Miscellaneous Van Adventures: Fuel and Coolant

Wednesday, May 21st, 2014 @ 4:23 | mikuvan

Ongoing van facility improvements have been happening as the semester has been winding down, now that the 2.00gokart season is over.  Strictly speaking, I’m well past the point of needing to do something, but all of those boxes I’ve been getting from Rock Auto over the past few months are starting to be overbearing. I think I have a full roster of parts to replace or fix anything that could potentially wear out or break next – things like a new water pump (like I’m ever going back into that engine), a transmission rebuild kit (it was on sale, OK?!), enough oil filters for the next 100,000 miles, and so on.

I’m doing unnecessary part repairs for two main reasons – first, so that I explore more of the subsystems that might not have been touched since the Bush Administration (no, I mean the first one in 1988), and second because I’m putting off more bodywork. On that front, I’m glad to say that all of my back-alley work has survived the winter.

One of the things that I was going to do immediately last year, but of course dropped because Well It’s Working, is the C-Clamp of Thermostat Flange Retaining:

I noticed this flange had a broken bolt as soon as we dug into the engine bay in the very first van adventure of OPERATION: BAD TIMING. It was the cause of a minor coolant leak. The seller did mention it went through coolant and he just topped off the radiator as needed, so this was probably the root cause. I threw a 2.5″ C-clamp on it just to hold the gasket together and mostly resolved the problem for the next year.

Over many cool-hot cycles, the C-clamp began to creep and every once in a while I’d have to tighten it some more, or there would be small dribbles of coolant the next time I had to bust out Vanpower for backup. As summer approached, I figured I would need the cooling system functioning properly again. I caught a break during winter, where it had enough trouble keeping warm – keeping the heaters on would drop the thermostat needle to near cold after a few minutes in short trip operation.

It was time for the C-clamp to be returned to MITERS.

Step 1: Remove the upper radiator hose and thermostat flange to reveal the seized and broken bolt. Remove gasket in about 100 small pieces, because that’s how servicing this thing just happens: assume every gasket has already disintegrated by the time you lay eyes upon it.

Step 2: Apply heat guns, vise grips, and cheater bars for half an hour and shear the remaining stud off. This thing is in there hardcore.

Step 3: Decide to drill and tap a smaller bolt down the center of the larger one, instead of trying to drill this one totally out.

Step 4: Discover that your drill plus bits are too long to fit in the gap between the engine block’s flange and the radiator.

Step 5: Purposefully break two drill bits to make them short enough to fit. I executed two of my shop’s precious tap drill sizes to make this happen. I’m ready to be tried for war crimes.

But it got the job done. I punched a center mark as accurately as I could, then used the small drill bit to pilot and the large drill bit to break through the bolt. Luckily, the small tap wrench fit in the available space just fine. I threaded this hole in M6 x 1.0. The original bolt was a M8.

Finally, add high-temperature gasketing silicone compound and let it all soak for an hour or two, then tighten down the bolts a little more.

Pitching the system back together! I have yet to find a new droplet spot, so I assume it’s at least asymptotically solved.

Next up, Charles plays with gasoline!

The fuel system is one of the last things I have not looked into, besides the transmission (which I will accept is run by elves and unicorns). I know the condition of the upper half – injectors, filter, and the like, but not the fuel pump. I bought a fuel pump on Rock Auto months ago because I knew it was a part that could potentially wear out, and because it was on sale for $19.99. I figured if nothing else, I would use it as Chibi-Mikuvan’s motor coolant pump.

As Maker Faire Bay Area approached, I was entertaining the idea of driving cross-country to meet up with the west coast crew. Well, wouldn’t it be embarrassing  if the fuel pump quit halfway for some reason? At this point, I wasn’t sure of the exact operating mechanics of an automotive fuel pump, just that mine might be as old as I am.

To replace the fuel pump is a procedure which involves dropping the fuel tank from the underbody regions. Reading the service procedure for this was where I first learned that modern fuel pumps reside inside the fuel tank itself. Hmm, for some reason I always thought it slurped the fuel out through a straw or something. This is, again, where I point out that automotive engineering is an entire other world, knowlege-wise, from “mechanical engineering” defined broadly. It’s something which if you don’t pay attention to, you’d never know.

So up on stands we go! Prior to this was when I filmed vansaroundboston: a purposeful 30+ mile drive (that video was 1/3rd of it) to empty the tank to the last gallon. I unloaded this through the fuel tank’s drain plug.

First up in the service procedures was to remove the easy stuff. High pressure hose, return hose, and filler hose. This was where I figured the pump might have been worn out or on its last legs in some way – the service procedure called for disconnecting the power supply and then running the engine until it stalled from loss of fuel pressure. Well, I couldn’t even get it to start. My reading told me that there’s check valves and the like in the pump itself, so if those parts were leaking or failed, the pump would lose pressure instantaneously upon shutdown. So maybe this was a worthwhile gasoline-derived brain melting adventure.


The high pressure and return hoses coming off. There were a few other hoses and tubes to remove:

These disassembly drawings always show the part or subsystem in isolation, ignoring the fact that it was all buried in between 90 other parts, a frame rail, and the source of my oil leak. For instance, after the filler hose, high pressure hose, and return hose, I had to remove the vapor hose and fuel pump connector.

which is above the driveshaft and on the back side of the tank, you fuckers. Then, the vapor hose was literally impossible to get to in the stated order. If I, he who doesn’t look out of place in cosplay as Hatsune Miku herself, could not get his hand above the fuel tank with a hose clip plier to reach it, then how was anyone else going to?

I left these two connections to be removed after I unbolted the tank itself, which was also a Three Stooges-like experience, except there was one stooge only. When I untightened the four bolts retaining the tank, it didn’t budge. I banged on it from the side a bit to see if maybe there was another hidden bolt, and the whole thing falls onto my face.

Granted, it fell less than an inch, but it did weigh 15 pounds or so empty. I got a great black smear on my nose for this one.

After a half hour of avoiding the oil leak sludge Self-Applying Undercoat while underneath, here’s the tank! It sure looks like this hasn’t been touched in a little while.

Observe the green can of CRC brake cleaner. I actually like using non-chlorinated brake cleaner for everything, because it seems to be just high pressure acetone in a can. Mild, but effective in combination with the spray jet. I use it to clean the shop bandsaws, or, in this case, to chase grime off the fuel pump flange.

Real brake cleaner is made of tetracreepywhatever, is much more effective, and dissolves like everything. I have a few cans of this that I only break out if lesser solvents can’t do the job. Like leaded solder, I figure this substance is going the way of the dinosaurs for being not part of this complete breakfast, so I’ll enjoy its disconcerting odor while it’s not banned in Massachusetts, unlike in California.

Undoing the 5 bolts holding the flange on, I reveal the fuel pump unit. It has its own little pre-filter attached that seems well-coated in goo.

Here it is side-by-side with my new pump unit. The old one isn’t in bad shape. Though it’s been in an environment that’s been majority-occupied by hydrocarbon vapors, which tend to preserve steel, and it’s still this tarnished, so who knows how old it actually is? I couldn’t find a date code, but did find a Nippon Denso logo. Unless the last service for the fuel system used OEM parts, this might be original equipment.

Strapping the new one in now.

Reinstallation was straightforward. I called for backup for someone to hold the tank while I started threading on the bolts, which was a nasty surprise for him because I didn’t say anything about the layer of oil sludge coating the underside of the fuel tank. I’m sorry, Julian. It was, indeed, quite gooey.

After I had the old fuel pump out, I was quite curious as to what went into one. The Internet™ had told me it was a DC motor running an impeller-type (centrifugal) pump. What the hell? Why would you put a brushed DC motor with its sparking commutator and all into a gasoline tank?

I proceeded to machine this thing apart using a metal lathe:

First to get popped off was the end with the impeller. I just took a cutoff tool and jammed it in until something fell off. It seems pretty normal here. A volute shaped chamber and a many-blade impeller.

Many cuts later, I popped out the rotor of the pump. Okay, it really is a brushed DC motor running submerged in a bucket of gasoline.

Now, I know this is actually the best possible place for such a thing, surrounded by cooling, nonconductive, non-ionic fluid, above its vapor explosion limit, that carries away the brush dust wear… In the grand scheme of things, it isn’t bad. But you know that trope that says you know obscenity when you see it? Well, this is obscene. I’m now afraid of every car that drives by.

Inspecting the state of the commutator and brushes, I concluded that the fuel pump motor itself was nowhere near failing and could have run for many more miles. However, not knowing the service interval of this part, I’m still satisfied with its replacement.

I’ve replaced about all the subsystems that can be replaced now. What’s next? I suppose I have these little boxes full of driveshaft U-joint parts… or I could go do more bodywork.



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    5 Responses to “Miscellaneous Van Adventures: Fuel and Coolant”

    1. FrankTheCat Says:

      if you had control of the automotive fuel pump industry, cars would be running brushless hobbyking outrunners for their fuel pumps, amirite?

    2. the chuxxor Says:

      Actually I thought fuel pumps were like aquarium pumps, like solenoids that pulled on a rubber diaphragm or something, so fuel never touched sparking commutator. It turns out older electric fuel pumps were exactly like that. It was something I never thought twice about until now.

      I do bet a handful of modern fuel pumps are brushless already.

    3. FrankTheCat Says:

      pre-1980′s cars primarily used mechanical diaphragm fuel pumps that were actuated using a lobe on the camshaft, yeah. electric fuel pumps have the advantage of running or not running independent of the engine, so you can prime the fuel system without cranking the engine.

    4. Doug Gallardo Jr Says:

      An Easy Out would have been perfect for that bolt situation.


    5. the chuxxor Says:

      Hah, I wish. I have a bunch of them, but there was no way to fit one in in the space given. That, and I figured if someone torqued the head right off the stud, then I torqued the stud right off itself, it was a little beyond hope for an extractor.