Man, all this is driving me crazy. I did a search and have some ideas, but I wanted to run my symptoms by the experts here for some feedback.

My '94 F-350 7.3 Turbo Deisel is having problems. Here are a list of my symptoms

1. Sometimes smokes more than normal on startup. Smoke looks white but isn't pure white like steam, but is more of a greyish white. I don't think its blue smoke, and I can't tell is its got a coolant smell or is just normal exhaust smell, I haven't had a deisel long enough to know whats normal, this truck has been "iffy" since I got it last month.

2. Last night, when I started it, it would crank once then stop, I didn't force it, I let off the starter immediately, then hit it again. From what I read somewhere on the search results here I know that water doesn't compress. If there was coolant in the cylinder, would that be sufficient to keep the engine from cranking more than once? After hitting the starter a couple of times it turned over and began to run a little rough, a little bit of the smoke, but not as much as it has done other times. Once warm, ran fine, but later I stopped at a store and when I cam out same deal, one or two cranks. Once it started it bellowed smoke for a good minute, maybe two, then once it got running again it did less smoke, but still enough to be conspicuous and have people gawk. Evened out about 4-5 minutes into trip and went away.

3. Next morining, today, I started it after parking on a downslope (backed into driveway) and it cranked like a champ and started right up with very little smoke, just a puff like it has always done, and didn't run rough.

Add to all that the fact that it loses coolant pretty steadily, I have to top it off once every two or three weeks, and that gets expensive. I first thought the obvious, that I was getting coolant into the engine somehow, but the parking downhill on a slope seemed to say it was fuel line related. Heck, I really don't know at all. Is there any hope for me to find a simple solutin I can fix at home, or should I take this in to a shop and have them look it over?

Any help would be absolutely appreciated.

 

If it is antifreeze the exhaust will have a very sweet smell to it.
Cavitation would most likely also show up as compression pressure in the radiator. Bubbling a stream of air out of the overflow tube in the overflow tank while it was running is a good indication of cavitation.

Do you see any indication of where the coolant is going?

A fuel prblem would not stop it from cranking, but it could cause the rough running and smoke.

 

yes a fuel problem would not cuase your starting problem, but the smoke on start up sometimes is normal as long as it is not excessive, if so white smoke could be your timing.

tom

 

If you are using coolant and have a sometimes hard time cranking, I would venture to guess there is a leak in the head gasket, cavitation or head itself. You could pressurize the cooling system and remove the glow plugs. If there is leakage, it will come up there.
I would get an oil sample for now and they can tell you if the oil is contaminated with antifreeze.

 

It doesn't sound good to me. A pinholed cylinder might not put any pressure in the radiator, but a head or gasket would. The pinholes usually show up halfway down the bore, so unless the piston stops all the way down you won't get the hard crank in the morning. If it does try to lock up on you, pull the rear glow plug on the driver's side. Then give the starter a short burst. You might squirt water all over (so don't stand over it), but you'll know the bad news.

 

Thanks for the replies. Fortunately I have a warranty that I bought with the truck, unfortunately they are apparently hard to deal with.

If it is cavitation or water/coolant getting into the engine, what kind of repairs are involved? New engine?

Also, being new to diesels, could someone explain cavitation to me? is it corrosion/wear of the cylinder bore, these pinholes you are refering to?

Thanks!

 

The cavitation is caused, as far as I can gather, by the diesel engine causing vibration within the cylinders. This vibration causes tiny bubbles to be released from the water jacket side of the cylinders. Each time a bubble releases, it takes a small piece of metal with it. There is additives to prevent this or at least slow it down, but once you got cavitation, you probably wont fix it. Malcolm, isnt there a position on the vibration dampner that would let all pistons low and wont pressurizing the water system let water into the cylinders, even with cavitation?? OR pressurize the system, let it stand for a while and let the cylinder that is the problem fill up, take out glow plugs or injectors and give it a crank. Have 2 more people help watch while it is being cranked. Also, would antifreeze test show cavitation particles? At least you will know which side is the culprit and remove the head on that side. There is my nickle worth. Hope it helps.

 

OK, an update. You folks have been a great help.

I took the truck in and had a new starter put in, the old one died and was on the outs to begin with. Also, a new battery cable. Apparently this was causing my no-start problems and hard starts, it just wasn't turning over with any umph.

They did a pressure test on my coolant system and found no leaks, after replacing my cheap radiator cap from which I was losing fluid. That was the major fluid loss.

Now she cranks over no problem, but every once in a while I am still rough starting and blowing smoke, looks white, may be bluish greyish white. So I still have a problem somewhere, but it seems I'm not having a coolant leak into the engine, at least not major. Still no pattern or reason why it does or doesn't smoke. It blew smoke this morning after I drove 2 miles (enough to warm it up a bit) and went into the filling station for some coffee. When I came out it rumbled a bit on start and blew some light colored smoke for a minute, then all was fine.

Would an injector problem be doing this? The guy at the shop (not a dedicated diesel shop) said he though I might have an injector stuck open or worn or something that may be flooding fuel intop the cylinder- does deisel burn whitish blue or light colored if not fully burned in the cylinder?

I would be very happy to have an injector problem as opposed to cavitation or coolant leaks. Any ideas based on this further info?

 

Check your glo plugs 1st,if they are ALL good,then have the injectors pop tested.BTW,find yourself a reputable diesel shop,it could save you big time $$$.Good luck.