Overheating Volvo Penta MD2040

[atoll]

Originally Posted by landonshaw

so I am thinking to take the vacuum valve of, clean it. Take the hose to the intake side of the heat exchanger off and clean it out. Take out the heat exchanger and clean. Clean anything in the large hose going to the heat exchanger. Put everything back together and start the engine. Check for water at the seawater filter and then at the exhaust coming out of the boat.

see post #8 for priming once you put it all back together

[landonshaw]

Went to the boat and started the project. Took off the vacuum impeller and cleaned, all was clear. Took off the hoses exit and entrance side of impeller to the heat exchanger and back to the valve, all was clear. Rinsed out both hoses. Got an idea that sine I had done this might as well open the impeller again and totally clean and be sure the short connections to the hoses were clear.
Opened the impeller and to my surprise the NEW impeller from Friday was missing 5 fins and the 6th was broken! Found an old impeller and used it when I put all back together. I will buy a new one on Monday and refit.
Opened the heat exchanger, found all of the fins on the entrance side and a few extra. The exchange looks clean, did not take it out because, yes I was afraid of the jackets tearing. The holes what I could see were clean.
Put everything back together and it runs very cool! To those diesal experts, can it run too cool? I did not have a load on but ran at 2000RPM for an hour and did not warm up like it had before. I probably had fins blocking the holes in the exchange before.
Thanks for all of your suggestions, hope this helps others with similar problems.

[atoll]

glad to hear you got it fixed,the thermostat controlls engine temp on the freshwater side of things opening at 75c i think for that engine.
may have to run in gear for it to heat up properly as the 2040 has a large reservoir and he for the size of engine.
full specks here
http://www.bluemoment.com/manuals/Vo...0-20-30-40.pdf

[landonshaw]

I will purchase a new thermastat on Monday and keep it in the boat but will not install. If all is going well, why disturb it.

[atoll]

very unlikely that you will ever need to change the thermostat!
a waste of money,.
in an emergency,just removing the faulty thermostat solves the problem.
you also need a set of seals for the water pump to do a proper job.

[Paul L]

Originally Posted by atoll

very unlikely that you will ever need to change the thermostat!
a waste of money,.
in an emergency,just removing the faulty thermostat solves the problem.
you also need a set of seals for the water pump to do a proper job.

Don't know about tbs Volvo but my Volvo 2003 thermostat works by shutting off the coolant bypass when it opens. So removing the thermostat is not possible.

[atoll]

from the text,a faulty thermostat will cause the engine to run cooler,and not overheat so no worries either way!
but yes is the same as the 2003 according to specs
Checking the thermostat
1. Check that the thermostat closes completely.
2. Heat up water in a vessel to 68°C 1 154.4°F
(MD2O10, MD2020), or to 75°C / 167°F (MD2030,
MD2040).
3. Submerge the thermostat in the water. Check after
at least 3-5 minutes that the thermostat is still
closed.
4. Raise the temperature to boiling point (100°C /
212°F). Check after 3-5 minutes that the thermostat
has opened at least 6 mm /.02362 in
(MD2O10, MD2020), or to 8 mm /.3149 in
(MD2030, MD2040).
Replace the thermostat if these specifications are not
met. NOTE! If the thermostat does not close completely
the engine will run at too low a temperature.
6 7
Fig. 109. Replacing the pump wheel
2. Pull and twist out the pump wheel (impeller) with a
pair of universal pliers.
3. Clean the housing internally. Grease in the pump
housing and inside of the cover with a little grease.
4. Press in the new wheel with a rotational motion

3.
(clockwise). Fit the sealing washer on the outer
end of the centre of the wheel.
5. Fit the cover together with a new gasket.
4.
6. Open the bottom cock, or the cock on the S-drive.
Start the engine and check that no leakage occurs.

[landonshaw]

I was thinking to get a welding rod that is just longer than the heat exchaner and take off the boot on the entrance side. Leave the other one on. Push the rod through the heat exchanger to cleanout the channels. Any items that you push out will get carried away once the engine is started. Quick way to keep the heat exchanger open. Less likely to damage the unit itself and the boots on either end. Also might be faster and cleaner. Thoughts?

[atoll]

should work fine,could use a battery drill with one end of the rod flattened if there is serious crustaecia,and vinegar or acid

[landonshaw]

I like the idea of a battery drill. I will measure the distance the first time and mark the rod so that I don't turn this good easy fix into a day long head ache. Thanks

[MarcW]

Take care with power tools with the brass of the heat exchanger easy to damage. I used a .17 air rifle cleaning rod with a brass brush did a great job.

I have found my major overheating problem was the exhuast elbow. This was replace just before I purchase her after my 2 years found it to be blocked again.

Used a 50/50 mix of Hydrochloric Acid with water this eat away the blockage after 3 hours. Personally after this problem arising again will inspect next year to see if it was me or previous owner.

Volvo owns watch your exhuast elbows.

[kjames]

Guru's, on the back of landonshaw’s thread here, I have a question. I have a MD 2040D in my boat. I noticed the antisyphon valve leaking the other day (fairly minor). I’ve never looked at it before, no experience, what should I do? Is it just a matter of cleaning it?? Cheers

[landonshaw]

I have constintly cleaned mine and it constantly leaks. Not much, and seems to leak just during the time the engine is warming up. It has been a problem for maybe two years. I will follow the thread and see if anyone has a suggestion.

[DeepFrz]

One suggestion that I have seen on this forum is to take the antisiphon valve out completely and route a small diameter tube to the cockpit right above the forward drain. You can see if the raw water pump is working and it reduces rust in the engine room.

[atoll]

just replace it, for about $20 jabsco make one in plastic,
Jabsco 3/4 Inch Vented Loop (Whale, Pumps) : Chandlery, Boats, Inflatables, Outboards, Canoes, Kayaks | Norfolk Marine Chandlery UK (Keelboat and Yacht Fittings)

or use 2 nipples,a bronze "T",and a non return valve,available from any plumbing supply shop