engine oil

[gezy]

hi all,mercruiser engine oil 5.7 mpi 350 mag.whats the best to put in?.and how much to put back in?.thanks

[3388sam]

I use Quicksilver 25W40. I change oil every 100 hrs so I don't use the Quicksilver Synthetic Blend, just the standard oil.
5 quarts but be careful - you usually can't get all the old oil pumped out, so I start watching the dip stick during the last quart.

[gezy]

thanks,
5 quarts.is that a gallon or 5ltr.? :oops:

[racer2c]

thanks,
5 quarts.is that a gallon or 5ltr.? :oops:

4 quarts = gallon.

In the US, a liquid quart is equal to 0.946 litre.

You're the second member here from Wales!

[gezy]

ok with you now (LOL) :lol: yes from wales.

been looking this up today,

a lot go for ,10/ 30 castrol 20/40 and i think mec,s own oil 25/40.


so it had me thinking if i do not go for Quicksilver oil .do you all
go for Quicksilver .or what else do you all use

[racer2c]

ok with you now (LOL) :lol: yes from wales.

been looking this up today,

a lot go for ,10/ 30 castrol 20/40 and i think mec,s own oil 25/40.


so it had me thinking if i do not go for Quicksilver oil .do you all
go for Quicksilver .or what else do you all use

According to Mercruiser's owners manual the preferred order of oils is;

1.Quicksilver Synthetic Blend, NMMA FC-W rated, 4 cycle oil.
2.Quicksilver 25/40 NMMA FC-W rated oil.
3. A NMMA FC-W rated oil.
4. Quicksilver 4-cycle 25W40, nonFC-W rated oil.
5. A good straight weight detergent automotive oil per the air temp (20W for 32degrees or below, 30W for 32 to 50 degrees and 40W for 50 up.)

The shop just changed my oil and put the Quicksilver Synthetic Blend in it. I only use full synthetic (Mobil 1) in my cars and love the results I've been getting. You can't go wrong with sysnthetic, it just costs an arm and a leg.

[Brit Rider]

Gezy,

Synthetic really isn't required for these big lump engines... it sounds stupid but because they were deisgned like 20-30 years ago, they really prefer that kind of lube... go with the quicksilver as the safest bet or any cheap and cheerful econoline junk... your engine will thank you for it.

and welcome to the forum, where abouts in Wales do you boat? I stick mine in around the Menai Straits off Anglesey. But hit The Llyn peninsular and Pembrokeshire every now and again.

[racer2c]

Gezy,

Synthetic really isn't required for these big lump engines... it sounds stupid but because they were deisgned like 20-30 years ago, they really prefer that kind of lube... go with the quicksilver as the safest bet or any cheap and cheerful econoline junk... your engine will thank you for it.

and welcome to the forum, where abouts in Wales do you boat? I stick mine in around the Menai Straits off Anglesey. But hit The Llyn peninsular and Pembrokeshire every now and again.

If I had a dollar for every dino vs synth oil thread I've read on various message boards I'd have enough to buy a bigger boat. :lol:

It's all about frequency of the change, but it's also true that synth will out last (viscosity breakdown) dino oil two to three times longer. Is it worth the expense to go synth if you are a stickler for oil changes, probably not. But personally I like knowing I can take it a little further (even if I don't) and that warrents the extra expense for me.

[gezy]

my boat at swansea marina and i spend a lot of time at saundersfoot and tenby.

so are we thinking quicksilver to be safe then.

the fitter at the marina did say go for 20/50.to me thats more of a car oil.
as the v8 in the boat gets more rpm for that oil.
and thats why i did this post.

[Max2100]

Just read an article in 'Boating' magazine. They said if you are using automotive oil in your boat you are killing your engine. Use only marine grade oil. I use only Mercury oil in my 5.7L and change it and the filter evry 100 hours.

[gezy]

i will run Quicksilver 25W40