Luck or low miles or?

[Danglerb]

We get a lot of opinions here, people with good luck or good results independent of luck, and some with terrible results. The variable that many don't consider or we talk about much is that many owners RARELY drive their cars, and often for very few miles. Cars that are not driven may have all sorts of issues that are slow to reveal themselves.

Cars that get driven frequently and for some distance may not have problems from issues that cause problems in less frequently driven cars. Specifically I am thinking about coolant damage, which usually shows up around the water pump and/or the head gaskets. Of the dozen or so engines I've seen torn down that have sat for any real length of time, 90% had moderate to serious damage. It looks almost like a termite with an 1/8 inch or so track that may wander over the surface under the gasket, or some kind of serious cavity.

Seems that once coolant gets under the gasket it goes bad fairly quickly and eats the aluminum, which allows more coolant in, repeat until junk.

Whether or not this presents a practical problem may depend on just how much its driven, and how long its parked and what type of coolant is used.

[Guest765]

Truth I'd rather not even have a really low mile car that is as old as ours. IMO the stuff that was "going to break" hasn't had a chance to break and get fixed already so I don't have to do it.

[Landseer]

Good points Danglerb.

My 85 van winkler found dead with 70,000 miles has 95,500 as of tonight.

Its an all weather, long distance DD for me. This year three round trips between Indiana and Virginia at 1600 miles a pop, plus two round trips to toronto, another 800 mi per, plus a lot of 20 mile commutes. To Saginaw and back two weeks ago, another 6 hours of driving.

When I brought it back to life the coolant system was full of oily stuff, maybe oil, maybe hose decay, not sure. I pressed it back into service anyway. Seems all that junk cleared-up after flushing, running some soap thru, new hoses, etc.

TB light keeps coming on under heavy accel when engine isn't fully warmed. Time to replace, its been tensioned 4 times now (conti). It uses a little bit of coolant, not sure where, might leak into combustion, but I don't care if it does. But I'm curious.

5 other ones I have are also used, or have been used, extensively since resurection. Most sat for several years prior to me owning them.

Not sure where the head corrosion cautions are coming from. I do remember the Greg son car thread, looking for 84 heads / engine and going thru many.

I've got a spare 32V engine that runs well. Not sure how to store it. Maybe I should pull the heads, refurb, and store dry with a fresh head gasket?

Or better, stick it into the van winkler, then disassmble the van winkler engine for review!

I also wonder how my surburban head/block interface looks, similar situation, Al on Al.

[Guest765]

Maybe its the water? Seems to be evidence that soft water can cause aluminium corrosion? Deposition Corrosion

Direct quote

Deposition Corrosion

Deposition corrosion is a subtle form of galvanic cell that can produce pitting in a liquid environment when a more cathodic metal is plated out of solution onto a metal surface. For example, soft water passing through a copper water pipe will accumulate some copper ions. If water is then admitted to a galvanized or aluminum vessel, particles of metallic copper will plate out, i.e. deposit on the surface and stimulate pitting by local cell action.

This plating out action, or deposition corrosion, may be an important factor in the corrosion of the more reactive metals near the top of the series, e.g. magnesium, zinc, and aluminum, when these latter metals come into contact with solutions containing ions of metals (particularly copper) lower in the series. Copper ions in concentrations less than one part per million have been observed to have a significant effect on the corrosion of aluminum by water. Metals, such as copper, that can aggravate corrosion of aluminum are sometimes referred to as "heavy metals in solution. The fact that they are heavier than aluminum is less significant than that they occupy a position lowers than aluminum in the electromotive or galvanic series.

Copper plates out onto aluminium, causes pitting that gives the corrrosion a place to start. Most people probably don't get distilled water for coolant changes and might add water from the tap just to top off or something? I don't know.

Looks like there's a big debate as to whether softened water is safe to use in aluminium boilers? Maybe a link there?

[Pete R]

I know that I had to put in a acid neutralizer in my house because it was slowly eating my copper pipes. I'm sure I would have experienced similar problems if it was in my car.
Why would a car that sat a long time matter though? It's a closed system. I can't see how circulating the same fluid would make a difference on corrosion. It seems like if there was a corrosive mixture in the engine, damage would be happening whether it's being run or not. Just wondering what the science it there

[Guest765]

Why does anything go bad when it sits? I guess chemical changes happen somehow idk. I've always been told since I was a kid that letting any mechanical thing like a car etc sit unused is bad for it without preparing it specially first.

[harborman]

Originally Posted by fwayfarer

Why does anything go bad when it sits? I guess chemical changes happen somehow idk. I've always been told since I was a kid that letting any mechanical thing like a car etc sit unused is bad for it without preparing it specially first.

Chemical reaction does go on just with time and inter-reaction with other chemicals and materials. Case in point, my ground strap to the battery went bad recently. The connector and braided cable corroded inside the crimp. You could not see it and all looked fine but when I pulled it apart, all full of white powder! As cars get older, rubber hardens, wire insulation deteriorates, fluids collect moisture, etc. In fact almost everything changes, some fast some slower, just like your body or the Universe. If you didn't keep fixing your house it would be a pile of dust eventually!

[silver89]

The 91 Gt I bought last August had 24K miles and had not been registered since 2003. When we did the TB and WP we checked the antifreeze and it was 100% antifreeze and no evidence of corrosion. Here is what the original WP looked like when we took it off. Guess not having mix with water prevented corrosion. I have put 2000 miles on it so far and no issues.

The car was stored in a climate controlled garage (min 55 degrees) for that time and also had radiant heated floors. It was well cared for!

[harborman]

You might check into this but, from my chemistry class many years ago, we discussed antifreeze and the way it works is it needs some water. Antifreeze alone is not as good. I believe it's called a colloidal suspension. When I did my TB i replaced antifreeze with new and mixed with distilled water.

[silver89]

We flushed and filled with 50/50, I agree 100 % antifreeze is not good when you drive the car. This one sat for 10 years, so maybe for a car that sits...100% isn't bad?

[Danglerb]

I keep about 4 gallons of distilled in the garage all the time, and use reverse osmosis water for stuff like washer fluid etc.

Climate controlled garage makes a HUGE difference, the heat cycling I think is the most damaging, but a close second would be condensation.

[harborman]

Originally Posted by silver89

We flushed and filled with 50/50, I agree 100 % antifreeze is not good when you drive the car. This one sat for 10 years, so maybe for a car that sits...100% isn't bad?

I forgot to mention, 100% antifreeze does not give the same freezing protection as mixed with water. Up here in the North, freezing is a problem.

[harborman]

Originally Posted by fwayfarer

Truth I'd rather not even have a really low mile car that is as old as ours. IMO the stuff that was "going to break" hasn't had a chance to break and get fixed already so I don't have to do it.

Well, I bought a low mileage car, with 38K on it for 1986 and I am glad I did! Everyone looks for a low mileage, one owner, well kept car! One of the other members saw my car at a local PCA meeting a month ago and he was impressed. Ask Landseer.

[Landseer]

Fantastic car, absolutely! Clean as a whistle, like new. Love the stereo system, too.

Imagine, Harborman and I go to a PCA meeting.

Only two Porsches at the meeting are 928.

His and mine (which look like twins, except mine is a spoiler delete and his has the full S spoiler setup).

[harborman]

Originally Posted by Landseer

Fantastic car, absolutely! Clean as a whistle, like new. Love the stereo system, too.

Imagine, Harborman and I go to a PCA meeting.

Only two Porsches at the meeting are 928.

His and mine (which look like twins, except mine is a spoiler delete and his has the full S spoiler setup).

I will have to attend another meeting sometime this Spring. Yes, we had the only two 928's. Nice small PCA club. Great to meet Landseer in person.

[Danglerb]

928's in exceptional condition usually have low miles. Exceptional 928's with low miles often end up as garage queens, so issues soon revealed in a daily driver may never show up.

928's that have sat more than a year or so are going to be a roll of the dice internally.

[Landseer]

No they are not.

You are drinking the wrong Koolaid from your west coast uber experts, I think.

[Danglerb]

Lucky with one doesn't outweigh looking at dozens, and until the heads come off how would anyone know if the gasket is perfect or mm's away from a leak that shows or hydrolocks?

[Landseer]

I've had luck with 6 + 2 944's, all down when I got them, for between 1 and 10 years each.
Never yet, knock on wood, have pulled a head.
Then again, maybe mine are just on the edge of failing and should all be preemptively repaired.

Not too worried because my investment is light. Nor do I thrash them like a boy racer. But agree, if I had one that I was making a golden chariot, it would get new head gaskets. Same with racing one or boosting one.

Am wondering if storing them on the shelf with inherent moisture, but open to atmosphere, accelerated some of the corrosion that gets pictured.
Also, I think there is a bit of fear mongering going on.

[Kiln_Red]

Originally Posted by Landseer

Also, I think there is a bit of fear mongering going on.

Now where would you ever get that idea?

Yes, there are unknows involved when acquiring a very low mileage 928 with no record of maintenance. There are advantages, in my opinion, to this situation. No record of maintenance usually means NO maintenace, so no butcher repairs to correct. Basicallly, you are starting with a clean sheet. If the block is good (not ruined from acidic coolant), then I think it is a *very* good starting point if you get the hypothetical car at a fair price and are capable of bringing the car back to a road worthy condition.

It's an opportunity to start over with a fresh 928!