Engine knock on 240D ($100 car)

[IZELJIC]

So I decided and purchased the 1982 240D for $100 yesterday. I drove it home about 10 miles and the engine knock kept getting louder. The car even stalled on me a few times when idling (only when warm). The knocking noise is comming from the top so from you experts I would need an opinion as to what could be causing it. The mechanic who I bought the car from said that the people ran out of oil and when they refilled it the noise appeared. How difficult is to remove the valve cover and see what's in there? Would it be something I could do myself (I have some tools and have the repair manual)? The body is decent, it has a manual tranny and the interior is great shape so I really hate to part the car.

Thanks a million for any help,

Igor

[kerry]

It's an easy job to remove the valve cover. It may be even easier to apply a mechanics stethoscope to the engine and isolate the sound before removing the valve cover.

[william rogers]

a knock from no oil usally means a rod bearing. If the rest of the car is nice I would go for a used engine or if you have time and skill rebuild it.A nice 240 D manual is sure worth saving........
William Rogers.......

[Mordecai]

Originally posted by IZELJIC
The knocking noise is comming from the top so from you experts I would need an opinion as to what could be causing it. The mechanic who I bought the car from said that the people ran out of oil and when they refilled it the noise appeared.

Regardless of where the sound is comming from, the first thing to go in a low oil situation is usually the rod bearings. Rod bearing failures have a distinctive sound and if you know that sound then you can diagnose the problem yourself.

If it's a rod bearing then expect the rod to fail and poke a hole in the side of the block if you keep driving it.

Still, it might have more than a 100 bucks in good parts in it.

Paul

[300SDog]

Igor, pulling and swapping engines is easy to do.... you can rent an engine hoist on wheels that works with hydraulic lever to pull the old engine, after disconnecting all the obvious connections, radiator, etc.

Good running 240 engine should be easy to find in MN as the engines often outlast the car. Shouldnt cost you more than $500. Junkyards should be able to locate an engine through their own network, even within 200 mile radius for really good low mileage engine.

Stick-shift 240s are big ticket item. Since you stole the car, none of your money will go down the drain. And immense satisfaction will be gained from building your own Benz.

Otherwise, I wouldnt bother with old engine run dry.... thinking other problems can occur down the road.

[IZELJIC]

Every one of you guys makes an excellent point. How difficult is to install a 300D or 300D Turbo engine? I might buy a car today that has a good engine (Turbo) but it's an automatic. I would love to have a manual TurboDiesel.

The injectors on 240D are obviously under pressure so what is the trick of releasing the pressure so that I can remove the injectors and therefore remove the valve cover? Can anyone describe the noise of the bad rod?

Again I thank everyone on their help.

Igor

[kerry]

You do not need to remove the injectors to get the valve cover off. You simply need to disconnect the linkages and unbolt the valve cover to remove it.

[P.E.Haiges]

IZELJIC,

The injectors are only under pressure when he engine is running.
And then for only a millisecond or less.

P E H

A bad rod will make a heavy knocking sound that will vary with the RPMS, at least most of the time., Although I have seen them where the engine just bangs away at most all RPMS. Much deeper sound than a lifter, and it is not that constant.

[rwthomas1]

Can you be sure its a rod knock? Maybe a really bad injector? Try cracking each injector line one at a time while the engine is running. If the knock goes away you just found your problem. Drain the oil and have a look at it. Bad rod bearings will sometimes leave metal in the oil and it is obvious. A rod knock sounds like a ball-pein hammer on solid concrete. Not at all like a lifter or injector. I had an old slant-6 (slant-sicks) dodge that would rod knock unless I had 2qts of 20w-50 and 3gts of 75w-90 gear lube in the pan! Ran it for 6 months with the gear lube in it... RT

2 qts of 20w-50 followed up with 3 qts of 75w-90? Sounds like glue to me. Must have been fun to get her warmed up and running in January!

[IZELJIC]

Actually the injector closest to the radiator had a really bad leak. When the car idles the engine just shakes but there is NO knocking. As soon as I hit the gas pedal even slightly the knocking occurs. What should I do in order to "test" whether that injector is bad?

[kerry]

You need to record the sound on your computer and post it here. In my opinion the symptoms are consistent with a rod knock.

[P.E.Haiges]

Pull the pan and visually inspect the rod bearings before you run the engine too much. Inspect the crankshaft too. If crankshaft journals are not scored you can replace the rod bearings. Also check main bearings and journals.

I you are lucky, you will just have to replace the bearings.

P E H

[300SDog]

At issue with 300D /SD/TD conversion for standard shift is flywheel that needs to be special ordered from Europe.... also you will want the 300D differential.

Check this out - there's an '82 240D engine at nearby Michigan that is currently priced at $49.95......

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2418229835&category=33615&rd=1

Better yet - there's even a fellow in Vancouver with BRAND NEW factory short block, complete with flywheel ballanced to the crankshaft.....

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2418095639&category=33615

Why on earth anybody would bother fiddling with engine making weird sounds that had been run out of oil is a mystery to me.