Yet another overheating VP 2003 question

[Kurlie1]

Hi all.
I have been reading numerous threads on this topic but have no answer to my problem ... please bare with me here. I am about to spend $20k on a re-power.


Details:
Engine is 1987 VP 2003 28hp (fresh water cooled)

Boat is Beneteau Idylle 1050.
Issue is the motor runs up the temperature and overheats after about 30 - 40 min running with load at about 1500rpm.

I have installed an "Engine Guard" (thanks to another CF members sugestion) to check head temp. Indicates up to 100c before engine alarm sounds and I close motor down.

Motor always starts well and runs smoothly. Pik attached



What I have done:

• Checked raw water intake.
• Cleaned strainor.
• Checked oil - Uses none and keeps a good colour.
• checked and replaced water pump impellor.
• Checked sensor - Mechanic with digital thermometer
• Removed and checked heat exchanger. (Mechaniic confirmed all clear)
• Replaced thermostat. (the correct model)
• Checked exhaust water discharge - week but only luke warm (see below)
• Checked hoses for blockages - all clear
• Checked and cleaned fresh water pump - replaced seal.
• Removed and checked exhaust elbow - all clear.
• I have had a mechanic go through all the "bolt-ons" ($1k spent)

Hints of problem:

• Exhaust water flow is week ... fills 16ltr bucket in exactly 2 min (8L/min)
• Coolant is dissapearing - Notice a green tinge in exhaust water on startup. No sign of water in oil. Motor uses no oil. Very little smoke.
• The overheating is a bit random - sometimes runs for an hour. I thought I had resolved this (an earlier post) but was on my way to Fiji last month (yes. I have clearance) and had to turn back as I was solo and this surfaced again.

It has been suggested that the distribution pipe in the head may be blocked but this is difficult to access and the mechanic quoted about $4k to remove the head to check internals. At this point I began to think "new motor"..... I still do!
Any suggestions would be greatly appreciated. Thanks

[Thumbs Up]

You should not be losing any coolant. A bad head gasket (+warped head) or a hole in the heat exchanger housing are likely. The 2003 had a bad reputation but shoudn't need replacing unless a basket case. If you keep your coolant topped up do you still overheat? You need to find someone else to work on it. 4k sounds crazy. You should pressure test the cooling system.

[Kurlie1]

Thanks for your reply. Yes. I thought the price high but he estimated 30hr labor and over $600 for head gasket kit. I always keep the coolant full still overheats

[Thumbs Up]

Here is one for $43.00: https://www.parts4engines.com/volvo-...op-gasket-set/

[kmacdonald]

If coolant is in the exhaust water it's the heat exchange leaking. Depending on its construction it may just need new seals. Replace the raw water hose between seacock and raw water pump. It may be collapsing internally under vacuum. Removing the head and lapping the valves is no more than $800 labor plus the head gasket. It's an easy job. Tight valve can cause overheating.

[Kurlie1]

Hmmm Thanks .. I will see about getting another mechanic quote.

[PegasusIX]

I had a similar cooling problem on my seawater cooled 2003. A good mechanic removed head, cleaned out all cooling passages in head and block, and this fixed the cooling problem. Not sure if yours is similar issue as yours is fresh water cooled.

[Mike Paget]

Hi Before you do anything more, on the front of the head is the thermostat housing remove the pipe that goes to the header tank(expansion) tank make sure the small hole is clear poke a small drill through it if this is blocked water does not circulate around the head. I had this many years ago when returning from the Med to the UK stuck in Portugal spent loads of cash trying to prevent overheating, then went out on test run and suddenly remembered an article I read about this problem, engine still running i removed the pipe poked drill through the hole got covered with hot water replaced the pipe and continued on my way home over heating cured.
Hope this helps.
Mike

[motretu]

+1 for what kmacdonald posted. seems you are at the mercy of one mechanic, given quoted prices and lack of solution, i'd look for another opinion.

loosing coolant is not a good sign, as you know. finding out why is 1st priorty, especially since it appears to be getting into exhaust stream.

your reported 8L/min exhaust water rate seems low, need to know what rpm the engine was turning, and was this during an o'heat episode? what about when engine is 1st started?

since raw water flow is tied to engine rpm (raw water pump speed) not engine load or temperature, you can run the engine at any rpm in neutral when 1st started. i would want to know the flow rate out of the raw water pump at 1500 engine rpm compared with exhaust water rate as a way of finding a water flow blockage (most likely the heat exchanger as others have said). running the engine for less than 2 min when "cold" at 1500rpm with out the raw water will not damage exhaust system nor cause the engine to o'heat. run the pump output to a bucket to collect sample.

[Jetx]

Possible leak from pressurized (fresh water) side to the raw water side at the heat exchanger end caps?

[Jono as 2234]

I have had two mysterious over heat issues which drove me crazy. The first was the coolant circulation coil in the hot water heater had developed pin holes and the engine coolant would leak into the boat's water tank or the water would get sucked, or pushed, into the coolant depending on relative pressures. Hard to notice as the coolant level will go up and down whilst motoring, and may be completely normal when you get around to check. New water heater fixed that. Diagnose by short circuiting the coolant loop.
Secondly, over heat with diminished exhaust water. I neglected to check the gear box oil cooler which preceded the engine HX. This was mostly occluded with yellowish crystals, which errupted like vesuvius once I ran a strong acid solution through. Clean oil cooler passage more than doubled my exhaust water flow.
Jon

[Northbound44]

I had the same engine on a Beneteau F375 1985. My heat exchanger was leaking causing the coolant been diluted with seawater ( seawater pressure is higher than coolant on this engine) but the engine never overheated.
In your case, I would guess that the head gasket but I would recommend a pressure test before you proceed.
Another possibility would be a warped engine block but, not so common with cast iron blocks.
I don’t know nothing about your mechanics ability but I rebuilt a VP 2003 15 years ago and changing the head gasket was not the most complicated task and is pretty straightforward.

[Emmalina]

Had a VP 2003 with an overheating prob.. In the end it was a calcium build up in the gearbox cooling tube reducing raw water flow. Only found it while replacing the tubes ! Very strange one ...

[Kurlie1]

Thanks all for the suggestions.
I will get to the boat today and look at these options and report back in a couple of days.

[olaf hart]

If the heat exchanger is gone perhaps you could convert the motor back to RWC?
You would need to replace the thermostat with the right one.
There are a few YouTube videos on sailing britaly, in one he removes and cleans the water distribution tube with the head in place, seems pretty easy, though I would not expect it to be a problem if the motor is not RWC...
You mentioned the exhaust elbow, did you check the water passages are clear as well as the exhaust tube?