Cap for Jeep closed system plastic bottle

dealer. Wouldn't hold pressure, returned it, >new one wouldn't hold pressure either, put old one back on. >I can't believe dealer would have two bad ones. Any clues? >Dealer not helpful, sympathetic, or intellectually curious! I'm >wondering if I was given an "Open System" cap, although it >certainly wasn't just a plain plastic cap.

a tiny oval ridge centered where the cap gasket >contacts.

(yes, I know now). Found the old one was >really badly corroded, obviously bad. After replacement >still had overheating - big time. Found system was very full >of air (native repair shop didn't know about this important >Jeep cooling pecularity); am still bleeding it (run, cool, fill); >overheating now under control. However, I live on a hilly >tropical island (up to

1500', steep) and it is obvious the >cooling system is marginal in this environment - heater is >bypassed for obvious environmental reasons. No surprise >that the cooling system is marginal from what I read in many

idle, but climbing the many hills gives me a little >over 2300 - or more. I really hate running that hot! Know all >the cures (radiator, open system, fan, etc,), thanx to this >group. But, I'm looking for an inexpensive workaround, even >if it's tacky -- kinda 3rd world here, 1000+ miles SE of

oil, still looks good - a little faded elegance!

I experienced much the same thing that you did with my '87 Cherokee. After diagnosing, swearing, diagnosing, swearing, ad naseum, I bought the bullet and threw a 3-row 1989 radiator (open system) in it. At the same time, I replaced the water pump (much easier with the radiator out), the thermostat, the hoses, and the fan clutch. My JEEP runs so cool now, it's amazing.

I still haven't converted the heater control valve, so I have no heater, but I really don't need it in Californication. Obviously, you've already bypassed yours, so you don't even need to worry about that.

Bite the bullet and do it right. If you motor's as tight as you say it is, you don't want to risk over heating and warping the head!

Larry

First off, the temperature gauge is notoriously inaccurate in Jeeps in general.

Second are you running a 50/50 mix of antifreeze? Antifreeze mixed

50/50 ups the boiling point to 265 F.

Running at 220 or 230 is ok really. There should be no issues there.

You do need a good cap on that stupid bottle though. One that holds about 16 psi I believe.

I also have seen bottles with a dent in the rim. That sounds like it would mate up to your cap with a bump under the gasket and make a positive or 'click' fit on the cap???

Maybe they made a couple designs of bottles and cap sets?

A cold t-stat isn't really an issue in a warm climate, it just sets the minimum temp the engine will run at. Here in Canada we want a 195 at least so the engine will at least get up to that so we have heat inside. We would freeze with a 160 in.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Charmen wrote:

Thank you both for your comments/suggestions/advice.  To paraphrase an old-time now-deceased politician: "In my heart I know you are right." Islander.

It sounds to me like you have a bad water pump. It is either spinning backwards (v-belt and serpentine belt types spin in opposite directions, and the pulley will fit either type), or the impeller is rotted away and does not pump anymore. You will notice "normal" temps at speed, but higher temps under load or going slow. You will also notice more normal temps at night when it is cool out, and higher temps during the day. If you heater was connected, you would notice that even though you had high temps, the heater would blow cold (relatively) air.

I don't think there is any such thing as an open system cap any more.

dealer. Wouldn't hold pressure, returned it, new one wouldn't hold pressure either, put old one back on. I can't believe dealer would have two bad ones. Any clues? Dealer not helpful, sympathetic, or intellectually curious! I'm wondering if I was given an "Open System" cap, although it certainly wasn't just a plain plastic cap.

a tiny oval ridge centered where the cap gasket contacts.

(yes, I know now). Found the old one was really badly corroded, obviously bad. After replacement still had overheating - big time. Found system was very full of air (native repair shop didn't know about this important Jeep cooling pecularity); am still bleeding it (run, cool, fill); overheating now under control. However, I live on a hilly tropical island (up to 1500', steep) and it is obvious the cooling system is marginal in this environment - heater is bypassed for obvious environmental reasons. No surprise that the cooling system is marginal from what I read in many posts in this group. On flat ground I'm OK - runs at 1600 except at idle, but climbing the many hills gives me a little over 2300 - or more. I really hate running that hot! Know all the cures (radiator, open system, fan, etc,), thanx to this group. But, I'm looking for an inexpensive workaround, even if it's tacky -- kinda 3rd world here, 1000+ miles SE of Miami, FL, USA.

oil, still looks good - a little faded elegance!