A question about engine oil changes

eohrnberger · #1 10-21-2004, 12:44 AM

Why is it that my Pontiac Grand Prix GT recommended oil changes are every 3K miles or when the DIC (drivers information center) lights up and says so, while the recommended oil change interval for my Porsche 944 is every 15K miles?

I just find it strange that the Porsche would have an oil change interval that's 5 times longer than the GM engine. Any ideas, knowledge or hints?

ec437 · #2 10-21-2004, 01:20 AM

Porsche=german
GM=american

need I say more?

neo the hacker · #3 10-21-2004, 02:29 AM

Like he said german. but i still change mine every 3k, because i love it!

83-944 · #4 10-21-2004, 06:36 AM

15k miles the maximum amount of miles before an oil change so long as you drive it only on clear, dust free days, on highways only, during certain times of the year, always shifting at 3krpm max, and changing your oil filter every 1000 miles. Otherwise change it sooner. j/k

930guy · #5 10-22-2004, 09:54 AM

Also 3K is recommended for any non-synthetic oil. Semi-synthetics and full synthetics range from 5K-15K depending on driving style. Here's my 2 cents on synthetic-Mobile 1 that you buy at Wal-mart or Auto Zone is NOT the same grade that Porsche came with. Most cars That I have delt with that had Mobile 1 in it showed extreme wear on the valve train(Cam specifically) Products like Amsoil, Royal Purple and Lucus are top grade synthetics that will protect you engine and last the 15K

neo the hacker · #6 10-23-2004, 03:37 AM

I wouldn't put anything thinner than a 15w40 in my 944, Comma do a 15w40 semi synthetic called XT2000.

eohrnberger · #7 10-27-2004, 12:21 AM

I've been a Mobile 1 type of guy for my Grand Prix since day one, and it's not treated me badly at all. Of course the car has only 25K miles on it, so it's probably too early to tell.

lost944 · #8 10-27-2004, 12:37 AM

I dont know if anyone really cares but I just got to watch my 944 burn to th ground because it took the fire dept. 20 mins. to go a 1/4 mile up the street to put my car out.
real bummer I had so many plans for my baby.

eohrnberger · #9 10-27-2004, 12:51 AM

Sorry to hear that. Must have been a really traumatic event for you. Hope that you are doing better these days.

neo the hacker · #10 10-27-2004, 03:09 AM

RIP 944, DONT WORRY, its gone to a place much better. Sorry mate.

930guy · #11 10-27-2004, 11:25 AM

Probably a sensitive subject-but how in the world did you manage to cook a 944?

zzpza · #12 10-27-2004, 11:41 AM

yeah, what happened?

RIP

eohrnberger · #13 10-27-2004, 12:25 PM

I'm particularly interested as I'd want to prevent it from happening to me. I'm sure that others would like to know as well.

83-944 · #14 10-28-2004, 02:16 AM

Ouch, that's sad to hear.

eohrnberger · #15 10-28-2004, 10:12 AM

I bought the 944 with 175,000 miles it, and I don't know which type of motor oils have previously been used. I plan on switching over to Mobile-1 when I have a lube, oil change, oil filter change performed at the next service.

I've heard that Mobile-1 is a high detergent oil, and could very well loosen up all the accumulated 'crud' in the lower 1/2 of the engine. This would probably choke the new oil filter. Best to clean it out first. When I asked the mechanic how to clean out the gunk before switching to Mobile-1, he said that a good procedure would be:

Put 2 quarts of ATF and then fill the rest with some crap motor oil
Drive very gingerly for 5 miles
Drain the old oil out
Replace with Mobile-1 and a new oil filter

I have to admit that I've never heard of such a procedure, but it would appear to make some sense to me. From what I understand, the ATF is a very high detergent oil, and would really clean out the engine's innards. It would also seem to me that a short 5 miles driving gingerly with that mix of stuff in the engine shouldn't damage anything. What do you guys think?

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