
There can be errors in the info.
If truck is manual trans it wouldn't probably be 2 core then maybe RS90 fits that.
RS62 at least the one I found on Amazon is 13 lb and I need 16 lb so I don't think that's it.
@RonD probably knows...

 

[James Morse]

wrong part on the radiator cap... that is the full size one and it won't fit your radiator. (made that mistake about 10 years ago. you want the Gates 31336 cap. it is a direct Motorcraft replacement.

Finally found this in my thread on the rad, when I was listing the parts already ordered. So I'll search that Gates 31336.
Edit: This should be the one. Says 1.1 which is 16 lbs, in atmospheres. I think. Also says 16 lbs in the listing which is correct for me.
Gates 31336 Radiator Cap - Walmart.com
So I pulled the trigger on that one.

 

[97RangerXLT]

Finally found this in my thread on the rad, when I was listing the parts already ordered. So I'll search that Gates 31336.
Edit: This should be the one. Says 1.1 which is 16 lbs, in atmospheres. I think. Also says 16 lbs in the listing which is correct for me.
Gates 31336 Radiator Cap - Walmart.com
So I pulled the trigger on that one.

Yep.. I feel your pain, and still have my full size brand new replacement cap as well lol

AJ

 

[James Morse]

Update - Walmart sent me 2 caps, I only pd for one. Maybe they had some come back, because, one doesn't grab the neck. I measured between the lock tabs and the one that doesn't fit is 40mm and the one that fits is 39mm so that 1mm is the difference. Seems like QC problem. The smaller dimension one does seem to grab firmly. That is the dimension of the one that was on there.
And I noticed that the one on there isn't 18 lbs it's 16 lbs I misread it before. So probably I didn't even need it, just seemed to make sense to replace it when I did the rad.
I'll use the new one just so I know I have a new one (though as Ford says, just because part is new doesn't mean it's good - case in point right here!).
You sure wouldn't want the whole rad cap coming off from a hot engine you would have coolant all over the place not to mention would have to replace liquid before you could go anywhere. But if you push on the spring, it doesn't take a lot, so I think it'd be ok. Meaning, spring would release pressure before there was enough to blow the cap.
Probably could make the smaller dimension one fit by bending slightly, maybe. I think the seal is not made by the actual metal outside part of the cap but by the rubber seals.
So now I have 3 caps, 2 fit, one probably could be made to fit... geesh... that's a lot of crap I went through for probably no upgrade at all. Stuck old cap in tool box for now just in case. Might as well throw a gallon of coolant in there too, I don't think you'd lose more than that if cap came off (a guess). It's not something that's ever happened to me.
My feeling is, if it feels tight and firm and no wiggle, it's probably fine, and if it were going to come off (which I doubt), it'd happen soon.
A lot of time for something totally simple. I suppose I could return the bad one but you can spend excessive time and energy chasing $8.

 

[James Morse]

Here's the deal, the little lock tabs on the bad one, you can see they weren't bent totally to 90 degrees. The one that fit, I bent them just a tiny bit - neck is 1.5" so they need to be just barely over that. You can do it with a pair of needle nose, bending just the tabs not the cap body itself, pretty easy to do. So I can fix the bad one too. Not going to worry about it now, it has a good grab on the plastic neck.
Made in Mexico. And here I thought it was only Chinese stuff that had these problems.
1.5" (neck) is 38.1mm so I make the distance between the tabs about 38.5 or so.
What a difference 1mm can make even on something relatively trivial like this. But it wouldn't be trivial if it came off!