The Lotus Marks Its Turf

No, not the just-purchased ’69 Lotus Elan +2 I wrote about last week. Lolita the ’74 Europa Twin Cam Special. The one that’s supposedly well-sorted.

It happened in an unexpected way. I was out doing a short version of my stress-busting leaf-peeping drive through the windy roads west of I-95. I noticed that the car’s dashboard-mounted voltmeter was reading a little low, and when I was stopped at a traffic light and the engine rpm spinning the alternator was down, the reading was very low, like under 12 volts. I wasn’t overly concerned about it, though, as I was less than ten miles from home, and even if the alternator weren’t charging the battery at all, the battery would have no problem continuing to fire the coil for several hours. I made a mental note to check the charging voltage with a multimeter when I got the car back to the garage.

But I had one stop to make—Trader Joe’s, for cereal and snacks. I parked the tiny little Lotus between two mid-sized SUVs whose doors looked like they could open above the car’s roof. When I got out of the car (no easy feat at age 66), a woman walking behind it said the last thing I expected (and no, it wasn’t, “Are you the Rob Siegel who was stupid enough to just buy a second vintage Lotus?”). It was:

“Excuse me, but is that green fluid antifreeze that’s coming from your car?”

Sure enough, yes and yes. I profusely thanked her for her eagle eyes.

Well then, I guess the cereal and snacks are going to have to wait.

A coolant leak is usually evidence of one of two different situations. The first is that a cooling system component has cracked and thus the system is no longer closed. If coolant is actually streaming out from under the engine, it usually isn’t difficult to trace the source of the leak, though the more modern the car is, the more Byzantine the plumbing can be, with rubber hoses and plastic pipes running behind the back of the engine and under the intake manifold. Still, it shouldn’t be brain surgery to figure out where in the coolant path—which involves the water pump, radiator, hoses, expansion tank, thermostat housing, heater core, and engine (block, head, and head gasket)—the fluid was leaking from.

The other situation is that the engine has overheated. This results in out-of-range coolant temperatures which create higher pressure than the radiator cap can handle. If the cooling system has an expansion tank, the excess coolant goes there, but if the expansion tank is full, it either flows out its vent hose or blows out under its cap just like it would a radiator cap. I suppose you could argue that this is no different than the first situation and that it’s just a different kind of leak, but I think about it differently because in the first case, the system becomes hot because the coolant is leaking, whereas in the second case, the coolant leaks because the system has become hot.

Of course, if an engine has overheated, you need to find out why. It could be that its cooling system has become overwhelmed by hard driving in hot temperatures (very common on vintage cars), or that the cooling fan isn’t pushing air through the radiator.

I hunted around inside and under the Europa’s rear-facing but very simple and accessible engine compartment (mid-engine car, remember?) and quickly found that the leak was the second variety, coming from the vent hose of the expansion tank. That meant that the car had been running hot, then boiled over. I cracked the key to turn on the dashboard gauges. In a few seconds, the Smith’s temperature gauge swung all the way to the right. I kicked myself for not seeing that I must’ve been driving with the gauge pegged and didn’t notice it, and hoped I hadn’t damaged the engine.

On the one hand, this was good—I mean, at least coolant wasn’t coming from the Europa’s strange integrated-and-can’t-replace-it-with-the-engine-in-the-car water pump, or (lord forbid) the head gasket. But it was odd, because this was a problem I’d already solved.

Five years ago, on Lolita’s first significant outing after I got it running, I drove it to the Lotus Owners Gathering (LOG) in Sturbridge, Massachusetts, in August 2019. It was only 50 miles—and coincidentally on the way to where I now store cars in Monson—but having just resurrected a car that was last on the road in the early 1980s, the journey felt like driving solo across the Yucatan Peninsula. The car did great … until I arrived at the event. There was a long line to get in, it was hot, the car’s temperature gauge kept creeping up, and despite my shutting the engine off except when I needed to move up in line, by the time I got in, the car—easily the rattiest Lotus there—was pissing coolant. It reminded me of when my son was training his dog to not urinate when people of authority entered the room, and referred to it as “submissive peeing.”

The problem was that which occurs when almost any old car runs hot—not enough heat shed by an ancient radiator, coupled with not enough airflow through it due to both low speed and an anemic fan. Because the Europa is a mid-engine car, the radiator is separated from the engine by about six feet, and thus there’s not a mechanically driven fan. Instead, there’s an electric one. This has been commonplace on front-wheel-drive cars with transverse-mounted engines for decades, but I’ve never really been fully comfortable with the configuration. I want an old-fashioned belt-driven fan where, when the engine revs up, it spins a fan that pushes air through the radiator, and the only thing that can fail is the belt or the fan blades themselves—there’s no electric motor to seize, or fuse to blow, or sensor to fail, or connector to corrode.

After the LOG overheating episode, I replaced the original radiator and fan with a new aluminum radiator, a proper Italian-made Spal fan, a new temperature sensor, relay, and fuse, and a switch so I could turn the fan on manually in case the sensor failed. I also installed an expansion tank (which isn’t a stock part of the Europa’s cooling system), but I’d only seen coolant in it once after I was caught in traffic in very hot weather.

So what happened during my nice late-autumn cruise to cause the car to overheat and the expansion tank to completely fill, then overflow?

My first thought was a lack of power to the fan. I keep a few tools in the nose compartment of the Europa—a small fire extinguisher, work gloves, and a zip-up valise with wrenches, screwdrivers, a multimeter, and some wire-crimping tools. I pulled out the multimeter, and found to my chagrin that the metal end of the negative probe had snapped off. Damn. Well, that’s what I get for having a $15 Harbor Freight meter bang around in there for five years.

So no multimeter. But this is simple, right, because I installed that switch to directly turn on the fan. I flipped it.

Nothing.

Okay, so, blown fuse, bad wiring, bad relay, or bad fan. Fuse first. Sure enough, the 30-amp fuse was blown.

But why would it blow? This isn’t some cheap eBay no-brand product on a car that’s accumulated 30,000 miles in dust, heat, snow, and salt—this is a high-quality Spal fan on a pampered car that’s seen 2000 miles, tops. Did it blow because it’s seized or has some restriction?

The radiator and fan are shoehorned in front of the right front wheel. I reached in and tried to spin the fan blades with my hand, and sure enough, there was a restriction. I tried to see what it was, but the combination of bright sunlight, my wearing photo-gradient glasses, and the fan being in a shaded crevice made it impossible to tell what I was looking at. I reached in and probed around the blades with my fingers, and felt… something soft. What was it? My first thought was a mouse, but it felt far larger. And with my squinty eyes, it looked black. What, a crow?

I turned on the flashlight on my phone, looked at it, and burst out laughing. It was one of the work gloves I’d thrown into the nose compartment years ago just in case I needed to lay hands on hot or dirty components. It had worked its way over to the right side of the compartment and gotten sucked into the fan.

I found a spare 30-amp fuse in the glovebox, installed it, flipped the manual switch, and the fan roared to life. I then went inside the store, did my shopping, came back, cracked the key, verified that the resting temperature had fallen to about the middle of the gauge, started the car, verified that it ran without leaking any further coolant, ensured that the fan came on normally when triggered by the sensor, and drove home, watching the temperature gauge like a hawk.

Oh, the low reading on the voltmeter while I was driving? Almost certainly caused by the fan drawing a lot of current—enough to blow a 30-amp fuse (quite impressive, actually)—while it was jammed up by the glove. After the fuse blew, the current draw was gone, the alternator and thus the voltmeter behaved normally, and the car ran fine until I left the sparse, windy country roads in the leafy suburbs and was back in suburban Newton, chock full of traffic and stop lights.

The danger, of course, in overheating a car is that you can warp or crack the head or blow the head gasket. It happens especially easily on cars with long, straight aluminum heads. Driving old BMWs with inline-4- and 6-cylinder engines, I’ve been hyper-aware of this for decades. And the cost of a replacement head for the Lotus-Ford Twin Cam engine in the Europa and the Elan is high enough to make you cry. But I think everything’s fine with Lolita.

Maybe she just wanted an excuse to mark Trader Joe’s as her territory. Though, with another Lotus now at the house, I’m surprised she didn’t choose the garage.

***

Rob’s latest book, The Best Of The Hack Mechanic™: 35 years of hacks, kluges, and assorted automotive mayhem, is available on Amazon here. His other seven books are available here on Amazon, or you can order personally inscribed copies from Rob’s website, www.robsiegel.com.