Oil Change

Tiny
STYLEMANMD
  • MEMBER
  • 1992 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 330,000 MILES
I've been changing oil in my own vehicles for years now, and it's just dawned on me that the amount of oil that drains out, including the oil in the filter (all totalling approx. 4 litres) is less than the 5 litres that was in the engine. I drain it while it's hot and even run it for 30 seconds while it's draining into the pan to make sure all the oil is pumped out of all the galleries, shut it off and then wait until it's completely drained.
How come?
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Wednesday, December 1st, 2010 AT 3:52 AM

6 Replies

Tiny
CARADIODOC
  • EXPERT
Agh! Don't run it when the oil is drained out. Once there is air in the pump, it will be harder for it to draw a prime later because the galleys are filled with oil that is hard to move. You won't ever get all of that oil out anyway. The manufacturers know that not all of the oil is going to drain out. To try to get it all out means restarting the engine with no oil in the passages. The V-6 engines actually hold over 7 quarts of oil, as in filling a freshly rebuilt engine, but all you'll get out when draining them is 4.5 quarts for the 3.0L and 4.8 quarts for the 3.3L. Besides draining out the gunk, the reason for putting in new oil is for the additives. There is enough additives in just one quart of oil to keep the engine happy. With five quarts of oil, the additives do not last five times longer. You just have five times as much additives wearing out at the same rate, so there is no advantage to draining the system for hours or overnight, ... (Even though I do that too), but I change my oil every other year, whether it needs it or not!

Caradiodoc
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Wednesday, December 1st, 2010 AT 4:03 AM
Tiny
STYLEMANMD
  • MEMBER
Thanks caradiodoc,
I take your advice seriously about running it with no oil in it. LL I won't do that again. Thanks for explaining why less oil comes out than what goes in.
Regards
Ron
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Wednesday, December 1st, 2010 AT 4:26 AM
Tiny
CARADIODOC
  • EXPERT
I hate to admit that on one of my vans, an '88 Grand Caravan with 379,000 miles, I change the filter once every other year, and add about a quart of oil every 1,000 miles. The drain plug hasn't been out since I left the dealership in 1999! That isn't neglect. That's abuse, and it made for lots of teasing from my students about being cheap, ... Ahh, ... I mean "frugal". And I use it to pull an enclosed trailer that's bigger than the van. That doesn't mean you shouldn't change your oil. It just goes to show what these engines are capable of. I just replaced the 12 year old spark plugs, cap and rotor too; sort of like a "thank you" gift to my van for being so reliable.

I also have a '93 Dynasty that gets its oil changed every 2,500 miles. It's had one in its lifetime so far and will be due for its second one in another 900 miles, which should be about four more years!

If you want to get really picky about clean oil, I have an '80 Volare that has an add-on filter that uses a roll of toilet paper for the filter material. Talk about a spotless engine. But you must also remember that oils weren't nearly as good 30 years ago as they are today. I added that filter when the car had 50 miles on it.

There are a lot of differing opinions about oil brands too. It seems the best course of action is to stick with one brand because they use different additive formulas and some of them are not compatible. It seems very often when someone tells me of a leak or burning oil, it happened shortly after changing brands. One student had a six inch puddle wherever he parked his Ford truck within two weeks of switching to a popular synthetic brand. He switched back to the cheaper oil at the next oil change and within a few weeks, the leak stopped. I use the cheapest stuff I can find in my old van. It's a store brand from a small chain called Fleet Farm, but if you read the fine print, it's actually made for them by Citgo. I often wonder about what experiences people have when they go to different speedy lube places that use different brands of oil. If my comment about changing brands of oil caused problems, you'd think we would hear more about it. Perhaps it applies more to high-mileage engines that have hardened rubber seals.

At any rate, I'm happy you're performing oil changes when you should. Don't worry about getting every last drop drained out. There's still two quarts stuck in there and there's not enough gravity to suck that out. One thing that a lot of people overlook though, when you take it to a shop for the oil change, they will usually perform a quick visual inspection of the steering and suspension parts. That can get overlooked by those of us laying on the ground to do our business, so to speak.

Caradiodoc
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Wednesday, December 1st, 2010 AT 5:12 AM
Tiny
STYLEMANMD
  • MEMBER
Caradiodoc
I gotta laugh at some of your comments. I can honestly relate to most of them. You really leave no stone unturned do you! Thanks so much for all the help you've offered.
The only thing I watch for IF I change brands on an old engine is to stay away from high detergent. It seems to wash away everything that's holding the motor together, and within a month, it begins to smoke because it's cleaned all the varnish from off the seals and the rings and anything else that's suppose to keep oil where it's suppose to be.
I do have one project coming up though I really don't want to tackle, and that's possibly removing the heater core. I just read through all the removal instructions in the manual and the last line says, "you're in for a ---- load of work". LL
Of course it has to have air conditioning on it too, so I think before I go to all that trouble, I'm going to hook up a garden hose to the heater core inlet and see what kind of flow comes from the outlet pipe. Not getting much heat and I've already changed the thermostat and checked all the hoses for soft/collapsed spots and they all seem ok.
Last fall I mixed up a batch of muriatic acid with water, about half and half and let it sit in the heater core for an hour and flushed it out and found that it was clean, and yet, still only half the heat it should be putting out. I even checked to make sure the doors were all closing and opening prperly, and they were, so now I've got a tarp closing off the front part of the van from the back which makes it bearable anyways in the winter.
Sure as ----, I'll finally get the heater working and the van will quit. Murphy's Law, I hate him! LL
Thanks again for all your help. I hope you get paid by some means for helping people like me who don't pay, and should.
I'm old, limited income and Christmas is coming and tons of kids to buy presents for, and no wife to help. LL
Thanks caradiodoc
Ron
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Wednesday, December 1st, 2010 AT 5:46 AM
Tiny
CARADIODOC
  • EXPERT
:) Donations are always appreciated but think of them as a tip, not a requirement, and I like that they set this site up that way. They help cover the cost of my six computer crashes in the first five months this year! Now I'm on a ten-year-old tank that works perfectly.

Side note that might not apply since you already checked the doors, but there was a service bulletin on the lack of heat. Condensation runs down the metal rod that the temperature door pivots on and rusts it tight. You would expect when that happens that the temperature lever would not move but in fact it moves perfectly normally. There is a metal clip on the arm for the door that has three fingers. The cable runs between them and magic, (well, friction actually), holds the cable in place. The idea is that when you move the lever from full hot to full cold, one of those ways the door will get to its stop first, then the cable will slide in those fingers as you continue moving the control lever. Once it does that, it is adjusted. It's a self-adjusting feature. When the door gets rusted tight, the cable just slides back and forth in the fingers giving the appearance everything is working.

The fix for that is to remove the center console if you have the one that bolts to the floor, throw a rag on the carpeting to protect it, find the inch-long nipple hanging down that holds that pivot rod, drill about a 1/8" hole through the plastic until you can see the rod, then soak it with a lubricant. Chrysler has a can of stuff called "Rust Penetrant" that works WAY better than WD-40 but it also promotes moisture following it in which makes things worse weeks later. Use that "nuclear waste" to free up the rod, then wash it out with brake parts cleaner or carb cleaner, then I like to use their Spray White Lube. It's a lithium grease with a liquid. The liquid soaks in and takes the grease with it, then the liquid evaporates leaving the grease behind. I use that stuff for everything except brushing my teeth.

That nipple is directly below where the rod comes out of the heater box up on top. I seem to recall you can see the rod with the clip if you pull out the heater control assembly, ... Or was it the radio?

Feel the two heater hoses when the engine is warmed up. They should be too hot to hold onto for very long. If the heater core is plugged, a garden hose should be sufficient to uncork it. Two other things to look for include bulk heater hose that was installed to replace the original molded ones that had 90 degree bends, (look for kinks in one of the hoses), and check the operation of the water valve if there is one. That will be in the middle of one of the hoses, and have a vacuum hose attached to it. Watch the actuator rod under it while a helper switches from heat to air conditioning with the engine running. That valve blocks coolant flow when the AC is on so it doesn't have to work so hard. They give very little trouble so I can't remember if they are spring-loaded open or closed. It would be more likely there is a problem with the vacuum supply to the heater control or to that valve.

Caradiodoc
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Wednesday, December 1st, 2010 AT 7:32 AM
Tiny
CARADIODOC
  • EXPERT
By the way, thank you for the kind words, but don't worry about donations. I wouldn't know if you donated a nickel or ten bucks. We do this to help people, not to get rich.

Caradiodoc
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Wednesday, December 1st, 2010 AT 7:35 AM

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