Changing Coolant in a Volvo Penta D1-13F

[Salish Sloop]

Looking for advice from anyone who has experience changing the coolant in a Volvo Penta D1-13F or similar models - we have an approx 4 yr old one that has been having overheating issues. We changed the raw water impeller which we think fixed the original overheating issue, and we also tested the thermostat and made sure the heat exchanger was clean.

However, we also drained the coolant and changed it according to the operations manual by refilling the reservoir. The manual instructions said that after changing the coolant, you should start the engine and let it heat up, and after the thermostat opened the coolant would start to flow into the system. However, when we tried that, it didn't happen - the coolant just stayed in the reservoir and the engine overheated. It seems like we needed to bleed air out of the system, but we aren't sure how to do that.

We have also heard that the freshwater system should also be flushed when the coolant is changed, but others told us that it wasn't necessary. Should we have done that?

Any advice is appreciated - thanks in advance!

[redbeard1]

Hello,

We’re about to change the coolant on our Volvo Penta 2003B as preventive maintenance (and because we don’t know what type the PO put in) and have been scouring the web in preparation. Some thoughts:


1) Should you have flushed - The web consensus (not unanimous) seems to be that if you are replacing an IAT coolant with an OAT coolant, you should flush the system thoroughly (we plan to do a minimum of four flushes with distilled water before adding the anti-freeze). If the two types of coolants mix, bad things can happen, although not what you describe in your post. So while I would flush the system, I don’t think your problems are related to not flushing.


2) What is causing the overheating – You write that the coolant is not circulating after the thermostat opens and that is causing the overheating. How much coolant fits in your system? How much did you pour in? When re-filling the system, I have read you need to leave the reservoir cap off. When the thermostat opens, the level in the reservoir will drop. You can then add more coolant to the reservoir. Leaving the cap off will also bleed the system. Did you leave the cap off when re-filling?


Part of the difficulty in debugging this, as you know, is you changed many different items before the problem began. Some wild guesses. Is it possible you re-installed the thermostat/heat exchanger incorrectly? I would eliminate the possibility it might still be the water pump">raw water pump impeller. Do you have good water flow out the exhaust?
Hope this helps.

[Captsteve53]

Did you check the small vent hose connected from the engine(heat exchanger) to the coolant expansion tank, this important hose allows air (and coolant) to travel up from the heat exchanger and thus provide a path for air to escape while filling, if this hose or the points it attaches too are blocked you will quite possibly get an air lock in the system!!(over heats)

For me @ 4 years old i would be replacing the thermo stat (just because) I have seen them open in a pan of water but unless you can check that water temp while doing the test you still dont know really what temp it's opening at(should be approx @ 79-81 Celsius).

Water pump impellers (rubber) should be replaced yearly (if you want a trouble free system)

The exhaust riser/elbow should be checked/replaced every four/five years again if you want a trouble free system

Cheers Steve

[Salish Sloop]

Thanks so much for the replies! I think we fixed the problem yesterday by venting the system. As soon as we did that, the coolant level in the reservoir dropped and coolant came out of the vent near the heat exchanger. So we missed a step - venting the system after refilling - and yep, there was air in the system blocking the coolant flow.

After we replaced the impeller, there was a good amount of water coming out of the exhaust. The old impeller was the first thing we checked, it didn't have any obvious damage but it was over a year old so we replaced it anyway. So I think we fixed the original overheating problem by replacing the impeller - but then caused an additional problem by not venting after refilling the coolant.

Now we are just hoping that we didn't cause any damage when it overheated. We also have a new thermostat on the way. Sounds like we should check the exhaust elbow as well just to be safe - we have a long trip coming up!

Thanks again for the advice.

[Cheechako]

One problem that can occur (any engine) is that if you have drained the engine, now there is air in the system, and the engine cold. When you run it.... the thermostat wont open as it doesnt see enough heat due to the air pocket. You have to fill the block below the thermostat manually, or put hot water in the engine before starting it so the coolant can flow and the air pockets can work their way out. Dont ask how I know this....