OK, 1st oil change (be nice please..lol)

[JESSEGG]

Hey everybody,

My oil filter is coming in from Pelican by the end of the week, granted the tragedy in Oklahoma doesn't slow down shipping. I appreciate all of the advice about which type of oil to use, so I did decide on a blend and I have six quarts of that coming as well by tomorrow. Now I don't want to start an OIL WAR here, what I am looking for is some feedback. I bought his vehicle on 03/27, from a private seller, engine, gearbox, clutch are all very strong. I have a minor oil leak that I haven't identified yet, I notice 2 spots on my driveway pan in the morning, (front and rear on the passenger side). I am going to investigate it further just before I do the change to try and figure it out.

I went with the Brad Penn 20w50 for now and I'm planning on doing an engine system cleaning before I do the change because I really have no clue what was put in this vehicle (oil wise) and have just been adding an SAE 20w50 to top it off the last few months. The speedo head says 151,891 miles on it..whenever it BROKE so I'm guessing this engine is over 200K..but still just a speculation, it runs very very strong. This vehicle was a rebuild.

I want to run this stuff in the engine before I do the oil change.



Any thoughts? I'd like to clean this motor out before I change the oil. Am I on the right track and if so what are your suggestions.

Thanks as always,

Jesse

[Panzer909]

You can use that stuff if you want and it should be fine. You'll obviously get wildly different opinions on this subject. Every once & a while I'll dump some ATF into my crank, let it idle for about 10mins, then drain the oil. And almost every time, I've seen small goups of gunk deposits come out. So it must be doing something right

[HondaDustR]

IMHO, 20W-50 is too thick. People get all up about holding "good" oil pressure even at idle, but think about it...it is a pressure relief system. If the pressure relief valve regulates the pressure at 4 bar, the oil pump is a constant volume positive displacement pump (flow rate follows rpm pretty linearly), and you're hitting 4 bar at 2000-2500 rpm, you are pumping most of your oil through the relief valve and not the engine bearings. You really only need a minimum of 10 psi per 1000 rpm to ensure sufficiently balanced oil supply to all the bearings, but I like to see 1 bar per 1000 rpm myself for extra assurance. Hydrodynamic bearings do not require pressure to operate. The pressure is just to ensure that every bearing is sufficiently supplied with oil, since it is a distributed hydraulic feed and not every bearing is going to present the exact same hydraulic flow resistance, causing some bearings to possibly starve in a low pressure condition (fluid flow is a lot like electricity...it will always show a preference for the easiest way through). Since oil flow is what cools the bearings, low flow through the bearings will make the bearings actually run hotter and wear faster, besides the localized hot spots will break down, or "shear out", the oil much quicker. A 50 weight would only be needed on "looser" engines that use oil or don't hold oil pressure when hot on thinner weights. It's the fluid shear friction inside the bearings that heat up the oil, requiring an oil cooler for extended high rpm applications (sports cars, race cars). The "stop and go" traffic that the oil ads tout as brutal for oil is actually about as easy a life as oil can get, since the shear loads are low at idle and the bearing temps are pretty much the engine temps. Run at 5000 rpm for an extended time and the sump oil temp will easily climb to 240+ deg F. The bearing oil temp with a slow flowing oil will be much much hotter than that, which will actually cause the oil to thin out much more inside the bearing, possibly compromising the film thickness under load possibly even more than just running a 30 weight and certainly accelerating the breakdown of the oil. You don't want to be relying on the boundary lubrication capabilities too much. Ideally, you want only sufficient pressure and as much flow as possible.

That being said, a 40 weight is a good all around choice. I run a 30 weight myself and it seems to be just fine, but I'd switch to a 40 weight for any autocross/track duty, as pressure drops a bit more than I'd like past 220 deg F on the oil temp gauge the off chance I get to run it that hard long enough.

[princej]

Originally Posted by HondaDustR

IMHO, 20W-50 is too thick. People get all up about holding "good" oil pressure even at idle, but think about it...it is a pressure relief system. If the pressure relief valve regulates the pressure at 4 bar, the oil pump is a constant volume positive displacement pump (flow rate follows rpm pretty linearly), and you're hitting 4 bar at 2000-2500 rpm, you are pumping most of your oil through the relief valve and not the engine bearings. You really only need a minimum of 10 psi per 1000 rpm to ensure sufficiently balanced oil supply to all the bearings, but I like to see 1 bar per 1000 rpm myself for extra assurance. Hydrodynamic bearings do not require pressure to operate. The pressure is just to ensure that every bearing is sufficiently supplied with oil, since it is a distributed hydraulic feed and not every bearing is going to present the exact same hydraulic flow resistance, causing some bearings to possibly starve in a low pressure condition (fluid flow is a lot like electricity...it will always show a preference for the easiest way through). Since oil flow is what cools the bearings, low flow through the bearings will make the bearings actually run hotter and wear faster, besides the localized hot spots will break down, or "shear out", the oil much quicker. A 50 weight would only be needed on "looser" engines that use oil or don't hold oil pressure when hot on thinner weights. It's the fluid shear friction inside the bearings that heat up the oil, requiring an oil cooler for extended high rpm applications (sports cars, race cars). The "stop and go" traffic that the oil ads tout as brutal for oil is actually about as easy a life as oil can get, since the shear loads are low at idle and the bearing temps are pretty much the engine temps. Run at 5000 rpm for an extended time and the sump oil temp will easily climb to 240+ deg F. The bearing oil temp with a slow flowing oil will be much much hotter than that, which will actually cause the oil to thin out much more inside the bearing, possibly compromising the film thickness under load possibly even more than just running a 30 weight and certainly accelerating the breakdown of the oil. You don't want to be relying on the boundary lubrication capabilities too much. Ideally, you want only sufficient pressure and as much flow as possible.

That being said, a 40 weight is a good all around choice. I run a 30 weight myself and it seems to be just fine, but I'd switch to a 40 weight for any autocross/track duty, as pressure drops a bit more than I'd like past 220 deg F on the oil temp gauge the off chance I get to run it that hard long enough.

what you say in theory makes sense.

but i did my first oil change last week. went from 10w40 to 20w50 VR1 racing oil. and honestly my car has never run better. quieter, smoother. all in all, 20w50 , my car seems to love it.


the only thing I forgot to do was the add some seafoam 15 minutes or so before I dumped the old oil out. next time i guess. and i was surprised how dirty the oil was, considering the low km's I put on it.

[alan6272]

20w50 European blend oil here

[mytrplseven]

Higher mileage engines within the proper temperature range (see the owners manual) are more than adequate. If it's too low viscosity, you'll notice lifter noise and strange oil pressure ranges. Most of us in the lower 48 run 20W50 on high mileage engines with no problem.

Now as far as the oil leak issue, I'd start with the easy issues first. If your car is a N/A car, there's a cork gasket at the rear of the cam tower that is a common leaker. It's close to the firewall which is a pain but It's worth changing. Don't tighten it down real tight or it'll crush it and make it leak again soon. Check a Haynes manual or see Clarks Garage for the proper torque value so you'll get an idea (although you won't be able to get a torque wrench in there anyway). If it's in the front of the engine, It's likely the forward cam seals and that's a bigger issue. Also the seal around the Oil Pressure Relief Valve.

To better chase these leaks down, buy a flourescent dye kit at the auto parts store (dye, glasses and special flashlight). Their cheap and a real God-send in chasing leaks. It can stay in the oil until the next oil change with no problem. Also remember, if there's a leak, it's usually from a rubber seal. All the seals are the same age so expect more of them to begin leaking in the near future. After my 3rd 944, I just went throught the whole engine, front to rear, and replaced every seal, including the little rubber ones in the Throttle Body (vacuum leak).

[Gawernator]

I also vote for 20-50w VR1 and Seafoam/Techron treatments

[fmartinez1897]

I put atf in the oil right before a change, let it idle for about 10-15 mins and changed the oil. The amount of sludge that came from the engine blew my mind! The 20w50 is great as recommended by some of the people on here (which I listened to and am very thankful). Seafoam is great stuff Use just 1/3 of the can if you're going to mix it with the oil though too much can seriously damage your engine.

[princej]

i was going to put less than a quarter of a can of seafoam.

how much atf did you add?

[porschetub]

You will never hurt your engine running 20/50W,don't like additives or cleaners but thats just me,but I have seen and experienced lifter problems with so called cleaner/flushers .
Everything you need is in the oil to start with ,so called oil improvers are best left behind the BS TV ads.
Extra oil changes will generally clean out a dirty motor - worked for me many times.

[princej]

Originally Posted by porschetub

You will never hurt your engine running 20/50W,don't like additives or cleaners but thats just me,but I have seen and experienced lifter problems with so called cleaner/flushers .
Everything you need is in the oil to start with ,so called oil improvers are best left behind the BS TV ads.
Extra oil changes will generally clean out a dirty motor - worked for me many times.

excellent advice.

a high quality 20w50 oil. dont need any additives.

[VINMAN]

[jep32]

We need 20w-50 or 15w-50 in our cars. Brad Penn or VR1 are what I run in my S2. There are many, many threads out there that would suggest the same thing.

[VirginiaF1]

Originally Posted by HondaDustR

IMHO, 20W-50 is too thick.
I run a 30 weight myself and it seems to be just fine.

Here in Virginia, your 30 weight seems "low" in contrast to the conventional wisdom of "50" often espoused...
But inlight of your flow vs. film treatise, it makes sense; especially during our mild Fall, Winter & Springs.

What viscosity are you currently running? 5w-30? 0w-30?
Will you switch to a 40 weight by summer?
Also, which brand & version? (eg: Valvoline VR1 10w-30)
TIA!

[HondaDustR]

Originally Posted by VirginiaF1

Here in Virginia, your 30 weight seems "low" in contrast to the conventional wisdom of "50" often espoused...
But inlight of your flow vs. film treatise, it makes sense; especially during our mild Fall, Winter & Springs.

What viscosity are you currently running? 5w-30? 0w-30?
Will you switch to a 40 weight by summer?
Also, which brand & version? (eg: Valvoline VR1 10w-30)
TIA!

I'm running Castrol edge 5W-30. It's a good oil, one of the best I'd say, and still a group IV synthetic as far as I'm aware, but just a little bit thin for a 30 weight, not my first choice for the summer, and I haven't seen it in a 40 weight. I prefer the Castrol syntec 0W-30 euro formula all year, as it is a bit thicker for a 30 weight and the 0W offers excellent cold start flow esp in the winter, but I can only find it at Autozone and it wasn't on sale at the time. It's like $8.50/qt unless they're running their oil and filter combo deal that drops it to around $5/qt for the first 5 qts when I can get 5 qts of edge for $26 at walmart. It's gotten a lot harder to find good stuff in a 40 weight locally, and I've been too busy/broke to buy online lately. I also will not run a 50 weight unless I actually get to run on a track one of these days and find out a 40 weight doesn't hold up pressure in the heat. I won't even consider using a pure conventional either. I redline my engine on a regular basis and I really prefer the seemingly higher shear stability of synthetic. Synthetic combined with frequent high revving keeps the insides of the engine spotless clean. My original engine autopsy revealed nearly nonexistent oil varnish, whereas the replacement for rebuild needed a lot of cleaning.

Back in the older days when I ran 20W-50 brad penn in the summer, it would seem to shear out and drop pressure a bit after a couple weeks of driving. Never dropped too much, but I could tell it changed the consistency of it. But that was back when I thought hitting 4 bar at 2000 rpm was a good thing, and it changed to only hitting 4 bar past about 4000 rpm. If the oil changes like that, something extraordinary must be happening in the bearings to cause it, and that can't be good, since it may also affect other important additives. Generally speaking, from what I remember on Bob is the oil guy, conventional oil needs additives to make it behave like a thicker oil when hot whereas synthetic needs additives to behave like a thinner oil when cold. So theoretically, conventional oil thins out to more like the "W" weight at high temp and synthetic tends to thicken up to more like the second number when cold when the viscosity modifiers get trashed.

20W-50 is an absolute no no in the winter I've found. One time where it got very cold a bit early and the oil was still fairly new, and I was stuck at school, the oil pressure was painfully slow to come up on startup. Back then it was on the old engine which used a qt every 500 miles, so I was topping it up with Mobil1 0W-20! If it takes 3 seconds to reach the peg on startup, it's just not even going to flow through the bearing clearances cold, and winter oil sump temps are maybe 120 degrees on the highway, too. Reminded me of the time I was trying to oil my A/C compressor freewheel bearing with gear oil through a hypodermic needle...virtually impossible to get any through it.

So long story short, for the lower oil temps of daily driving, I like the additional flow, cold start circulation, and all season performance of the 30 weights. For track duty, for which I have not yet had experience with (some day!), I think I'd definitely prefer a 40 weight, although I have had a couple chances for extended hard running out in the mountains last summer and the syntec 0W-30 held oil pressure just fine at 220-230 deg F oil sump temp.

[333pg333]

If running a thicker dino oil was so bad at startup, why back in the late 70's, through the whole 80's and into the 90's (ie 924, 944 n/a, 951, S2 & 968 era) weren't there literally thousands upon thousands of these cars worldwide suffering massive engine wear/failure?? Nobody was running 0w/30 synthetic back then? Conversely, why do workshops see cars that have been running low visc synth with low ZDDP with accelerated engine wear yet the ones that they have run a 20w/50 dino on last many many hundreds of thousands of kilometers and upon inspection look virtually brand new inside???

[HondaDustR]

Keyword "with low ZDDP"...apples and oranges man. Boundary EP lubrication is totally different from hydrodynamic lubrication and ZDDP is only significant when considering boundary lubrication mostly found in the top end. That's a completely different issue. It gets complicated, because today's oils are nothing like what was on the shelf 30 years ago. Most cars from the 70's/80's are long gone, and the few that I have seen go personally growing up had some pretty tired engines. A lot of that I bet has to do with just outdated metallurgy, manufacturing tolerances, and stone age engineering.

There are three things I have learned never to discuss with people...no, wait, make that four things: religion, politics, the Great Pumpkin, and choice of motor oil.

Even my dad gets defensive when I show only passive approval for royal purple.

[333pg333]

You make a plausible argument but are either very wordy, technically experienced, neither, or both....but you also make my point for me. By virtue of the outdated metallurgy, outdated oils and general lack of awareness for oil analysis let alone no understanding of ZDDP and general oil packages back in those aforementioned decades, we then should have, as stated before, historical examples of maybe 100,000's of failed Porsche 944's. By your own distinctions alone we have been using the wrong oils for decades....yet...yet...the cars running these dinosaur...I mean, dino oils, are still spinning along happily. That's Part 1. Part 2 is the converse. Many workshops suddenly found excessive wear in flat tappet motors. What was the common denominator??? Mobil 1 low viscosity synth oil. The truth is the truth is the truth...

[HondaDustR]

Well, Mobil1, along with a lot of others, long since went to hell back when the API SL spec hit the shelves. Haven't used or endorsed that oil in quite some time. I also would not put the engineering technology that went into the 944 engine on the same level of comparison to that of any american iron from the same era. The bottom end of that motor has remained essentially unchanged from the prototype '82 LeMans car that was making 400+ hp with a turbocharged 16v head, and won IIRC.

But the flat tappet issue should not be a function of oil viscosity, as it is an issue of boundary lubrication, meaning metal on metal, requiring the phosphorous compounds to act as a barrier to that. The pressures encountered in flat tappet valvetrain will squeeze any oil out, so I bet viscosity has little to do with the issue. The issue there is the EPA mandating 100,000 mile warranties on catalysts, and phosphorous kills catalysts. The easy solution is to cut phosphorous compounds and either replace them with some other unknown EP edditive that is not as effective, or just assume that enough vehicles are running crappy econno low lift cams with 4 valve per cyl roller followers and 6K rpm redlines so they can get the spring pressures and the valve acceleration profiles down to where it doesn't matter anymore to run less EP additives. The automakers would just worry about how to get through that 100K window, and then the rest is on you, the owner. Passing the buck, so to speak.

But for 99% of the market, the only thing that's ultimately going to matter is to change the oil often enough, which is much shorter for conventional than synthetic. 99% of the vehicles never see the backside of 3K rpm, and the ones that do don't see it for long. It just doesn't matter in the grand scheme of things, but I like to at least have a plausible reason for why I do what I do. What I'd like to do is get some track time, wear out a couple engines doing what they're meant to do, and then form an updated opinion based on that. But based on my experience so far and my mechanical engineer's intuition, I think a 50 weight is needlessly thick for the vast majority of vehicles made in the last 25 years with bottom ends in spec.

[JESSEGG]

Originally Posted by mytrplseven

Higher mileage engines within the proper temperature range (see the owners manual) are more than adequate. If it's too low viscosity, you'll notice lifter noise and strange oil pressure ranges. Most of us in the lower 48 run 20W50 on high mileage engines with no problem.

Now as far as the oil leak issue, I'd start with the easy issues first. If your car is a N/A car, there's a cork gasket at the rear of the cam tower that is a common leaker. It's close to the firewall which is a pain but It's worth changing. Don't tighten it down real tight or it'll crush it and make it leak again soon. Check a Haynes manual or see Clarks Garage for the proper torque value so you'll get an idea (although you won't be able to get a torque wrench in there anyway). If it's in the front of the engine, It's likely the forward cam seals and that's a bigger issue. Also the seal around the Oil Pressure Relief Valve.

To better chase these leaks down, buy a flourescent dye kit at the auto parts store (dye, glasses and special flashlight). Their cheap and a real God-send in chasing leaks. It can stay in the oil until the next oil change with no problem. Also remember, if there's a leak, it's usually from a rubber seal. All the seals are the same age so expect more of them to begin leaking in the near future. After my 3rd 944, I just went throught the whole engine, front to rear, and replaced every seal, including the little rubber ones in the Throttle Body (vacuum leak).

Great advice man, appreciate you. I'll do it.