How to do a Sea-Doo Coolant Flush on a 4-TEC Jetski DIY

Seadoo battery coolant flush

How to do a Sea-Doo Coolant Flush on a Jetski

A Sea-Doo Coolant Flush on a 4-TEC Rotax engine is a lot like a modern car engine. It uses Type A coolant to keep the engine at the correct operating temperature. If you haven’t replaced the green coolant in over 200 hours or 2 years it’s time to get it done.

My Sea-Doo GTI jet ski coolant was well overdue at 3 years. Coolant will start to lose its anti-corrosive properties and fail, so best to get it replaced at the manufacturer’s recommendations.

Replace Sea-Doo Coolant

Now you can take your Sea-doo 4-tec to your local dealership, and start handing out your hard-earned cash, or you can do it yourself. The Jet-ski coolant flush should only take around 20 minutes. Your owner’s guide manual will say, it has to be done by the dealer, but it is really easy to do it yourself.

Sea-doo coolant flush drain green

First, run into your local auto supply store and pick up some Type A Coolant, usually made of Ethylene Glycol together with some protective additives. It is mixed with water to produce coolant. You can either get the ready mixed stuff or the concentrate and mix our own with Demineralised water, 50 – 50 mix.

5 Liters will be enough to completely change out your jet-ski coolant.

I always use Calibre Anti-Freeze/Anti-Boil Type A, 5 years or 250,000km protection here in Australia. If you would like the official Genuine BRP (Ski-Doo, Sea-Doo, Can-Am) “Red” pre-mixed antifreeze/coolant. Then you can get it from Amazon.

It comes in 1-liter bottles.

If your coolant is green then stick with the green color. If it is red then stick with the red coolant. But saying that there is no issue from completely flushing your coolant and then swapping over to another color. Just don’t mix the colors.

Sea-Doo Coolant Flush ProcedureSea-doo coolant drain bolt plug location

  1. Remove the coolant pressure cap from the overflow plastic tank.
  2. Carefully remove the stainless drain plug from the bottom of the ride plate using a hex Allen key and drain it into a container. Do this where spillage won’t matter.
  3. Pour demineralized water into the overflow tank and flush out any remaining coolant. When it’s finished draining pour a 50/50 mix into the overflow tank.
  4. Have someone watch the drain plug as you pour the mix in, as soon as there are no air bubbles, screw in the drain plug. This is optional but helps not to have to re-top up coolant next time you go for a ride.
  5. Fill the overflow tank to the correct line. Not too much, too little.
  6. Replace the overflow coolant tank cap.
  7. If you have a torque wrench torque up the drain plug – 75lbf.inch
  8. Run the Sea-Doo jet ski engine for 30 seconds, and recheck the coolant level. Top up if required.
  9. Failure to flush and top-up your cooling system can cause your boat, jetski, or car to overheat.

Thanks to 3ftDeep for this detailed Sea-Doo Coolant Flush procedure


Sea-doo closed loop cooling system diagram

Below is the Sea-doo 4-tec cooling system diagram to help you diagnose any overheat issues.

seadoo closed loop cooling system diagram


What Can Go Wrong – Snapping a Bolt or Screw

For some reason, the hex stainless drain bolt for the Sea-doo is made out of butter. It must be a cheap stainless steel bolt. Not sure if it’s a bad batch or a bad design but there are a few cases of people snapping off the heads of these bolts. Possibly being over-tightened at the Sea-doo factory or at the dealer if your coolant has been changed out before.

broken seadoo coolant drain bolt

I was very aware of this issue and I even managed to break off the head of my drain bolt. As you can see there is no corrosion on the threads.

So how do you get out the snapped bolt? Well there are a few devices made to help with broken bolts but the 2 that are very common are:

Easy Outs, SpeedOuts,  Damaged Screw Extractor & Bolt Extractor Set

 and Left Handed drill bits.


Everyone should have these in their toolbox.

How to Remove a Broken Bolt on your Sea-doo

First, centre punch the center of your broken Sea-doo bolt. This will help your left-handed drill bit get a good start in life. The stainless is a very hard metal so take it slow.

Use your drill on a slow speed first to start drilling. If you are using a left-handed drill bit make sure the drill is in reverse. If using only normal right-twisted drill bits you want to run forward direction. Be careful with bolts that go into a cavity.

The Sea-doo drain plug stops fluid from coming out. There is nothing stopping the bolt from traveling into the center of the ride plate cooling reservoir if the bolt head snaps off. Be careful if using normal drill bits to drill out the broken bolt, because if running forward direction and the drill bit catches, you will wind the drain bolt all the way into the ride plate. You will never get it out.

Most times the bolt will self-wind out if using a left-handed bit. If it won’t, once you have drilled in about 1 cm you can use this Easy Out from Amazon, Job done.

Sea-doo overheating problems

You could be low on engine coolant or have an air pocket in the cooling system. Check that there is some coolant in the overflow bottle. Drain the coolant and replace it.

Make sure as you top up the coolant that you have someone screw in the drain plug at the rear of the Sea-doo ride plate.

Check that there are no obstructions or debris between the ride plate and the Sea-doo hull. Make sure that all engine cooling hoses are tight and that there are no leaks.

Can you use car coolant in a Jetski or Motorcycle?

Yes, you can use car coolant in your Jetski or motorcycle. Just make sure the coolant is pre-mixed or you will need to add desalinated water yourself.

Also don’t mix coolant colors. If your Jetski has a green coolant then use a new green coolant. Don’t mix the red coolant with the green as it will gum up your internal cooling system.

Can you put water in jet ski coolant?

Yes but only if it is desalinated water as normal tap water has impurities that will leave mineral deposits in your cooling system that can cause blockages over time. If you have a bottle of coolant concentrate then follow the instructions to dilute the concentrate to the approved ration often 50:50

How do I add coolant to my Seadoo?

How do I add coolant to my Seadoo?

Look for the coolant expansion bottle which is white and semi-clear. This bottle is often located at the top of the engine bay just under the seat on the right-hand side.

Unscrew the lid and top it up with a pre-mix coolant of the correct color to the recommended mark on the bottle.

Continue With your Jet Ski Service

Now that you have done the coolant flush why not continue with doing a Sea Doo oil change. It’s easy and won’t take too long. Think of all the money you have now saved now go out and have fun with your fully serviced toy.

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  1. Well on attempt to torque to 75 lbs drain bolt snapped on me as well. Can’t seem to find anywhere what size bolt that is. Any info would be great.

  2. Hello Matthew, a very good article. A question.
    How can I tell if the engine had antifreeze? Rotax 1630 ACE (RXT X 300 RS, 2017).

    Best regards


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