101 V8 Died (3.5l)

Hi , one of the beautys of lpg is that when there is a lack of warmth to the convertor they stop running .

The converter problem you have described matches your symptoms .

The reason for stopping and not restarting when warm is that the converter is icing up , which stops the gas flow .

The white smoke is the coolant inside the hot engine and the coolant out the exhaust is the same both from the converter coolant jacket failure both via inlet manifold entry .

So long as it was running on lpg when it got hot and stopped running there is unlikely to be any damage done if it was running on petrol when it stopped it most probably would have stopped differently and would be damaged because petrol doesn`t care if there is coolant there or not but your description says to me it was on lpg .

Replace the converter and other than the loss of some carbon it should be similar to how it was .

cheers.

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Originally Posted by 101 Ron

Garry
You have a Impco gas convertor and they have a bad habit of
corroding though if coolant has not been used at some stage of the motors life.
Remove the two cooling system hoses running to the gas convertor at the gas convertor end and join them together with fittings and another hose.
Top up the cooling system and test drive.(On petrol)
If the convertor is corroded though, there is usually water drop lets present in the lowest parts of the large gas vapour supply hose to the gas mixer.
I hope it is the problem as it is a easy fix.

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Thanks Ron - I think that is exactly what happened - as the diffuser is much lower than the converter with a U turn in the air intake being the lowest point and the coolant pooled here and was sucked into the engine. I think I will get both the converter and the diffuser reconditioned or replaced.

Garry

Quote:

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Originally Posted by PLR

So long as it was running on lpg when it got hot and stopped running there is unlikely to be any damage done if it was running on petrol when it stopped it most probably would have stopped differently and would be damaged because petrol doesn`t care if there is coolant there or not but your description says to me it was on lpg.

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The day before it was running on LPG. On the morning when this all happened I was on petrol as mine has to start on it. I had switched the petrol/lpg switch to the no fuel position and was about to switch it to LPG. The engine had only been running for about 2 minutes so would not normally have been hot - however with no coolant I guess the block would have still been cold but the pistons/liners would have been quite warm.

Garry

If it is the gas convertor, you will need a new one.
If you pull the old gas convertor apart they normally have a pin hole from the water tube inside the convertor though to a diaphram chamber.
The Impco gas mixer....you call it a diffuser should be unaffected by the water going though it and there is really no need to play with it.
Garry if you give me the model number of the Impco gas convertor I can most likely get one to you at trade price .

Bypassed the converter and checked the gas mixer. It was full of coolant as was the air intake plumbing. I am surprised how much the gas mixer restricts the airflow into the engine - must have an impact on engine performance.

Anyway - put it all back together and after some cranking the engine fired and seemed to run OK - as soon as I revved it up it died and white smoke poured out and my depression increased. It would not start hot but when cooled started Ok - this time did not die or have white smoke.

So went for a drive around the block (so I could roll it home - had to call the NRMA yesterday). Drove Ok until power was required - died and white smoke but did recover and no smoke (no blue stuff at all). Each time I drove around the block it coughed and spluttered but was starting to run better - pinged on the thought the engine was OK and every cough and splutter was in fact clearing its throat of the coolant that must have been hiding in all sorts of places.

So drove up a big hill and it pulled OK - no smoke or steam or spluttering and the engine was beginning to sound like its old self. So after driving about 10km all seems to be OK. I will go for a 100km drive tomorrow just to make sure - I am going to Bendethra this weekend and I want to make it back.

An engine low water alarm was on my list of things to do so I will get one next week. As far as the LPG system is concerned, the converter is hard to get too so I will pull that out next week (I have turned the gas off).

So - for the moment all seems OK.

Thanks to everyone for your input - I can assure everyone that water in the air intake system does mimic a blown headgasket - particularly when it is a 40 degree day and that water is coolant draining from you cooling system.

Garry

Glad to hear all seems well. An oil and filter change may be a good idea after the 100k drive. Even if no water got into the sump, it has likely dislodged a lot of carbon, not all of which will leave via the exhaust.

Good point - thanks Ben.

Garry

Finally managed to get all the coolant out of the air intake system and the engine is back to running like it should. No smoke at all so it seems that all is OK for the moment. The engine did over heat so I guess time will tell if there will be other problems later.

Thanks to everyone for your input.

Cheers

Garry

Good result.
the gas convertor would have stopped the motor before any damage occurred to the motor.
It happens alot in my game the forklift trade.........gas convertoes freezing up after a radiator hose has blown has saved many a motor.

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Originally Posted by 101 Ron

Good result.
the gas convertor would have stopped the motor before any damage occurred to the motor.
It happens alot in my game the forklift trade.........gas convertoes freezing up after a radiator hose has blown has saved many a motor.

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That is a good feature :), but also worth mentioning that if the corroded through converter problem happens, disconnect the converter to inlet pipe and check for coolant in the manifold BEFORE starting engine. I have seen hydraulic lock occur after the converter failed, and the vehicle was left sitting for a while, and then attempted to start it with an inlet manifold and 1 cylinder (with an open inlet valve), full of water:(
Glad all is up and running again, can't stop that mighty little 3.5:)


JC