Heeeeeeelp VP 2020D

[wiggy]

So two weeks ago I left shoreham for Portsmouth within 20 minutes I noticed water was flowing from the radiator cap pressure relief valve of my VP 2020D, salty water set that, at low revs it stopped. Returned to shoreham and engineer diagnosed blocked exhaust elbow which was so corroded it had to be replaced. All seemed fine.

Today I left again and as there was no wind, motored at about 2000 rpm and checked engine, sorted. 2 hours in revs went high randomly, stuck it in neutral and it died. On checking water was yet again flowing from the radiator pressure relief valve and the engine was increadably hot. Turned it off and had a pleasant sail back yet again to shoreham

Once moored I had a poke around, fresh water seems to be flowing to the calorifier, so not the fresh water pump, engineers suspicion is the thermostat had failed, but why after 2 hours?

Has any one got any ideas at all?

 

[europe172]

Check the cap seal is good, a leaking cap can cause this you could also remove the thermostat and try it like that.,

 

[Seajet]

Just off the top of my head, have you checked the air relief valve in the fuel tank ?

 

[wiggy]

Just off the top of my head, have you checked the air relief valve in the fuel tank ?

Is this the breather? Fuel is not the problem, it's overheating and ejecting coolant.

 

[NickRobinson]

N

 

[sailorman]

Is this the breather? Fuel is not the problem, it's overheating and ejecting coolant.

is it the head gasket

 

[Houleaux]

So two weeks ago I left shoreham for Portsmouth within 20 minutes I noticed water was flowing from the radiator cap pressure relief valve of my VP 2020D, salty water set that, at low revs it stopped. Returned to shoreham and engineer diagnosed blocked exhaust elbow which was so corroded it had to be replaced. All seemed fine.

Today I left again and as there was no wind, motored at about 2000 rpm and checked engine, sorted. 2 hours in revs went high randomly, stuck it in neutral and it died. On checking water was yet again flowing from the radiator pressure relief valve and the engine was increadably hot. Turned it off and had a pleasant sail back yet again to shoreham

Once moored I had a poke around, fresh water seems to be flowing to the calorifier, so not the fresh water pump, engineers suspicion is the thermostat had failed, but why after 2 hours?

Has any one got any ideas at all?

You've mentioned that salty water was flowing from the radiator cap pressure relief valve. The fresh and salt water systems of your engine should be entirely separate and you should not be getting salt water from the radiator cap pressure relief valve. I don't know the 2020 engine specifically (I have a 2002) but the only place that salt water and fresh water get close to each other is in the heat exchanger. If the exhaust elbow really was blocked, is it possible that the salt water side of the heat exchanger became pressurised by the impeller and blew the seals between the salt and fresh water systems - allowing the salt water to flow into the fresh water system and out through the radiator cap? I have had a problem with the heat exchanger seals on the 2002 which lead to salt water "topping up" the fresh water system - though in my case it was more of a leak between the two than a gush! - which I solved with new seals.

Maybe all seemed fine to start with when you set off again because it took a while for the expansion tank to fill up with the addition of salt water, or the seals held up until everything got warm. I can't explain why the revs would go high randomly but the fact that it died may have been because it was starting to nip up through overheating. But, then again, I don't see why a leak between the salt and fresh water systems should lead to overheating (perhaps it was the thermostat sticking after all?)! I assume that you had plenty of water exiting your exhaust?

Maybe I'm barking up the wrong tree - and hopefully I am because heat exchangers are expensive! - but the first thing I'd do in your position is to check whether the water in your fresh water system is actually fresh or if it's salt. If it is salt, you need to find out why.

Good luck.

Rob

 

[vyv_cox]

I think Houleaux has it pretty much right. Under normal conditions the pressure on the coolant side is far higher than on the raw water side but if the exhaust manifold becomes salted up this can reverse, causing the seals in the heat exchanger to fail. Having fixed the exhaust manifold problem it might have been best to test the heat exchanger seals before using the engine. I think you will find that's the problem.

This is quite a common problem on Volvo heat exchangers.

 

[wiggy]

The initial problem wasn't helped by the end seals not being sat properly, but now they are spot on, but old so new ones have been ordered. I recon either thermostat or head gasket but can't work out why head gasket would cause overheating, on a test the head got very hot very quickly.

 

[vyv_cox]

You said the calorifier flow was good. My experience is that when a head gasket goes any ancillaries, such as heaters and calorifiers, are the first things to stop working. They airlock almost immediately. Thermostat failing would be something of a coincidence.

 

[wiggy]

Well here's an update, seems like piston rings are the problem, when engineer removed dip stick, oil sprayed out along with exhaust gasses. Now, where's my wallet?

 

[vyv_cox]

Well here's an update, seems like piston rings are the problem, when engineer removed dip stick, oil sprayed out along with exhaust gasses. Now, where's my wallet?

Sorry, there is no way the symptoms you described initially are anything to do with piston rings. If they were the problem you would be blowing blue smoke out of the exhaust and out of the oil filler cap if you removed it. Engines with failed piston rings often run cool because compression is low. Sounds like your 'engineer' may be clutching at straws.

 

[wiggy]

Clutching at straws or not it was making a very odd noise when run was back home. I think it overheated causing slight seize and damage to rings. He's going to steam clean out all the fresh water channels, I recon salt water has been entering the fresh side for a while due to wrong fitment of heat exchanger boot by previous owners engineer.

 

[Houleaux]

Well here's an update, seems like piston rings are the problem, when engineer removed dip stick, oil sprayed out along with exhaust gasses. Now, where's my wallet?

Wouldn't a blown head gasket potentially have the same effect? Exhaust gases from combustion crossing between the cylinders and the oil ways to the head (via the blown gasket) and pressurising the crankcases? Is there any water in the oil (it would be emulsified) as this is often a further symptom of a blown head gasket?

Blown head gaskets can result from overheating an engine as, in a worst case scenario, the head can warp. They can also lead to pressurising of the water jacket and hence loss of water via the expansion tank cap relief valve.

Hope you get it fixed soon and it doesn't cost too much anyway!

 

[sailorman]

Wouldn't a blown head gasket potentially have the same effect? Exhaust gases from combustion crossing between the cylinders and the oil ways to the head (via the blown gasket) and pressurising the crankcases? Is there any water in the oil (it would be emulsified) as this is often a further symptom of a blown head gasket?

Blown head gaskets can result from overheating an engine as, in a worst case scenario, the head can warp. They can also lead to pressurising of the water jacket and hence loss of water via the expansion tank cap relief valve.

Hope you get it fixed soon and it doesn't cost too much anyway!

#6 :encouragement:

 

[wiggy]

Wouldn't a blown head gasket potentially have the same effect? Exhaust gases from combustion crossing between the cylinders and the oil ways to the head (via the blown gasket) and pressurising the crankcases? Is there any water in the oil (it would be emulsified) as this is often a further symptom of a blown head gasket?

Blown head gaskets can result from overheating an engine as, in a worst case scenario, the head can warp. They can also lead to pressurising of the water jacket and hence loss of water via the expansion tank cap relief valve.

Hope you get it fixed soon and it doesn't cost too much anyway!

Head gasket was original though but the odd whirling noise is expected to be piston rings, also links with stalling on tick over.

 

[tawhiri]

You will need to do a pressure test. It is quite easy if you have a portable compressor. I have not done this on a Diesel though. However the principle with a petrol engine should be the same.
I used an old spark plug and punched out the insides then brazed a compressed air fitting to the end. Possibly there are already to buy fitting for diesel engines.
Set the piston to TDC and pressurize the cylinder. You will see if the air is coming out the crankcase, water system or exhaust to indicate the area at fault.

 

[wiggy]

Now I'm back in the water here's an update. Turned out the thermostat failed due to salt water entering the fresh system as pressure built up in sea water side due to a blocked exhaust elbow. The thermostat failed shut and the engine overheated and seized, no warning from exhaust temp alarm (lots of nice cold seawater passing through) and buzzer has never worked for engine panel alarm.
Needed re-bore, new pistons, new rubber dampers inside flywheel and all water courses thoroughly cleaning. It was a complete re-build, no invoice yet but hideously expensive I expect (pistons wre £192 each!)
Just to really upset me I've now got a dose of the dreaded diesel bug.