Black smoke / loss of power

[jules18375]

Engine is a 1.6 Diesel JX - 120K miles
Tried to 'Run the Ring' last weekend, but just didn't have any power esp uphill. Van ended up covered in black soot all over the boot. Been to the garage today and they've said it's overheating and losing coolant.

Bit of background - has lost coolant slowly during the last 4 years. Replaced the dalek cap with one that quacks and replaced water pump and temp sensor, due to a crack in the water pump that was leaking when hot. Temp needle since has sat slightly higher (12 o'clock rather than 1130 before changing) and on the failed run, it was going up higher whilst working hard (up to 1 o'clock). The rad fan never kicked in though (and I tested last summer that it does work). Had buzzer of doom intermittently before we abandoned hope for the day and got recovered back home.

Garage has said the black smoke is not an issue and it's losing power due to overheating and the coolant is dripping on the exhaust.

My mechanical experience is poor so just wondered whether this sort of diagnosis is "Sounds spot on" or whether I should seek a second opinion. I'm happy to pay to get it mended, but I just hate chasing faults around by replacing bits one by one. I guess if the coolant is leaking, that needs doing anyway, but doesn't feel to me that it explains why we could only get up to 14mph on some 'hills' on the M25 (They're not exactly hills!).

Thoughts? Thanks for your help as ever.

[Cecil]

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My thoughts,
l can’t see how black smoke that leaves soot that covers the back of the van is “not an issue” and I am not sure that overheating would cause it.
 Did it have a significant shortage of coolant or boil over ,if not ,what do the garage think caused the overheating?
My immediate thought and worry would be ,could the timing belt  be half shredded/slack /about to self destruct and jumped a tooth thus causing loss of power ,smoke and overheating due to incorrect timing ,but plain loss of coolant and overheating due to failing head gasket and partial Engine seizure Perhaps most likely.
If  the problem was caused  by significant loss of coolant , I guess a repair to the coolant leak and a full consignment of coolant might be sufficient to get it going again but with overheating there is the strong possibility that the head gasket / engine generally has been damaged.
E D I T . Another thought, was the oil level ok before and after the breakdown and could it have been oil spots rather than soot on the back of the van?
E D I T . Shortage of coolant should  be an unlikely happening because the low coolant warning should save the day but I worry how dependable the warning system is.Also it is not obvious what the little red light in the temperature gauge is trying to tell the driver!

[jules18375]

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My thoughts,
l can’t see how black smoke that leaves soot that covers the back of the van is “not an issue” and I am not sure that overheating would cause it.
 Did it have a significant shortage of coolant or boil over ,if not ,what do the garage think caused the overheating?
My immediate thought and worry would be ,could the timing belt  be half shredded/slack /about to self destruct and jumped a tooth thus causing loss of power ,smoke and overheating due to incorrect timing ,but plain loss of coolant and overheating due to failing head gasket and partial Engine seizure Perhaps most likely.
If  the problem was caused  by significant loss of coolant , I guess a repair to the coolant leak and a full consignment of coolant might be sufficient to get it going again but with overheating there is the strong possibility that the head gasket / engine generally has been damaged.
E D I T . Another thought, was the oil level ok before and after the breakdown and could it have been oil spots rather than soot on the back of the van?
E D I T . Shortage of coolant should  be an unlikely happening because the low coolant warning should save the day but I worry how dependable the warning system is.Also it is not obvious what the little red light in the temperature gauge is trying to tell the driver!

Thanks for this. They wanted to change just a few coolant flanges so they've done that and we'll see how she goes when the weather is better. His explanation was that a leak near the head causes the head and main block to heat up differently (one is alloy, one steel) and then it loses compression. Feels like it drives OK bringing it back from the garage - guess we'll wait and see how it performs once the weather and lockdown improve!
 

[Mr Bean]

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My thoughts,
l can’t see how black smoke that leaves soot that covers the back of the van is “not an issue” and I am not sure that overheating would cause it.
 Did it have a significant shortage of coolant or boil over ,if not ,what do the garage think caused the overheating?
My immediate thought and worry would be ,could the timing belt  be half shredded/slack /about to self destruct and jumped a tooth thus causing loss of power ,smoke and overheating due to incorrect timing ,but plain loss of coolant and overheating due to failing head gasket and partial Engine seizure Perhaps most likely.
If  the problem was caused  by significant loss of coolant , I guess a repair to the coolant leak and a full consignment of coolant might be sufficient to get it going again but with overheating there is the strong possibility that the head gasket / engine generally has been damaged.
E D I T . Another thought, was the oil level ok before and after the breakdown and could it have been oil spots rather than soot on the back of the van?
E D I T . Shortage of coolant should  be an unlikely happening because the low coolant warning should save the day but I worry how dependable the warning system is.Also it is not obvious what the little red light in the temperature gauge is trying to tell the driver!

Thanks for this. They wanted to change just a few coolant flanges so they've done that and we'll see how she goes when the weather is better. His explanation was that a leak near the head causes the head and main block to heat up differently (one is alloy, one steel) and then it loses compression. Feels like it drives OK bringing it back from the garage - guess we'll wait and see how it performs once the weather and lockdown improve!

Never heard that compression thing before but as you say time will tell I suppose. I don't do diesels but I have seen random clouds of black smoke shoot out of their exhaust occasionally in vehicles that should work better particularly when under hard acceleration . But what happened to the black smoke on your way home from the garage?