Volvo IPS 500 Overheating

Since you stated that the overheating issue started occuring since a trip to Key West. It might be possible that some of that fine sea-grass that you find floating in that area might have gotten through the sea-strainers and partially clogged a seawater passage or elbow?

Hi,

This thought is part of the reason I mentioned testing the sea water pressure in Post No 8, the fact that one of the sea water hoses started leaking after the trouble started could well be an indication of a greatly elevated pressure within the sea water system.



If the waterways after the cooler are restricted the cooling is still going to suffer when the water flow gets to a high volume as one would expect as the engine revs increase regardless of how clean the inlet, strainer, cooler and anodes are.

The charge air cooler if one is fitted to these engines can also cause a rapid rise in inlet temp which corresponds to a increase in EGT and JWT if it is not able to have the correct flow of water through itself.

How does the sea water discharge after it has been used to cool the engine mounted coolers with one of these setups?

Can you see the EGT on this vessel when you are running and if so what happens to it when the JWT is very high?

EGT= Exhaust Gas Temp
JWT= Jacket Water Temp (coolant)

Check the heat exchangers for sea grass. It can bypass filters and collect in HE's.

Check the air filters also, try running without them if they won't suck up debris......I ran a boat with Volvo's one time that some less than intelligent person before me decided to rinse the paper filters out. Well the boat ran great for a few hours, then started losing rpm and started black smoking.....and then it would only turn 1200 rpms.

Cpt Dad,

There is a method to the madness of trouble shooting a HE cooled marine engine.

First, verify that the engine(s) is/are actually overheating. Instrumentation at the helm should not always be trusted. In your case with two engines doing the same thing it would be unlikely/unusual that two separate and independent systems would give you the same, false, reading.

Are we getting sea water in adequate volume through the system ? Start with checking the SW pump(s). Is the impeller in good condition ? The cam ? The housing ?
In your case with two engines doing the same thing it would be unlikely/unusual that two separate and independent SW pumps would develop the same failure at the same time.

Pump(s) OK – Is the sea water getting through the system unrestricted (Grass, weed, sand, etc. etc.) In the case of the D6 the circuit is as follows: Intake – SW pump – Fuel Cooler – After Cooler – HE – Trans Cooler – Exhaust elbow – discharge.

Once all coolers have been verified to be clean proceed to the FW (Fresh Water) side of the system.

Is the circulation pump turning and actually circulating the coolant ? In your case with two engines doing the same thing it would be unlikely/unusual that two separate and independent FW pumps would develop the same failure at the same time.

Are the thermostats working correctly ? How to check them has been described in this tread.
In your case with two engines doing the same thing it would be unlikely/unusual that two thermostats would develop the same failure at the same time.

Is the coolant mixture correct ? I think Volvo recommends 50/50 H2O/Volvo coolant.
Unless you are operating in Antarctica I recommend 60% H2O. Once you go over 50% coolant content the ability for the mixture to transfer heat goes down.

In the case of the engines used in the IPS500 system (D6 @ 370 hp) don’t get hung up on speculations as far as the capacity of the cooling system. The 370 version is using the same HE as the 435 hp and there is cooling capacity margin with the 435.
Your describing an overheat condition starting at 2,700 rpm. On the prop load curve you are not pulling more than 200 – 220 hp out of the motors. This, of course would be different if you made a prop change so that you are way over wheeled.
This would also change if your bottom, pods and props were extremely fouled. You say “..Bottom and propellers are clean. We do a monthly bottom service…”

Engine room air supply and ventilation ? Did you seal off all air intakes and fan to the engine room ? If not, take this off the list – The boat ran fine for 200 hours if I understand you correctly.

Is the surrounding sea water 100F ? If not take it off the list.

Cracked heads ? I have seen these motors overheat to the point were all the paint is burnt off, wire harnesses melted, all liners scuffed but no cracked or warped head.
Possible ? Yes, but highly unlikely.

Have your tech focus on the above - Don’t worry about EGT

Something basic and simple has been missed here.

Karl

Hi,

A wet exhaust engine will also smoke for the same reasons as a dry stack one.

The fuel consumption will not increase as such it is just it's ratio to the amount of air available for combustion increases causing the smoke.

Most engines these days have a pretty sound way of managing the fuel air ratio, previously in fairly rudimentary setups it was done solely on boost pressure and was sometimes referred to as a puff limiter ,now a few more parameters are looked at, that may explain why your ECU isn't making you a coffee......... yet.

I have just looked back to the start of this thread, Is this problem occurring from say 2700 to 2750 just like the flick of a switch and it all returns to normal and calms down just as quickly when you back off?

Do the IPS pickup the seawater from the drive itself for the engines? Could it be a blockage inside of the drives? I'm not too familiar with the IPS setup.

Since the problem is endimic to both engines You need to look at whats common to both.

The Hull & props,that already been covered.

The glycol/water mix, covered ,but should be verified with a glycol refractometer.

The fuel.......different fuel blends have a different cetane (like octane is gasoline) thus a different combustion effciency. A mix of diesel & biofuels or a un-intended mix of different fuels could run hotter.I assume since the boat doen't have a large fuel bunker that you refueled on your trip. Did the problem start afterwards? Get the fuel checked.

Other thoughts,non-invasive testing:

Infrared temperature meters are great for temperature checks but the emissivity has to be set for the color/reflective characteristics of the surface tested. This is difficult on meters that have adjustable emissivity without a lot of experience. Meters that don't adjust are usually set for black. Pointing one at a shinny surface (usually not even close) or lighter color will skew the readings . A few strips of black electrical tape will fix the emissivity problem if the surface is cool enough to allow it not to melt & the meter is set for black. It's always good to verify the temperature of the spot tested with a K-type thermocouple or a pt100 probe.At least until you get a feel for the accuracy of infrared meters.

A non-invasive doppler ultrasound meter is great tool for measuring the velocity inside the plumbing. They just strap on to a tube.Once the velocity is known it's a simple calculation ,velocity x area to get a flow rate.

Hi,

Cpt. Dad: Did you make any progress with finding out what was causing your problems?

If so an update would be great as it would add to the YF Info Database and maybe help someone else with the same problem later on.

Dirty fuel filters, clogged air filters could also be a source of not achieving rpm's.

The Detroit coolant would not reduce the temps in a normally operating system, you MAY see a few degrees from one coolant to another depending on the surfactant added. Water wetter is a supplemental surfactant you could try? With all the random issues you have, has anyone checked the wiring to the engines and control modules. Some of these issues sound like they could be a ground or signal return issue with the electronics.

Steve

No and Hell no. And even if for some bizarre reason that was true, you would only be covering up the problem.

Volvo has a new extended life coolant that is yellow in colour and must never, EVER be mixed with the old green coolant. Volvo and CAT coolants are very specific about how they are used.

On a friend's Volvo, some numbnut had filled it with automotive antifreeze. Each and every coolant run, exchanger and pipe was clogged with a jelly of coolant crud. A lot of hard work to clean that lot out ensued. Not nice.

Just to be clear,

I was NOT advocating using a mis matched coolant, only to point out that any coolant mixture in the proper concentration of a healthy engine will absorb heat with similar results. The buffers and anti-cavitation additives from each manufacture ARE very specific.

Steve