I did an oil change recently, and was almost positive that I put in 15W-40 Delo 400. However, I had about a quart left over (threw the other containers away), and realized that it was 30-weight Delo 400 instead of the multi-grade. If I put in some or all 30-weight oil instead of the multi-grade, will it hurt my truck? I live in Seattle, where the weather is 40-50 degrees this time of year. Since I realized the mistake I may have make, I've used the engine block heater religiously. When I start it up, the oil pressure goes to the high end of what I assume is the "normal" range on the gauge (between 40 and 110), but drops to normal once it's warmed up.

 

If it were me for peace of mind I'd change it. Not that expensive for 11 guarts of oil and you shouldn't even need to change the filter. If you decide not to IMHO I doubt if it will hurt anything.

 

IIRC, there is a bar chart in the owner's manual that shows the temperature ranges in which a given oil viscosity can be used. You might check there to see what they say about the 30 weight.

I know what you mean - I changed oil in the truck over the weekend and almost grabbed the 1 gallon jugs of Delo 400 30 weight at the auto parts store - I had to look twice to see that they weren't the 15W-40 that I was looking for.

Rusty

 

What's the Diesel rating on that straight 30 wt? Probably a CD/CF? No worries either way.

You will be ok in your part of the world. Just need to be sure the oil is fully warmed up before hitting it hard. Using the block heater is a good idea. With that and waiting for your T-Stat to open up...you'll be fine till the next oil change.

I run a 30wt multigrade through the winter months. As you seem to already know...your only concern is thinning the oil out a little before driving much.

I'd be a little careful towing your horses trailer with the 30 wt in there. Delo 400 is, IMO, the best national brand oil out there and should hold up ok but I would not push it hard while towing, just to be on safe side.

RJ

 

Well, I already towed the horses 1100 miles with the 30wt. I always baby the truck until the engine is warmed up, even with multigrade. I think I'll leave it in there for now, but I'm towing the horses cross-country this summer, and I'll change it before then. I'm guessing what probably happened was the first gallon I grabbed was 15w40, and one or more of the rest of it was 30wt.

 

We run 30W in all of our tractors at home. As long as it is a diesel rated oil you will be fine, and if it isn't a diesel rated oil you will just need to change it sooner. The sulfur will build up in the regular oil. The 30W won't hurt it a bit, but if it worries you then change it.