First pickup truck - Oil recommendations

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Apr 22, 2007
Houston, Tx, USA
Well, I decided that as a man in Texas I needed a pickup. I got a '95 Dakota 4x2 with the Magnum 3.9 V6 175hp engine. I got it off my FIL, who is almost on a BITOG level of obsession about maintenance. It's been very well kept and is in excellent condition. It has 165,000 miles and has had the oil changed with only M1 10W-30 EP at 5k OCI since new. It has a one gallon sump. Mobil 1 filters were favored, but other brands were used intermittently. I plan to use the M1-301 filter from this point on but if you can suggest a better option, please do.

The reason I'm posting here is because I thought it might be a good idea to switch it to HDEO considering it's age and mileage. Also, I'll be towing a small boat and doing some light to medium duty hauling of things from time to time.

Any ideas? I was thinking a 5W-40 might be in order but I'm open to suggestions. No idea what a good OCI would be. Keep in mind I'm down here in Texas and it does get a little warm for most of the year. Cost of the oil is not a factor but availability is. I only use oils that can be bought off a shelf without too much searching.
Since you use RTS 5W-40 that and a quality purolater or wix filter would be fine. But you also use PP 5W-30 and this should work just as well or better with a filter of your choice. Keep a reasonable OCI and you should have no worries.
To establish a baseline or to prove that running a synthetic is unnecessary? What would I be looking for? Also, what weight and which analysis company would you recommend? Dyson is out of the question due to cost consideration. (Also, I'm not really interested in RLI Biosyn.)
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If it's not a daily driver (presuming your other vehicles are), then even if it's your "Texas man's truck" you're probably not going to drive it much.

I can't imagine much wrong with that engine after 165k miles of Mobil 1 oil/filters every 5k miles. Two quick and inexpensive things you can check are the cleanliness and compression. Pop a valve cover and see how clean the upper end is. Check compression and you'll see how well the rings/cylinders are doing. That's not a total picture of engine health, but these two tips are very cheap to do (basically free) and they go a long way to knowing how the engine is fairing. Then also consider a UOA as well. That will give a very good idea of just how well the engine has been treated. (Note: I suspect with the M1 oil/fiter routine, there is nothing wrong with that engine).

I'd stick with a good quality dino PCMO (YB or DC5k), or possibly the PP for a bit of added cost. Any quality brand name filter (Wix/NG, Purolator, etc) will suffice too. I would think that if you want to keep the inventory down, just run the PP and be done with it. I don't see any real advantage in running the RTS for this vehicle.
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I agree with dnewton. Also, the PP isn't so expensive these days either. I saw a 4.4 liter jug for 21.97 Canadian at Wally. If I needed gas engine oil, I would have bought it.
Thanks for the detailed reply. It's going to be a pretty much daily driver. I'm going to be mothballing the Honda soon, once I'm satisfied with my knowledge of the truck and it's condition. It's due for inspection next month and when I bring it in for that I'll get them to check the compression. As soon as I have some free time, I'll pop that valve cover... I guess blackstone is the best bet for the UOA?
Great truck and great motor. I'd go with a $4-5 filter, no need for the M1.

Pay attention to the AT if it has one, maybe get an external cooler and keep up on the changes... really I'd obsess over that first and the motor second.
I got a '95 Dakota 4x2
To REALLY be a 'man's truck', shouldn't it be a 4x4?

Here in PA that's a requirement, even though we actually use the 4x4 about once a year..

Anyway, Rotella T 10-30 would be another one (probably won't beat RTS 5-40, but I had to put something in there...).
I have a 91 v6 dakota. I run a supertech filter. I will use name brand or supertech. Whatever is cheaper.

It got valvoline just the other day because I had some 5.5 gal jugs I bought for $9 at walmart. Before that is was supertech.
Originally Posted By: Steve S
Stay the course.

Good advice. Just keep using what got it to 165k. If you change brands/weights..etc.. there is a 'chance' that consumption will change.
Originally Posted By: eljefino
Great truck and great motor. I'd go with a $4-5 filter, no need for the M1.

Pay attention to the AT if it has one, maybe get an external cooler and keep up on the changes... really I'd obsess over that first and the motor second.

Couldn't agree more. External cooler and a magnefine is an easy add. Transmissions cost as much as engines these days. I'm willing to bet there are millions of cars in north america that have had religious 3k oil changes that have never had trans fluid service. I've never understood this.

If I lived in texas and drove a truck like yours, I'd be running whatever name brand 15w-40 was on sale. I'd sleep well doing it too.
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