Author Topic: How to Change Your Car's Oil at Home - DIY and Save $  (Read 16193 times)

Offline jdn181

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Re: How to Change Your Car's Oil at Home - DIY and Save $
« Reply #30 on: April 05, 2010, 11:21:00 PM »
One thing I do differently is I run the engine for a few seconds before checking the oil level. Some of the oil will fill the filter and will show low. I was taught this by my grandfather who owned a gas station, "back in the day" (as my daughter would say) when your gas station was also a mechanics shop.

Brandon

Yup, typical oil filters will hold about half a quart or so. After running the engine for a min or so check the oil level and refill.

Also, what I do on every oil change is pre-fill the oil filter if you can. On vertical-mounting filters this is east. Horizontal-mounting filters....not so much (but you CAN pre-fill them a bit). Reason being is that, once you start the car on an empty oil filter, it typically takes about 10 seconds or so before the fresh oil fills the filter and reaches the bearings. Running your vehical on no oil pressure for a prolonged period of time will usually destroy the engine. The engine bearings are elastohydrodynamic bearings - meaning they need oil pressure flow and pressure to work. Otherwise it's just metal on metal and will fail - resulting in a needed engine rebuild.

Some quicky numbers - if it takes 10sec to fill the filter with the engine on, and assuming running your engine for 5mins without oil pressure is engine death, then over the course of 90,000mi - or 30 oil changes - you will have run the engine for a cumulative 5mins without oil pressure.

An alternative method is to not prefill the filter, but pull the fuse in the fusebox labeled "ECM", "INJ", or "IGN". Any of these is will disable the engine from firing up, but still allow you to rotate it over with the starter. When the oil change is complete, and the fuse pulled, turn the engine over with your key until your pressure guage reads a pressure (or) your presure idiot light turns off (or) for approx 10 to 15sec if you have neither gauge nor idiot light. Caution: Do NOT run your starter longer than 10 straight seconds as this could overheat it. If you count off 10 sec and still see no pressure just turn it off and let it sit a min or two before re-cranking the engine.

Ideally I use both methods - pre-fill the filter and then top it off using the starter only. Using the starter method there isn't any downward load on the crank bearings due to combustion pressure (transmitted through the connecting rods to the crank) so any metal on metal contact will be light instead of pounding. 

I figure why take the chance. Yes; engine bearings are rather inexpensive. It's getting to them that's not!




Offline Crispy Critter

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Re: How to Change Your Car's Oil at Home - DIY and Save $
« Reply #31 on: April 20, 2010, 06:37:48 AM »
This thread might qualify for a sticky. At least it should be revived every week or so...driving season is just around the corner here.

Offline patrat

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Re: How to Change Your Car's Oil at Home - DIY and Save $
« Reply #32 on: April 23, 2010, 05:20:12 PM »
Harbor freight, among others sells oil filter sockets. These work great on stuck filters, or innaccesible ones (Porsche 944).

Quick tip:
Before an oil change, pull the fuel pump fuse and crank the car until it stops trying to start. Do the oil change as normal. Once you have refilled, crank the engine for 30 seconds without the fuel pump fuse in. This allows the car to build oil pressure, fill the filter, and generally get the lubrication working again. Then replace the fuse.

If you dont do this, you essentially run your car at idle with no oil pressure until that system refills and reprimes. This causes much unneccesary wear on the engine.