What to look for in a used GL 240 Diesel?

[Dartron]

Hello all. I'm going to take a look at an 83 240 GL Diesel. I'm pretty set on buying one of these cars and was wondering if anyone had any tips of what to inspect when I go to look at/test drive it. Any help would be most appreciated.

[hvguy]

listen to the engine on startup.. is it shaking around? is it hard to start?

also, unplug the hose coming from the valve cover and see how much air/smoke is coming from it... this indicates the amount of "blow-by" which is caused by worn out piston rings... the more smoke/air the more worn-out...

my engine has a pretty good amount and its got 260k

also if its a m46 4 speed manual w/ overdrive be sure the OD works properly...


thats all I can say since I dont know much on the subject.

[v8volvo]

The main concern on these engines as they age is deteriorating compression due to ring and cylinder bore wear. Whether an engine is worn or not depends mostly on maintenance and use; if the motor is cared for and used for long-distance driving it can have hundreds of thousands of miles on it and still be in great shape, but if it was used for short trips and maintenance was neglected, it can be in bad shape even if it has low miles on it. That makes it tricky, because going just by the odometer reading really doesn't tell you much. I have seen them in fantastic shape with 260,000+ original miles on them, and I have also seen them completely worn out with barely over 100k. Without doing a full compression test it is always something of a gamble buying one, because it is hard to know for sure what kind of state it is in. One good thing to check is what was mentioned above about checking blowby by removing the crankcase vent hose.... but unless you have some basis for comparison, i.e., another Volvo diesel right there to check it against, you will have no way of determining what is "a lot" or "a little". It's not a very scientific test and won't mean much to you if you're not already familiar with how these things run and act when they are healthy vs ill. Even one in perfect condition will have lots of blowby compared to any gas engine, so if that is what you are used to, your yardstick will be way off no matter what.

There are other ways of checking out the engine that will give you a better indication of its internal condition. Even when these engines are completely worn out, they will still start great when they are cold as long as they have 6 good glow plugs in them and a good starter and battery. They will also restart fine when hot and just driven. However, a "warm start", i.e. restarting after having been driven and warmed up but then allowed to sit and cool off for a period of time, can be a challenge if a motor is worn out. You want to try to look for that as a way to assess whether this car's motor has strong compression or not.

To do this test, first drive the car it until it is fairly warm (shoot for around 20 minutes or so of normal driving, you want to see the temp gauge get all the way to its "normal" reading). Then park it, turn it off and let it sit for 30 minutes while you check out the rest of the car, talk with the owner, get a cup of coffee etc. Now pop the hood, find the glow plug relay (a smallish black plastic box with wires and plugs on the bottom, mounted to the washer reservoir bottle on the drivers side of the engine compartment on a 240), and disconnect the black ground wire from the bottom of it to disable the glow plugs (you're looking for a bare female spade terminal at the end of a black wire). Bend the wire so the loose terminal hangs out of the way; don't let it short out any of the B+ stuff in that area, such as the hot wire going to the glow plug relay.

With the relay disabled and the engine having sat for about 30 minutes (try to really make it pretty close to 30 or else the results of your test will be thrown off), now get in the car and start the engine. Just turn the key, don't put your foot on the gas, wait for a glow light (there won't be one), or anything else. If the engine is in excellent condition, it will start instantly under these conditions. If it is in good-to-OK condition, it will crank a few revolutions but start up fairly readily, with a small but visible puff of gray smoke out the exhaust. If it is in just-fair condition, it will start, but it may struggle a bit, crank for an abnormally long time, and make a fair amount of smoke and clatter when it does light off. If it is in poor condition, it will eventually start but not without significant effort, lots of cranking, foot to the floor, cussing, lots of smoke, etc...... and if the motor is really on its last legs, under these circumstances it will not start at all.

This is a seat of the pants test and is still not very scientific (still depends on how ambient weather conditions, how warm the engine got on the drive, whether the engine is properly timed, etc), but I think it is the best way to assess the condition of the rings other than doing a real compression test. If you do this test on a good motor and then immediately again on a worn motor, you can see very obvious differences in how they stack up. I have owned D24Ts that fall into every category of condition above, from one that starts instantly to one that will not warm start at all unless I activate the glow plugs. This test really makes the differences come out.

Try this out and see what you come up with. Afterwards don't forget to reconnect the ground wire to the glow plug relay, otherwise it won't start again the next morning. And don't forget to ask the important questions like who serviced it, when the timing belts were last changed and if the job was done right, timing set properly, etc, what kind of oil was used and when it was changed, whether it uses any, etc. And how it runs is a good indication too -- if it idles smoothly, has good low-end torque and high-end pull, and doesn't smoke much, then odds are it is in OK shape whereas if it is sluggish and smoky it is either in a poor state of tune (ie timing or injectors), or worn out.