Engine Overheating - Volvo MD2030

[Paul Carey]

A known common problem on this family of engines is corrosion of the exhaust coolant combination elbow , open up & have a look at it ,, aftermarket stainless replacements are available cheaper than the V/P cast iron part ,, We had a competent welder fabricator in Turkey make ours up on our twin MD2020 , problem permanently solved ...

[Apollo366]

My engine overheating problems have been caused , over several years, by Clogged exhaust elbow, Barnacles in the SW intake hose, failed FW pump.

Looks like you've covered these areas, now what?

[Emouchet]

You may want to clean the heat exchanger copper cylinder. If the little conduits are jammed, there is no circulation of raw water. It is easy to remove, beware of the orientation.

The thermostat is something to look at. On my MD2030 it froze open, so the engine was not able to reach a good temperature.
If it froze close, then there is no circulation of the coolant.
On the MD2030, the thermostat is a pain to get to, as it sits behind the coolant water pump.
You will have to loos the alternator, free the belt, remove the water pump, order new gasket for the pump...

[zams 1006]

Originally Posted by jimbunyard

These are known for restrictions building up in the raw water side of the exhaust elbow, especially if you have the high rise version.

They may seem to pass enough water, when in fact they do not. From memory, flow should be on the order of 2-4 gal/min.

The advice given previously about the boots is sound; make sure the sealing areas are clean to bare metal, the small bleed hole in the HE bundle is at the top when you reinstall it, that the bundle is centered in the HE housing, that the boot clamps are tight and that the boots don't have any attached scale on their sealing surfaces. Depending on the severity of the interchange between fresh and salt water, leaking boots may or may not cause overheating, but having saltwater in the freshwater side kinda defeats the whole HE purpose...

Could also be simply a bad t'stat, which ain't so simple as you have to remove the HE housing to get at at it.

Fresh water pump would be my last suspect.

Is it summer where you're at?

Yeah it’s summer here!

I just measured the exhaust and it’s about 0.5Gpm around 2 litres when the engine is idle. That’s not right... I’ll have to isolate the water pump and see where that takes me.

[manitu]

As someone earlier mentioned, it is of uttermost importance that the hose from the trough-hull to the salt water pump is a steel coil reinforced vacuum rated hose.


On my first sailboat , the PO had used glass fibre reinforced pressure rated hose.
I had no problems , until the trough-hull strainer got partially blocked (like 25%)
The small increase in vacuum was enough to make the hose collapse.


.manitu

[zams 1006]

Hi everyone,

Just an update with my situation. I've isolated the Raw water pump, it's pumping around 2L per minute (Very low). I've gone through and cleaned all the hoses and the raw water strainer.

I found the issue when I removed the hose from the seacock, added a new one on and opened the seacock. Only a trickle came out. My saildrive in take has a block in it somewhere, as I feel like the water should be gushing out.

That being said, I'm at a loss with what to do and how to safely clear the obstruction without sinking my boat.

Thanks all!

[olaf hart]

Just poke some fencing wire down the tap into the saildrive and wriggle it around.

Then haul the boat and clean the bottom, the saildrive is full of barnacles..

[johnn33]

Hi I have a MD2020 with Volvo saildrive, both 16 years old. The heat exchanger rubber ends are a poor design and earlier posts emphasise the cleanliness and exact positioning when replacing it. Strangely, there is no small pencil sacrificial anode.

You have not described your location or your boat, but if you ask a local Volvo mechanic, he may say you do not need to use the convenient sea water intake through the saildrive leg but instead use a new through hull seacock close to your raw water pump.
John

[Mickeyrouse]

Not all engine installations will permit use of wire-wound hose for raw water feed. Some just require more curvature than wire-wound allows. Yes, you can get water to the pump from the sea-cock if you use elbows, each one of which will introduce a slight restriction. In our boat, that would require 4 elbows. I recognize that poor water flow could collapse a hose to a greater or lesser degree, but the hose isn’t the problem- it’s the barnacles, or zebra mussels, or a plastic bag or whatever. If you’re preventing hose collapse with wire-wound, you’ve just re-located the problem- no improvement in flow, with impeller vanes stripping off, for example. In 40 years of sailing on boats with inboard engines, I’ve never had a collapsed hose with flexible fabric reinforced hose- but I make sure the seawater inlet is clear.

[donradcliffe]

If you suspect the problem is a partially blocked thru hull, try hooking the hose from the thru hull to a dock water hose and blasting the blockage out backwards.

[harth]

Hello ZAMS 1006, I have a very similar experience with my volvo 2030 and came across your post on the forum.
I have so far done all the things you described and came up with the same result. Still heating up after about 25 min running at 1800 revs.
Decision time : bought a new thermostat together with the hoses connecting the HE and the circulating pump. Intend to remove the pump ant test/replace the thermostat. Keeping fingers crossed that this will cure the "Evil ".
I would be very interested to hear how you got on with your experience.
Where is your boat moored? I am at Murdunna Tas.
If anybody could assist with an idea what it is that I might be missing I'd very much appreciate a hint.

[bil56]

check/change your water lines, a hernia may develop inside and reduce flow (I had that) ...

[Mickeyrouse]

Presumably by this time you’ve changed thermostat and serviced the heat exchanger. We had over-heating issues once and a heat exchanger raw water side was the issue. The scaling didn’t seem all that severe, but it was.

[bil56]

are you sure to have the good reference for the thermostat (55°C)

[Don C L]

Originally Posted by donradcliffe

If you suspect the problem is a partially blocked thru hull, try hooking the hose from the thru hull to a dock water hose and blasting the blockage out backwards.

Yeah I'd check that too.
I know this is an old thread, but these things are always useful in the archives.

My buddy has a MD7A and when he bought the boat it was fine. Then, not long after the purchase, there was very low water flow and overheating. We went through everything, even pulled the engine and had a mechanic friend rebuild it! While it was hauled out we decided to change out the old seacock. It turned out that handle/gate had been pretty corroded and on one of the occasions of closing the seacock we had broken the handle and didn't know it, leaving the gate half closed.

On the bright side, he has a like-new engine now!

BTW, this social group may be of use to Volvo owners:
https://www.cruisersforum.com/forums...o+engines.html