Last month I was blessed enough to buy my dream car, a 986 Boxster S. It's a 2000 at a price I couldn't pass up from someone who knew the car had issues at 93k miles. He was convinced the motor was blown because it would smoke under load. Replacing the AOS completely fixed the smoke, but now I'm realizing the car does have other unresolved issues which may push the envelope of my capacity.
Yesterday I noticed some brown droplets in the expansion tank 3 weeks after flushing the old coolant. I went for a 20 mile drive and noticed more oil. It's not completely intermixed, but a few ounces floating up top. Needless to say I haven't driven it since. They're doesn't appear to be coolant in the oil, and the car runs great with no smoke even at start up since I've changed the AOS.
I understand the intermix can be caused from numerous modes of failure and was hoping this knowledgeable group might be know of tests to help eliminate some possibilities and possibly pinpoint the issue. Here's what I'm hoping to DIY:

1) Pressure test the Heat Exchanger- according to Raby it's pretty rare failure point but its worth a shot, right?
2) Conduct a leakdown test- I'm worried about misdiagnosing a leaky chamber as the issue. Although this would be an issue to resolve in of itself, it doesn't mean it's the cause of the intermix. Is there anything else I should try to pinpoint the issue short of removing the engine? I'm pretty handy, but I don't have a lift nor the funds to take it in for a thorough rebuild.

Here's what I've done to the car since I purchased it. BIG thanks to Pedro's DIY!
1) Replaced AOS- The old AOS was covered with thick brown scum, which my local parts store said was OK considering it's failure. No smoke what so ever now, only from my cigars.
2) Cleaned the throttle body, vacuum hoses and intake manifold. It was really oily, but black and clean.
3) Coolant Flush- (I did notice an oil sheen, and brown color but it was watery, not milky. I figured I would change it before worrying.
4) Replaced clutch fluid- added Swepco 201. (Smooth as a baby's rear)
5) Spark plug and O-ring replacement- The oil on the tubes were black and clean. The plugs threads were covered in oil. The spark plugs were gray ash fouled.
6) Replaced thermostat & housing to low temp to 160F- the temp was constantly just south of 200F so this helped quite a bit.
7) Cleaned the MAF
8) Replaced the Air Filter
9) Changed the oil. No sign of coolant.

Thanks in advance for your help everyone!
-Julio

from which oil can get into the coolant. That the engine is running good with no check engine light and the plugs came out with no signs of coolant having gotten on them (they would be rather clean ("steam cleaned" from the coolant) I am thinking any leaks from a head gasket or cracked head or cracked block or porosity are probably down on the list of possible explanations.

My WAG would be the leak is with the oil/water heat exchanger. This may have developed a pin hole leak or a bad o-ring.

BTW, the clutch fluid uses the brake fluid so you want to be sure you use a suitable brake fluid and flush/bleed the brakes then the clutch.

Not sure that T-stat change the right thing to do. Studies have shown engine wear goes up as coolant temperature goes down. But for now focus on id'ing how the oil is getting into the coolant.

... fluid that you replaced with Swepco 201
The reason why your car is running cooler now with the new thermostat is because its new, not because its a 160 t-stat.
Your old t-stat was probably not opening enough to allow good coolant circulation.
After the engine reaches its operating temperature no thermostat in the world is going to reduce the temperature.
Once a t-stat opens that's it. I can't control anything after that.
The 160 degree thermostat (to me) is a ripoff.
The heat exchanger can intermix, so testing it makes sense,
A cracked cylinder, a porous block or a leaky gasket are the other possibilities.
Good luck.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 314,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

My apologies for getting it mixed up, remember I'm new at this. Thankfully, all your time and effort to know these cars imparted a wealth of knowledge to my disposal, and I'm hoping I can fix this issue without breaking the bank.

Is there a way to diagnose a cracked head compared to a faulty gasket, porous block or other anomaly without dropping the engine? I'm fairly certain I'm going to have to drop it regardless, but if I have a good sense of what the issue might save me from a costly full tear down.

... major engine work, test the heat exchanger.
It's the simplest and cheapest of the possible causes.
Good luck
Pedro

Pedro Bonilla
1998 Boxster 986 - 314,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

Ah, you have me reminiscing about my younger days when cars were designed to fall apart the moment warranty lapsed, and I had no money.

Remember starting ether? Ms Ether was my closest friend.

Peace
Bruce in Philly

I do. Or there once was my Alfa that had a problem with the starter gear engaging so I carried a dowel and a hammer around. To start, raise hood, apply dowel to starter, apply hammer to dowel, close hood and start.

Those were the days, my friends...

Grant

gee-lenahan-at-gee-mail-dot-com

Thanks Boxsterra, I'll be sure to give that recommendation a try. I heard you get best results when 3 cans are added right into the gas tank. Would you be a pal and try it on your car first, and tell me the results? Just consider it a preventative measure.

It's intended to be used in the coolant. Only a little more than one bottle is the recommended dosage. It's fairly expensive so I would go with one bottle and see if it works.

that's why he asked you to do it

Grant

gee-lenahan-at-gee-mail-dot-com

I would add some kseal to the coolant.

+1 on Pedros recommendation: check the heat exchanger

I replaced the oil cooler/ heat exchanger. Once the engine warmed after a coolant flush I found some intermix in the oil for the first time. Just before I changed out the oil cooler I pumped out 3 oz to send for analysis- It looked black & normal then, but not anymore. So I guess there is some good news- I don't have to worry about that oil analysis!
Next up- leak down test, which I'll have to perform on a cold engine. I don't need that intermix causing more damage. If the pressures come back (at least fairly) normal I'll change the oil, warm the car and try it again.

I forgot to mention- I pressure tested the cooling system before the flush, and it dropped 1 psi (from 19 to 20) in about 10 mins. How long should the pressure normally hold?

then afterwards run the engine some -- let it idle until warm -- then change the oil/filter again. To be safe I'd be tempted to provided the engine was behaving ok to drive the car around say an hour to get the engine fully up to temperature then do another oil/filter service.

No need to beat on the engine but use some RPMs to ensure the oil in the lifters gets flushed and replaced with fresh oil. Stay close to home though or within good cell phone coverage for if the engine begins acting up any at all shut off the engine ASAP and get the car towed. I don't think the engine will have suffered any. I've come across worse cases of intermix and the engine with proper post intermix care -- mainly oil/filter changes -- came out unscathed.

The first drain gets rid of most of the contaminated oil. The second drain removes the oil that has intermingled with any residual oil left in the engine that was intermixed. The 3rd drain then removes the oil that has had a good chance to intermingle with the oil in the lifters.

The result of after 3 oil/filter services is the oil in the engine is about as free of any coolant intermix as it can be.

Overkill? Maybe. But to me if the engine came out of the intermix event with no obvious problems I would have considered myself very lucky in dodging a very big bullet and I would be reluctant to press my luck believing that I could scrimp on the oil/filter services and come out lucky a second time.

If the engine is running ok and with no CEL I'd not bother with a leak down test. The leak down test could deliver invalid results which could have to you worried for nothing. As the engine runs the DME constantly checks each cylinder for proper operation -- by measuring the acceleration imparted to the flywheel during the power stroke - and if it finds one or more weak cylinders will log the appropriate error code and turn on the CEL. Then you do a leak down test to help you determine where in the cylinder the problem might be.

If someone is doing the 3 quick turnaround oil changes as you suggested, are they to use Mobil 1 or a cheaper grade of oil?

How does the DME check the acceleration imparted from each cylinder to the flywheel?

intend to run in the engine afterwards.

I know using say Mobil 1 0w-40 or one of the other approved oils is expensive, but I would be willing to spare no expense, well, within reason, to ensure the engine was free of the contaminated oil. At the same time I would not like use some inappropriate oil that puts the engine at risk of insufficient lubrication during this flushing process.

IOWs, I would always use the right oil (any one of the approved oils) for this flushing to avoid while escaping from the frying pan only to possibly end up in the fire from using an unsuitable oil in this flushing process.

There is another problem in that some of this unsuitable oil remains in the engine so one works to remove intermixed oil only to replace this intermixed oil with a similar amount of an unsuitable oil. While the unsuitable oil is (probably) not as bad for the engine as the intermixed oil when you then fill up the engine with (hopefully) the good stuff oil this good stuff oil gets diluted some, degraded some, with the remnants of the unsuitable oil using for flushing the engine.

The DME uses the signal from the crankshaft position sensor to measure acceleration imparted by each cylinder to the flywheel. This sensor -- it is most often a Hall effect sensor -- gets triggered every time a metal tab on the flywheel whizzes pas the sensor which is mounted to have just a small gap of air between it and the tabs. Oh, the tabs are courtesy of a ring of tabs located towards outer circumference the flywheel which has around it a ring of metal tabs evenly spaced, save for one spot that has one (or possibly) two) tabs missing.

As each cylinder enters its power stroke and the burning fuel mixture presses down on the piston this should cause the flywheel to accelerate a measurable amount. By timing the time between the consecutive signals from the crankshaft position sensor the DME knows the cylinder is healthy or not healthy.

If one or more cylinders result in unhealthy readings for too many power strokes the DME registers a misfire for those cylinders and turns on the CEL.

Any name brand 10w30 or 5w30 would be fine. They are all 100% compatible. The big differences will be:

1. performance under high temperatures, which you will avoid
2. long term breakdown will be more, but you wont keep it long term
3. high rpm protection will be less, but you wont run it at hgih rpm, not sustained
4. additive packages will be less - but you wont run it long

The one caveat is that you want a good detergent package - that's part of what you are using during the flush.

but do not run it hard when you have a dino 10w30 or 5w30 in it.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

you are going to use in the engine to do any flushing.

Its simply a waste of money. You need a compatible fluid to float the bearings and drive the hydraulics. No more. They have the same viscosity within modest temperatures. Give just one technical reason why not,, and I'll seriously listen.

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 10/25/2014 06:54AM by grant. (view changes)

a Raby postings where he suggests flushing with an oil (Valvoline VR-1 in 2011, Gibbs BR-40 in 2014) that is different than the oil he recommends for long term use (Gibbs DT-40).

Certainly Marc's suggestion is very safe, no question. But if i sat down to formulate an oil for this purpose it would be:

- adequate performance for modest temps, and rpm's
- minimal buffering
- maximum detergent
- minimal viscosity consistent with #1 above
- cheap

Which is why i suggested what i did.

Is it a great choice for long term use? No - bad in fact.

but this is not long term or even normal use.

Same reason you go thicker, less buffers, more post-hydrodynamic protection additives for track use. All stuff you might NOT want in a normal mix.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

if what you post is truly what he recommends is another one.

One must not lose sight of the fact the flushing oil still has to perform its job as an oil to protect the engine from any metal to metal contact while acting to flush the engine and its recesses of whatever.

The engine's oiling requirements are not suspended, reduced, during this flushing process.

All approved oils are high detergent (yet have additives that control foaming that can occur with a high detergent oil in a high RPM engine) and all will flow quite readily to every nook and cranny in the engine. This is what the oil does regardless if it is being used to flush an engine or just act as a lubricant.

Cheap doesn't enter into the equation as far as I'm concerned. I would certainly seek to buy the oil at a discount if possible, but even if the 5w-30 oil was free, vs. paying say $8/quart for the other oil, $72 is what one is willing to save while betting his engine? Geesh.

Cylinder pressures are highest at part throttle low RPM engine operation.

There's more: While my Boxster doesn't have an oil pressure gage my 996 does. Even with 5w-50 in the engine on a warm day after driving the car around town and with RPMs kept below 4K the oil pressure at hot idle drops to 1.5 bar. I can only imagine what the oil pressure would be with 5w-30 oil in the engine. (The 996 engine generally runs cooler than the Boxster engine, too.) Upon take off from a stop then the oil pressure climbs to around 3 bar at 2K RPMs. One can only guess what oil pressure the 5w-30 oil would have under similar circumstances. One can only hope it would be enough.

So much at stake. Why risk so much for so little? Saving a few dollars on oil vs. potentially facing thousands of dollars for internal engine work.

Even if the engine manages to avoid any damage from low oil pressure the engine still has around a quart or more of this flushing oil in it. So after the flushing then the engine has approx. 8 parts approved oil and 1 part flushing oil in it. (Some owners go bat you know what crazy just thinking about leaving one quart of the approved oil in the engine during a regular oil/filter service.) Thus the engine starts out with sub-par lubrication. And then one has to try to be a super crystal ball gazer to know how this might affect the oil's performance going forward. Almost certainly the service life of this hybrid oil will be shorter. But by how much? Does a 7.5K oil/filter service get dropped to 5K miles? 4K miles? 3.5K miles? How to know other than to bet the oil stays good enough long enough. And one's betting the health of his engine. And even before the oil's service life is up how is the oil's performance compromised? One crystal ball is not enough.

My recommendation stands. And it is not one I made up on my own but is what I was told by the mechanics back when I was getting my admittedly informal education and training regarding automobiles.

If the engine needs flushing, and this is only necessary under special circumstances, and in this case to resurrect an engine from a coolant/oil intermix problem is a special circumstance, when flushing the engine to use the same oil one intends to use in the engine after the flushing.

Before i go into it - your position is, of course, the "safer" position. It will always be fine - no risk. But i has a cost, about double for the oil.
And i think the risk is negligible. But if you want no risk, ....there is no such thing.

In truth the two assumptions/points are related....so maybe there is just one...

The first is that, at moderate temperatures, a 5w30 is thinner than a 5w40. While in practice it is, marginally, its really very small. It simply has a narrower range over which it maintains its film strength. Look at the ACEA or SAE curves, or the even better ones from Lubrizol.

The second is that the oil pressure at idle will be lower with a 5w30. It is certainly possible, depending on the oil, but its unlikely to be significant. again, they will have very similar viscosities in the range of 125-175 degF, which we are probably focused on. We're just flushing contaminated oil and putting around town a few miles, right?

Bear in mind that until very recently Porsche recommended 5w30 and 10w30 for "ambient typically below 50degF" They understand the temperature relationship.

I will almost promise that a 5w30 will have better film strength at 175degF than a 5w40 will at 250 degF.

I too have oil pressure and temp gauges in two cars. It shows zippo difference between them until quite hot. (not Porsche motors, but motors are motors)

Finally, the concern with thin oil is not that it will fail to float a bearing under most normal pressures, but that it cannot continue to do it when the pressure is high, combined with the rpms being high and the temperature being high, which is what the HT/HS test measures. Note that Porches A40 list is nearly a match of "search on A3/B4", which explicitly sacrifices other qualities for HT/HS.

In fact all this points to why i also suggest the flip side as well - only for hot/fast/hard use, that we intelligently modify Porsche's recommendations to maintain the viscosity and film strength under those circumstances. Its the flip side. For the record, when racing, Porsche does just this.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 10/26/2014 11:39AM by grant. (view changes)

And i don't have time to look for it.

SAE and ACEA stuff is still there if anyone chooses to dig.

Bottom line - about 10% difference at 100C

Sorry.

Grant

gee-lenahan-at-gee-mail-dot-com

I'm going to split the baby and use A40 Castrol Edge for $21.66 for 5 Qts to flush the system. Although, once I get the car right I'm going to use Mobil 5w50. I live in South Florida and hardly ever see temps under 50F. Thanks again for the help and tips
Another question- I'd really like to get this oil out of the cooling system. Would it be alright to remove the drain plug, bring a water hose to the expansion tank and run the engine? Or would this create other problems?

I have little experience flushing the coolant except when i had everything apart.
Others like have much more BTDT

Grant

gee-lenahan-at-gee-mail-dot-com

Obviously kidding. This is my oil after 512 miles and 2 months. Here's what's even more disturbing- the oil filter:


They took the wrong damned filter and just jammed it up there. I was beyond upset when I saw this. Good thing it had barely 500 miles in.

Grant

gee-lenahan-at-gee-mail-dot-com

To get oil out of the cooling system requires some kind of flushing fluid with a detergent. The detergent breaks up the oil and loosens its grip on the cooling system surfaces so it can be removed as the flushing fluid is drained out of the system.

Fortunately I have never had to deal with an intermix problem directly.

Thus I have never used any flushing fluid and do not know which one is best. (I have used the plain old water method when no oil was involved.)

About all I can suggest is you consult with a reputable radiator shop to see what it recommends for a proper flushing fluid.

The flushing fluid will have directions how it should be used.

You might be able to use Dawn dishwashing liquid. This has superb detergents to break down oil and is not harsh at all. (Dawn is used to wash animals exposed to spilled oil.) How much to use? Start with a teaspoon per gallon of water. Fill a gallon bucket with hot tap water and add a tablespoon of olive oil or cooking oil. Add a teaspoon of detergent and stir the water. Watch how the oil reacts. You want to see the oil break up and dissolve. You want to see the oil be removed from the side of the bucket. But you do not want the water to suds up dramatically. Add more detergent if you need to until you get the desired results.

Reproduce the ratio of Dawn to water in your car's cooling system.

If you use Dawn after you drain the water with Dawn (and the dissolved oil in it) from the car then you can use the water from a hose to flush the system. Put the hose into the exit hose from the radiators to flush the system backwards.

Do the same to the engine. Flush backwards whenever you can.

More than water-That's for sure. I changed the oil this morning, came back after a long day to let it idle for about 10 minutes. No fault codes, smoke, funny noises or rough idle. All was looking good and I was ready to take it out the driveway, but I thought I'd check the dipstick first. Low and behold it was milky; more coolant. It looks almost as bad as the shit I changed out this morning. So no 10 minute drive for me tonight. This will have to suffice:

this strongly suggests the intermix problem has not been resolved.

Again stating the obvious you must be absolutely sure this intermix problem has been resolved before any oil (or coolant) flushing takes place.