Overheating D4

G

GrahamHR

Well-Known Member
Joined
12 Nov 2009
Messages
3,332
Location
Cheshire
Visit site
Unexpectedly, the D4 on our boat overheated. Normally it runs rock solid at 85 deg. C on the EVC tacho. (the temperature gauge in in deg. F). Naturally it caused an alarm message.

I opened the engine compartment; there was little water in the strainer. I immediately though it was a blocked strainer; not so. We let the engine cool down and on idle the water flow into the strainer looked normal We set off slowly; rock solid at 85 deg.C again until we went faster than 2500 rpm, then the temperature increased. Again. little water in the strainer. when we opened the engine compartment cover

We came back with the engine compartment open so we could watch the strainer (what a noisy engine compared to the V8 petrols I am used to !); water flow didn't seem a problem at all , the strainer housing was always full of water at anything above idle.

The D4 layout is inlet/ pump/ strainer/ heat exchanger so I think it can only have been an inlet blockage of some sort. Exporation on Saturday, any suggestions welcome.
 
I think it must be outdrive by the layout above been, inlet pump strainer rather than most shaft been inlet strainer pump.
But I stand to be corrected.
 
Racingfrank7 said:
I think it must be outdrive by the layout above been, inlet pump strainer rather than most shaft been inlet strainer pump.
But I stand to be corrected.
Click to expand...

Fair enough - if it's outdrive, and the strainer basket is clear, then I'd pull the impeller. If that's ok, then next suspect would be the coolers, so pull a raw water pipe and have a look. Depending on how old the engine is, and how many hours run, perhaps the coolers are due a clean - but I wouldn't have thought that a clogged-up cooler would oresent as a sudden overheat.

So if all ok so far, next suspect would be the water pickup elbow fitting in the leg. I'm not sure which specific leg we're talking abiut here, but in the dp-h this fitting can fail, and when it does, it creates a turbulent inlet flow which reduces the effectiveness of the cooling system and you get a higher-rpm overheat. Sometimes you can diagnose this by trimming the leg up and down to see if it alters the overheat behaviour, otherwise it needs a lift to inspect and replace.
 
jimmy_the_builder said:
Fair enough - if it's outdrive, and the strainer basket is clear, then I'd pull the impeller. If that's ok, then next suspect would be the coolers, so pull a raw water pipe and have a look. Depending on how old the engine is, and how many hours run, perhaps the coolers are due a clean - but I wouldn't have thought that a clogged-up cooler would oresent as a sudden overheat.

So if all ok so far, next suspect would be the water pickup elbow fitting in the leg. I'm not sure which specific leg we're talking abiut here, but in the dp-h this fitting can fail, and when it does, it creates a turbulent inlet flow which reduces the effectiveness of the cooling system and you get a higher-rpm overheat. Sometimes you can diagnose this by trimming the leg up and down to see if it alters the overheat behaviour, otherwise it needs a lift to inspect and replace.
Click to expand...

It's a DPH drive. 2009 but only 45 or so engine hours. From ca 15 engine hours the raw water side has been flushed with fresh water after every trip ( via a T-piece in the water pump inlet hose).

Thanks for the advice; I'll report back after the weekend.
 
GrahamHR said:
It's a DPH drive. 2009 but only 45 or so engine hours. From ca 15 engine hours the raw water side has been flushed with fresh water after every trip ( via a T-piece in the water pump inlet hose).

Thanks for the advice; I'll report back after the weekend.
Click to expand...

Blimey - 45 hours in 7 years??
 
jimmy_the_builder said:
Blimey - 45 hours in 7 years??
Click to expand...

It was unsold/ largely unused for the first 5 years. Bought with ca 6 engine hours. Then the 6th year, the first year I had it, problems with the EVC system and batteries discharging wrote the season off for me. ( less than 2 engine hours). Last year was OK, "only" a MAP sensor failure at the end of the season. This year it's been fine up to now.
 
GrahamHR said:
It was unsold/ largely unused for the first 5 years. Bought with ca 6 engine hours. Then the 6th year, the first year I had it, problems with the EVC system and batteries discharging wrote the season off for me. ( less than 2 engine hours). Last year was OK, "only" a MAP sensor failure at the end of the season. This year it's been fine up to now.
Click to expand...

From what you've said, it's unlikely to be the cooler given its relative youth and your flushing regime. Have you checked the impeller? Otherwise I'd bet on the water pickup fitting, seven years is quite old for these I think. Number 3 in this diagram:

24944.jpg
 
jimmy_the_builder said:
From what you've said, it's unlikely to be the cooler given its relative youth and your flushing regime. Have you checked the impeller? Otherwise I'd bet on the water pickup fitting, seven years is quite old for these I think. Number 3 in this diagram:

24944.jpg
Click to expand...

Thanks for the diagram. Am I right in assuming there's a hose going from that fitting to the transom shield? ( I am very familiar with the DPS drives, much less so with the DPH).
 
Beyondhelp said:
Thread aside (sorry) but an engine that has run 45hrs and already had, DVC problems, map sensor, and an overheat issue is horrendous :s
Click to expand...

I agree. Compared to my previous ancient technology American V8 petrols and American DPS drives, the D4 and DPH/ DPRs seem rather fragile. I really can't thinks of a single mechanical issue I had with such power units in the 14 years I had them.

I don't understand why VP didn't just upgrade the DPS drive to take the torque of the D4/ D6.

Maybe rivalry between VP USA and VP Sweden.

EVC problem was basically the shift acruator/ shift cable; what an unnecessary complication.
MAP sensor failure is common in cars as well, but the 24V VP sensor is 2 x the cost.
The overheat issue, well I don't know what caused it yet. If it is the part that Jimmy indicated, well, what an awful design.

The battery drain issues were due to the boat builder, not VP.
 
volvopaul said:
Welcome to the world of Volvopenta marine propulsion .
Click to expand...

I never thought I'd save a huge amount of money my having a D4 diesel compared to the 5,7 litre petrols; just the convenience of having diesel aviaiable at the marina. Now it seems having a diesel is more expensive and less reliable.
 
My previous boat had a merc petrol v8, current boat has VP d4. What I save on fuel costs with the diesel I more than spend on maintenance.

VP parts prices are just crazy compared to merc
 
GrahamHR said:
I never thought I'd save a huge amount of money my having a D4 diesel compared to the 5,7 litre petrols; just the convenience of having diesel aviaiable at the marina. Now it seems having a diesel is more expensive and less reliable.
Click to expand...

Have you had the drive serviced by a pro recently?
 
Hi i had this prob some years ago was indeed the water intake elbo .Just corroded away.New one was £35.00 .You will have to lift her to change it.
 
volvopaul said:
Have you had the drive serviced by a pro recently?
Click to expand...

The boat had not seen saltwater until 2014.

Bellows and oil change in late 2014 by VP dealer. Not used subsequently in 2014. About 35 hours use since then so to get it serviced again in 2015 and 2016 seemed excessive. Pre the 2015 and 2016 season I did of course check for oil leaks, milkiness in oil, bellows condition etc..

New aluminium anodes for the 2015 season ( plus electronic corrosion protection system) . Electrical continuity between all components checked pre launch and OK. Normal protection indicated by ACP control box. No corrosion on drive on lift out

New aluminium anodes for the 2016 season Continuity pre launch OK. Normal protection level indicated by ACP box.

What are these elbows made of, that causes them corrode away ? Are they not in electrical contact with the rest of the drive and protected ?
 
You must log in or register to reply here.

Other threads that may be of interest

catnick1
Volvo M2020 best way to winterise cooling sytem
Replies
3
Views
166
catnick1
catnick1

Share this page

Top