View Full Version : Engine Oil

04-13-2004, 03:51 PM
Question: I know Indmar says use the Pennzoil 15W-40 Marine Oil. Someone else told me it was just as good to use regular Pennzoil 10W-40. Any thoughts?

04-13-2004, 03:58 PM
Yeah, void warrenty!

I use Amsoil marine grade, I don't care for the penzoil

04-13-2004, 09:12 PM
Been using Penzoil 15W 40 "Longlife" from WalMart. Somewhere on the board we determined last year that the Marine grade wasn't necessary.

Why would you prefer 10W? Availability?

04-13-2004, 09:33 PM
Marty,last year I e-mailed Indmar,and told them I could not get Penzoil marine oil locally.They told me it was fine to use the 15w40 heavy duty oil.I printed the reply and am saving it.

04-13-2004, 09:37 PM

james yarosz
04-13-2004, 11:45 PM
Last year I e-mailed Indmar and told them I could not get the penzoil marine oil locally.They told me it was ok to use 15w40 penzoil heavy duty oil.

james yarosz
04-13-2004, 11:47 PM
This year I'm going to Amsoil 15w40 synthetic marine oil.

04-18-2004, 12:24 PM
15W-40 oil will have the viscosity of 15W oil when the engine is cold and that of 40 oil when the engine is warm. The "W" indicates that the oil is desirable for use in winter driving conditions. The Indmar manual recommends using 10W-30 Penzoil Marine if the engine will be used below 20 degrees. I have not been able to determine if "Marine" oil has some additive that regular oil does not. However, most oils have rust and corrosion inhibitors already in them and this should be a closed system.

Anybody out there been running the readily available 10W-30 or 40 for a long time in their engines? Any problems?

04-20-2004, 12:19 AM
Most of the 15W-40 I have found around here appears to be designated for use in Diesel engines. The guy at the NAPA store recommended against it in a gas engine.

I have a source for 15W-40 Marine Penz so no problems.

04-22-2004, 09:39 AM
Found the Penzoil Marine at Wal-Mart so I stayed with that. Hard to believe I called all over town looking for it and ended up finding it at the local Wal-Mart.

04-29-2004, 01:32 PM
Im thinking of using Mobil one 15W-40 Race Proven oil. Any thoughts on it?

04-30-2004, 02:44 PM
I think you'll be fine Keaton.

05-01-2004, 09:58 PM
the oil I have seen in wal-mart says it for outboards is this what you all are finding

05-03-2004, 09:51 AM
No. There are 2 different kinds. Fortunately, my Walmart had the outboard/2 stroke oil and the 15W-40 which is what we need. The 15W-40 is much harder to find. A lot of sporting goods stores and boating stores carry the outboard oil only.

05-04-2004, 11:16 PM
thanks for the clarification I quess my wal-mart just sucks

05-07-2004, 05:01 PM
I have found that West Marine also carries Penzoil Marine 15w-40. If you don't have a store near you here is a link to the web page. http://www.westmarine.com/webapp/wcs/stores/servlet/SiteSearch?storeId=10001&catalogId=10001&keyword=P enzoil+

I called Penzoil and the tech said that the diff. between marine and hd oil was that they added a few more rust and corrosion inhibitors in it.

james yarosz
05-09-2004, 12:03 AM
My last inboard (not a moomba) had a 351 ford motor.Had it for 12 years,over 1400hours.Always used Penzoil 30wt. Chanbed it every fall.It never used a drop and never had any engine work.My neighbor bought it and still runs it almost everyday.Just my 2 cents

05-10-2004, 12:12 AM
I wrote to Indmar and asked about the use on any 15w-40. I currently own 2 Valvoline Instant Oil Changes in the Charlotte NC area and know a little about motor oils. I also do the oil changes and winterization on my boat. There are several things that are important. Indmar reccommends using a motor oil that is is 15w40 and has SL and CI grades. Just about all of the diesel/gasoline (mixed fleet) oils meet this standard (i.e., Shell Rotella, Valvoline Cummins Premium Blue and others.). The Indmar Product Manager told me that Rotella and Valvoline All Fleet were fine to use. (I email-d him.) THEY WILL NOT VOID THE WARRENTY. (Look up the Magnuson Moss Act if you have questions). Another issue if you will notice, Indmar says to wait to 100 hours before using a synthetic. Their reasoning behind this is that the piston rings have not fully seated and that synthetics can prevent them from fully seating until they have over 100 hours. DON'T USE SAE 30! It is hard on the oil pump and lines and will void the warrenty. Use SAE 30 in an old 57 Chevy or lawn mower but not in a modern day engine. You can get Shell Rotella or Valvoline Premium Blue in Wal-mart or Autozone. Personnally I am going to use 15w40 Premium Blue until I have 100 hours then I will switch to synthetic for better protection, fuel economy, power and easier starts.

05-14-2004, 12:38 PM
I am a little concerned with your post sloppy. How is a 30 weight oil going to affect the oil pump? a 30 weight oil is lighter than a 40 weight When hot.


05-14-2004, 09:26 PM
You are right Brent, when hot, 40 weight will be thicker than 30 weight. The problem is when the oil is not warmed up. This is the advantage of 15w40. It has properties of a 15 weight oil when colder so it is easier on line and pumps. This is the reason for multigrade oil. It's thickness remains more constant during temperature changes. Viscosity is measured by the passage of oil through an area at different TEMPERATURES. This is important because an SAE 30 weight will stay thick at start up and thin out more during heat. The 30 weight is much harder at start up and cold weather situations. (Put SAE30 in and notice the high oil pressure until the engine is warmed). The start, warm up and power changes cause the most wear and tear on your engine. When your engines is hot a 40 weight is fine because 15w40 when heated will stay thin the same as a straight 40 weight when hot. Write Indmar about this, GM, Pennzoil, Mobil, Valvoline or any others. They won't recommend SAE 30 for your engine, BUT it's your engine, if you like SAE 30 go for it. I should take back my earlier statement and instead of saying "do not use SAE30 in your engine it will void your warrenty" I will say "I choose not to use SAE30 and it WILL void your warrenty". Hope this helps


05-15-2004, 08:37 AM
This is a quote from the owner manual for my MerCruiser 350 Magnum EFI Gen + Tournament Ski engine.

"To help obtain optimum engine performance and to provide maximum, protection, we strongly recommend the use of Quicksilver 4-cycle Marine Engine Oil. If not available, a good grade, straight weight, detergent automotive oil of the correct viscosity, with an API classification of SG/CD II, may be used.

The chart below is a guide to crankcase oil selection. Oil filter should always be changed with oil.

In those areas where recommended straight weight oil is not available, a multi-viscosity 20W-40 (SG/CD II) or as a second but less preferable choice, 20W50 (SG/CD II) may be used.

IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than 20W-40 or 20W-50), low quality oils or oils which contain additives specifically are not recommended."

The chart mentioned above basically shows the temperature ranges for the oil weights above. 50 deg. F and above use 40W. 32 deg. to 50 deg. use 30W. Below 32 deg. Use 20W.

I've used Castrol Heavy Duty 40W in my engine since purchased new in 96 with no problems. I also use a regular ACDelco PF1218 filter.

05-15-2004, 10:04 PM
Brent, Ajones and you both bring up a good point. If you have a Mercury engine I would go exactly by their guidelines. I have an Indmar in mine. The manual reccomends 15w40 wilth an SJ/CG-4 grade. The viscosity in 15w40 or any multigrade gives properties like a 15 weight when cooler and 40 weight when hot. SAE30 is thicker when cool than 15w40 and thinner when hot. The reason many boat and car manufacturers went with a multiviscosity is to give better starting, and cold weather protection. The main wear and tear on is during starting and power changes. To be honest with you the reason I started changing my own oil is that the Marina I was docked at put SAE30 weight in there. I noticed that the oil pressure was extremely high until the boat was warmed up. The new 15w40 oils have SL/CI-4 grade which exceeds SJ/CG-4 standards. I wrote Indmar with some tecnical questions on Motor Oil. There product manager wrote me back and told me what I listed in the last post. I did not think about the possibility of others having engines besides Indmar in their boat. Sorry about that. I have an 01 Outback LS with a Indmar 350 EFI. I am going by those guidelines. Best of luck.