1984 760 TurboDiesel

nisan17 · Post by **nisan17** » 21 Jan 2009, 10:28

Hi Group,

I have my eyes on the aforementioned sedan which is for sale. I want to know ahead what type of project this could be. The car is mint but the diesel according to the owner was blowing smoke and overheated. Now it won't start. We're thinking head gasket, glow plugs, relays?!
BTW: He wants $1k for the car and was informed a new crate motor for $2900.

Thanks in advance,
Kevin

Post by **billofdurham** » 21 Jan 2009, 12:23

Kevin,

The D24T, straight six was virtually an unstoppable engine, unless neglected.

When a diesel starts blowing smoke I check the injectors as they tend to foul easier than petrol injectors. The glow plugs don't usually cause it to blow smoke except on initial start-up. In fact the usual glow plug problem is when they stop working. Their life span is governed by many factors but they should last at least 100,000 miles on an engine of that era. There is a relay which switches on/off the glow plugs but it tends to give little trouble as it is not overworked.

The overheating may well have been caused by the head gasket going. To remove/refit the head is timed at 5.4 hours so it is more complex than the petrol engine. Unfortunately, I don't have a diesel workshop manual for that engine.

new crate motor for $2900.

Cross pond terminology again. Is that an engine ready to drop in?

Bill.

nisan17 · Post by **nisan17** » 21 Jan 2009, 15:37

Yes, drop in ready to go except for some minor swapping of periphial components.
Sorry, I thought that was universal language!!

jaluhn · Post by **jaluhn** » 31 Jan 2009, 00:10

If it overheated, I'd be inclined to believe that the head is warped and the gasket is blown. If it was running / starting well before and hasn't sat for a while, that's about all that likely to be wrong. You can check the glow plugs pretty easily, either by testing the current draw (something like 12 amps per plug, so ~72 amp total, less indicates bad plugs / me remembering the numbers wrong) or test the resistance of the individual plugs (requires the bus bar to be removed) Should be ~1 ohm per plug, infinite indicates burnt out plugs.

Head gasket isn't terribly hard on these, but still a fair amount of work. You'll need some special tools to lock the cam and time the pump, but these are the same as for a VW 4 banger, and can be had for $50-100 on e-bay. I've got the manual if you happen to need any info, PM me if you do since I'm not in this forum much.

Where was the $2900 quote from? I was not aware anyone had crate motors for these anymore, and I'd think closer to $3500+ if they did. Admittedly, that's more of a WAG than a real quote, but I'd be hesitant to put too much faith in that number unless I had it in writing from the vendor. If you do, then IMHO that sounds like a decent deal.

As another option, I have a more or less dealer reman long block I'm probably going to sell before too long, PM me if you want more info.
~John