Landseer

Great thread, I learned some things.

Nice win!

j.kenzie@sbcglobal.net

+1
Vice grips have a myriad of uses. It's great to have purpose specific tools for everything, but if you don't, it's even better to know how to make common tools serve a purpose.
Glad you got the bolt out, and I did learn about these great looking extractors.
Thanks,
Dave

dr bob

I held off on this until the mangled plug was actually out.

For those playing along at home, there was a thread in te last few years discussing these drain plugs and the factory torque recommendation. I've adopted a gentler approach to installation, including a coating of TFE thread sealing past on the bolt threads, and the sealing faces and washer. Then tighten to 15 lbs/ft or so. The threads are NOT tapered pipe threads, so let the sealing paste block fluid passage on the back of the straight threads. The paste on the sealing faces solves a galling issue typically required with sealing washers. You can use Hylomar if you don't have the TFE paste. The TFE lubricates the threads (steel into the aluminum block) and keeps them from sticking when the coolant pH starts to drop with age.

Removing just one drain plug leaves coolant in the other galley, level determined by the lower hose connection to the block. This is pretty high on the 928 engine. If you are changing the water pump, that level drops to the bottom of the water pump cavity. Bottom line, it's a Good Idea to pull the drains on both sides and get as much of the old coolant out as you can.

Part of the coolant additive package is tasked with binding any minerals left in the water. Of course the coolant recommendation includes "silicate free" to help extend the pump seal life, so having minerals in the coolant package is a no-no. Use distilled water for any flushing if you can, and for sure use it to mix with the coolant going into the car. It's too cheap to ignore.

---

In my collection of tools there's a 6-point half-inch-drive socket for the block drain bolts. Use a long bar on the correct socket, giving it a hard 'snap' pull to break any chemical bond that may have developed. The steel plug in the aluminum block, with coolant flowing continuously across the junction, is almost a perfect condition for making a Galvanic battery cell. The TFE paste does a good job of slowing the reaction by reducing the contact area, plus it lubricates the threads and sealing faces. Since these plugs come out every couple years with coolant changes, tthey should remain serviceable forever with the right care.

James Bailey

I doubt that many people actually ever drain the block........

dr bob

There's gotta be a "death spiral" GIF someplace. Changing 2/3 of the coolant every few years is kinda like removing the oil filter, draining the oil out of the filter, putting new oil in the filter and reinstalling it. Then thinking that "the oil and filter were changed". The aluminum block and heads suffer severely when the coolant pH drops below about 8.5 or so. The coolant starts scavenging aluminum ions from the surrounding metal. Leaving a quarter of the coolant load in there unchanged is like cutting off your left leg an inch at a time, then wondering why you walk in circles. The old fraction is buffered some by the new coolant, but in fact the pH of the diluted solution won't ever be right. It will continue to scavenge aluminum, just at a lower rate than a whole load of old coolant. We really want to have good enough coolant in there to leave all the aluminum where it is, I think.

monkez

I'm joining the conversation late, but that's never stopped me. Since we're talking about various tools to get into tight spots, I'm a big fan of the tite-reach. Works pretty good, can handle impact drivers and works with torque drivers.

This thread is great because I now know what to ask Santa for Christmas: Rounded Bolt Extractors.

Congrats on getting the bolt out!

dr bob

For the short/tight stuff, I'm getting some use from this set from Harbor Freight

That said, the drain bolts aren't so tough to access with a regular 6-pt impact socket and a long-handled 1/2"-drive "breaker bar" or ratchet with a short extension on one side. I have a 1/2"-drive ratchet with a 18" handle, long enough to get some real torque without flexing much. The 6-pt socket makes rounding the head a little less of a risk. For my first 928 coolant change way back when, I was concerned about the amount of force I was trying to put on what appeared to be a 8mm bolt (based on hex head size) with a 3/8-drive flex-head spark-plug ratchet. Folks in the group improved my knowledge with bolt sizes and a clue that it takes a lot more than one might initially think. So the next time it was due, out came the bigger stuff and suddenly it was a lot easier. Gotta love leverage.

Adk46

Felix said:
Oscar says:

Those who maintain aquariums use the term "change the water", by which they mean only about half of it. The fish are not removed, you see.

The procedure reduces the concentration of ammonia and other bad stuff by half. It has to be done often enough to keep the bad stuff below an acceptable level. Imagine a plot of ammonia concentration - a sawtooth waveform rising from 50 to 100% of the maximum tolerable level. The average value is 75%.

Doing "all at once" changes like we prefer in cars also produces a sawtooth waveform, but with a minimum of zero, and therefore an average of 50% - better, unless it's a binary good/bad effect of concentration (or pH). Additive depletion will go the same way. Compared to the fish guy, we have to do it only half as often* - also better, unless full draining is difficult or impossible. (It usually is impossible to drain 100%.)

I think it may be more a compulsion to want to get all the bad stuff out of our engine. It's very satisfying to achieve the godly state of Cleanliness. But think of it this way: for the 100-1000 miles we drive before a scheduled oil change, our oil is filthy! Kissing the limit of filthiness! Ugh. Lowering the filth concentration from nearly 100% to 10% would be good, very good. Sure, we might get it down to 3%, but it's going to rise to 10% before we know it anyway.

*Less often, actually, even when assuming a linear damage accumulation model.

SwayBar

This is the winning tool, purchase time!

dr bob

Poindexter (related to the other Felix...) says:

By this protocol, one would change about half the coolant, but twice as often, and therefore keep the pH higher than 9 at all times. No worries.

Do you vacuum the bottom of the aquarium to get the processed and unprocessed food particles out of the mix?



The cooling system seems to gather precipitate of some kind in the lower reaches even with regular coolant changes. In my experience, we want to remove that with the coolant. Looking at tired radiators, the dissolved solids seem to drop out of solution based on gravity and temperature, and to some extent on mechanical agitation/circulation. So the deposits end up starting near the bottom of the radiator on the outlet side, and in the bottom sections of the galleys on either side. If the bottom radiator tubes aren't yet plugged, you can flush them out with the garden hose from the top nozzle out through the bottom nozzle in the radiator. Inspect with a small mirror or a scope camera through the outlet nozzle. Meanwhile, sediment in the block galleys has only the drain bolt holes through which to escape. There is no easy path to induce a higher-velocity flow through those holes, unfortunately. Several clinic a cars have had the galley drains removed and no flow available through the drains; the bottoms of the galleys and the holes were plugged with sediment. The butt end of some arc-welding rod is usually tough enough to work through the sediment and establish flow. But only near the holes where you can scrape and poke the deposits to get chunks to come loose. Just about any chemical cleaner that will dissolve the deposits will do the same to the aluminum, so most decide to live with the problem. Out of sight, out of mind I guess. While the option is there early to prevent that accumulation from starting or growing, I'm all for it. Just pull the bolts, kill the mineral fish, and call it good. IMO anyway. In our case, amines may be a good thing.

Landseer

ez red splined gear wrench is also a good tool.

I've always wrapped the plugs with a little Teflon tape, careful to keep it high on the threads.

M. Requin

Hmm. Why not Al alloy drain plugs, eliminating electrolysis (almost- depending on the alloy I think) completely? Made with 7075 or 2024 they would be plenty hard enough.

TheUnscented

TFE Paste, just put some in my cart. What else should it be used on? Oil plugs? Spark plug threads?

dr bob

The TFE paste is good for sealing/lubricating fluid connections/connectors, including drain plugs and drain bolts. I like it for the tensioner bolt that otherwise weeps, and water pump bolts to both help with sealing and reduce corrosion issues for later removal. Like anti-seize though, you'll want to adjust tightening torque specs down maybe 20-30% because of the lubricity, especially on bolts and fittings that are otherwise placed dry.

Not for spark plugs!

dr bob

Also -- Remember that the WSM torque spec for the drain bolts is too high. There are a few threads on this. My personal opinion is that about 16 lbs/ft, with the TFE paste on the threads, washer and sealing faces, is plenty for the galley drain bolts.