All of a sudden during a cold spell this 6cyl 300 engine lost oil pressure. I caught it in time and shut it off. The lifters were getting noisy which alerted me. The oil level was ok. The engine does start right up, so no rods are blown or anything like that. (Of course I'm not letting it run).
I was told that either the oil pump itself broke, or the shaft that drives it broke or stripped out under the distributor. Several people said I have to pull the pan, which itself dont seem too difficult, but to get it off, I was told that the engine and tranny mounts must be unbolted, intake manifold, starter, radiator, exhaust pipes and linkages removed. I'm NOT willing to do all this. Too much work for an old 1988 beater - farm truck. I'd rather just junk it.
However, someone else told me that it's more likely the shaft that drives the pump, than the pump itself. He said they strip out under the distributor. He said he's heard of guys pulling the distributor and removing this shaft with a long needle-nose plyers. That seems simple enough. But is this true? How long needle-nose do I need? I figure that I'll give this a try before I junk it, if it's not that shaft, I'm not out much time and no cost (unless I need to buy a longer needle-nose).
If it's the engine I'm thinking of I also think it's accessible through the distributor hole... seen photos of them, they twist up all nice and neat like some kind of wrought iron artwork... almost like it was made that way.
IIRC, the drive shaft is a piece of, oh maybe 5/16" hex stock, tapered at the ends, and fits down into the oil pump; and the distributor fits down over the upper end. Might have a snap ring like 'stop' on it.
Don't think it's down all that far, if regular needle nose don't work, maybe a strong magnet, or cobble up some sorta noose arrangement with a piece of scrap tubing and some string. I think all that'll be holding it it will be oil 'suction' in the oil pump socket, and/or maybe some sludge. I bet it comes out easy. If it's busted, be sure you account for it all...
Make sure the oil pump isn't seized or it'll do it again.
More... If you don't know how to re-time the distributor/engine relationship, make careful note as to 1) the position of the distributor body, AND 2) the rotor position before removing the distributor! (I'm not talking about merely adjusting ignition timing here, there is a big difference.)
VERY important is to not rotate the engine while the distributor is removed. The distributor shaft may or may not rotate a bit one way or the other during removal because of helical drive gears... don't remember if it does on that engine or not. In any case, once back together the rotor must be pointing in the same direction as it was originally.
Should the distributor/engine relationship be disturbed, it's not the end of the world, but can be extremely frustrating to get running again if you've never been through it.
Rant mode on:
Out of passing interest... In high school auto shop back in the 60's, re-timing a distributor was one procedure every single student had to successfully demonstrate in order to pass auto 1. They had 3 runable Chevy 350's mounted on stands to ease accessibility... you pulled the distributor, gave it a spin & cranked the engine for a second in front of the instructor? then you timed it back up. He was a great instructor who motivated and covered everything in great detail... don't recall anyone ever having issues with his shop assignments.
However, through the years, I've noted that re-timing distributor/engine relationships are a huge ordeal for lots of technicians out there... including more 'old timers' than you'd think.
Some years back, I interviewed potential new hires for one shop. I'd start by taking them to lunch, and talking 'shop' a while. Having them just explain that procedure was an issue for most... maybe only 30%, knew how. Many of the remaining acknowledged being stumped with that very issue at one time or another. Many of these guys had had extensive dealership experience...
That's always been a struggle for me too. The last time I removed a distributor, I marked the rotor tip on the shell of the dist. I never turned the engine. Went right back in and ran fine
Again, working from memory... and I very well may be wrong, as it's been decades... and my memory isn't what it used to be.
If I recall correctly, that oil pump drive shaft had a 'stop' on it, held in place by a snap ring, and was assembled prior to installation in the engine. The new shaft might even come complete with the stop already assembled.
You should be able to reach in through the distributor hole with a long hex wrench and turn the oil pump by hand to check it... I think they were 5/16", but check before buying any tools.
The "snap ring" just keeps the shaft from falling all the way into the pump. Put the new shaft in and try turning it (a peice of fuel line works good and is also a real handy tool for removing thr broken shaft) If it happened in the extreme cold it was likely thick oil that did it in rather than a bad pump. I think I've seen ONE seized pump in
Yes, this did happen in very cold weather. From looking at photos of the "works" (innards) of these oil pumps online, it's hard to imagine how they could seize up as long as there was plenty of oil in the pan (which there was).
I guess you're saying to jam the fuel line into the pump shaft...?
I'm gonna go to the parts store and look at a shaft, so I have a better idea what it looks like. That always helps. I found a pic on the web, but a side view only looked like a piece of round steel. Not helpful. At this point, I'm assuming it's sort of like a pipe, hollow inside, and has a hex on both ends to fit over the pumps shaft and the end of the distributor.
Just curious, is this a typical thing to happen on *Just* this particular engine, or to all Ford engines? Every brand has it's trouble spots. I've never heard of this problem on Chevy engines, and I had a chevy with well over 300K miles that still ran well when the car's frame broke in half, forcing me to junk it.
This is the second Ford straight 6 engine that I've known to have a complete loss of oil pressure. The first one was not my car, and the guy just junked it, so I dont know what was the cause. That was a used car in the early 80's so was much older than my 88. But this makes me wonder if this part tends to be a little too weak for the job in all Ford 6cyl or ALL Ford engines????
IIRC, the drive shaft is solid, made from maybe 5/16" hex stock, with tapered ends to ease assembly. Both the oil pump and distributor have female hex 'sockets' to accept it. The 'stop' on the shaft is to keep the shaft from sliding down through the otherwise 'open' oil pump drive 'socket'.
Far as I know, winding up the oil pump drive shaft was a fairly common issue with most, if not all Ford straight sixes.
Nope - it looks like a pencil and is about 5/16" AF- It drops into a hex hole in the pump and the dist drive gear slips over it at the top like a socket, if it is the same as other Ford engines I've worked on
20, 30, and more years ago.
Chevy doesn't use the same setup. It's been kinda a Ford trademark since the 260 V8.
And 260, 289, 351 for sure, and likely the rest of the V8s that used the same setup. Can't remember if the 390 and FE family stuff had the same problem or not. I just know I've fished out a few of them over the years.
Thanks for the detailed info. Now I have a better idea of what it is.
I was told several times that Ford makes some of the best engines. Now I tend to question that..... You'd think that a simple shaft like this could be made stronger. Especially if this has been going on for many years.
If they made the shaft stronger something else would have to break - and the shaft is cheap and simple. Imagine if it stripped off the drive teeth on the camshaft instead.
Biggest problem was oil not changed often enough and having moisture in it, or oil too thick - and extreme cold weather.
Using light oil in the winter, changed on time (way too early according to some people) and a block heater in extreme cold will totally prevent this failure.
It may also be a design consideration. You'd want the pump drive shaft to be strong enough to drive the pump under normal circumstances, but not destroy the distributor drive gears if the pump seizes.
You're not gonna believe this. I dont. I decided the weather was nice enough to pull the distributor today and to see if that shaft was broken. But just for the heck of it, I decided to crank the engine over a few times in warm weather and see if it would still run, or if I was wasting my time. It started instantly, and the oil pressure went right up to a little below the half mark. Since it had oil pressure. I left it idle for a few minutes, then decided to move it to a better place. Amazingly it's running just fine, no more noisy lifters or anything.
Being totally puzzled, I went to a local auto shop and asked a mechanic how this could be possible. He asked me if it was cold when I had the problem, and I told him it was around zero. He said that there must be water in the oil, and there is enough in the pan, which settled to the bottom and froze to block the suction tube on the pump.
What he said makes sense, in fact it's the only thing that makes sense. He said I could have done other damage to the engine, but since it runs good, I may have lucked out, particularly since I only ran it a few minutes without oil pressure.
He said to drain the oil thoroughly, and let it drain for a few hours with the truck on the level. Then change the oil and filter.
This is what I intend to do. I might run some engine cleaner thru it before I drain the oil too. What I dont understand is how the water got in there. I dont smell anti-freeze in the oil, and the radiator has anti-freee. Plus it's not overfilled. In fact when there was no oil pressure, it was a quart low so I added a quart. The oil was not really nasty looking at that time.
I bought this truck in September. When I got it, I asked the seller when the oil was last changed, and he said it was in May or June, and he only used the truck a couple times to haul lumber. The oil looked good then too. So I'm left with the puzzler of how the water got in there. That mechanic told me that since I only ran it around the farm since I bought it and never let it really warm up, that condensation built up. I dont know how close that oil pump pickup is to the pan bottom, but it must be darn close if just condensation froze it up.
I'm glad it runs and sounds good, but at the same time this truck has be nothing but trouble since the day I bought it. It's just been a lemon. So, once I change the oil, it's getting a For Sale sign. I might still replace the other rear brake shoes, but that's it. (I replaced one side before the weather got really cold, so I never did the other side, but have the parts).
One comment, had I known this was possible (cuz I've never seen or heard of it before, and I've been driving for over 40 years), I would have put a magnetic heater on the pan and then changed the oil a month ago. (Plus saved the 3 chains that broke towing it on snow and ice). I Guess we learn something new all the time no matter how old we are, but this one really seems quite bizarre....
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