starter motor keeps burning out

[autopian]

Not familiar with common rails, but how much fuel would drip out of an injector if the cut off became intermittantly faulty? Using my experience of hydraulically pressure testing huge vessels, I would think that if 0.5ml leaked, then all residual pressure in the common rail would be gone. No mention of black exhaust smoke.

you are correct, i don't think enough fuel could leak from a faulty injector to cause this, i only mentioned it as its just as unlikely as a head job. sorry if i never put this across correctly.

 

[Danny DeVito]

I have a question.

If a water pressure test, shows no leaks . .
Then how does it leak into the engine. . if the test shows no leaks?
So it leaks, when it tests with no leaks. .

Am I the only one that cant get my head around that!

Anyway here is my two pence worth.

If the starter motor was staying engaged with the engine (sometimes) due to faulty electrics or worn flywheel / alignment not allowing the bendix to disengage, then this would occasionally “drive” the starter motor and burn it out (turning it inn effect into a dynamo and cause a burn out). When the engine was stopped, the motor would more likely disengage then due to loss of centrifugal force etc.

However sometimes the motor would stay engaged and this would also give the impression the engine was “locked” on trying to start again due to the fact that when you tried to start the car, as the bendix was still stuck, it gave the same symptoms as a hydraulic locked engine.

I have come across this fault on Scammell Commanders (tank transporters) in the Army, and we ended up fitting two starter motors such was the high failure rate. When we tried to start and got a “lock” a good thump of the starter motors with a hammer would allow the motor to disengage and it would then start.

Good luck and strangely I hope I am proved wrong about the gasket, but something is scratching my head so much that I had to say something.

Cheers

I don't think if the bendix is out that it would try to start would it ? Ok forget that i'm thinking nonsense

 

[Danny DeVito]

So really the only definite info is

1 The starter is burning out ( for whatever reason )
2 Its loosing coolant somewhere inside
3 The gearbox fluid is ok
4 Europa can't see anything through the glow plug holes

You know when my car overheats it just pumps the coolant out the exp bottle, and the only sign of it is that the top cover is a little wet. It doesn't even have to be at 100 for this to happen on mine. I don't even see any underneath either. Could this be happening on yours ?

 

[mafya]

So really the only definite info is

1 The starter is burning out ( for whatever reason )
2 Its loosing coolant somewhere inside
3 The gearbox fluid is ok
4 Europa can't see anything through the glow plug holes

You know when my car overheats it just pumps the coolant out the exp bottle, and the only sign of it is that the top cover is a little wet. It doesn't even have to be at 100 for this to happen on mine. I don't even see any underneath either. Could this be happening on yours ?

I have checked for this and found no evidence of coolant anywhere.

 

[Danny DeVito]

I guess its a case of things i would do if it were mine. I really REALLY think you should have the block test done before removing the head !

Dieselman, are you saying that a hydro lock is uncommon in a diesel ? I am unfamiliar with this sort of thing

 

[Dieselman]

Dieselman, are you saying that a hydro lock is uncommon in a diesel ? I am unfamiliar with this sort of thing

Due to the high compression and gas expansion rate, any leakage between the cooling system and cylinder always results in water being blown out of the system.

Just removing the coolant tank cap and watching for bubbles is often a reasonable indicator, but a block test would be conclusive.

 

[Danny DeVito]

How long should you look for ? Sometimes i'vs seen bubbles caused by the vibration of the engine ( at least i think it was ) ((i hope it was ))

 

[Dieselman]

Bubbles is gas, not vibration.

 

[Danny DeVito]

Oh dear, luck it's not on my current vehicle ! Y'know every time i see yr avatar i can't help with your obvious experience , i can't help a picture in my mind of you shaking your head at some of the q's here and saying aww jaysus 'Don't you people know anything' It makes me laugh ! So Thanks.

 

[whitenemesis]

Bubbles is gas, not vibration.

But vibration liberates gas, thereby causing bubbles?

 

[Danny DeVito]

I can see a paradox looming

 

[mafya]

I guess its a case of things i would do if it were mine. I really REALLY think you should have the block test done before removing the head !

Dieselman, are you saying that a hydro lock is uncommon in a diesel ? I am unfamiliar with this sort of thing

The reason i'm going ahead with the head job is i know it was loosing water before this starter problem, there are no external leaks but the water is disappearing somewhere.
The mechanic who has the car now is very good and highly recommended by one of my good mates and is only charging me £520 but i'm supplying the gaskets, head bolts, coolant, oil and oil filter and the price includes him sending the head off to be tested and skimmed if required.
He will be starting it on Tuesday so will keep you all updated.

 

[Dichtung]

Due to the high compression and gas expansion rate, any leakage between the cooling system and cylinder always results in water being blown out of the system.

Just removing the coolant tank cap and watching for bubbles is often a reasonable indicator, but a block test would be conclusive.

100% agreed; and it`s looking like that could be happening as he drives the car; but isn`t the scenario here, one of an engine standing overnight, where there is no highly compressed gas expanding etc.

The only pressure possible might be from the cooling system as it cools, and Mafya states that the top hose gets very hard.

So; is it not feasible that, occasionally, a piston , stopped all night on its compression stroke could have a cupful of coolant on it?

Hope Mafya`s new guy finds something conclusive.

 

[mafya]

100% agreed; and it`s looking like that could be happening as he drives the car; but isn`t the scenario here, one of an engine standing overnight, where there is no highly compressed gas expanding etc.

The only pressure possible might be from the cooling system as it cools, and Mafya states that the top hose gets very hard.

So; is it not feasible that, occasionally, a piston , stopped all night on its compression stroke could have a cupful of coolant on it?

Hope Mafya`s new guy finds something conclusive.

What you said is what me, Europa and the new mechanic are thinking, when the car is running it is getting rid of coolant through the exhaust but really hard to notice. When it is parked overnight if the affected cylinder is on compression stroke then we think it fills up and makes the engine hard to turn for the starter and burns it out due to it auto running for 10 seconds.
Tommorow he starts on my car so will find out the truth soon.

Billy

 

[Danny DeVito]

I don't see what u guys mean there at all. If the piston is on comp stroke then shouldn't the pressure in the cylinder keep liquid out ? Or do u think the pressure releases through a hole , but if this is the case then why not on any other part of the cycle ? And then back to my original point that if water gets in and u try to start, it locks, then shouldn't the pressure force the water past the rings or back out through the hole and then at some stage allow the car to start again. I just don't understand how the car starts after the starter is replaced if nothing else is done. Surely by leaving the car an appropriate amount of time after the fault occurs ( without damaging the starter ) the car should start as normal ?

 

[Mercsys]

#65 if a cyl stops in a comp stroke the charge pressure will decay completely within a few tens of seconds, then the up to 2 bar of coolant pressure will come into play with the heat soak which will also be an abnormal heat flow that occurs post shutdown as the coolant stops flowing but the cyl, pistons, turbo, are still at normal running temp, if there is any doubt that this heating may cause a problem calculate out how much the average I6 aly block grows from ambient to 100° I’d put it around 1-2mm! Add to that, separate components, different materials and cooling rates, thermal conduction paths, and the rad is still working with stat wide open but the coolant is only circulating by convection, so the block will cool first while the head is still hot.. Also the +1 bar over pressure will be maintained for perhaps an hour or more.
On starting the locked cyl has <10 seconds to force any liquid (~30cc) back into its point of origin or past the rings and get over tdc and start or burn the starter, if it burns the starter or is stopped (key out) then the compressed gas laying over the liquid in the cyl will purge the excess liquid in the following time (mins) following the stop thus allowing the successful second attempt. And the reason the pressure is maintained now is there is perfect liquid ring as well as the metal one doing the sealing.

 

[mafya]

update

Started on the car today, injectors were giving mechanic a hard time. Two came out easy and 3 were stuck solid but managed to get 2 out using the puller tool but the 5th one is stuck solid. If the 5th one doesn't come out tommorow after an overnight soak then mechanic is going to weld a puller onto it so it will defo need a new injector if the puller tool is welded on and going to drop the other 4 off at John Hoggs diesel specialist to be refurbed.
Hopefully the head should be off tommorow.

Billy

 

[BlackC55]

Be careful if you skim it. It will need a thicker head gasket. Only get a mb one and follow the WIS instructions on how much to skim off

 

[Danny DeVito]

#65 if a cyl stops in a comp stroke the charge pressure will decay completely within a few tens of seconds, then the up to 2 bar of coolant pressure will come into play with the heat soak which will also be an abnormal heat flow that occurs post shutdown as the coolant stops flowing but the cyl, pistons, turbo, are still at normal running temp, if there is any doubt that this heating may cause a problem calculate out how much the average I6 aly block grows from ambient to 100° I’d put it around 1-2mm! Add to that, separate components, different materials and cooling rates, thermal conduction paths, and the rad is still working with stat wide open but the coolant is only circulating by convection, so the block will cool first while the head is still hot.. Also the +1 bar over pressure will be maintained for perhaps an hour or more.
On starting the locked cyl has <10 seconds to force any liquid (~30cc) back into its point of origin or past the rings and get over tdc and start or burn the starter, if it burns the starter or is stopped (key out) then the compressed gas laying over the liquid in the cyl will purge the excess liquid in the following time (mins) following the stop thus allowing the successful second attempt. And the reason the pressure is maintained now is there is perfect liquid ring as well as the metal one doing the sealing.

Well that clears that up for me , do you write text books ?

 

[mafya]

Be careful if you skim it. It will need a thicker head gasket. Only get a mb one and follow the WIS instructions on how much to skim off

I have bought a genuine MB head gasket kit. What are WIS instructions?