Hello All. There are two parts to this post, a cautionary tale and an unfolding question.
Edited Update: I want to thank everyone that helped me with this, I am really humbled by you taking time to respond here.
If you are coming to this thread fresh there are now two (lockdown fever induced) videos that would do a good job of getting you up to speed: The first shows the two tank veg oil conversion we did on our 2005 1.9 Caddy van.
The second follows my investigations into what went wrong with the engine and can be found here.
First a quick intro: I enjoy a bit of hobby mechanics, and have been playing with our 1.9Tdi PD 2005 Caddy. It's been re-mapped (was before we acquired it at 47kmiles, so don't know the details, but when you put your food down it goes!).
At 140k, I decided it was time to dabble in running it on straight veg oil and began a two tank conversion. We produce a youtube channel, called Flowering Elbow, and thought it might be an interesting thing to share with our subscribers there… To cut a long story short, we recorded the conversion process, got the van up and running, did 500 miles (in two long trips).
Then we did a few short 1-2mile (diesel powered) trips, the last of which there was an audible bang on startup, but ran fine… Before a serious problem…
Starting on diesel, we noticed more smoke than normal. Should have stopped then, but my wife had urgent appointment. Drove very cautiously - basically idling through town, got to a hill, low power, engine suddenly increased noise, plume of smoke Luckily there was a place to pull over right there and I cut the engine quite quickly, after noise increase. We got toed and my wife never made her appointment
Upon Investigation: There was fuel (diesel) in the oil. Lots of it! When I drained the sump, there was about 12L of oil-diesel in there. So I guess hydrolocking may have been a thing? There was also about 1l filling the pipe from turbo to bottom of the intercooler.
My Theory: The lift pump for the new aux diesel tank was too high pressure. I was working from the assumption that the tandem pump would regulate pressure and send any unused fuel back along the return line. Of course the tandem pump may have just failed anyway... But I strongly suspect my lackadaisical testing of the new diesel pump and feed pressure causing tandem pump to blow seal between fuel and oil?
How bad is it?: Pulling the sump, I haven't found any debris, and the bottom of the connecting rods an crankshaft look ok (to my untrained eye). If a connecting rod was bent is there a way to tell by looking?
The turbo looks surprisingly ok? At least the turbine blades seem intact, if oily, and I can move it by hand without huge amounts of play – although, again, I don’t know how much play is unacceptable?
Looking behind the valve cover, I see quite a bit of wear on the cam shaft (I guess that’s expected when you lube it with half and half diesel-oil right The chamfer on the sides of the lobe peaks is worn and I can feel a burr there. I can’t see how worn the lifters are until I have the shaft out, so I don’t know if I have any holes in them yet…
And so, my questions to you: I think the tandem pump was the problem, but equally, fuel could be leaking round the unit injector O-rings (but maybe not in that quantity?) Either way I may as well have the unit injectors out and get them tested / new seals…
A new camshaft kit is £360, new tandem pump £240. I have the option of getting a new (to me) engine inc. tandem pump, camshaft turbo, and injectors that’s done 85k for £610… I don’t know what to do – try with new parts which should last longer assuming cylinders ect. are ok. Or just get the whole engine and then if injectors or some other bit is bad, I can replace…
What else should I be looking at with this? What other obvious components that might have failed due to oil dilution / over volume?
Thanks friends,
Bongo.
Edited Update: I want to thank everyone that helped me with this, I am really humbled by you taking time to respond here.
If you are coming to this thread fresh there are now two (lockdown fever induced) videos that would do a good job of getting you up to speed: The first shows the two tank veg oil conversion we did on our 2005 1.9 Caddy van.
The second follows my investigations into what went wrong with the engine and can be found here.
First a quick intro: I enjoy a bit of hobby mechanics, and have been playing with our 1.9Tdi PD 2005 Caddy. It's been re-mapped (was before we acquired it at 47kmiles, so don't know the details, but when you put your food down it goes!).
At 140k, I decided it was time to dabble in running it on straight veg oil and began a two tank conversion. We produce a youtube channel, called Flowering Elbow, and thought it might be an interesting thing to share with our subscribers there… To cut a long story short, we recorded the conversion process, got the van up and running, did 500 miles (in two long trips).
Then we did a few short 1-2mile (diesel powered) trips, the last of which there was an audible bang on startup, but ran fine… Before a serious problem…
Starting on diesel, we noticed more smoke than normal. Should have stopped then, but my wife had urgent appointment. Drove very cautiously - basically idling through town, got to a hill, low power, engine suddenly increased noise, plume of smoke Luckily there was a place to pull over right there and I cut the engine quite quickly, after noise increase. We got toed and my wife never made her appointment
Upon Investigation: There was fuel (diesel) in the oil. Lots of it! When I drained the sump, there was about 12L of oil-diesel in there. So I guess hydrolocking may have been a thing? There was also about 1l filling the pipe from turbo to bottom of the intercooler.
My Theory: The lift pump for the new aux diesel tank was too high pressure. I was working from the assumption that the tandem pump would regulate pressure and send any unused fuel back along the return line. Of course the tandem pump may have just failed anyway... But I strongly suspect my lackadaisical testing of the new diesel pump and feed pressure causing tandem pump to blow seal between fuel and oil?
How bad is it?: Pulling the sump, I haven't found any debris, and the bottom of the connecting rods an crankshaft look ok (to my untrained eye). If a connecting rod was bent is there a way to tell by looking?
The turbo looks surprisingly ok? At least the turbine blades seem intact, if oily, and I can move it by hand without huge amounts of play – although, again, I don’t know how much play is unacceptable?
Looking behind the valve cover, I see quite a bit of wear on the cam shaft (I guess that’s expected when you lube it with half and half diesel-oil right The chamfer on the sides of the lobe peaks is worn and I can feel a burr there. I can’t see how worn the lifters are until I have the shaft out, so I don’t know if I have any holes in them yet…
And so, my questions to you: I think the tandem pump was the problem, but equally, fuel could be leaking round the unit injector O-rings (but maybe not in that quantity?) Either way I may as well have the unit injectors out and get them tested / new seals…
A new camshaft kit is £360, new tandem pump £240. I have the option of getting a new (to me) engine inc. tandem pump, camshaft turbo, and injectors that’s done 85k for £610… I don’t know what to do – try with new parts which should last longer assuming cylinders ect. are ok. Or just get the whole engine and then if injectors or some other bit is bad, I can replace…
What else should I be looking at with this? What other obvious components that might have failed due to oil dilution / over volume?
Thanks friends,
Bongo.
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