About 6 months ago I switched my '02 Grand Caravan (54,000 miles) to Walmart brand 5w-30 synthetic oil. Since then it has gone through 2.5 quarts of oil in about 3,500 miles. Prior to that it used no measurable amount of oil.
At the same time I switched my '91 Ford Ranger (184,000 miles) to the same synthetic. The Ranger hasn't used any oil.
I need to figure out what to do.
Should I go back to dino oil?
Should I stick it out with the synthetic and see if the oil usage stops?
Should I switch brands of synthetic?
Phoenixtsintsin
06-12-2008, 01:13 PM
I've been using the Walmart Super Tech synthetic and dino oil for years. Love the stuff. Can't beat the price.
I figured I'd take a step up and picked up a 5 quart jug of Quaker State high mileage ... $12. Not too shabby. I figured I'd give it a try and see if this high mileage oil really makes any difference.
The only thing about the Super Tech oil is the volume is weird. I've put in all 5 quarts into the Caravan and it'll barely register on the dipstick. It usually takes a 6th quart before it shows full on the dipstick. The engine capacity states 4.5 quarts, but even at 5 quarts, it doesn't register on the dipstick.
I'll see if I get the same weirdness with the Quaker State.
XDGT03
06-12-2008, 01:17 PM
What weight of dino oil were you using? What state do you live in? Is it hot right now. Personally, I would start with going to a 10w30 first (if it is hot).
HRTKD
06-12-2008, 01:47 PM
I live in Colorado. During the period the synthetic oil was in use I would not consider it hot. More like very cold to warm.
I haven't seen any evidence on the garage floor that oil is leaking from the engine. The spark plugs were replaced last weekend and they didn't look bad.
RickMN
06-12-2008, 07:16 PM
Synthetic oil flows better when cold. Down side to that is that metal contracts when cold, so clearances are greater. Greater clearances and more flow equals more oil burned.
You sure it's not leaking?
HRTKD
06-12-2008, 07:19 PM
You sure it's not leaking?
I am positive that it isn't leaking in the garage. My garage floor is painted and it is spotless. I don't see anything on the driveway either. The van is almost always parked in the garage.
jmontes
06-16-2008, 10:59 AM
I have a 2002 3.3. This van uses about 1 quart between oil changes of 3000 miles since it has been new. I use conventional oil. The van now has 54,000 miles and runs great. No leaks the engine and the floor of my garage are clean. Any opinions?
StormTrooper03
06-16-2008, 11:02 AM
Have you two checked the PCV system? That could be a perfect place to start.
hungaryhyena
06-16-2008, 04:17 PM
My 2001 GC was having the same issue.
Lost about 1 quart per 2000-3000 miles.
Just replaced the oil pan gasket, so far 2000 miles and no oil usage :cool:
I had no oil spills on the garage floor but there were some slight oil residue on the side of the oil pan. I think most of the oil was lost during driving.
XDGT03
06-16-2008, 06:52 PM
Mine has always used some. Not leaked but ate. It is better since the motor was replaced under warranty 60k ago. I have used nothing but synthetic since.
psyknyd
07-13-2008, 05:45 AM
Synthetic oil is blended to be consistent on a molecular level which means all of the molecules of synthetic oil are the same size. Synthetic oil molecules are also smaller than the molecules of petroleum based oils. The molecules in petroleum based oils vary dramaticly in size from one another. This creates the "easier flow" mentioned by another poster. :rck:
How this effects "oil disappearing" from higher milage engines is this: Seal and gaskets absorb the oils even if on a small level. Cork gaskets are espescially susceptible to this but rubber gaskets can be effected as well. This absorption causes swelling of those seals and gaskets. This process naturally assists in a higher efficiency of the seals by causing them to further close those metal tolerances mentioned by that other poster. When a vehicle has been used with petroleum based oils for a long time the seals swell to their maximum ability with those inconsistently sized molecules. When sythetic oil is added to that same vehicle's engine the natural absoption of the smaller synthetic molecules reduce the seals size slightly and thus no longer filling those metal tolerances as well. Once this occurs leakage will often happen during driving conditions when under pressure.
To solve this you should either change all seals and gaskets, tighten all bolts within the engine to reduce tolerances, or switch back to conventional oil.
Synthetic oil does not tend to burn off as easily as petroleum oils. It is designed to resist the heat better. Either your vehicle is leaking oil or it is burning it off. As we all know, your oil can leak out the sides, into coolants, or burned/blown out the exhaust. You could have a potentially serious problem on your hands either way. I have never recommended synthetic oil for anything with higher mileage. With the profit margin, no retailer (I have ever heard of) will try to turn you away from a synthetic switch by warning you that while synthetic is better in every way, your car will leak if you have run conventional for a while.
I hope that explains things way more than necessary. lol :gr_patrio
HRTKD
07-13-2008, 10:00 AM
Thanks for the information guys. It looks like I need to do a close inspection of the engine. While swapping the tires (winter -> summer) I noticed on the drivers side that there seemed to be a buildup of gunk on the side of the engine. Since there wasn't any oil on the garage floor I figured it must not be too bad a leak so I blew it off. I'll look into it more carefully now.
