Hey Friends!

(This might get a little technical for some, but I thought I’d share with you all where my head’s been at with my veggie oil truck since it died a couple months ago.)

Well, I think I figured out what is wrong with my truck. Here’s the story:

It died on the freeway a couple months ago and I had it towed to my studio. I had gotten a lot of water in my veggie oil from a collection at a restaurant where the lid was off the barrel in the rain, so my first thought was just a fuel problem. But switching to biodiesel, and changing all the filters didn’t solve the problem, plus now the engine wasn’t cranking at normal speed, it was really slow.

I replaced the starter and checked the batteries, cables and connections, but it was still turning over too slowly, plus there was no fuel reaching the engine. The mechanical fuel pump was working, (I had fuel coming out at the filter) but nothing was coming out of the injector lines when I cracked them open.

So my first guess was the injection pump, so I had to remove the intake manifold and all the fuel lines to pull the pump, which I thought would be really hard but I’ve been taking it in stages. Last week I took off the intake manifold, (see picture) to get to the pump, ?and yesterday I pulled the 8 fuel lines and the pump.

But the pump seems to be ok, at least it spins freely, doesn’t appear to be jammed or damaged. Which means that it might be something more serious in the cylinder-head, or piston related. Or it could be a stuck valve. I also wanted to do a compression test on the cylinders, but in order to do that you have to pull the injectors, all eight of them, and some of them were blocked by the valve covers. So I pulled the valve covers, and all the valves are closing and there is no broken pushrods or anything funny looking going on (see picture).?

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So next I pulled all the injectors (see picture) They looked kinda blocked up, and I bet cleaning them would make a big difference with fuel consumption – IF I can ever repair this thing! ? With the injectors out there would be no compression resistance in the cylinders (similar to pulling the spark plugs on a gasoline engine) and that would help me to narrow in on the problem.

I put the injection pump back in and reconnected the batteries so that I could spin the engine with the starter motor, and it spun really easily! Which was really good news, but also confusing; If the injection pump is not slowing down the engine, and the valves are all opening and closing, then why would the truck be spinning at slow rpms? (A good mechanic would have figured it out by now but there was one more thing for me to try...) Probably the no fuel at the injectors is a result of the low rpms too, because I learned the the injection pump needs a certain amount of pressure from the speed of the engine to properly function. So, it’s not fuel, not pump, and not a broken timing chain or pushrods or camshaft... Process of elimination.

Next was to do a compression test on each cylinder, which involves sticking a little device (similar to the thing that tells you your air pressure on your tires) into the hole where the injectors lived, and then cranking the engine to get a pressure reading. Well cylinders 1 & 2 weren’t reading much pressure at all, like 50 or 60 lbs, when it should be between 300 & 400lbs! But maybe the device wasn’t working properly. However, when I tried the third cylinder, so much pressure built up by the third crank that I couldn’t hold the device in the hole! It maxed at 160lbs – not an accurate reading, but I didn’t need the device to tell me that there was no compression in the first two cylinders! I continued checking the rest of the cylinders and turns out that 1,2 and 6 were bad. Something was wrong inside those cylinder heads... obviously affecting the compression.... But it could be a mechanical failure, so I drained the oil to make sure there wasn’t any bits of metal swimming around down there and it looked good.

Ok now I’ve gone as far as I can without removing the head. I was considering removing the oil pan to check the mechanics from beneath the engine, but then my friend Phil did some research online and deducted what the problem most likely is; A blown Head Gasket! The 6.2L Chevy diesel engine is prone to head gasket failures because of a small gap between the cylinder and the coolant channel near some of the cylinders. We looked in the radiator and discovered low levels of fluid and gunked up water, which means that oil is getting blown out into the coolant, another sure sign.

So the good news is I can do the repairs myself – I’m already half-way there with so much pulled off the engine. The bad news is that I HAVE to do it myself cause I can’t afford to pay a mechanic... And the next month and 1/2 are crazy busy... The other concern I have is that I won’t remember how it all goes back together! Or that I won’t put it back according to specs.... Or I might forget tighten a bolt enough or too much.

Anyhow that’s the saga, the mystery, the story and the possible solution! I’ve been learning a lot and I’ll probably never get this dirt out from ‘neath my nails.

Thanks Mom and Dad for the loaner truck in the meantime, it is saving my but.

Love you all! Send some magic!

Thomas

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Tom Sepe

APSARA
www.apsaralivingart.org
thomas@ apsaralivingart.org
510-499-0946