4 Tec 250 coolant help

[Liberty195]

My 2017 Scarab with the 4 tec 250 came with green coolant in it. I believe it’s original but I don’t know for sure, just bought it last fall. Decided to change the coolant and lots of folks online like the peak orange dex/cool for extended life in rotax so I used the process in the manual to drain the green and re fill with orange dex cool. Watched all the green pee out and turn solid orange with my helpers filling and then put the drain screw in. Then a hour later I started googling to see what my coolant capacity is because I was thinking i need another gallon for top offf and read how you should not switch from green or orange line I did. Darn it!

Soooo 90 min after finishing filling with orange, I drained the orange and then poured 3 gallons of filtered water through to be sure I got all of the orange out. Have nice clear pee now. Can’t imagine gelling in 90 min. Engine has not been ran.

I’m thinking I should just put green back in, correct? Engine never ran so the green still in the block didn’t mix with the orange. Best to use like a zerex all purpose green and call it a day?

 

[Liberty195]

So following up on this I do plan to just buy the XPS green coolant and continue with what I already had in there from the start.

But based on what I said above any concerns? Right now the system is empty since I drained the mistake orange dex/cool and flushed with water. Could that orange have mixed with the green still in the block past the thermostat? Or is the coolant past the thermostat pretty isolated off? Or does that drain too?

 

[Sidarousmg]

I wish I could help, but I really don't know the answer as to how far coolant goes without running the engines. maybe @Luc Lafreniere would have some insight. my guess is you're perfectly fine, especially if you've already flushed the old coolant with water. curious, why would you not be able to change from one type of coolant to another?

 

[Liberty195]

Thanks. As I understand things many coolants are mixable but the green IAT and orange OAT are not and could gel. XPS green is 2 years and orange is 5 years so green has to be flushed before change or there is a risk of gelling. Yea was hoping to hear from Luc when he can. Thanks

 

[Luc Lafreniere]

Sorry, I was pretty busy today.

So although I've read that before about the green vs orange, I've never understood why that would be a problem. In fact, I switched to orange a few years ago myself because of the 5 year life span. Zero issues. Did the flush just like you described. Purged the air and presto. Good for 5 years.

I wouldn't mix them though. But yeah, sorry, you could have kept the orange stuff instead of wasting it. My 230HP supercharged Sea-Doo GTX uses the orange. So I have no idea why we shouldn't be switching to orange when it's time to change it.

 

[Liberty195]

Thanks Luc! Hey one question, is the “old” green still in the block since I’ve not ran the engine? Or did that drain out when I drained the system out the ride plate?

 

[Luc Lafreniere]

Pretty sure it's gravity assisted and will empty on its own. So as long as you purge it with deionized water before switching colours, you're good.

2 years here and my engine hasn't blown up.

 

[Liberty195]

Great thanks! Used filtered water from the kitchen to do the first 3 gal of purge and about to put 2 gal of distilled through. No dionised around here. Have 6 qt of green XPS on order.

 

[Luc Lafreniere]

That's perfectly fine. Just make sure there are no trapped bubbles. Don't run the engine out of water for too long (2 min max bit I highly recommend below 1 min). Use proper flushing procedure. Engine on, water on. Water off, engine off. In that order.

Reservoir should be between the min and max lines when everything is COLD. The first time you bring her on water after, I recommend bringing some extra coolant and monitor it. Sometimes more air bubbles work their way out.

 

[Liberty195]

Thanks Luc! Very helpful and understood. Appreciate it!

 

[Liberty195]

Took her out today on a maiden voyage post coolant change. Throttled up and ran a half mile or so. Slowed down to idle to enjoy the view, and the overheat light came on (no sound). I was off shore so I decided to leave the engine on and point toward the ramp and continue to idle to see if it went off, and get closer to shore in case I have to shut down. After a minute or two of idling the light was still on so I opened the hatch and the coolant tank was empty so I added more to over the middle line. Took a couple of min or so but the light went off. After that I figured out how to see the coolant temp and it was 190. From there I motored for a bit at 3000rpm and then zipped around at 6500-7500 rpm and it stayed at 190. Came on and off plane and had some fun for a half hour or so. Added just a little more coolant before calling it a day, in total added around 3/4 of a quart, maybe a little more but not a full quart.

It is possible that the coolant cap was not fully secure when I started, but seems like probably a nice air pocket was in there from the coolant change and that’s why I overheated. It sat with no coolant and no ride plate plug for a few days waiting for coolant to arrive so it drained pretty well.

Any further concern? Everything looked fine in the engine room.

 

[Luc Lafreniere]

Sounds like that problem is solved. That's a lot of air. I'm not sure what exactly you did, but when refilling, the drain plug should be off. One person should be filling while the other stands with the drain plug at the ready. When there's a nice consistent flow, without stopping, you put the drain plug in. In my experience that prevents air bubbles of significance.

Either way, sounds like it burped fully. It's why I recommend bringing coolant on the first ride after.

Now hopefully you get to enjoy the boat!

 

[Liberty195]

Thanks Luc, we did re fill as a two person team. Wife added while I watched the drain hole and I inserted the screw with the correct loctite once I saw solid green peeling out but by then she’d only poured in under 2 quarts. May have had more air because we fully drained and flushed with water and let it sit drained for several days awaiting the right coolant to arrive. Glad we are set, thanks!