Volvo 2030 overheating.

[wully1]

Any overheating gurus out there?

my new to me 2005 MD2030D starts and runs beautifully with no smoke, no water in the oil and no oil in the water. After between 15- 45 minutes the coolant starts squirting out the header tank overflow shortly followed by the over heat alarm.

So far I’ve replaced the raw water impeller, stripped and cleaned the tube stack and heat exchanger - which was pretty clean- removed and cleaned the (stainless steel )exhaust elbow and replaced the thermostat. When replacing that there was whitish/yellow mush around the hose connection at the bottom of the water pump casting... The water pump looked ok to me but I’m no expert.. I bought some radiator flush stuff from Eurocar Parts and left that to soak in the engine as i was afraid the whitish/yellow mush might be blocking the engine cooling galleries.
The boatyard pressure tested the cooling system and that was OK.

There appears to be plenty sea water going through the system.

One weird thing is a hose running from the top of the sea water siphon breaker to exit overboard from the front of the cockpit locker that sprays a jet of water out when the engine is running - quite a substantial jet at any revs. Never seen that before.

It has been suggested that the head gasket might be leaking but there is no smoke/steam/oil water issues...

Anyone have any clever ideas before I need to get serious with the spanner’s?

 

[Tamar]

+1 for head gasket. How is the sump oil? Any increase to the level? Good luck.

 

[TernVI]

Is the heat exchanger getting as hot as the engine?
Is the heat getting to the seawater?
Possibly the coolant is not flowing around the engine properly, not getting the heat to the seawater.
Are you using the correct coolant? anti freeze raises the boiling point as well as lowering the freezing point.

The excess flow from the tell tale suggests back pressure, maybe the elbow is blocked a little or is not the right design?
Do you have a calorifier? Is it getting hot?

 

[RichardS]

Does the water coming out of the exhaust always feel cool? I suspect it does and that your seawater system is fine. I'm not sure what the syphon break spray is all about. If there is no blockage downstream of the impeller the perhaps the break valve is simply stuck open?

The overheating and a lack of oil in water/water in oil sounds to me like poor coolant circulation. Is the belt slipping? Have the pump vanes become disconnected from the shaft. Is there a blockage somewhere?

Feel the coolant hoses and heat exchanger and start the engine from cold and make sure that you can feel the thermostat opening and trace the progress of hot water around the system. The hoses downstream of the thermostat should go from cool to too hot to keep your hand on within the space of a minute or two as the block comes up to temperature and the circulation pump pushes the coolant past the thermostat.

Richard

 

[PaulRainbow]

One weird thing is a hose running from the top of the sea water siphon breaker to exit overboard from the front of the cockpit locker that sprays a jet of water out when the engine is running - quite a substantial jet at any revs. Never seen that before.

Commonly known as a "pee pipe". Rather than having a syphon break with a valve in it to break the syphon this method just uses a small bore pipe to break the syphon by allowing air into the system when the engine stops. It should be a fine jet of water, something akin to an outboard "pee jet". Usually pees a few feet away.

 

[PaulRainbow]

Feel the coolant hoses and heat exchanger and start the engine from cold and make sure that you can feel the thermostat opening and trace the progress of hot water around the system. The hoses downstream of the thermostat should go from cool to too hot to keep your hand on within the space of a minute or two as the block comes up to temperature and the circulation pump pushes the coolant past the thermostat.

Richard

Good advice from Richard. This, or treat yourself to an IR thermometer, for example Ir Laser Infrared Digital Thermometer for sale | eBay

 

[peteK]

It may be the fresh water coolant not being circulated the pump is driven by the fan belt,they are known to fail on these Perkins based engines

 

[wully1]

+1 for head gasket. How is the sump oil? Any increase to the level? Good luck.

oil level has been constant, no trace of water in it..

 

[wully1]

Thanks guys, I’m going to remove the water pump and thermostat housing again and check over the pump/pulley connection to see if that’s sound before filling up the system again.

I’ll report back.

 

[robmcg]

I would second a cooling pump failure. It could be slipping on the shaft.

 

[MM5AHO]

Thanks guys, I’m going to remove the water pump and thermostat housing again and check over the pump/pulley connection to see if that’s sound before filling up the system again.

I’ll report back.

Note that there's two water pumps. By the sound of it the seawater pump isn't the problem, but possibly the freshwater pump. Whatever the case, you have a lack of cooling in the fresh water circuit, given all the other points made. The tracing the heat method sound solid advice.

 

[Never Grumble]

Let us know what you find.

 

[wully1]

Removed the fresh water pump this afternoon and all seemed OK although I did note some sludgy stuff in the end of the cooling gallery I could see. I'll see if I can upload a photo of the gunge in the pump when I first stripped it

here you go:

 

[robmcg]

That sludge is about a 40% reduction in water flow or more. Does it clean off easily, or is it a hard deposit?

 

[RichardS]

Removed the fresh water pump this afternoon and all seemed OK although I did note some sludgy stuff in the end of the cooling gallery I could see. I'll see if I can upload a photo of the gunge in the pump when I first stripped it

here you go:

If that sludgy stuff is soft like mayonnaise, then I suspect that it must be oil, which almost certainly does mean that your head gasket has blown.

Sorry.

A compression test would probably prove the case but, you might as well just take the head off as, unless someone had added oil to the coolant system by accident, there unlikely to be any other explanation.

Richard

 

[wully1]

That sludge is about a 40% reduction in water flow or more. Does it clean off easily, or is it a hard deposit?

Soft, crumbly, mushy- that’s the only place it has appeared, no sign of it anywhere else.

 

[Birdseye]

Your water pump should not look like that. Am slightly puzzled by the yellow colour - an oil / water emulsion should be greay rather than canary yellow. Either way you do not have proper circulation of the fresh water cooling so you are getting local overheating and pressurising the system. If the boatyard has pressure tested the freshwater cooling system and done the job properly I do not see how your problem could be a head gasket. More likely corrosion, rust and lack of antifreeze. Anyway I would start at that point with a thorough pressure flush of the fresh water system using a flushing compound and after taking out the thermostat .

 

[TernVI]

You might as well get the cooling system clean before taking the head off.
It is (most probably) either a cooling system problem, or cylinder pressure leaking into the cooling system via the head gasket.
Clearly there is an issue with the cooling system, it needs cleaning of that sludge.
A few temperature sensors might tell you if the cooling is functioning, does the water temp in the exhaust lag the cylinder head temp?
You should be able to see the HE start working once the thermostat opens.

Even if you take the head off and change the gasket, you still need to eliminate the root cause, or you will be back to square one about Easter.
Could that sludge include the bearing grease from the water pump bearing?
I'd maybe see what cleaners work on it? Try a bit of detergent first maybe?

 

[RichardS]

Soft, crumbly, mushy- that’s the only place it has appeared, no sign of it anywhere else.

It doesn't sound like oil in water emulsion so I don't know what it is .... but it certainly needs cleaning up and there might be a deposit of it somewhere else as well in a more restricted area which might well ruin the circulation. The head gasket could well be OK in this case.

I still reckon that poor coolant circulation is the issue so following the water around the system is probably your best bet.

Richard

 

[Kinsale373]

Just wonder if that Gunk is caused by someone putting in the wrong type of Anti freeze or some other chemical into the fresh water system. There are some types that turn into a gel and cause problems. If the thermostat is just getting blocked with the gunk that may cause overheating after some time. There may be some procedure for cleaning /flushing out the fresh water side. I haven't come across it , someone else on the site may know.
Kinsale 373