Thread: 300tdi won't turn over or turns slowly or runs briefly then screeches and stops.

Mine started making a noise at about 400K. I identified where the noise was coming from after taking the belt of and turning it by hand. Very stiff. I replaced it with a 100 amp job. all good now.
don.

Originally Posted by TJWA

My Daughter was driving my boys 110 Defender 300tdi yesterday while he was away, she came up to a set of lights, went to put it in 2nd and it conked out while she had the clutch in, tried to restart it but nothing, it would not even turn over. She said the engine had been sitting between 80 to 90c (it has a mechanical gauge) and there was no evidence of overheating.

A day later and sometimes it starts easily then runs perfectly for a few seconds at most and then screeches and stops abrupty, other times the starter motor tries to turn it over but struggles to turn the engine very slowly while pulling 800+amps.

I loosened the pulley at the front, checked the new water pump, alternator, idler, power steering pump, viscous fan pulley etc and everything turned ok by hand, but the alternator bearing was noisy and rough.

I took off the rocker cover, no sign of damage, no sign of loose rockers, I turned the engine over very slowly with the starter motor and could see the rockers move.

I took the starter motor off, it worked perfectly and spun freely.

I took the front drive belt off, the motor ran perfectly.

I tested the alternator again by hand, but this time wrapped a rag around the pulley and spun it fast, it screeched and locked up, problem found.

Conclusion - A faulty bearing on an alternator can bring a 300tdi engine to a complete stop or prevent it from turning over to start!

I hope this short post helps someone save some time in the future.

Interesting post. Are you telling us that a faulty alternator bearing stopped a 300TDi? Because I seriously doubt it. I also doubt that any ancillary on the serpentine belt would stop a 300TDi in normal driving. I reckon you'll find it will stop again, and the issue will NOT be the alternator. BTW, the starter motor ( 800 amps you say ) generates far more torque than an alternator, faulty bearing or not, can hope to overcome.

More to this than meets the eye, if the OP has told us the whole story. A running 300TDi takes some stopping.

I'd say check again.

Originally Posted by Don 130

Mine started making a noise at about 400K. I identified where the noise was coming from after taking the belt of and turning it by hand. Very stiff. I replaced it with a 100 amp job. all good now.
don.

Fine. Did it stop the engine? Was drive lost? I ask because these were the symptoms the OP suggested.

When the crappy little bearing at the back of one of those alternators seizes, the cavity it lives in is shredded and metal fragments go everywhere. Then it stops turning when the rotor hits the stator. Anyway, plenty of stories on here about seized idler pulleys being mistaken for a seized engine. The short and simple test is always to remove the serpentine belt and testing the starting ability. A serpentine belt with a lot of crankshaft wrap can transmit a few HP and will have no trouble stalling an engine at idle.

Originally Posted by bee utey

A serpentine belt with a lot of crankshaft wrap can transmit a few HP and will have no trouble stalling an engine at idle.

Will it prevent the starter from functioning? Would it do this?:

went to put it in 2nd and it conked out while she had the clutch in, tried to restart it but nothing, it would not even turn over.

Did you read the entire post? There is more here than meets the eye, if you can be bothered to read. But I'll bow out, now the expert has arrived.

I'll look forward to the solution.

Originally Posted by johntins

....

I'll look forward to the solution.

Not unheard of in other vehicles too.
BeeUteys comments make sense, re the bearing/housing analysis.
I'm sure Rick had the TD5 idler seizure issue a while ago too.

I vividly remember way back when I was a courier, one of my fellow couriers in a VN Commodore came to a halt on a busy road at peak hour with what looked like a seized motor.
He described it as motor locked up.
I was close by and went to help him move car out of harms way, and another chap also came over from not too far off, and ex mechanic, and described to us what the problem was.
To get him going quickly to get the seized alternator sorted, the other guy(Ringo) told him to get a serpentine belt from whatever make model to bypass the alternator just to get it going and get him to a workshop.

So, seized alternator stopping motor, and hence vehicle .. not uncommon.

Originally Posted by johntins

Fine. Did it stop the engine? Was drive lost? I ask because these were the symptoms the OP suggested.

No, it didn't stop the engine, nor did I loose drive. I heard a new noise and when it didn't' go away after a day or two I investigated. You know the rest.
Don.