Corvette: Second thing fixed

These mid-60s Corvettes tend to overheat. There's a whole FAQ about the subject on the Corvette Forum. Ideally, the coolant temperature would be stable around 180 degrees. That's the temp at which the thermostat opens up and the coolant flows through the radiator (under 180 degrees, you don't want the coolant to flow, because you want the engine to warm up to 180 degrees, which is the intended operating temperature). As the temperature rises, the radiator fan kicks in to boost cooling. And thanks to a fan clutch, the fan speeds up as the engine heats up. It's a pretty simple, all analog system. It was built in 1965, after all.

So here's what was happening with mine: under regular highway driving conditions, the temperature was a stable 180 degrees. But if, after highway driving, you were trapped in traffic, with the engine idling, it would overheat. After some testing and deduction, it was clear to me that the problem was not the thermostat (if it were, it would overheat all the time) or the water pump (same) or the hoses collapsing (same). After some more diagnosing with an infrared thermometer, I narrowed things down to the fan clutch (not enough air being drawn over the radiator at stand still) or perhaps the radiator (enough cooling capacity with lots of airflow, but not enough otherwise). There was also a question of whether it might be related to the distributor (and here we enter the decidedly analog world of mechanical and vacuum distributor advances).

Now out of my depth, I called in the experts at Precision Motive. After replacing the fan clutch, fixing the vacuum advance, and adjusting the distributor timing, the overheating problem is under control, with the engine running around 180 nearly all the time. After a long idle at standstill, it still gets up to about 195, but it's stable there, and there's no harm to the engine at that temperature.

While it was in the shop, I also them replace the ignition coil (one terminal was stripped), change the oil, lubricate the chassis, and adjust the driver's side hood latch. Total cost = ~$900.

Now we're ready for some weekend trips!

Comments

Post a Comment

Popular posts from this blog

Fixing the clock in a C2 Corvette

Image
After fixing the radio in the Corvette, it was time to tackle the clock. We tried mightily to revive the patient, but in the end, a heart transplant was necessary. The clocks in the "midyear" Corvettes (1963-67) are electro-mechanical units made by Borg Instruments. They were used in a bunch of other GM cars of the period, in addition to the Corvette. This article gives a nice description of the clock and what commonly goes wrong with it. These are analog, spring-wound clocks with an electric winder that is supposed to reset the spring mechanism every 3 minutes or so. To see how it's supposed to work, check out this video (currently at 460 views, many of which are from me!). The design doesn't exactly inspire confidence, as it depends on a set of 12 volt contact points reliably closing every 3 minutes or so, pretty much forever. Those contact points build up corrosion over time, which will kill the rewinding mechanism. Thanks to a bunch of threads on the...
Read more

Five Year Miataversary

Image
  Five years, fifteen thousand miles. Time flies.  The car remains a joy to drive. As I anticipated when I bought it , I don't miss the extra horsepower you get in the 2019 and onward model years (aka ND2). That extra power is reportedly mostly at the top of the rev band, an area where I don't spend much time. The joy in this car, for me, is less about going fast than about the ways it engages you in the act of driving.  Cost of ownership? Here's the math:  Maintenance = $1,057 (basically oil changes, plus an engine air filter and transmission oil change) Depreciation = $500 (yes, Kelly Blue Book says I can basically get what I paid for it!) This makes the Miata by far the cheapest car to own that I've had, beating out my 2010 Honda Fit . Most of this is down the the crazy high post-pandemic used car prices holding depreciation in check. But that doesn't diminish the joys of simple reliability, which not all newer cars can provide.  Here's to the next 5 years!...
Read more

S550: 12 Month Cost of Ownership

Image
Everyone knows that a Mercedes S Class is an expensive car to own. That's partly why they depreciate so quickly. Well, this car more than lived up to that reputation, proving to be far and away the most expensive car to own of those I've discussed on this blog (compare 2018 Mazda Miata , 2010 Honda Fit , 2002 Porsche 911 Turbo , 1965 Chevy Corvette ).  Deep breath. Total one-year cost of ownership = $27,853. Holy smokes. $2,321/month. I could have (maybe should have) leased a new one for that (although the shortest leases are 24 months, so I'd have ended up spending a lot more total).  The inflated pandemic used car market certainly accounts for a bunch of this. Yes, I knew it was a bad time to buy, and yes I overpaid to get the car I wanted , but I didn't count on another $10k of depreciation in one year. The problem with selling an S550 is the plethora of cheap, minimally optioned cars out there. If you want to get above those prices, you need to find someone who valu...
Read more