2002 Carver 346 6.2 MPI coolant

[Pha8]

Looking to drain and replace the coolant in my 2002 Mercruiser 6.2 MPI's. Which coolant would you recommend?

[waybomb]

Whatever is in there now. You don't want to mix types.
If you feel you must use a newer af, you must completely drain and flush the entire system. There can't be any of the old stuff in there.
The engine will be fine using the original type of coolant. It's all iron.

[Pha8]

Not sure what is in there currently, but I plan on draining it and adding new stuff. From what Ive researched, I should use Dexcool but not sure if their is a specific type or brand to use?

[waybomb]

Dexcool was designed for modern engines with aluminum block and or heads. Doesn't mean you can't use it. It will be fine.
But remember, you need to drain all the old stuff. Every drop.
I've also read that Dexcool has a negative affect on intake manifold gaskets.

[Pha8]

Source of the post Dexcool was designed for modern engines with aluminum block and or heads. Doesn't mean you can't use it. It will be fine.
But remember, you need to drain all the old stuff. Every drop.
I've also read that Dexcool has a negative affect on intake manifold gaskets.

What coolant would you recommend?

[waybomb]

I'm no expert.
The thing came with the regular old green stuff. I believe it has a higher amount of rust inhibitors than the stuff made for aluminum metal.
I'd go old fashioned green of you can determine that's what is in there now

[Viper]

What colour is your coolant, green or orange? If it's orange, chances are it's Merc's longlife coolant.

[Pha8]

Source of the post What colour is your coolant, green or orange? If it's orange, chances are it's Merc's longlife coolant.

Yes it is orange in colour.

[Viper]

Why do you want to change it, did you test it? Unless it failed testing, is really discoloured, or you know you have raw water leaking into the closed cooling side, I wouldn't bother replacing it.

I use a refractometer to test coolant during my winterizing routine. It's good to have one in your tool bag. Apparently the old style floating glass tube types are no longer accurate with today's formulations. The refractometer is way easier to use too, a couple of drops of coolant is all it takes for testing. Once you calibrate it (with distilled water), it's pretty accurate. They're readily available at automotive parts retailers and on line. Don't forget to test your generator too if applicable.

How long have you owned the boat, do you know when it was last changed?

[Pha8]

Source of the post Why do you want to change it, did you test it? Unless it failed testing, is really discoloured, or you know you have raw water leaking into the closed cooling side, I wouldn't bother replacing it.

I use a refractometer to test coolant during my winterizing routine. It's good to have one in your tool bag. Apparently the old style floating glass tube types are no longer accurate with today's formulations. The refractometer is way easier to use too, a couple of drops of coolant is all it takes for testing. Once you calibrate it (with distilled water), it's pretty accurate. They're readily available at automotive parts retailers and on line. Don't forget to test your generator too if applicable.

How long have you owned the boat, do you know when it was last changed?

I just purchased the boat last fall before it was put on the hard for the winter. Have not tested it but Judging by the condition of the oil/fuel filters and plugs, I suspect it has not been changed for a while if ever.