One more thing to watch out for when shopping

[Jeremy5848]

Visited my local mechanic just to say hello. He had a 1980 300D NA in the shop with the head off. Turned out it had been purchased by a local guy for his daughter, attending Sonoma State, as safe and reliable transportation. What they didn't know was that a PO had cracked the head in several places and, instead of replacing the head, had "pinned" the cracks and reinstalled it, then dumped it on the new owners.

The girl had called the mechanic to say that she was coming in, the car was overheating. When she arrived, the wrench was surprised to find the engine idling beautifully, even though the temp gauge was off scale high. He found the radiator cold to the touch – no coolant at all! but the block measured 300 (F or C, I forgot to ask) on his infrared meter. Apparently, the pinned cracks had leaked small amounts of coolant into the combustion chamber and without the driver realizing it, eventually drained the cooling system. After the engine cooled, the mechanic put some water in it but the leakage (combustion gases into the coolant passages) blew it out as fast as he poured it in so he went on to pull the head. Daddy is now searching the junkyards for a good NA head – apparently he is limited to just two or three model years for this engine.

I was not aware of this pinning procedure and see it as a good way to get burned on a used car purchase. If the leak is very small, there's no way the typical pre-purchase inspection will reveal it. The mechanic showed me the head, which had been pinned in at least three places. Anyone ever seen this type of repair before? For those who, like me, have not, the procedure is to drill a hole at the end of the crack and then press in a steel pin. It stops the crack from growing, at least for awhile.

Jeremy

[Simpler=Better]

for that kind of trouble why not grind out the crack and then fill with weld? Cast iron *can* be welded, even if it's tricky.

A 1980 300D? Any 76-81 300D/CD should work fine.

[Jeremy5848]

Originally Posted by ForcedInduction

A 1980 300D? Any 76-81 300D/CD should work fine.

For a '76-79 head you have to either retrofit the old loop-style glow plugs or drill and tap the holes to take the later glow plugs. The owner and mechanic don't want to do that so they are stuck with trying to find a head from an '80-'81 model year 300D.

My concern was simply the difficulty of avoiding a car with a repaired head if the seller is not honest enough to disclose it up front. Some repairs (bodywork, etc.) are easy to spot – even I can catch them – but this seems like it would be hard to detect.

[bgkast]

Originally Posted by Jeremy5848

For a '76-79 head you have to either retrofit the old loop-style glow plugs or drill and tap the holes to take the later glow plugs. The owner and mechanic don't want to do that so they are stuck with trying to find a head from an '80-'81 model year 300D.

Actually you can just screw in an adaptor.

[LuckyEddie]

Back in the days that I had 220's I had the head furnace brazed and never had another problem with it. I don't know if that can be done anymore but it was an acceptable fix at that time.

[Jerry_W]

The 'pinning' may be the same repair done on certain 5.9 Cummins engines, however it is only to repair blocks that crack at frost plugs, or into the water jacket elsewhere, first time I ever heard of it being done for a head. Guess some folks will do anything for a $. (Meaning both the PO and the shop that did it. I don't think it is a DIY repair.)

[the heap]

Bosch makes a Duratherm pencil-type glow plug that fits in the older loop-style thread pattern. I've installed them on my '77 300D NA, $19.40/ea at NAPA. No adapter required.

[t walgamuth]

Many cracks can be repaired, but it depends on where they are. A good used head might well be cheaper or the indie may not have a good shop at his disposal.

Good luck.