Oil Cooler Questions

[zodman]

First the background:

Out of necessity, the oil cooler was removed to help remove the 1-3 manifold. Upon its removal, two pieces of an older water pump blade were found. (One large fragment, almost the length of one blade. The smaller one is about the size of the tip of another blade.) These have been lurking in the coolant for at least as long as I've had the car. (2007) I have changed the water pump once already for reasons of preventative maintenance. The one in the car now and the previous one I replaced were not damaged. I don't know if all the fragments of the blades from the previous owner have been found, but there are a few tiny bits of black debris in the flywheel side of the anti-freeze channel inside the oil cooler, lodged in the layers inside....These could also be tiny bits of the rubber seals for the oil cooler as the old seals on the coolant side appear to be starting to disintegrate.

The driver side channel (where the hose connects as well) appears to be clear. The residual content in both oil cooler channels of the oil cooler appear to be clear.

Which leads to these few questions related to the Oil Cooler on a 2001 6speed BoxsterS:

1. I'm considering just buying a new oil cooler, but if I can just "flush" out the debris with the old oil cooler submerged in a water bucket and a hose to blast out the gunk (however minor) would the old one be good to use if dried out properly? (It appears on the surface to be no different from the LN Engineering reusable oil filter.)

2. I put a funnel down the anti-freeze channel/flywheel side of the engine where the oil cooler mounts and ran some of the previously drained coolant after I filtered it so it would backwash out through the thermostat hookup after I removed it....I can see there is some more debris along that channel hole...Can I just use a water-hose on low power or would that leave a few bits of Ionized water inside the anti-freeze passages of the engine where there shouldn't be any? The goal is to help flush any potential bits out.

3. There is a slight chance some coolant entered the oil holes right where the oil cooler mounts when the oil cooler was first removed. Possibly 1 or 2 teaspoons to maybe none at all....it happened very quickly and I moved it away from the block to spill the rest of its contents on the floor. So, if I pull the oil filter and also drop the oil pan, would that suffice to confirm the presence and removal of said coolant? (I recall the flywheel side of the oil passage portion of the oil cooler leads to the oil filter.)

3a. A few drops may have also bypassed the taped over passage of Cylinder 3 and dripped in - but highly unlikely. If it did, it will likely evaporate by the time I get the whole job done.

4. Since the car has had zero problems running other than the RMS leak and apparently a failed 'positive crankcase ventilation valve' for these last 6 years, wouldn't dropping the engine and pulling the heads would amount to overkill for remnants of a water pump blade as these may have been the only fragments - or the remaining fragments of a previous water pump failure?

Sorry about being wordy...just trying to be accurate as I can be. Thanks for your input on this, it is much appreciated.

Z

[JFP in PA]

First the background:

Out of necessity, the oil cooler was removed to help remove the 1-3 manifold. Upon its removal, two pieces of an older water pump blade were found. (One large fragment, almost the length of one blade. The smaller one is about the size of the tip of another blade.) These have been lurking in the coolant for at least as long as I've had the car. (2007) I have changed the water pump once already for reasons of preventative maintenance. The one in the car now and the previous one I replaced were not damaged. I don't know if all the fragments of the blades from the previous owner have been found, but there are a few tiny bits of black debris in the flywheel side of the anti-freeze channel inside the oil cooler, lodged in the layers inside....These could also be tiny bits of the rubber seals for the oil cooler as the old seals on the coolant side appear to be starting to disintegrate.

The driver side channel (where the hose connects as well) appears to be clear. The residual content in both oil cooler channels of the oil cooler appear to be clear.

Which leads to these few questions related to the Oil Cooler on a 2001 6speed BoxsterS:

1. I'm considering just buying a new oil cooler, but if I can just "flush" out the debris with the old oil cooler submerged in a water bucket and a hose to blast out the gunk (however minor) would the old one be good to use if dried out properly? (It appears on the surface to be no different from the LN Engineering reusable oil filter.)

2. I put a funnel down the anti-freeze channel/flywheel side of the engine where the oil cooler mounts and ran some of the previously drained coolant after I filtered it so it would backwash out through the thermostat hookup after I removed it....I can see there is some more debris along that channel hole...Can I just use a water-hose on low power or would that leave a few bits of Ionized water inside the anti-freeze passages of the engine where there shouldn't be any? The goal is to help flush any potential bits out.

3. There is a slight chance some coolant entered the oil holes right where the oil cooler mounts when the oil cooler was first removed. Possibly 1 or 2 teaspoons to maybe none at all....it happened very quickly and I moved it away from the block to spill the rest of its contents on the floor. So, if I pull the oil filter and also drop the oil pan, would that suffice to confirm the presence and removal of said coolant? (I recall the flywheel side of the oil passage portion of the oil cooler leads to the oil filter.)

3a. A few drops may have also bypassed the taped over passage of Cylinder 3 and dripped in - but highly unlikely. If it did, it will likely evaporate by the time I get the whole job done.

4. Since the car has had zero problems running other than the RMS leak and apparently a failed 'positive crankcase ventilation valve' for these last 6 years, wouldn't dropping the engine and pulling the heads would amount to overkill for remnants of a water pump blade as these may have been the only fragments - or the remaining fragments of a previous water pump failure?

Sorry about being wordy...just trying to be accurate as I can be. Thanks for your input on this, it is much appreciated.

Z

Failure of the composite water pump impeller is a constant issue on the M96/97 cars, but switching to a metal impeller is a complete no-no as the clearance between the impeller and the engine case is very tight, and as soon as the water pump shaft starts to wobble a bit (and they all do), you are going do some impromptu machine work on the engine case, filling the cooling system with fine metal filings as well. Getting as much of the composite impeller out of the system is a priority, as even small bits can block critical passages in the cylinder head, leading to very big problems.

When trying to back flush the cooling system with the oil cooler removed, rubber stoppers (Lowes and other home centers sell them in various sizes) are your best friend. Plug the oil openings with rubber stoppers and no coolant will enter the oil system. If you have inadvertently gotten coolant into the oil system, you best bet is a full oil and filter change once the car is back together, followed by a long drive to heat everything up and flash off any residual coolant.

Cleaning out the oil cooler assembly is often troublesome as some passages are very small. Again, the use of rubber stoppers can help keep the wrong fluids out of the wrong passages. If you are uncomfortable about some impeller bits remaining, the easiest and best way is to just buy a new cooler (about $200 or so at Sunset Porsche). But regardless of whether you clean yours out or get a replacement, get all new O-rings as these cheap seals are single use only items.

[zodman]

O-rings and other seals will be replaced just as a precaution and as proper maintenance. Getting a new water pump with metal blades is out of the question from the get-go...I thought I was pretty clear that all previous (known) blades were composite, with the last two (pumps) intact and pristine, with zero metal frags in the coolant. Only plastic bits from an unknown previous owner's water pump failure were found. Any new water pumps handled by me for this car will also be composite.

I'll look into getting some rubber stoppers...Wish I could find the transom plug as well at Lowes for removing the spark plug tubes.

If the oil cooler could be reused, that would lend more money in my budget for other tools/+or that fabspeed exhaust, but without seeing the actual build schematic of the oil cooler, to aid in flushing it out, I'm leaning towards replacing it.

Thanks for the bits of info JFP