Radiator cap, which one?

flingshot

NAXJA Forum User
I looked around a bit and couldn't find this info so sorry if this a repost.
On top of that I loaned out my manual and might not get it back.:flamemad:

I noticed a little steam coming out of my grill on the driver's side (very little) the other day and I have tried to make it do it again while the hood is open but so far it hasn't.

I thought maybe as a precaution I would get a new cap. The one on there was a 16 and very old so I went to the parts store and the one they show for it in the computer is a 13. I bought the 13 and installed it.
This AM, same little wisp of steam comes out. I've been trying again to see where it's at but it won't do it while I'm watching with the hood up.

BTW
94 XJ 4.0 HO
Not running hot
fluid looks a little on the brown side in the overflow bottle but nice and green in the radiator.????
Heater works great.
Occasionally I smell antifreeze very faintly.

Thanks in advance for the help.
 
There are 7 caps listed on rockauto.com, 6 of which are rated 13 psi (SAE 12-16 psi), and one is rated 15 psi w/o SAE rating.

I would say the cap is right.

Rent a pressure tester, pump it up about 18-20 psi and check it then.
 
I run an 18lb cap. At a certain point the extra pressure could cause a leak. But I run everything with premium gaskets and tight, so I like the extra pressure. All it does is allow the coolant to absorb more heat before hitting the boiling point.
 
you need a 16 lbs cap. Autozone has one for $7 that I have that works great. it has the red release lever on the top of it.

I had one of those and caused nothing but trouble. I thought the idea of the little lever would be great to release pressure while it's hot if I ever need to. I trashed it and got one from the dealer and never had a problem since.
 
I have tried 13 to 18 lb caps over the years on various vehicles. I only use 16 lb lever caps now. The lever is a safety item, to relieve pressure first if and when you intent to remove the cap. I would not use anything less than 16 lbs, unless I lived way up north maybe. If I lived in high altitude I might go to 18 lbs.
 
The manual says 16 lb cap.

Nobody around here has them. The dealer thinks I need a 13 pound cap.
I installed a 13 pound cap, it has worked fine all summer.
 
The manual says 16 lb cap.

Nobody around here has them. The dealer thinks I need a 13 pound cap.
I installed a 13 pound cap, it has worked fine all summer.

any local auto parts store Will have them. If they give you a hard time about the 16lb cap, just follow them out onto the parts floor, and when they reach for and hand you the 13lb cap, just look for a 16lb cap that is the same size and shape. For the jeep type cap there is one shape and about 5 different pressures you could get. 16lb is one of them.
 
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