Coolant / Radiator Cap Question...

StephSH · **Posted:** Fri Jun 22, 2007 5:35 pm

Hi Everyone,
My 2002 Limited started occasionally emitting steam from the radiator cap when I'd turn off the engine last summer, took it to my VERY trusty mechanic, and they said they didnt know what caused it; it wasn't overheating or anything that they could tell. I could have told that it wasnt overheating, but ok, off I went. It only did it occasionally, and the engine wasnt running hot, so not a big deal I thought.
Anyway, I took it back this summer, it was starting to do it more often, they tested the radiator cap and replaced the stock one with a 17 psi one that they said they got from a dealer. They said they dont like the ones from Autozone/ Advance because they arent as good. My mechanics really are great, so I didnt question this. I was a little worried about the higher PSI tho....
So today it did it again, great waves of steam coming out of the radiator cap. Jeep engine isnt running hot, isnt doing that running rough thing that engines do when they are running hot, so I am confident the thermostat is fine....Any clues as to what might be causing this? Is the 17 PSI cap ok to have on there or am I going to blow up my engine?? What is making it steam, it's making me nuts....
2002 Liberty Limited 3.7 6 cyl. engine....141400 k miles (mostly highway)
Any thoughts are GREATLY appreciated!!
Steph

Jeepjeepster · **Posted:** Fri Jun 22, 2007 6:21 pm

What is the PSI on the stock cap? I dont even know.

Are you loosing any coolant? If your not, are you sure its coolant that is steaming? Have you actually seen it coming from around the cap?

The drain for the A/C is on the firewall just below that.. Possibility it may have something to do with that..

StephSH · **Posted:** Fri Jun 22, 2007 6:54 pm

Hi,
PSI on the stock cap is 16 PSI, and yes, it's definitely coolant, it has that yummy coolant smell that my '66 Mustang used to have when it was overheating
:-)

Also, I've seen it come out of cap, or rather around the cap and of course it steams when it hits the engine....
I am wondering, is it possible that if I turn the Jeep off when the coolant is getting ready to cycle, that turning it off at just the right time before it can cycle is causing it to do this? Or is that a totally lame thing to even think?
Thanks....
Steph

Jeepjeepster · **Posted:** Fri Jun 22, 2007 7:16 pm

It shouldnt put off steam at anytime.

The coolant tank is also the over flow tank.. There are two tanks in one. Have you had the coolant changed or anything? If to much coolant got into the system some way, it would just come out of the over flow bottle which is normal.

You didnt say if its getting low on coolant..

Cowcatcher · **Posted:** Fri Jun 22, 2007 7:25 pm

Caps do wear out their ability to seal and can leak a little coolant and steam as a result. Years ago auto parts stores has pumps with gauges that you could put the cap on and pump to see if it held proper preasure. Not sure if they still do.

LiLredLibby · **Posted:** Fri Jun 22, 2007 10:37 pm

Sounds to me like your getting combustion in your cooling system.A blown head gasket or cracked head can cause combustion to enter your cooling system and still not be running hot.Where I work I have a tester that you fill with a special blue liquid(Litmous?),hold it over top of your radiator and suck the fumes up into the tester.If the blue liquid turns yellow or green,it's telling you that it smells exhaust in the cooling system.Most good shops can do this test at a fairly resonable cost.Better parts houses sell these testers and come with good instructions.Hope this helps.

Ron

Skipperb · **Posted:** Fri Jun 22, 2007 11:25 pm

I change mine last month. Had it pressure check it was down to 5 psi got a new one at 16 or 18 cant remember now. but I have 137+miles so I was lucky.
I used Prestone 50/50 and it seems to be OK. just not positive about Prestone anymore.

Coolant / Radiator Cap Question...

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