5W40 synthetic diesel engine oil in a modern gasoline engine?

[Wolfy]

I just recently switched my 3 diesel tractors over to 5W40. They all had started hard in the winter, but I was hesitant due to their age ('77, '84, '86) However, no leaks so far. I am not convinced that 5W30 would hold up to the summer heat while mowing in my 3 gas mowers ('64, '67, '67). I have been using the 10W30 in my Buick LeSabre, just seemed that thicker oil would be good for it.

 

[Will_C]

My newer Toyotas require synthetic and have them changed at the dealers-still getting free changes and they take replaceable element filters-haven't trained myself on those yet.

My 2002 Camry gets the 5w-30 I have ran for years. The ATV gets Honda oil-it doesn't get changed often due low usage. I have switched the Kubotas and all small engines (pressure washer, push mower, generator)to Rotella T6. Works well and I am just changing all oils in the spring now-way under the hourly recommendations.

Will

 

[LD1]

I just recently switched my 3 diesel tractors over to 5W40. They all had started hard in the winter, but I was hesitant due to their age ('77, '84, '86) However, no leaks so far. I am not convinced that 5W30 would hold up to the summer heat while mowing in my 3 gas mowers ('64, '67, '67). I have been using the 10W30 in my Buick LeSabre, just seemed that thicker oil would be good for it.

Your logic is flawed as are many others.

5w30 is NOT thinner than 10w30
5w40 is NOT thinner than 15w40

They are the SAME.

Last number (after the w) is the oil thickness. The first number tells you how much it thickens when cold. That is why you don't notice any additional leakage in the old tractors. Because you are running the SAME weight oil in there. Just a little better performing as it don't thicken up "as much" when cold as 15w40 does.

 

[Wolfy]

LD1, thanks for clarifying that. I had always assumed 5Wxx was thinner than 10wxx. You really do learn things every day. Will, I also have that cartridge filter set up on my wife's Corolla. They are kind of a pain. I discovered that the oil filter wrench for my LeSabre fits the cartridge housing of the Corolla real nice. Everyone else, thanks for the feedback. I think what I am going to do is, use 5W40 synthetic for all my tractors and small engines. And 5W30 synthetic for all of my vehicles, which are all gasoline fueled. I can handle just 2 weights of oil on the shelf.

 

[ray66v]

I use a name brand of exactly the recommended weight and class of oil in each of my engines. I haven't had to add oil between changes to an engine in 30 or 40 years.

I've seen expensive vehicles that use oil from day one.

I have seen properly maintained vehicles, (5k mile oil changes, recommended grade of quality oil), start to use oil, as they get higher mileage.

And, I have a vehicle that has 240K, which has not been babied, and it's never used a drop of oil.

You don't necessarily have much control over it.

 

[Leejohn]

When you guys change over to synthetic how often do you change oil?

 

[Will_C]

I am changing the Kubotas every year-that's about 100 hours on the tractor and 50 on the RTV. Small engines is annually-probably overkill but it simple to remember- change all oil in the spring.

Will

 

[Bota4me]

I am changing the Kubotas every year-that's about 100 hours on the tractor and 50 on the RTV. Small engines is annually-probably overkill but it simple to remember- change all oil in the spring. Will

Thats the same practice i use Will.
I figure the hours arent there but oil and additives have been in a year so cheap insurance imo

 

[Wolfy]

My owner manuals state to change the engine oil every 100 hours, and filter every 200 hours. But since they were written of the oils around 30 to 40 years ago, I believe with synthetic, I could go 200 hours and then change the oil and filter.

 

[sixdogs]

When you guys change over to synthetic how often do you change oil?

Recently in my V8 truck in non-severe service I went almost 10,000 mile on synthetic oil with a quality filter. I used to change with less mileage than this but a lot of guys that test their oil say it can go even longer than 10,000 miles. In tractors that get severe usage I change once a year and in those with lighter usage maybe 18 months. I don't usually hit the 100 hours between changes.

I change a tractor to synthetic at 100 hours or so and vehicles at maybe a few thousand miles. I think even this is changing because I have owned two vehicles that came from the factory with full synthetic.