i'm in a mountain campground. itasca sun cruiser overheated on trip up here;lost a little coolant. Days later, can't remove the radiator cap.tried using a channel lock pliers;no joy. concerned about putting too much torque on it;might break the plastic filler tube. Anyone got the secret to getting this Workhorse radiator cap off?

Try pressing down hard and I mean really hard when unscrewing the cap.

Yes, you must press before turning!

It is like not moving at all or moves a bit then stops?I had one failed on a Blazer and the guy at NAPA finally got it off but had to bust off the plastic grip on the cap and bend back some of the metal on the cap that got bent/deformed the last time it was put back on the radiator.Never had that happen before in my life.Best of luck and let us know how it goes.If a big block gets hot you have an issue to address. In the order of the cap, thermostat, fan clutch then the radiator (blockage external between AC condenser and the radiator or internal blockage or cool fin separation) is my approach. After 10+ years most radiators could benefit from being recored if copper/brass.

Thanks for the replies. One problem is it is difficult to get a grip on the cap due to big air intake tube resting against it. So a marine mechanic here at the camp used a large channel lock on it and did not budge. Not sure if we pushed down hard enough due to the air tube mentioned above. But, on my toad , a '12 grand Cherokee, the cap turns half way then you push down and turn the rest of the way.looks like i need to remove the air tube (and buy my own large channel lock); other choice is just drive it down the mountain cause i don'tthink i lost much coolant. Was pulling the 5000 lb jeep up highway18 from Barstow to Big Bear ca. When it over heated i unhooked the jeep and drove the rest of the way without trouble. looked like about a pint of coolant on the ground.

There are only a couple of screws holding the tuba on. I had to remove it to get my radiator cap off. Still had to push down pretty darn hard as I turned it.

workhorse 8.1 radiator cap | Good Sam Community

wcorkey
Explorer
Sep 23, 2013
Thought i would update this since there were so many helpful suggestions to my dilemma. Been home about a week now. today, took off the air intake tube to get better access to the rad cap. Used a channel lock plies (had tried that before) and pushed down on the cap with a 1X3 board(had not tried before). Had to kind of wiggle the pliers as i turned it and dam if it didn't turn all the way and come off. Coolant was about a half gallon low. So i think there is a slight leak as i noticed previously.
So before next trip will drain and flush and pressure check.
Thanks again for the interest and suggestions.
Gale_Hawkins
Explorer
Jul 26, 2013
Good point on it could be sucking air somewhere.

Clearly the cap is going to come off one way or the other.

WH dealers may be few in a mountain campground in NV based on our experience in 2011 but it was beautiful near Elko. :)
mikim
Explorer
Jul 26, 2013
it was a pita to remove my radiator cap.
make sure the engine is cold.
i turned it as far as i could by hand then used a large channel lock plier to turn it while pushing down on the cap with a 2x4. my dw exercised the pliers while i pushed down with the 2x4.

I got this from a quick search on Google from IRV2 web site.

You need to make sure that the engine is cool.
MEXICOWANDERER
Explorer
Jul 26, 2013
Beware of home brew remedies. Engines can have hot (under pressure) leaks and then cold leaks (ambient pressure). A tiny suction leak (air) between radiator and water pump can cause the most hysterical, impossible to diagnose overheating symptoms you can imagine.

I am going to recommend yet another path to try...

The dealer. The manufacturer of the chassis. Surely the Parts Department counter guy has run into this and knows the best way to resolve it.

My next trip to the states I am going to buy a STANT cooling system pressure tester kit. It would have found my nightmare suction leak in a few minutes.
Gale_Hawkins
Explorer
Jul 26, 2013
wcorkey wrote:
wilanddij wrote:
Can't you add coolant by pouring it into the overflow bottle when the engine is hot and it will get sucked into the system when the engine cools? Maybe an option till you can get it serviced.

Did not seem to work;
over filled the overflow bottle, idled engine til hot, off and let cool,
no detectable loss in overflow bottle.

Then perhaps the radiator is quite low OR the cap has failed as a two way valve and will let it out but not suck it back from the over flow bottle. I thought by the 8.1 era they had moved to the pressurized filler tanks?

You may have to saw it up into smaller pieces making sure you do not saw into the radiator neck itself.
wcorkey
Explorer
Jul 26, 2013
wilanddij wrote:
Can't you add coolant by pouring it into the overflow bottle when the engine is hot and it will get sucked into the system when the engine cools? Maybe an option till you can get it serviced.

Did not seem to work;
over filled the overflow bottle, idled engine til hot, off and let cool,
no detectable loss in overflow bottle.
wilanddij
Explorer
Jul 26, 2013
Can't you add coolant by pouring it into the overflow bottle when the engine is hot and it will get sucked into the system when the engine cools? Maybe an option till you can get it serviced.
wcorkey
Explorer
Jul 26, 2013
K Charles wrote:
GM cap wrench

Item description says it is for GM plastic radiator caps;not familiar with them but my engine has a conventional metal cap.
K_Charles
Explorer
Jul 23, 2013
GM cap wrench
Clay_L
Explorer
Jul 23, 2013
There are only a couple of screws holding the tuba on. I had to remove it to get my radiator cap off. Still had to push down pretty darn hard as I turned it.