Radiator cap?

Help Support SkidSteer Forum:

cchardwick

Well-known member
Joined
Jan 25, 2007
Messages
52
I have a Case 1737 Uniloader skid steer and I think the radiator cap is bad. When it gets hot I get a bunch of antifreeze coming out of the overflow by the cap and the spring on the plunger of the cap seems real weak. I called a local Case dealer and he said he can't get parts for my skid steer because its so old (made in the mid 70s). I tried the Case website but you need a model number to go from when searching parts and it won't recognize my model number. I tried a regular radiator cap from Checkers and it fits good but the plunger doesn't go down far enough to seal. It seems like this is a non-typical radiator cap. Anyone know where I can get a replacement cap or how to fix the cap I have?
 

cchardwick

Well-known member
Joined
Jan 25, 2007
Messages
52
Ive had good luck at NAPA Jeff
This is weird, I went to NAPA and they didn't have one long enough. I called another CASE dealer and they said they had one so they shipped it and wouldn't you know it, it wasn't deep enough to seal the radiator. Not sure what is going on here. I did manage to 'rig' the old cap. I took the cap from NAPA (that wasn't deep enough) and took it apart with a hammer / chisel / vice and took the spring out. Then I stretched out the spring making it wider around and pulled the ends out a bit. Then I was able to put the 'rigged' spring in the old cap. Looks like it worked good, I'll find out soon enough as soon as I get some more parts that I ordered and put my skid steer back together again. I'm going to call the dealer again tomorrow to see if he gave me the right cap. This is such a weird problem....
 

Tazza

Administrator
Staff member
Admin
Joined
Dec 7, 2004
Messages
16,697
This is weird, I went to NAPA and they didn't have one long enough. I called another CASE dealer and they said they had one so they shipped it and wouldn't you know it, it wasn't deep enough to seal the radiator. Not sure what is going on here. I did manage to 'rig' the old cap. I took the cap from NAPA (that wasn't deep enough) and took it apart with a hammer / chisel / vice and took the spring out. Then I stretched out the spring making it wider around and pulled the ends out a bit. Then I was able to put the 'rigged' spring in the old cap. Looks like it worked good, I'll find out soon enough as soon as I get some more parts that I ordered and put my skid steer back together again. I'm going to call the dealer again tomorrow to see if he gave me the right cap. This is such a weird problem....
The only problem with what you have done is you will have changed the opening pressure of the cap as you stretched the spring. If its too high you risk blowing the radiator out or possibly a radiator hose.
Good luck finding the correct one
 

cchardwick

Well-known member
Joined
Jan 25, 2007
Messages
52
The only problem with what you have done is you will have changed the opening pressure of the cap as you stretched the spring. If its too high you risk blowing the radiator out or possibly a radiator hose.
Good luck finding the correct one
I thought about that, but that will only happen if the radiator overheats. I used a 16 pound spring and stretched it out so I'm assuming it's now probably over 20 pounds, the max for a radiator cap. The original cap was a seven pound cap. I'm still searching for a replacement cap but want to get it ready to drive for the next snow storm and can't wait around for a cap. Hopefully this is a short term fix.
 

Tazza

Administrator
Staff member
Admin
Joined
Dec 7, 2004
Messages
16,697
I thought about that, but that will only happen if the radiator overheats. I used a 16 pound spring and stretched it out so I'm assuming it's now probably over 20 pounds, the max for a radiator cap. The original cap was a seven pound cap. I'm still searching for a replacement cap but want to get it ready to drive for the next snow storm and can't wait around for a cap. Hopefully this is a short term fix.
Unfortunatly thats not how it works. As the water heats up it expands, when this happens the radiator cap allows the extra coolant flow to the overflow tank. When the system cools off the water shrinks and draws coolant back from the overflow tank.
If the origonal cap was 7lb you really should have stuck with 7lb not 16.... Like i said you *may* damage the radiator running it at a higher pressure than it was built for.
Just be carefull, you don't want to kill the radiator
 

cchardwick

Well-known member
Joined
Jan 25, 2007
Messages
52
Unfortunatly thats not how it works. As the water heats up it expands, when this happens the radiator cap allows the extra coolant flow to the overflow tank. When the system cools off the water shrinks and draws coolant back from the overflow tank.
If the origonal cap was 7lb you really should have stuck with 7lb not 16.... Like i said you *may* damage the radiator running it at a higher pressure than it was built for.
Just be carefull, you don't want to kill the radiator
Um...... I don't have an overflow tank. Just an overflow tube that drains on the ground.
 

cchardwick

Well-known member
Joined
Jan 25, 2007
Messages
52
Um...... I don't have an overflow tank. Just an overflow tube that drains on the ground.
Hey, I was just thinking, if I put on a real strong radiator cap that has been rigged to deliver a higher pressure, is there a possibility that I can blow a head gasket? That would really be a bummer.
 

skidsteer.ca

Well-known member
Joined
Jan 20, 2006
Messages
3,853
Hey, I was just thinking, if I put on a real strong radiator cap that has been rigged to deliver a higher pressure, is there a possibility that I can blow a head gasket? That would really be a bummer.
I know we had a JD 540 c skidder that had a std diameter cap with a real long spring. Rad had a tall neck @ 1/1/2”, if you have no luck elsewhere you may want to check with deere on there selection.
Ken
 

Tazza

Administrator
Staff member
Admin
Joined
Dec 7, 2004
Messages
16,697
I know we had a JD 540 c skidder that had a std diameter cap with a real long spring. Rad had a tall neck @ 1/1/2”, if you have no luck elsewhere you may want to check with deere on there selection.
Ken
I got ya, its not a recovery system.
The pressure generated in the cooling system is WAY lower than compression pressure. That will never blow a head gasket.. Starting compression on a diesel is up to 450 PSI then when running it will be a lot higher. Compare that to the 20 or so PSI of coolant pressure.
 
Top