Engine Oil FAQ

[rohan]

sure the bearings might have oil in them but what about the cylinders?  To me that's where damage at start u p might come from along with other parts that drain.  And I wasn't really talking about 10w vs 5 w but more like 5w-20 vs 10w30.  Alot of engines now are using that because of the modern tightness of the engines.  And what engine uses 20w50?  That almost sounds like some race car oil or something

[S204STi]

sure the bearings might have oil in them but what about the cylinders?  To me that's where damage at start u p might come from along with other parts that drain.  And I wasn't really talking about 10w vs 5 w but more like 5w-20 vs 10w30.  Alot of engines now are using that because of the modern tightness of the engines.  And what engine uses 20w50?  That almost sounds like some race car oil or something

Diesels use 15w-40, and some motorcycles use heavier stuff.  Some old air cooled motors have to have 50 weight, but like you said most modern engines use much thinner stuff.

[r0tor]

a) start-up wear is real
b) depending on the oils, at 100deg C 5W-30 and 10W-30 can be the same viscosity - check mobil 1's website
c) He advocates oil thickness based on what is needed to trip the oil systems high pressure relief valve as thats what will give you maximum flow to the bearing.  Max flow means max cooling , max stability, and max lubrication.  In most cases, this is a 30 weight oil.  Contrary to popular belief, most racing series that are on the edge are running 20-30 weight oils

[rohan]

Here I found this it's pretty interesting- what's 0w5 oil thick or thin?


http://www.joegibbsracingoil.com/trainingcenter/082106.html

[Eye of the Tiger]

Here I found this it's pretty interesting- what's 0w5 oil thick or thin?


http://www.joegibbsracingoil.com/trainingcenter/082106.html

Operating temp LOL. Those drag race engines never run long enough to warm up.

[S204STi]

Updated the OLM section on page one with a caviat that I found in GM SI about distance driven on any oil fill.

[JWC]

So, what happens when you don't change your oil?   This....

....this was a 2003 Windstar, photo taken in 2004.  The van was used by a drug rep, so it was almost all highway miles.  It was one year old when towed in with a locked up motor.  Still had the original factory installed oil filter, meaning that it had never been serviced.  The odometer was reading just over 33,000 miles.  Oil was 5w-30 synthetic blend.

[Eye of the Tiger]

The awesomeness of some people's stupidity... 

[S204STi]

So, what happens when you don't change your oil?   This....

....this was a 2003 Windstar, photo taken in 2004.  The van was used by a drug rep, so it was almost all highway miles.  It was one year old when towed in with a locked up motor.  Still had the original factory installed oil filter, meaning that it had never been serviced.  The odometer was reading just over 33,000 miles.  Oil was 5w-30 synthetic blend.

[JWC]

It cost the rep around 5,000 dollars...and probably his job.   Since it was a lease vehicle, he evidently felt that making money for himself was more important than stopping somewhere for 30 or 40 minutes and getting the company vehicle serviced.  I took some photos for the lease company as evidence and happened to come across them this morning while looking for photos for the auto competition.

In situations such as this, the lease company will pay for the repairs, but will charge it back to the company the vehicle is leased to.  The adjuster told me that the usual outcome is to garnish the wages of the driver until the bill is repaid, then fire them.

Anyway, I added the photos here because I thought it would be a good example of what happens when you don't change your oil regularly. 

[Eye of the Tiger]

I know someone who never changed the oil in their brand new F-150. He towed big ass trailers with it until the 4.6L Triton turned into a 4.6L boat anchor. Not sure how many miles it lasted, but I think it was over a year of hard use, anyway.

[Byteme]

  And what engine uses 20w50?  That almost sounds like some race car oil or something

Jaguar E-Types, 4.2L engines.  20-W-50 was/is the factory recommended lubricant.

[S204STi]

Jaguar E-Types, 4.2L engines.  20-W-50 was/is the factory recommended lubricant.

Air cooled VWs too, right?  I think even the Wasserboxer liked it. 

[JWC]

Air cooled VWs too, right?  I think even the Wasserboxer liked it. 

Castrol 20W-50 was all I ever ran in my rebuilt VW engines, as well as all my Hondas. 

In my current engine, I'm running Rotella 30W.

[SVT_Power]

So one guy I know runs diesel engine oil in his Subie (400hp Legacy GT). I thought about it for a little while, and kind of seems like a good idea since diesel engines are under so much more stress than gasoline engines. So is this disaster waiting to happen for that guy's engine?

[S204STi]

No, it's perfectly safe, assuming it's a good viscosity for his motor.  If he has a built motor like that I hope he'll at least send out a couple of UOAs to make sure it's working out for him.

[AutobahnSHO]

I am really bad about oil changes. I do them probably every 5-6k miles.

I've only had one car-failure that could be caused by oil issues-
But on the SHO they said you MUST change the crankshaft/rod bearings at 100k and mine blew up on the original bearings at 172k...
So I don't blame the oil changes (or lack of) on that one.

I change the auto tranny fluid every couple years, whether there are any issues or not.

[hounddog]

Looking for a high quality, high detergent oil for the Cummins.

Went with the free-bee change that came with the purchase, but will be wanting to do quality oil in the next change.

Suggestions?

[Secret Chimp]

Looking for a high quality, high detergent oil for the Cummins.

Went with the free-bee change that came with the purchase, but will be wanting to do quality oil in the next change.

Suggestions?

Rotella synthetic is supposed to be good stuff and isn't very expensive at Wallyworld.

[hounddog]

Hmmm.  Interesting thought.

Thanks.

[Soup DeVille]

Air cooled VWs too, right?  I think even the Wasserboxer liked it. 

I remember being told to run straight 30 weight oil in the VWs. That "conventional wisdom" may have changed several times since.

[S204STi]

Looking for a high quality, high detergent oil for the Cummins.

Went with the free-bee change that came with the purchase, but will be wanting to do quality oil in the next change.

Suggestions?

Rotella, Valvoline's Blue stuff (forget the name) are both good choices.

[hounddog]

I just had to change the oil again at 8,400 miles.  That is twice as often as it is supposed to be done.

Is it the wear in period, or, is there possibly something wrong with the engine?  My fathers 2010 goes about 8,000 between changes before his computer tells him it is due.  Of course, his is the old 6.7 not the 800 lb-ft torque so it makes me wonder if mine has an issue. 

[S204STi]

Sounds perfectly normal to me.

If you're uncertain, send in to Blackstone Labs for a sampling kit, take a sample per the directions, and send it in.  They'll respond with a report that will indicate whether there are any problems whatsoever with the engine. This is a tried and true method in motorsports.

[hounddog]

Well, the oil is in the bin now, unfortunately.  I will have to wait until the next change.

It just strikes me as odd since both the manual and the dealership are telling me 7,500 between changes is what the engine is supposed to be, yet the vehicle is saying 4,000.  Who do you believe?

I have an appointment for a diagnostic on Monday, but i get the feeling they will find nothing wrong.  

I guess it really does not matter since the warranty runs for 100,000 miles, but still.  Thanks for the advice.  

[Rupert]

Believe the truck. I imagine there is a heavy duty thing that might apply.

[Galaxy]

Shell has some pretty funky oils like their 10W 60 Helix Ultra.

[mzziaz]

I filled my snowblower with 10w40 even though 10w30 was clearly specified. Did I fuck up?

[S204STi]

I filled my snowblower with 10w40 even though 10w30 was clearly specified. Did I fuck up?

Probably not. 

[S204STi]

I guess I missread your post.  I read it as, "I had to change my oil at an 8400mi interval again."

The OLM is fairly accurate, so like Rupert mentioned it's probably best to go with that.  There could be something about your driving habits or the environment around you which triggers a more aggressive response by the oil life monitor.  High humidity, cold starting temps, short trips; etc.

Well, the oil is in the bin now, unfortunately.  I will have to wait until the next change.

It just strikes me as odd since both the manual and the dealership are telling me 7,500 between changes is what the engine is supposed to be, yet the vehicle is saying 4,000.  Who do you believe?

I have an appointment for a diagnostic on Monday, but i get the feeling they will find nothing wrong. 

I guess it really does not matter since the warranty runs for 100,000 miles, but still.  Thanks for the advice.