VP2003 erratic heating behavior

[eladn]

Hi all,

We have a VP2003 mounted on our Carter 33 and some erratic engine temperature has been observed recently. It is a dual fresh-saltwater cooled engine with a heat exchanger mounted above the alternator. I shall first lay out the observations then list what was done with regards to the cooling system:

• Under no load the engine does not heat above the normal working temperature - the needle fluctuates between around 78-80c as the thermostat does its work
• The other day I was motoring for several hours at a decent 2000 RPMs, no problem
• The day after, motored for 2 hours. During the end of the run, after about 1h45m the engine temperature needle went up erratically to about 90-95 momentarily, then back down to about 80-85. RPMs were lowered to about 1100 to allow latent heat to discharge, after which temperature was under control around 85c
• The day after, doing some checks on piping, making sure enough saltwater goes in and out of the system, did a load test while motoring out of the bay, for about 20m, out of which 10-15m were at 2500 RPMs, temperature was holding on about 80c
• The day after, while motoring on idle+ under very little load, temperature was at 90c and holding, later on that day while motoring into the bay no problems were observed (on low RPMs)
• A visual inspection on the motor yesterday showed that the forward part of the HE has suffered some high temperatures, with some slight deposits around the point where the faceplate meets the cylinder (looks like salt but I haven't tasted it), and the large gasket seems a bit bloated than before (see attachment)
• After reading this very useful thread, did a test (no load, about 2000 RPMs) to get the engine to working temp so that the tstat opens (took about 10m). HE then warms up but only at the front part (about half of it at the front is warm). If I touch the HE at the back (where the spigot is), it is still at ambient temp. I was allowing the motor to keep on running for another 5m with no change on this, still back of HE is "cold".

What was done on the cooling system (the overheating problem has persisted in one way or another for several seasons so we're picking it apart piece by piece):

• Freshwater pump (circulation) was removed and completely renovated a few weeks ago
• Impeller checked a few weeks ago (and as checked, saltwater flow looks good throughout)
• Saltwater strainer checked and cleaned (not much was in there)
• Front HE gasket replaced by our engineer a few weeks ago (not an original gasket; cutout from a different material)
• Exhaust elbow taken off and cleaned (about 2 years ago)
• Thermostat replaced a few weeks ago
• We have not used any cooling system flushing compound (i.e. decalc). The motor was bought only a couple of years back, and the boat has been in the water since (with motor regularly started over the winter periods. i.e. no coolant in the SW circuit on layup)

Our engineer reckons that the freshwater system is blocked at some point, my speculation is that due to the HE gasket deformities the HE is the culprit.

Questions:

• Would it be possible to clean the HE just by opening the faceplate cover at the aft section? Having taken the HE off before I am not so much looking forward to putting it on again (push-fittings and all). I have nevertheless ordered all necessary gaskets and o-rings to do so. Would it be possible to clean it just by boring the small shafts or is there a risk of damaging them such that the freshwater might be mixing with the saltwater then?
• In case that the HE needs to be taken off for cleaning, my understanding that needs to be done with acid, however which and at which concentration?
• I would expect a uniform temperature diffusion across the whole body of the HE once the tstat opens, is this a correct assumption?
• Would it be ok to flush the freshwater circuit with pressure? Is there a risk of damaging anything?
• Would it make sense to try to go into the block FW circuit with some wire and try to poke at it? Some people mentioned poking in there with a hanger-wire, is there a risk of damaging anything?
• Some forums mention de-calcifying the cooling system (salt or freshwater?). Does this need to be done on-top of cleaning the HE? is the freshwater system even at risk from any sediment/deposit?

Many thanks in advance for any useful advice
Elad (mnemonic: "a lad")

 

[scottie]

Check that the element and seals are properly aligned .
water flow is determined by seal washers blocking flow to segments
lack of overall heat is a good clue and the alignment is not as simple as it would appear

short term heat spikes are not uncommon as water supply is often temporary blocked by floating plastic bags etc

Suggest that you look at relevant manuals and replace end seals especially the distorted i Ed

 

[kalanka]

I am not sure this is relevant but I had some very mysterious overheating symptoms with my VP 2003. After much dismantling and replacement I found that a professionally refurbished (with a VP refurb kit) and recently installed freshwater circulation pump had an impeller that would spin on its shaft, but only when the water was hot...

 

[Plum]

Hi all,

We have a VP2003 mounted on our Carter 33 and some erratic engine temperature has been observed recently. It is a dual fresh-saltwater cooled engine with a heat exchanger mounted above the alternator. I shall first lay out the observations then list what was done with regards to the cooling system:

• Under no load the engine does not heat above the normal working temperature - the needle fluctuates between around 78-80c as the thermostat does its work
• The other day I was motoring for several hours at a decent 2000 RPMs, no problem
• The day after, motored for 2 hours. During the end of the run, after about 1h45m the engine temperature needle went up erratically to about 90-95 momentarily, then back down to about 80-85. RPMs were lowered to about 1100 to allow latent heat to discharge, after which temperature was under control around 85c
• The day after, doing some checks on piping, making sure enough saltwater goes in and out of the system, did a load test while motoring out of the bay, for about 20m, out of which 10-15m were at 2500 RPMs, temperature was holding on about 80c
• The day after, while motoring on idle+ under very little load, temperature was at 90c and holding, later on that day while motoring into the bay no problems were observed (on low RPMs)
• A visual inspection on the motor yesterday showed that the forward part of the HE has suffered some high temperatures, with some slight deposits around the point where the faceplate meets the cylinder (looks like salt but I haven't tasted it), and the large gasket seems a bit bloated than before (see attachment)
• After reading this very useful thread, did a test (no load, about 2000 RPMs) to get the engine to working temp so that the tstat opens (took about 10m). HE then warms up but only at the front part (about half of it at the front is warm). If I touch the HE at the back (where the spigot is), it is still at ambient temp. I was allowing the motor to keep on running for another 5m with no change on this, still back of HE is "cold".

What was done on the cooling system (the overheating problem has persisted in one way or another for several seasons so we're picking it apart piece by piece):

• Freshwater pump (circulation) was removed and completely renovated a few weeks ago
• Impeller checked a few weeks ago (and as checked, saltwater flow looks good throughout)
• Saltwater strainer checked and cleaned (not much was in there)
• Front HE gasket replaced by our engineer a few weeks ago (not an original gasket; cutout from a different material)
• Exhaust elbow taken off and cleaned (about 2 years ago)
• Thermostat replaced a few weeks ago
• We have not used any cooling system flushing compound (i.e. decalc). The motor was bought only a couple of years back, and the boat has been in the water since (with motor regularly started over the winter periods. i.e. no coolant in the SW circuit on layup)

Our engineer reckons that the freshwater system is blocked at some point, my speculation is that due to the HE gasket deformities the HE is the culprit.

Questions:

• Would it be possible to clean the HE just by opening the faceplate cover at the aft section? Having taken the HE off before I am not so much looking forward to putting it on again (push-fittings and all). I have nevertheless ordered all necessary gaskets and o-rings to do so. Would it be possible to clean it just by boring the small shafts or is there a risk of damaging them such that the freshwater might be mixing with the saltwater then?
• In case that the HE needs to be taken off for cleaning, my understanding that needs to be done with acid, however which and at which concentration?
• I would expect a uniform temperature diffusion across the whole body of the HE once the tstat opens, is this a correct assumption?
• Would it be ok to flush the freshwater circuit with pressure? Is there a risk of damaging anything?
• Would it make sense to try to go into the block FW circuit with some wire and try to poke at it? Some people mentioned poking in there with a hanger-wire, is there a risk of damaging anything?
• Some forums mention de-calcifying the cooling system (salt or freshwater?). Does this need to be done on-top of cleaning the HE? is the freshwater system even at risk from any sediment/deposit?

Many thanks in advance for any useful advice
Elad (mnemonic: "a lad")

You obviously need to fix those leaks, evident from the salt deposits, but what evidence do you have that you have an overheating problem. A water temperature of occasionally 90 to 95 is not unusual. Are you losing coolant?

Www.solocoastalsailing.co.uk

 

[Boater Sam]

Could you have trapped air which will reduce or stop flow through the HE? You seem to have had it apart quite a lot.
Is the end cap and HE stack correctly aligned?

 

[eladn]

I am not sure this is relevant but I had some very mysterious overheating symptoms with my VP 2003. After much dismantling and replacement I found that a professionally refurbished (with a VP refurb kit) and recently installed freshwater circulation pump had an impeller that would spin on its shaft, but only when the water was hot...

Oh dear... I wonder how one would go about figuring that one out...

You obviously need to fix those leaks, evident from the salt deposits, but what evidence do you have that you have an overheating problem. A water temperature of occasionally 90 to 95 is not unusual. Are you losing coolant?

Www.solocoastalsailing.co.uk

Not losing coolant, but since the engine tstats are rated for about 74-87c, anything above that starts worrying. Also due to the fact that temperature alarms are unreliable and I'm doing single handed sailing which in turn means that temperature has to be observed quite regularly and the prospect of an approach into a harbor/bay under various load conditions while the engine is running over temperature makes me moderately sweat. Our previously installed MD17 was regularly heating up without any alarm going off (luckily I just secured myself onto the mooring a few moments before it gave its last few strokes of life, seizing up thereafter).

Could you have trapped air which will reduce or stop flow through the HE? You seem to have had it apart quite a lot.
Is the end cap and HE stack correctly aligned?

I read somewhere that the freshwater system is supposed to self-bleed (there's no water-heater connected). Is this not the case? How would one go about bleeding it if not?
About alignment - I haven't done the last gasket change, our engineer did, so intuitively I'd say "yes" but I have no way of knowing. Could you explain which parts need to be aligned and how? The HE will come off in the upcoming days once the parts arrive and I'll try to do that.

I've watched this video that shows the HE being picked apart, however they don't mention how the faceplate should be correctly aligned. Also, it is not clear why at 1:27 they mention that the nut should be removed prior to installation.

With regards to cleaning the HE, is the internal part (the "hive") supposed to come off or is it supposed to stay in one piece with the cylinder enclosure and just get properly rinsed/soaked in acid?

Check that the element and seals are properly aligned .
water flow is determined by seal washers blocking flow to segments
lack of overall heat is a good clue and the alignment is not as simple as it would appear

short term heat spikes are not uncommon as water supply is often temporary blocked by floating plastic bags etc

Suggest that you look at relevant manuals and replace end seals especially the distorted i Ed

The manuals that I've read don't really specify how the HE cover should be aligned. May I ask for some further details here?
Also in the context of "alignment" - perhaps it would be good to mention things to watch out for. Does "no leaks" constitute as correct alignment of the elements or is there an actual external to internal reference/guides to look out for?

Many thanks to all for their answers

 

[scottie]

The oil cooler on the non turbo versions is an add on as part of the fresh water conversion kit which was available at much lower price than the components so worth checking if still available.

The water flow through the heat exchanger is easy to get wrong if the seals and end caps are not fitted in the correct inclanation it has 4 sections
Water flows along one quarter and is reversed back along adjacent qtr then along the Ist direction and finally back along 4th qtr

 

[kalanka]

I eventually figured out the location of the problem using a simple IR thermometer to monitor the temp of each component and bit of pipe. Because it had just been professionally refurbed I had assumed (incorrectly!) that the freshwater circulation pump could not be the problem. The temp readings pointed to it so I eventually dismantled the pump and found (after much experimentation) that when dunked in hot water the impeller would turn freely on the shaft. A drilled hole and a self tapper got me home and eventually the VP agent fitted a new unit FOC The confusing issue was that when engine was cool and warming up the problem was not present - only when normal operating temperature was reached, at which point it quickly became very hot. I note you have refurbed the same item...

 

[scottie]

This has been referred to in previous posts I think