[gobbolino]

Question: the car I was asking about earlier was bought in the full knowledge that it had a "Cracked Crankshaft" apparently due to overheating - the cure was removal of thermostat - apparently to stop overheating. I have been trying to get the heating working again. Anyway - how would anyone know a crankshaft was cracked without actually taking the engine apart and looking? The car drives OK and apart from the heater problem I cant really understand why it should have overheated and cracked the crankshaft. It has only 127k miles.

crakshaft? I mean cranksaft...

 

[eamo]

Not sure how ou would tell without pulling out the engine but you can drop the sump and have a peek. That may help

 

[michael320]

Sump off and rotate her, a crack would be hard to spot though,

 

[gobbolino]

Yes, I wonder how they did it, maybe just a guess or does a a broken crankshaft make a particular noise - or does it just self destruct the engine?
Thanks folks....I am secretly hoping it is not broken at all...

 

[John_D]

I would have thought a cracked crankshaft would disintegrate itself fairly quickly considering the forces acting on it and the speed it is turning.

 

[oilburner]

A crankshaft usually breaks within a bearing journal so you are unlikely to see anything from below.

The engine will sound like a bag of spanners though.

 

[Dicko]

As already said , crankshafts dont really crack , they usually break big style , if its broken you will know all about it .

 

[gobbolino]

Well, I brought it for a drive this evening and nothing exploded or disintegrated. So - perhaps it is not cracked after all? It sounds quite clunky at the start when it is warming up - maybe oil not getting to all the hard to reach places. I have previously had it on the motorway and done a good 100km in it. Would a knackered crankshaft manage it? I am almost confident in the car now.....

 

[michael320]

Well, I brought it for a drive this evening and nothing exploded or disintegrated. So - perhaps it is not cracked after all? It sounds quite clunky at the start when it is warming up - maybe oil not getting to all the hard to reach places. I have previously had it on the motorway and done a good 100km in it. Would a knackered crankshaft manage it? I am almost confident in the car now.....

Im guessing your safe enough at this stage, it may be crank bearings?

Is there any chace it could have been starved of oil?

 

[gobbolino]

I know it overheated at least once, when I got it the thermostat had been removed - it had overheated and stopped at least once in its life. I was told that after this the crankshaft had cracked. I read that 1.8 engines had problems with an oil feed blocking (it sprays oil over the engine?) and this often caused problems. It is an M40, so I guess it might be the same engine as on 318 of that time.
I don't think it ever ran out of oil, and it seems to have been well maintained, but it is possible...
Does anyone have a good ear for engines that would be able to tell by listening?

 

[beemerchris]

I know it overheated at least once, when I got it the thermostat had been removed - it had overheated and stopped at least once in its life. I was told that after this the crankshaft had cracked. I read that 1.8 engines had problems with an oil feed blocking (it sprays oil over the engine?) and this often caused problems. It is an M40, so I guess it might be the same engine as on 318 of that time.
I don't think it ever ran out of oil, and it seems to have been well maintained, but it is possible...
Does anyone have a good ear for engines that would be able to tell by listening?

If you're close to Sandyford/Wicklow I can have a listen to it. Your mentioned "spray-bar" issue is for the Camshaft and not the Crank

 

[gobbolino]

Thanks for that, I will take you up on that if I get it back on the road. At the moment I am reduced to starting it with a battery pack and filling the cooling system with water (c. 2 litres) every time i drive it up to the shops (1 mile). You are right about the camshaft thing, i am just baffled as to how anyone could diagnose a cracked crankshaft......