Dead Sled Wrenchers

Oil and oil analysis


Today I want to talk about sled haulers, the cars and trucks we use to move our sleds around.

So my previous rap on oil created much controversy  so I expect this will too.

What do you know about the oil in the engine of your sled hauler? Do you know how long its been in there? Do you know if its still in good shape or if it needs to be replaced?

Most car manufacturers today recommend you change the oil at around 5,000 miles. Most quickie oil change places recommend you change the oil at 3,000 miles. What neither of those recommendations really takes into account is the actual status of the oil.

For years I'd used the 3,000 mile recommendation and changed the oil religiously. Then some time in 2001 my 1996 Dodge Dakota's rear main seal started leaking, it progressed to leaking BAD, like a quart of oil in 700 miles. Being a cheapskate I was reluctant to spend the big money to replace the seal. I'd heard that switching to synthetic oil could help some leaks. The quickie lube place I'd been going to had Mobil 1 synthetic oil available so I had them put that in. It cost nearly twice as much...

The result was quite honestly not all that exciting if you're looking for a quick fix. Still over the next 5 years the rate of leakage from the rear main slowed to the point that now so 70,000 miles later it leaks only about 1 quart in 3,500 miles. I consider this an amazing rejuvenation but as I say it took a long time. Based on Mobil's recommendation I took the oil change interval out to 6,000 miles. So the cost of the change was twice as much but I was doing it half as frequently. I liked that because I've got better stuff to do on a Saturday morning than hang around the quickie lube place.

It wasn't until I got a diesel Mercedes car that I got real interested in synthetic oil. Anybody who has an older diesel vehicle knows that when its real cold out you need every advantage you can get. At 0F conventional 15w40 oil is thick like honey, Mobil 1 synthetic 15w50 is thin like, well like oil.

First lets talk about synthetic oil, non-synthetic oil and the stuff thats in between.

Non-synthetic oils: For the purposes of this page we'll say non-synthetic oils are oils that don't claim to be synthetic. They're also called conventional or dino oil. Theres a ton of different brands of conventional oil, some are better or worse than others. In the world of conventional oils I'll tend to be pretty conservative in oil change interval like 3,000 miles.

Synthetic oils: For our purposes these are Group IV and V true synthetic oils like Mobil 1, Amsoil and Redline. These are pretty much the best oils you can get. With analysis you can safely extend oil change duration Mobil says out to 15,000 miles, Amsoil claims even more.

Other oils: In this category we've got the Group III "synthetics". Group III synthetics include Castrol Syntec, Penzoil Synthetic, and the horribly named Quaker Sate Full Synthetic. Group III oils are NOT synthetic, they're highly refined conventional oils. I can't get over how robbed I feel by this. As such I will not use any of the Group III oils nor will I buy oil products from any of those companies. They're lying to us and should not be rewarded for it.

Of course one big problem is finding reliable information. Now I use Mobil 1 because its pretty easy to get, Wal-Mart, Autozone and the like have it. Amsoil has this wacky 1970s marketing scheme of dealers and preferred buyers and get your friends to sell it. They also sponsor, or authorize, or at least don't do anything to stop an amazing flood of websites proclaiming Amsoil's superiority. While I don't have anything in particular against Amsoil I'm not a fan of their marketing scheme.

Oil analysis has been very common for heavy over the road trucks, tractor trailers and such, for some time now. Companies running big trucks for millions of miles know they need to stretch every last penny out of those engines and all of the fluids in them. Big semi trucks can run multiple gallons of oil and changeing the oil needlessly wastes big money. Analysis also gives you a picture into the inside of your engine, a place that is so difficult to see otherwise. Caterpillar for instance uses oil analysis to help the heavy equipment owner keep his or her equipment in top shape, they call it SOS Fluid Analysis and you can read it at of us with regular cars and trucks can also benefit from actually knowing when the oil needs to be changed rather than just guessing at it.

How do you know? Well you call up Larry T at 800-222-0071 or head on over to  and order online. For $55 Larry will sell you a nifty set of 3 bellows bottles, 3 tubes, plastic baggies, cardboard boxes and the associated paperwork. You take your bellows bottle, put the tube on the end and then stuff the tube down the dipstick tube in the car. Smart money says to do this once the engine is warmed up so the crud in the engine is well mixed in with the oil. Compress the bellows bottle and when you release it the warm oil will draw up the tube into the bottle. Get the bottle filled, cap it, seal it into the supplied plastic bag, fill out the paperwork and put the whole mess in the cardboard box and ship it out.

A week or so later you get an email with a .pdf document. About a week after that you get a hardcopy of the pdf. On the right you can see two of the reports I've gotten on my '96 Dakota and two from my '85 Mercedes diesel car.

  Dodge Dakota Oil Analysis #1 35k
Dodge Dakota Oil Analysis #2 35.5k

Mercedes Benz 190D Oil Analysis #1 37k
Mercedes Benz 190D Oil Analysis #2 37k

My Dakota gets used mostly for short trips, thats why in Analysis #2 you can see that the fuel dilution has risen. Notice thats with nearly 8,000 miles since the last oil change. Since then I've continued with changes at around 8,000 miles. I feel that mileage still leaves some safety factor especially during the summer time when we drive the truck more. If our driving style for the Dakota changes I'll do another 8,000 mile sample.

On my Mercedes you can see that the oil is way out of spec at 7400 miles. This was the first time I'd ever changed the oil in that car and to be quite honest I'm not sure I did a very good job at getting all the old oil out. Changing the oil outside in February will do that to you... At any rate I'll sample again when the next oil change reaches 7,000 miles and we'll see whats happening then.

What do you think about this story? Let me know!