Why would anyone recommend a multi-grade oil for a i/o or inboard boat engine? Aren't multi-grades (15w-40) good in sub freezing weather? The 15w is only when the temps are under 32f - correct? Indmar recommends 15w40, when my 1992 PCM says to use straight 30w or 40w. Volvo says a straight 30 also - i think.
Multi-grade or straight weight?
- Thread starter JonS
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Most O.E.M's recommend the use of mineral 15w40's down to around a consistent 15F, but for optimal engine lubrication, I'd recommend something else.
What engine is this?
How hard do you run it?
What engine is this?
How hard do you run it?
My engine is a 5.0 liter v-8 Ford in a direct drive Moomba ski boat. My manual calls for 30-40w and when i called PCM they also say to use 30w. I asked about 15w40's and they said i would have more consumption with it. Even the dealers put 30w in the new PCM motors.
Kinda reminds me of the whole lawn mower engine thing...manufacturers recommend a straight thirty weight, but there are many out there that run multi-weight oils with great results.
I personally feel that in consumer marine applications, the use of a good multi-weight oil is the best bet.
I also do not agree with PCM about 15w40's causing higher consumption. If anything, consumption will be reduced in comparison to a SAE 30 PCEO.
If you want to use a mineral oil, you only have one choice IMHO...a HDEO 15w40.
If you want to use a synthetic, you have many, many choices.
Technically yes, but would you or the engine know a difference at 100F, no. I ran a straight wt. 30 in my 3.0 two summers ago. After being run hard and dropped back down to neutral, oil pressure really dropped. But, that is going to happen with any oil. However, last year I ran the Valvoline Racing 20W-50, now it held oil pressure better after the hard run, but during the run, it was pegging the meter, over 60 psi. Made me a little nervous. This year I'm running the Pennz. 15w40 LL in it and see how it holds pressure. Hopefully it won't be 60 psi at a full run but won't drop to 15psi afterwards either. The straight weights have been more shear stable, at least the old school thought, that is why the push. Boat engines will beat the be-jesus out of a motor oil. I think the newer Group III and above multigrades will hold up just as well. I'm going to do a used oil analysis on this oil at the end of the season. Boat should probably have about 20 to 30 hours on it. Never thought I'd say this, but I am now glad I have the 3.0, doesn't hurt so much to fill it up.
I have used Mobil 1 15W-50 in our 4.3LX since '94. Probably 800 hours.
The only worry I have is that it appears to get aerated as I see some drop off in pressure to about 45 psi even at 4800 rpm after hot runs then stopping/starting. If I then go on a long run it will eventually gain some more pressure. This could also be the oil cooling down since the engine does have a oil/water cooler.
The engine has never used any oil all season (April to November), and we use it most weekends since we live a block from the lake. The temps here regularly break 100 F during the summer. Never installed an hour meter, but I am fairly certain that we put probably 150 hours/season.
The other issue may be lack of corrosion inhibitors in the additive package (there are some I think) relative to the Mercruiser oil. I only boat in fresh water so doesn't seem to be a problem.
The motor inside the valve covers is still grey metal after 10 years. Some black carbon spots here and there which I think is understandable in a carburated engine with a 143 degree thermostat.
[ May 18, 2004, 10:14 PM: Message edited by: Geoff ]
The only worry I have is that it appears to get aerated as I see some drop off in pressure to about 45 psi even at 4800 rpm after hot runs then stopping/starting. If I then go on a long run it will eventually gain some more pressure. This could also be the oil cooling down since the engine does have a oil/water cooler.
The engine has never used any oil all season (April to November), and we use it most weekends since we live a block from the lake. The temps here regularly break 100 F during the summer. Never installed an hour meter, but I am fairly certain that we put probably 150 hours/season.
The other issue may be lack of corrosion inhibitors in the additive package (there are some I think) relative to the Mercruiser oil. I only boat in fresh water so doesn't seem to be a problem.
The motor inside the valve covers is still grey metal after 10 years. Some black carbon spots here and there which I think is understandable in a carburated engine with a 143 degree thermostat.
[ May 18, 2004, 10:14 PM: Message edited by: Geoff ]
Have you had it out yet?
Schmoe??
I've got 10 hours on my Merc conventional 25W40 so far this year. When I get to 30, I'm dumping it, doing an UOA, and going to a synthetic.
I'm going to use Mobil 1 SuperSyn 15w50. I may "thin" in down a bit using a quart of Mobil 1 0W30 race.
2001 Mercruiser I/O 4.3L V6 210 HP throttle body with Alpha I Gen II drive.
On a 2750 lb (dry) 19'6" boat.
[ May 20, 2004, 11:11 AM: Message edited by: Grease is the word ]
On a 2750 lb (dry) 19'6" boat.
[ May 20, 2004, 11:11 AM: Message edited by: Grease is the word ]
I am having trouble finding a diesel rated 30w oil. I usually use Delo 400 30w. If i can't find one, would i be better with a 20w-50 or 15w40. I can find lots of SL 30w's, but i feel they are too weak. I think the 15w40 would be too thin, but is a 20w-50 too thick? I can get a 40w in Chevron or Valvoline.
What's the word Schmoe? How did the Long-Life work out?
If Indmar is recommending 15w40 then I would think you'd be fine. Chevron Delo has apparently the best base stock of the conventional oils. The no brainer is to go Amsoil 15w40 Marine. I can't imagine Mobil 1 15w-50 would do nothing but protect very well also (see my post above). The thicker oil just may reduce your top end hp a little.
Volvo Penta recommends straight 30 synthetic for most of their gas engines.
Volvo Penta recommends straight 30 synthetic for most of their gas engines.
Well, I've got 40 hours on the Merc conventional oil and since the season is half over I'm going to keep it in and do the used oil analysis at the end of the season and go synthetic when I winterize. I can't wait to see the used oil analysis on this oil after 80 hours.
Well, so far, I've been very pleased with this oil. I have taken a bunch of tubers out this summer and for those of you that don't know, that's a lot of "extra" work for a 3.0. I'm talking quick take off's and sharp high rpm turns, I just can't stand it when someone dares me to throw them off or says that I can't throw them off
That's it....they are going down......my kid, neighbor kid, my brother, neighbors sexy wife....I don't care....they are getting thrown....
Anyway, this summer the boat has been worked a lot harder than I would like but I haven't lost one drop of oil. Dipstick is still at the full mark....which really surprized me because the other brands from the past have sucked a quart down within 6 hours of use. The oil pressure is great.....but it does fluctuate.....but I haven't seen it drop below 40 psi and at WOT it will push no more than 50. So I'm looking at a 10 psi difference from hard running to complete idle. I mean even a couple weeks ago, a bass boat died and I just happen to be there so I towed him in, about 4 miles miles at 1800 rpm, oil pressure stayed constant throughout. Hate to say it because I was on the band wagon of switching everything to M1 like I have my three vehicles, but after watching how the Pennz. LL 15w40 is behaving in the boat, oil pressure, oil consumption and the oil itself is still very very clean (thought I was out of oil for a minute because the dipstick was so clean)I don't think I can improve on that...like Dad said...if it ain't broke, don't fix it.
Anyway, this summer the boat has been worked a lot harder than I would like but I haven't lost one drop of oil. Dipstick is still at the full mark....which really surprized me because the other brands from the past have sucked a quart down within 6 hours of use. The oil pressure is great.....but it does fluctuate.....but I haven't seen it drop below 40 psi and at WOT it will push no more than 50. So I'm looking at a 10 psi difference from hard running to complete idle. I mean even a couple weeks ago, a bass boat died and I just happen to be there so I towed him in, about 4 miles miles at 1800 rpm, oil pressure stayed constant throughout. Hate to say it because I was on the band wagon of switching everything to M1 like I have my three vehicles, but after watching how the Pennz. LL 15w40 is behaving in the boat, oil pressure, oil consumption and the oil itself is still very very clean (thought I was out of oil for a minute because the dipstick was so clean)I don't think I can improve on that...like Dad said...if it ain't broke, don't fix it.
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