VP MD30 running cool.

smb

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My engine rarely gets above 55c as measured by the temp gauge and confirmed by an ir thermometer, and it takes a long time to get there.

The pair of thermostats are new and tested both in a saucepan and observed in situ by removing the access cover above them. The only water coming up is through the bleed holes, and on one stat I have blocked that to see if it made a difference. It didn't.

It seems the standard oil cooler is extracting all the heat generated. As far as I can make out the oil cooler is always in circuit with no thermo control.

My questions are will this prove a problem and what could be causing it.

Despite nearing 4000hrs its starts easily, there is no smoke obvious and fuel consumption is steady at around 2ltrs/hr.
That being said it is overdue an injector clean and tappets check.

Steve
 

Heckler

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My engine rarely gets above 55c as measured by the temp gauge and confirmed by an ir thermometer, and it takes a long time to get there.

The pair of thermostats are new and tested both in a saucepan and observed in situ by removing the access cover above them. The only water coming up is through the bleed holes, and on one stat I have blocked that to see if it made a difference. It didn't.

It seems the standard oil cooler is extracting all the heat generated. As far as I can make out the oil cooler is always in circuit with no thermo control.

My questions are will this prove a problem and what could be causing it.

Despite nearing 4000hrs its starts easily, there is no smoke obvious and fuel consumption is steady at around 2ltrs/hr.
That being said it is overdue an injector clean and tappets check.

Steve
if it starts easily and doesnt smoke, leave the injectors alone! The tappets are easy to do yourself, presume you mean the VP MD2030?
S
 

VicS

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presume you mean the VP MD2030?
S
He mentions a pair of thermostats
There are not two thermostats in an MD2030 .. are there ?

There's not normally an oil cooler either is there???

There are two thermostats and an oil cooler in an MD30 why not assume that is what he means ? I believe its one of the engines that might have been fitted in the OP's boat as original equipment

I'd suggest looking closely at the way the thermostats are fitted and the condition of the various retainers and sealing rings.
 
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smb

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Thanks for the reply. Its the MD30a, 4cyl non turbo 2.4 litre. 62-65hp depending on what literature you read.

I've followed the well advised 'leave alone' strategy for a while now but the running temp has got slowly lower over the years, and I fear this years trip north through the French canals with 100+ hours at or near idle may have helped clog the injectors. Whether that would induce cooler running I don't know, but water from the calorifier used to take the skin off your hands and now it barely cleans the dishes.

I've ordered some Diesel Purge and will give that the direct treatment after doing the tappets.

Steve
 

VicS

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Thanks for the reply. Its the MD30a, 4cyl non turbo 2.4 litre. 62-65hp depending on what literature you read.

I've followed the well advised 'leave alone' strategy for a while now but the running temp has got slowly lower over the years, and I fear this years trip north through the French canals with 100+ hours at or near idle may have helped clog the injectors. Whether that would induce cooler running I don't know, but water from the calorifier used to take the skin off your hands and now it barely cleans the dishes.

I've ordered some Diesel Purge and will give that the direct treatment after doing the tappets.

Steve

I am sure you have to look at the cooling system but if it's due for an injector clean and tappet adjustment by all means do those tasks

Not found out anything about the engine apart from the figures you quote, the parts diagram and the owners manual. Not even a decent diagram of the cooling system.

For it to be over-cooling there must be too much water ( coolant) passing through the HE. This flow should be controlled by the thermostats, hence the reason for looking at the seals etc.
When you checked them did you examine them closely to ensure they were both properly shut and heat them slowly in a pan of water and note the temperature at which they only just started to open. That is often difficult to see but one trick is to suspend them by a thread trapped under the flap. When they fall off the thread they have just started to open. That should be at 75C . IIRC they should be fully open at 90C. The figures are in the owners manual.

If thermostats and associated bits and pieces check out then ..... ?? ... dunno......... perhaps have close look at the HE to see if there is any way in which the coolant could be by-passing the thermostats.

I
 

smb

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Vic, thanks for your interest. There's not a lot of info around about the engine, guess it was not very popular and soon superseded by turbo versions of smaller lumps.

I'm pretty sure the stats and seals check out ok. When in place they are clamped by a single plate resembling spectacles frame, and when the engine is as hot as it gets the only 'upswell' is that through the bleed holes, and that's very obvious.

I had considered corrosion in the HE allowing coolant to bypass the stats, but last time down I drained the HE and had a good feel around and a look with an endoscope at wherever I could access. All looked good and the body of the HE remains cool when the engine is running at 55deg.

What I'd like to try is divert the seawater around the HE altogether to eliminate coolant/HE issues once and for all, but the steel pipework and fittings involved mean that's not going to be a five minute job with bits and bobs from the bosuns bag. Cutting out the oil cooler might be easier from a plumbing point of view but access is terrible.

That's how I ended up thinking that the other side of the over cooling coin is not enough heat being produced, and maybe the motor is performing considerably below par but that has been masked by the fitting of an Autoprop 11 years ago.

I'll do the tappets and injector clean and report back.

Steve
 

Heckler

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He mentions a pair of thermostats
There are not two thermostats in an MD2030 .. are there ?

There's not normally an oil cooler either is there???

There are two thermostats and an oil cooler in an MD30 why not assume that is what he means ? I believe its one of the engines that might have been fitted in the OP's boat as original equipment

I'd suggest looking closely at the way the thermostats are fitted and the condition of the various retainers and sealing rings.
I asked the question, I try to help peeps in the same way that you do! Dont let your dislike of me affect your replies if it is going to impact on someone else!
Much as you have many years of experience as a chemist so do I as a diesel man.
I repeat to the OP, if the engine is not "missing" or blowing smoke, either white or black out, the injectors will be fine.
If they are not taken out on a regular basis there is every possibility that they will be stuck in place or that if you dont have the correct tools to clean up the seats or whatever that they will leak combustion gases when you replace them. Bad injectors will be quite evident. I suspect that the undercooling is more to do with thermostats.
S
 

scottie

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MD30 is the 4 cyl version of the MD40 and is likely to give long service as a yacht engine
One option would be the "Italian tune up " or give the boot for 1/2 hour as they are often on the powerful side for the boat but beware that it may be governed down to about 3000 from the 3800 normally found in power boats
Worth checking water temp before and after the coolers including gearbox which should show what is happening
2ltr per hour will only give 10hp so is the boat way down on speed what state are the fuel filters in including any in the lift pump?

Injector cleaner should do no harm and slackening off each injector pipe would give an indication to the state of them.
 

smb

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So....

I checked the valve clearances and changed the fuel filters and primed them with stp cleaner as the Liqui Moli has not turned up yet.
No change.
Backed off each feed pipe in turn and got immediate and similar responses from each cylinder.
No change
Blocked off with rag where the exhaust manifold discharges into the he.
No change, but the calorifier circuit reversed direction.

Ran it up to a stable temperature (1200rpm in gear, 19 inch autoprop kicking up a wash, 20mins)and took some measurements.

Fresh water
Riser cyl hd to ex man 55deg
Thermo housing/header/he 53 deg
He to Pump 52 deg

Sea water
pump output 18deg, leads to oil cooler
Oil cooler exit 23 deg, leads to HE via anti syphon valve
He inlet 23 deg
HE outlet 25 deg

Does this suggest anything obvious?
The calorifier did not play a part as all the emptying and filling has left it air locked, though I did discover its coil is plumbed hot to bottom so must change that some time.

Steve
 

VicS

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Nothing obvious to me.

But surprised at there being a bigger increase in water temp across the oil cooler than across the HE.
I have nothing to compare it with though .... just surprises me.
 

scottie

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Engine is still not working hard !!!!!!!! revs should be over 3000 maybe up to 3800 so
1200 is only a high idle so won't generate much heat
You could bypass calorifier or even turn it of if it has taps on engine block
 
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