How Hot Do 440 Invaders Run?

[quadgoat]

Hi Everyone!
           I haven't been on here for quite a while, surprised and saddened me to see we lost the old forum, but these things happen I guess.

Anyway I have a '79 Invader 440 in nice shape that I bought a couple winters ago knowing it had a coolant leak when I bought it. I rode it some before the leak got bad enough I didn't dare to ride it anymore. It turned out that the water pump was leaking. I bought a used one and put it on, but that one leaked too. I ended up sending one of my pumps out to a place called The Flying Dutchman and he did a great job rebuilding it for me.

I got everything back together (yes, I did the crank seals while I had the engine out, although the ones in there didn't seem to be dried out - someone had been in the engine before me I'd say) and then we never had enough snow last winter to bother trying to run the sled. It sat in the garage all summer and didn't leak a drop of coolant. Fast forward to today, with a foot and a half or so of fresh powder on the ground I decided to put some fuel in the old girl and try her out. The sled fired up easily and ran great, just as it did last time I had it running. After about 10 minutes or so of riding around the yard the temperature gauge was showing about 190-200 degrees (top of the "green", starting into the "yellow" area of the gauge) After another 5-10 minutes it started creeping up toward 220 or so and it didn't seem to matter if I got in deep powder and kicked snow up on the heat exchanger or not. It just didn't seem like it was going to cool back down.

I shut it down for a few minutes and put some snow on the radiator. When I fired it back up the temperature gauge dropped right down to 160-180 and I rode it another 10 minutes or so until it crept back up to 220ish.

Is it normal for these sleds to run hot like this? Would I most likely not see the temperature come up as high if I was actually trail riding rather than bombing around the yard?

I'm just trying to get a feel for whether or not I still have a problem, or if it's just "par for the course" with an old liquid cooled sled.

Thanks very much in advance for any and all help/advice!

-Paul

P.S. What pressure should the radiator cap be on this sled? It has a Stant cap on it right now rated at 7 PSI. When it gets up to 220 or so it starts pushing coolant out the overflow tube...

[Checkmarks]

Paul,

I suspect your thermostat caused some problems but only until it cracks open from sitting for a duration.  Maybe.  Then you may not be riding fast enough to get air through your radiator.  If you have no windshield, that's a problem.  The windshield creates a low pressure system to draw air through the radiator directly.

Whoo Hooing and being slightly scared ripping around the sled should run in the green.  Driving slow enough to tow a six year old on a toboggan and you head for the yellow and red zone soon.   

[quadgoat]

I do have a windshield, it is in nice shape, but has sagged some so it touches the hood where it says "440 Invader" underneath the windshield. I imagine it should still do the job for creating a low pressure area despite that though, shouldn't it?

I didn't even watch my speedometer but I doubt if I ever got over 15 MPH around the yard. Maybe 20-25 for quick bursts through my small field, but pretty slow going overall.

I thought about the thermostat when I had everything apart, but didn't know of a good source for a replacement right off at the time, so I didn't replace it. Is there any sort of source for new thermostats for these beasts?

Thanks for the reply!!

-Paul

[bryan_damone]

I think someone on the old forum said that they brought their thermostat to NAPA and found a match. Don't recall the details. You can also test your current thermostat in a pot of water on the stove. You can check if it opens and at which temperature with a thermometer.

[jimvw57]

could be you got an air bubble in the cooling system. you used the bleeder on the top of the thermostat housing right?? Maybe get the front end up in the air to fill the tunnel cooler and make sure it is clean inside the tunnel, not caked with mud or ??

[quadgoat]

Good idea on checking with Napa. I work at an automotive repair shop and we do a ton of business with Napa. I'll check into it. If I find a match I'll post up a part number too!. I did fill the system with the bleeder open and have topped off the coolant a couple times since I first ran it. There could still be an air bubble certainly, but it doesn't act quite like that. The temperature doesn't suddenly peg, it just slowly climbs as the sled is being ridden, and never drops until you shut it off and let it cool for a bit. The tunnel and heat exchangers are very clean. I will try running it some more with the bleeder out though, just to be sure there isn't any air trapped.

-Paul

[mswyka]

Paul, my 440, when it runs tends to reach 200 or 220 with little effort.  Speed and pointing into the wind seem to be the only things that keep it cool.  I have a NAPA radiator cap number at home if you need it.  If you find you have a thermostat problem we probably have one of those too.

[quadgoat]

Thanks Mark, That sounds pretty similar to what I'm experiencing with mine at this point. Just have to keep in mind that it's not a sled I can just bomb around the yard on without letting it cool down every now and then...

-Paul

[gixxer6]

My 79' 440 runs 160-180 nomally, and my 81' 440 with the larger heat exchanger runs 120-150. 

[quadgoat]

Interesting...does it run those temperatures consistently, or does it heat up more when just bombing around the yard?

-Paul

[gixxer6]

It's fairly consistent.  Sometimes my 81' runs even cooler than that.  I don't spend much time idling or at extreme slow speeds. 

The only time I had much trouble with my temps is before I switched to NOS 4/6 head gaskets.  I could not get any other type of gasket to seal. 

[fast-ice05x]

My 79 Runs Around 180 190 just playing around never seen get any higher

[quadgoat]

Hmmm.....perhaps I'm not all done working on this thing for now. At least the heads come off easily! LOL I'm going to try getting it out on the trail and seeing how it does first, but maybe I'm going to have to track down some 4/6 gaskets too.....

What's the best way to check these machines for a head gasket leak? Pressurize the cooling system and watch for a pressure drop, just like in an automotive application?

-Paul

[Lloyd (ljm)]

 Yes that is what I would do to find a coolant leak. Shouldn't need much pressure.

 Lloyd

[gixxer6]

I see there are some 4/6 rubber gaskets on ebay for a fair price.  I think I can help with the fire rings. 

I will never run anything but the 4/6 gaskets in any of my Invaders.  After fighting with leaky head gaskets countless times.  I tried numerous types of sealant, on Winderosa, Cometic, Kimpex, NOS kawi, NOS Deere, and probably a few more...  With time, every single one leaked.  I put the 4/6 gaskets on without any sealant, and torqued it down and haven't had a problem since.  Best of all, they are reusable!