Volvo Penta 2003 (non-turbo), Overheating?

[Capt Ben]

DougR, I'm pretty sure I have a late model 2003 as the engine mfg is 1990. Sorry for my naiveté but when you state to check the freshwater pump impeller are you speaking of the seawater pump or the coolant circulator pump? I replace my impeller (rubber) in the seawater pump every few years. I've never removed or opened up the circulator pump. From the diagrams I've seen, I can't tell if this impeller is of metal or some other material. I have sort of assumed it was metal and nearly indestructible (diagram attached).

Originally Posted by DougR

If, after trying all the flushes, coolant ratios, and plugged exhaust elbows, the engine still runs hot at high RPM, check the impeller in the fresh water pump. Early versions of this pump had a plastic impeller and it could slip on the shaft at high loads.

DougR

[DougR]

Capt. Ben,
When I talk about the freshwater pump, I am referring to the antifreeze circulation pump, not the rubber impeller "seawater" pump. 2000 series engines were produced from about 1983 to 1993 so I' m sure that your engine came with the metal impeller version of circulation pump. It is still possible that there is a problem with your circulation pump, however.

The fact that you can comfortably place your hand on the heat exchanger while the engine is overheating is pretty good evidence that the coolant is not circulating thru the heat exchanger, or that not enough coolant is circulating thru the HE. For this I think you need to clean the antifreeze side of the HE, make sure the thermostat is opening at the correct temp, and that the block off plate on the thermostat is functioning correctly to close off the bypass opening. Use your heat gun to determine if there is water flow. Last but not least is checking the circ pump for damage.

DougR

[Capt Ben]

DougR, Thank you for all of your suggestions. I will take further temp readings at the HE tomorrow. I'll also remove the new tStat and immerse in a pot of water and test operation. I'll also try and determine if the TStat blocking plate is functioning. In regards to the block off plate, I'm not quite sure what you are speaking of but I'll probably understand better when I observe the functioning as I heat the water.

Are there suggested methods of cleaning the antifreeze side of the HE besides removing one of the pipes and insuring that the fluid readily passes through? I've read suggestions of immersing the entire HE in a muriatic bath. I assume that if I was to do that I should first acquire new end plate gaskets and then disassemble and then immerse in a solution of muriatic acid. If muriatic acid is the way to go, what dilution would your recommend? Have you any less invasive suggestions of how to clean/flush the coolant side of the HE?

Originally Posted by DougR

Capt. Ben,
For this I think you need to clean the antifreeze side of the HE, make sure the thermostat is opening at the correct temp, and that the block off plate on the thermostat is functioning correctly to close off the bypass opening. Use your heat gun to determine if there is water flow. Last but not least is checking the circ pump for damage.

DougR

[Neptune's Gear]

Take the HE off the engine. Remove the end cap. Withdraw the tubed core. Look thru the tubes. Should be clean and clear. Bet they are not. A .22 cal cleaning brush fits them well. Clean them all out, reassemble. This is part of the normal periodic maint. I do mine every year. May as well do the oil cooler at the same time, if it is fitted to the non turbo model. (mines a turbo).

[Capt Ben]

Neptune's Gear, Thank you for the response. Mine is the non-turbo thus no oil cooler. Must I get a replacement gasket for that end cap or can the old one typically be re-used? Getting these parts can be difficult and take time.

Originally Posted by Neptune's Gear

Take the HE off the engine. Remove the end cap. Withdraw the tubed core. Look thru the tubes. Should be clean and clear. Bet they are not. A .22 cal cleaning brush fits them well. Clean them all out, reassemble. This is part of the normal periodic maint. I do mine every year. May as well do the oil cooler at the same time, if it is fitted to the non turbo model. (mines a turbo).

[Neptune's Gear]

You can usually get away without any parts - but may need the O-ring and or some gasket goo. O-ring from any supplier, no need for Volvo one!

[jimbunyard]

Just a shot in the dark here:

Do you have a thermostat that looks like this (875795):




Or one that looks like this (877355):


The one in the first picture is the one that is for the freshwater cooled engine, the block off plate described by Doug is the flat metal disc that circles the brass colored wax bulb adjacent to the spring seen at the bottom of the tstat.

The tstat in the second picture is for the raw water cooled engine, and as you can see has no block off feature.

If you have the correct tstat, you might also check that the surface that the block off plate closes off is good, on my TAMD41 there are two, and both were pretty bad. I wound up having them bored out and making and installing bushings to replace them (have a friend with a machine shop) but I don't know if that is applicable in your situation...

[Rustic Charm]

Originally Posted by Neptune's Gear

Temp check with gun is good as above.
Then start with the simple stuff. Pump impellor, thru hull not blocked, sea cock fully on etc. Then how hot is the heat exchanger - it should never be too hot to touch, if it is its restricted - has too little flow - so its fouled, the pump isn't working properly, or there is a blockage somewhere. Thermostat working? If the water at engine output is really hot, but heat exchanger is cool, then the circ pump is the place to start.


Mine is the turbo version, and in the tube between the thermostat housing and the exhaust riser there is a small plastic insert (inside copper tube, you can't see it). It has a small hole in it, and that can block and will cause overheating. I've been told it is not in some of the non turbo ones, but if all else seems ok, its worth looking. It is often overlooked by service guys...
Good luck!

I'm a bit late to this conversation, but I was going to raise this same little thing. Mine is a Turbo too and this little plastic thingy, had slipped along the pipe and was blocking the pipe to the cooler. The result was that it began overheating at high revs. But I'm not sure the non turbo ones have them.

[DougR]

Capt. Ben,
The photos posted by Jim show the two different thermostats that could have been used in the 2003. As he says, you need the upper type with the block off plate.

Go on-line to "stant.com" ( thermostat maker) and scroll down to the bottom of the home page where you will find a link to "installation instructions". There you will find instructions for "normal" and "bypass" types of thermostats. The instructions for the bypass type will show the type of installation and water flow that you have with your engine, and you can get an idea of how the bypass function works.

No worries regarding the "plastic restrictor" as mentioned by those with turbo versions of the engine. The piping between the two versions of the engine is different and yours doesn't have the restrictor. (The purpose of the restrictor was to prevent too much flow thru the turbo at the expense of flow thru the thermostat)

Whenever I use muriatic acid to clean a heat exchanger I buy the stuff at the local home store, which is usually 20% concentration, and then I dilute it 50/50 with water so I end up with 10% strength. This seems very adequate to do the job.

DougR

Go back with not more than a 50/50 mix of antifreeze. If you can get by with a 40% antifreeze mix it's even better for cooling and still plenty adequate for corrosion control.

[Dsanduril]

One check you can do on this engine is to remove the t'stat entirely and then put a plug in the bypass pipe (wooden cone, ...). This will force all the coolant through the block. The bypass is really intended to allow your engine to get up to a good operating temperature, but since your engine clearly gets there....

If the problem remains with the bypass completely blocked then the problem is in the block or HE (or the cooling loop in general, like the channels to the transmission, etc.). If the problem goes away then your problem is in the t'stat area, allowing too much/all flow through the bypass.

If you are testing at the dock you can also use a hose to temporarily bypass the transmission cooling (takes a little ingenuity to get a hose connected), that will help tell if the problem is in that part of the loop.

The IR gun is your friend, may help bypass some of these things, but if you don't have readings to compare too... (note to self, write down normal readings in the engine log at a bunch of different places in the cooling loop).

[Capt Ben]

Great suggestions from so many. THANK YOU.

Well, I've removed the TStat (yes I have the ones with the plate) and tested it along with 2 old ones I had around. The Tstats all began opening around 168F and were fully opened by 185 or so as per spec. I am curious how this blocking plate works as it doesn't come in contact with the inner pipe bore. I measure that the pipe bore top is about 20mm from the top of the TStat housing but the Tstats plate is only about 11mm from the rim of the Tstat. IE, the plate when installed with the gasket on the TStat is approx 10mm from the pipe port thus not even close to closing off that bybass. All of my Tstats that I have are of the same dimension and they are part Volvo # VP 875795-7

Temps of coolant pipes at HE are hard to determine accurately as the IR light on my thermometer doesn't seem to accurately point at what I'm measuring (easy to get block and other near by areas). After running the engine to warm it up, the inlet began to physically transfer the heat of the TStat housing as well which after a while exceeded 190F.

BTW, the boat is set up with a hot water tank. Off the Fresh Water pump there is a hose returning that was relatively cool compared to the hose exiting the block that goes to the hot water tank. It seems to me that if there is a blockage in the hot water hose runs that should not affect the cooling of the engine as would not these ports be plugged if there was not a hot water tank installed?

I still have a feeling my Fresh Water pump is iffy. I'm afraid to pull it apart with out replacement gaskets in hand as I'd then be out of commission. Same thing for HE. Can anyone advise the size of the O-Ring/s required for the HE such that I might procccur some spares from a local supplier to have on hand?


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[Capt Ben]

More info... I decided to place an older TStat which was one that passed the hot pot test back into the engine. After bringing the engine back up to temp I still was getting a hot water temp from block to water heater and a cold return to pump. Also noticed I wasn't generating hot water (tank) after about 15 minutes. I then thought I might have an air lock or air pocket in the HE. While the engine was running, I opened the drain plug on the HE to possibly purge the system of air and then added more water to the reservoir which had quickly emptied. Opened drain plug for a moment again to insure no air and water dribbles. After another 10 minutes or so I was now getting hot water from my tank and the return water line was hot.

Measured temp on TStat housing and she stayed between 158 and 170 which seems about normal as that's close to the spec of the TStat. Esentially, every thing now seems normal except that the reservoir tends to dribble out of the top blue cap even though the level of water is about half. Oh, and when I shut the engine off, even more water came out of the cap. After resting for a few minutes the water level in the reservoir is still about 1/2. BTW, as I've been spilling and discharging so much of my initial 50/50 mix and for now just topping off with filtered tap water, I assume my ratio is more like 90/10 (water to coolant). Is it possible that my blue cap requires replacing as it's not able to maintain a certain amount of pressure in the system?


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[jimbunyard]

Looked into it a little more, and after (I think) deciphering Volvo's byzantine cooling system on this engine, I might have a better grip on it.
I don't have one of these engines, nor have I ever worked on one, so anyone with corrections, please speak up.

First off is this the heat exchanger you have?



If so, it is a two pass exchanger, meaning that the sea water enters and runs down one half the exchanger and then back up the other half to exit into the exhaust elbow. The freshwater (antifreeze/water mixture) runs from the circulation pump to the head and passes through the head and block to the t'stat housing, where it is routed either through the H/E or through the bypass (back to the circulation pump). If the freshwater goes through the H/E, it starts at the outside inlet of the H/E on the end where the raw water enters and exits, and moves through the exchanger to the outlet on the opposite end and goes back to the circulation pump, completing the circuit.

I hope that's clear, if not there's a drawing here, http://www.bluemoment.com/manuals/vo...002_worksh.pdf

that shows all the pipes and where they all are fitted. There are no page numbers, but the drawing is about 3/4's way through, just before the wiring diagrams.

Now to a little meat.

It seems I remember you advising that the outside of the H/E was relatively cool even when the engine was hot. As others have noted, that means that either the circulation pump is not working, there is a blockage somewhere, or the bypass isn't working.

If you pull the pipe that goes into the lower position on the head and spin the circulation pump by hand water should come out. If the circ. pump isn't making noise or leaking there's most likely nothing wrong with it.

An obstructed head or block is harder to diagnose, but an idea can be had by the condition of the water when you drain the system...

The seat that provides the bypass should be in the head: the bypass is open until the engine heats up, lowering the bypass disc onto the seat, which directs the water through the t'stat hsg into the H/E.

The only other thing has to do with the H/E itself, something that I couldn't determine from any of the pictures or drawings I could find. Since this is a double pass H/E, there should be a separator plate that divides the raw water inlet and outlet sides from each other. It may be built into the endplate, or it could be loose with some flat rubber seals. Without separation between the inlet and outlet, raw cooling water will not travel from one end of the heat exchanger to the other, but will instead just flow directly from inlet to outlet, essentially just bypassing the H/E altogether.

Again, I could find no mention of this in anything I saw or could find, pictures, service or parts manuals.

There's no mention of this in the TAMD41 literature either, and it has the same double pass, raw water inlet and outlet on one end H/E. I can assure you that if you leave them out (they're loose on the TAMD41, held by interference between the end plate and the H/E core) the engine overheats almost immediately.

[Paul L]

The FW side of these engines were designed (loose wording) to be self bleeding. If you have changed the coolant, then they should have "self bled". If you have an external water heater in the circuit, then the self bleeding often doesn't work. You can bleed the system by running the engine and slightly pulling off the higher of the two hoses at the water heater, letting the air bleed out. You will also see if you have any coolant flow. . My old 2003 required this if I emptied the coolant -- sometimes 2 or 3 times

[Capt Ben]

Hi PaulL,
I have a feeling that you may have put your finger on the crux of my overheating issues. I will attempt this bleeding method.
I am still concerned that the HE is remaining nearly cool to the touch. I'm going to order the assortment of seals and gaskets/O-rings, such that I can remove and clean the HE as soon as possible.
Thank you again.
Ben

Originally Posted by Paul L

The FW side of these engines were designed (loose wording) to be self bleeding. If you have changed the coolant, then they should have "self bled". If you have an external water heater in the circuit, then the self bleeding often doesn't work. You can bleed the system by running the engine and slightly pulling off the higher of the two hoses at the water heater, letting the air bleed out. You will also see if you have any coolant flow. . My old 2003 required this if I emptied the coolant -- sometimes 2 or 3 times