Heat Exchanger Replacement and Coolant Refill

[DJ Hennessy]

Hi,

Just looking for some quick tips... I have 06 Apex RTX with a cracked heat exchanger on the right side. Its currently filled with typical dark green coolant and I've had my heat light come on a couple times while riding. While I change the exchanger, I'm adding a rear as well, and going to refill the coolant with Engine Ice. From reading posts, I know I'm to loosen the bleeder valve at the back and refill slowly. Should I be lifting the rear slightly higher than the reservoirs at the front while filling or can I just leave it on the ground? Also, I read on one post, Engine Ice should not mix with the standard coolant... So should I do some sort of flush first and can I just use distilled water for that? While flushing it, do I need to start the engine and rev a couple times or just fill and go?

 

[steiner]

The installation of the rear cooler will for the most part keep the temp light off.
Its tough to get a true flush on any coolant system without using an extreme amount of new coolant.
This is what I do for a basic coolant flush. Drain all that you can. Fill with distilled water, run the motor and drain the system again. This should get most of the of the old coolant out. You could do that procedure a few times if you like.
I fill with the sled flat and with the thermostat out. Then raise the rear to burp and fill the running boards and rear exchangers using the bleed screw in the rear exchanger.
I then run the sled with the rear exchanger bleed screw out and the rear of the sled just above the coolant tank height to let the remaining air to escape.
Check the boards and rear exchanger if they are getting warm. This confirms flow thru the exchangers. If they don't get warm after a few minutes you may have an airlock somewhere.
Sometimes rocking or lifting the front end will allow the trapped air to come out as long as you have the cap off while doing that. I have not had an air lock yet on these Apex motors.
With distilled water used in flushing system I refill the system a little stronger than spec'd. After a good test ride I check the coolant strength and level and adjust as needed.

 

[DJ Hennessy]

The installation of the rear cooler will for the most part keep the temp light off.
Its tough to get a true flush on any coolant system without using an extreme amount of new coolant.
This is what I do for a basic coolant flush. Drain all that you can. Fill with distilled water, run the motor and drain the system again. This should get most of the of the old coolant out. You could do that procedure a few times if you like.
I fill with the sled flat and with the thermostat out. Then raise the rear to burp and fill the running boards and rear exchangers using the bleed screw in the rear exchanger.
I then run the sled with the rear exchanger bleed screw out and the rear of the sled just above the coolant tank height to let the remaining air to escape.
Check the boards and rear exchanger if they are getting warm. This confirms flow thru the exchangers. If they don't get warm after a few minutes you may have an airlock somewhere.
Sometimes rocking or lifting the front end will allow the trapped air to come out as long as you have the cap off while doing that. I have not had an air lock yet on these Apex motors.
With distilled water used in flushing system I refill the system a little stronger than spec'd. After a good test ride I check the coolant strength and level and adjust as needed.

Awesome reply, thank you! I'll follow these steps for sure! When you say you test the coolant strength, how do you do that and what should I be looking for there? I was planning on just refilling with straight engine ice, didn't think I'd need to mix that?

 

[steiner]

Your coolant should be around -40c. On the Engine Ice website it states that it is good to -32c. If you have a l/2 a liter of distilled water left in the system from flushing I would guess that you would be left with about -29c protection or so. Not enough in my opinion. I use straight glycol/coolant/antifreeze mixed 60/40 with distilled water. This is good for -45c on my tester which can be bought at any autoparts store. With the diluted mixed left in the system it usually works out close to -40c

With the rear exchanger you should not have overheating issues. The only time my light will come on is when I pull the kids around on tubes on the ice. Not enough airflow nor snowdust is being kicked up to the exchangers.
If you think you need more cooling and some scratchers.

 

[DJ Hennessy]

Your coolant should be around -40c. On the Engine Ice website it states that it is good to -32c. If you have a l/2 a liter of distilled water left in the system from flushing I would guess that you would be left with about -29c protection or so. Not enough in my opinion. I use straight glycol/coolant/antifreeze mixed 60/40 with distilled water. This is good for -45c on my tester which can be bought at any autoparts store. With the diluted mixed left in the system it usually works out close to -40c

With the rear exchanger you should not have overheating issues. The only time my light will come on is when I pull the kids around on tubes on the ice. Not enough airflow nor snowdust is being kicked up to the exchangers.
If you think you need more cooling and some scratchers.

Thanks Steiner! Flush complete, I actually ran distilled water through it twice to clean out the old then used a fluid extractor from princess auto to get the of the remaining fluid out. Pulled about 4-1/2L out total and capacity is only 4.7... Followed the rest of your tips and all worked out perfect! Thanks again!

 

[steiner]

Excellent.