600 HO SDI Overheating (and starting issue) Help!

[Marley]

REV 600 HO SDI - first the overheating problem: the sled has had intermittent overheating problems usually controlled by jumping into some deep snow. Last time out same thing but at the end of the day nothing worked to cool it down.

What I know:
engine temp sensor says it is too hot,
the heat exchanger at the back of the tunnel is cool to the touch,
The coolant cap seems to work fine,
System is full of coolant,
With cap off and engine revved, coolant is coming (pumping?) up inside the internal tube inside the tank.

Now the starting issue is only when it is cold. Takes 10-15 seconds of cranking to get the engine fired. (My 2011 Summit X fires in milliseconds) When warm it starts fairly quickly. It puts out a lot of smoke when cold.

I'm hoping it isn't the circ pump as that looks like a pain to get to and work on...
I haven't pulled the thermostat yet as it appears it has to be taken out from the underside. Pulled the hose fitting on the of the thermostat and coolant appeared to be getting by (wiped off the coolant and more came up).

Any ideas where to go from here?

 

[Marley]

Update:

Went through the procedure in the manual to refill the cooling system (even though it was close to full already).
'Cap off, cold engine, start engine, run until tunnel heat exchangers warm, install cap, lift rear of machine up, rev to 7000, lower machine, add coolant, lift front of machine up, idle 2 minutes, let engine cool, check coolant level'.

In the shop the overheating light and beeper come on after a couple of minutes of running but engine is warm, not hot, to the touch and coolant tank cap is cool and it can be taken off without issue.

 

[tukernater]

The senser is giving you false reading?I ran mine for probly close to 10 min before it got to 6 bars on heat gauge. 3 min before exchanger even got any heat to it.

 

[Marley]

The senser is giving you false reading?I ran mine for probly close to 10 min before it got to 6 bars on heat gauge. 3 min before exchanger even got any heat to it.

This is a 2005 machine and does not have a temperature gauge - only a light and beeper come on when it is 'hot'. I am going to try to get any air out again and if that doesn't work I will test the CTS with an ohm meter.

 

[TylerG]

This is a 2005 machine and does not have a temperature gauge - only a light and beeper come on when it is 'hot'. I am going to try to get any air out again and if that doesn't work I will test the CTS with an ohm meter.

on the revs aren't you supposed to elevate the front of the sled (put ski's up on milk crates or something) and run them with the rad cap off until the thermostat opens?

 

[plio7]

i have had mine air lock up before, i usually just pull the cap, sometimes lean it over on the opposite side of the resivior, and rev her up just a but.....it bubbles over a little and problem solved. but thats on my M8

 

[tukernater]

This is a 2005 machine and does not have a temperature gauge - only a light and beeper come on when it is 'hot'. I am going to try to get any air out again and if that doesn't work I will test the CTS with an ohm meter.

Sorry I mean temp senser in the head part#515 175 748 I just changed one in my buddies sled.Fix'd his problem .

 

[Marley]

Thanks for all the replies.

I started the sled from cold and it went over 10 minutes sitting at the door of the shop without overheating and the heat exchangers got warm so I'm thinking that both the pump and the thermostat are working.
Took it for a quick ride (less than 1 km) around my place and through some deep snow and in that short time the temperature light started to flash, beeper going steady and the yellow service engine light was on. Just for shits and giggles I pulled the exhaust gas temperature sensor out while engine was still running but the flashing and beeping continued.

Checked the resistance of the CTS at the connector (pin 1&2) and got a reading of about 65 ohms. Engine did not feel hot and I could take the coolant tank cap off without any apparent pressure in the system...