[Dodes2003]

What is the appropriate coolant temp for a 660? I have a 03 660 full sparks exhaust, pro designs intake with open air box and stage 1 hot cam, 12/40 sprockets. About 2 years ago got a tusk radiator cap temp gauge and it frequently gets up to 220-230 when riding in the dunes. I recently rebuilt the water pump and installed a mishimoto radiator and new fan. This past weekend it got up to 240 at times (it was about 95-100 degrees). Fan cycles on and off normally, and I verified the thermostat works by starting it with the radiator cap off and I see coolant starting to flow after a few minutes of idling. When riding hard pack at higher speeds it hardly ever gets over 180, only seems to get hot in the dunes. I’m considering wiring the fan to a switch so I can turn it on sooner when riding in the dunes. Does these temps seem appropriate or do I have a cooling system issue?

Fist post here but I’ve been reading these threads for years, thanks everyone for all the great information.

 

[Wilson]

What is the appropriate coolant temp for a 660? I have a 03 660 full sparks exhaust, pro designs intake with open air box and stage 1 hot cam, 12/40 sprockets. About 2 years ago got a tusk radiator cap temp gauge and it frequently gets up to 220-230 when riding in the dunes. I recently rebuilt the water pump and installed a mishimoto radiator and new fan. This past weekend it got up to 240 at times (it was about 95-100 degrees). Fan cycles on and off normally, and I verified the thermostat works by starting it with the radiator cap off and I see coolant starting to flow after a few minutes of idling. When riding hard pack at higher speeds it hardly ever gets over 180, only seems to get hot in the dunes. I’m considering wiring the fan to a switch so I can turn it on sooner when riding in the dunes. Does these temps seem appropriate or do I have a cooling system issue?

Fist post here but I’ve been reading these threads for years, thanks everyone for all the great information.

@QuadManiac is the resident expert with the cooling system, he'll have the best answer for you. Sand dunes obviously create lots of resistance, so some rise in temp is to be expected, but 240 does seem a bit higher than you'd like to see. Did the red light ever come on?

 

[Dodes2003]

@QuadManiac is the resident expert with the cooling system, he'll have the best answer for you. Sand dunes obviously create lots of resistance, so some rise in temp is to be expected, but 240 does seem a bit higher than you'd like to see. Did the red light ever come on?

It did not come on, and once I stopped the fan was able to bring it back down to around 220 when the fan shut off.

 

[Montana]

What size tires and how many paddles are you running? What is your gearing for the dunes?

 

[Dodes2003]

What size tires and how many paddles are you running? What is your gearing for the dunes?

22x11x10 8 paddle v’s running about 8 psi. 12/40 gearing.

 

[Sixpack577]

Engine Ice will bring temperatures down a couple degrees.
Manual fan switch is a good idea.
Sounds like a normal 660 to me.

 

[Dodes2003]

Engine Ice will bring temperatures down a couple degrees.
Manual fan switch is a good idea.
Sounds like a normal 660 to me.

I tried royal purple additive before with little to no effect but I’ll give the engine ice a try for the next trip

 

[Sixpack577]

I tried royal purple additive before with little to no effect but I’ll give the engine ice a try for the next trip

Flush the old coolant first, don't just drain and refill.
White vinegar and distilled water, flushed twice, refill, good to go.

 

[Dodes2003]

Flush the old coolant first, don't just drain and refill.
White vinegar and distilled water, flushed twice, refill, good to go.

Will do, it’s got fresh coolant now since I just installed the mishimoto radiator. I’ll flush with vinegar though just to be sure. Should I run it and let it circulate at all with the distilled water/vinegar or just fill the rad and let it drain out of the water pump?

 

[morphrider]

I have also heard in other forums to not trust that Tusk cap to be accurate.

 

[Dodes2003]

I have also heard in other forums to not trust that Tusk cap to be accurate.

I was curious about that as well. Good to know maybe I’ll get an inline gauge

 

[Sixpack577]

Will do, it’s got fresh coolant now since I just installed the mishimoto radiator. I’ll flush with vinegar though just to be sure. Should I run it and let it circulate at all with the distilled water/vinegar or just fill the rad and let it drain out of the water pump?

Run it, drain it hot.

 

[Montana]

Engine Ice will bring temperatures down a couple degrees.

Is that all you have experienced with Engine Ice, a couple degrees? I have ran water wetter a couple times and I can't say there was any difference in the temperature. You would think that for the hype there would be 15 degree difference with Engine Ice.

 

[QuadManiac]

Thermostat starts opening at about 156F. Fan is supposed to come on at 208F. Warning light at 248F.

Sure sounds to me like your cooling system is working as designed. Sand is a heavy load.

 

[Sixpack577]

Is that all you have experienced with Engine Ice, a couple degrees? I have ran water wetter a couple times and I can't say there was any difference in the temperature. You would think that for the hype there would be 15 degree difference with Engine Ice.

Actual temperature drop varies by machine, and a few degrees is normal(temp gun).
I have and do run it in several different ones, and any drop is a plus.
I like to think of it as 212°f is boiling...where as 211 is just really hot.

 

[Wilson]

@Sixpack577 Since you mentioned using a tempgun, what are your sidewall temps on the non exhaust side at the absolute max? In the sand and hot conditions, my sidewalls are about 190 to 200. Around the yard and hardpack dirt, usually like 160 to 170.

 

[Sixpack577]

@Sixpack577 Since you mentioned using a tempgun, what are your sidewall temps on the non exhaust side at the absolute max? In the sand and hot conditions, my sidewalls are about 190 to 200. Around the yard and hardpack dirt, usually like 160 to 170.

I don't remember, I havn't owned a 660 in years, but those numbers sound ok too.
I think your 660 is fine, they all run hot, and the sand just works the engine harder.
I have put a manual fan switch on several 660s, and it helps, as the fan temp switch in the bottom of the radiator doesn't turn the fan on until it's already really hot.

 

[Dodes2003]

Thermostat starts opening at about 156F. Fan is supposed to come on at 208F. Warning light at 248F.

Sure sounds to me like your cooling system is working as designed. Sand is a heavy load.

Sounds good, thanks. I’ll run engine ice next trip which is Veterans Day and report back.

 

[Dodes2003]

I ended up wiring my fan to a switch, which seems to have helped a lot. When riding in sand I just turn it on when it gets to about 160 and leave it on. I rode pretty hard last weekend and never saw it above 200. If anyone’s having problems overheating, and you’ve already determined your cooling system doesn’t have any issues I’d recommend the fan switch.

 

[QuadManiac]

I like to think of it as 212°f is boiling...where as 211 is just really hot.

I like to think about it as 212°F is only one degree greater tnan 211°F... insignificant! ;-}