Routine Maintenance Question - Thermostat

[Gin]

This month, I'm doing my annual maintenance on my R31. I'm at the 4 year point, so I'm going to replace the coolant in addition to the usual one-year maintenance items. My question is: Should I change the thermostat while I'm at it?

I've read through as many old threads as possible. I've seen Brian Brown's recommendation that if you are flushing and changing the coolant, that is a good time to replace the thermostat as a preventative measure. On the other hand, I've seen several posts about how reliable thermostats generally are, suggesting they may fall into the "if it ain't broke, don't fix it" category. Of note, for my D4-300, Volvo specifies replacing the coolant at 48 months, but there is no spec for replacing the thermostat, suggesting that Volvo believes it needs replacing only as needed.

Finally, in the FWIW category, my coolant has been rock solid for 4 years. I've never had to add any coolant to the system. Temps are always right where they should be. The coolant still looks pristine.

Turns out a thermostat for the D4 is not a cheap item. About $125. Plus there are two o-rings and a sealing ring that bring the price up another $40.

So, the question of the day is: All things considered, would you replace the thermostat or wait until there is either a need or the next coolant change, whichever comes first?

Thanks in advance for your thoughts.

Gini

 

[dbsea]

Gini,

I'd replace it only when needed. My engine (D6-435) has every other year recommendation on changing the coolant but doesn't state anywhere in the maintenance schedule that the thermostat should be replaced. As you know, I had my mechanic change my coolant, and it was pretty cruddy. I'm unclear if it was ever changed by either of the prior owners over the 6-year life of the boat to date. Going forward, I will stick to the every other year recommendation as mentioned at the end of the manual for the engine in the ongoing maintenance section.

 

[knotflying]

If it works, don't fix it. Long ago I had a problem with the engine (Yanmar) running too cool. Turned out the thermostat was fine. It actually dislodged from position and was allowing way too much coolant to pass through. A rather crazy setup that Yanmar has. It turns and snaps into the elbow under the heat exchanger. It requires quite a bit of downward force and turning to snap it in. I suspect it was not set in properly from the get go and eventually worked loose.

 

[Gin]

Dave and Knotflying, thanks for weighing in. I think that's where I'm headed -- don't fix until broken.

Sure is interesting how different the coolant change spec is from one engine to the next. The spec on the D4-300I-F is every 48 months or 2000 hours. Not the every-other-year like yours Dave. And I think in a thread a month or so ago it looked like for some of the D3s that the spec is 48 months or 800 hours. Lots of variation.

But the more interesting thing is that the service protocol has added something since the last time I checked it. I think the last time I printed it out was early in 2022. I did it again a couple of weeks ago, but I just noticed that my new printout is different from my older one. Volvo now includes "sea water pump overhaul" under the service to be done at "48 months or 2000 hours." This is the second time in the four years that I've owned the boat that I've found changes to the service protocols. That's kind of a big one!

So I have a new recommendation for everyone on this forum: Check your service protocol periodically. You can do that by going to this link and putting in your engine serial number. https://www.volvopenta.com/en-us/service-and-support/your-engine/manuals-and-handbooks/

Another benefit is that you can get the latest versions of several manuals in pdf form. In my case, I can get pdfs pf the Operator's Manual, the Service and Maintenance Manual, and a data sheet explaining the emergency procedure for shifting the transmission out of gear. The fact that Volvo changes the service protocols from time to time (apparently without notice to registered owners!) makes me wonder if the Owner's Manual or Service and Maintenance Manuals also get changed or updated. Guess I'll have to download new copies just in case.

Gini

(Note: Addition to my original post. I've already discovered one change to the Service and Maintenance Manual that differs from the one I've had since I got my boat. The change is to the torque specs for tightening the tension on the drive belt and the bolts that hold the tensioner in place. I decided to make a separate post about updating service protocols and getting newer manuals via Volvo's website since that may be a topic of broader interest to members of the forum).

 

[dbsea]

Interesting on the service protocol, i've never seen those. I punched in my serial number, and low and behold, same recommendation as yours on the coolant change. I was going by the maintenance schedule in my original manual that came with the boat. learn something new every day...

 

[Gin]

That’s one of the benefits of this forum . . . new info every day! Glad it was helpful Dave.

Gini

 

[scross]

Thanks Gini!
My D4-260 has had the coolant change interval increased to 8,000 hours as well. Our C-28 is a 2017 with only 160 hours on the engine so I’m going to get the coolant flushed this spring regardless.
BUT, what was more helpful, and a bit nerve wracking, was getting a message that my D4 engine is subject to a factory recall! Called into a Portland VP Dealer immediately to see what that’s about! Don’t remember seeing that notice when I looked up the engine S/N in November.

PS: Recall is probably an old one involving the positive lead wire to the alternator recall that has been discussed on tugnuts before. If anything different I will update the group.

 

[Gin]

Wow, Al, that’s interesting. Did you learn anything about the recall or are you still waiting to hear? I suspect there other D4-260 owners on the forum that may be affected, so you might do a general post on it once it gets pinned down, at least if its something more than the dealer suspects. That lookup feature on Volvo’s site is more helpful than I realized.

Gini

 

[scross]

Gini,
Yes, heard back from VP Dealer.
It is the old R0031 recall on the D4 engines.
Per Tim Bates of Fluid Motion summer of 2018 on Tugnuts:

Hello everyone,

The Volvo D4 alternator campaign is concerning the positive (Red) wire connected to the alternator. The wire on some D4 engines was connected in such a way that the wire is too close to the alternator itself, which could potentially cause chaffing. The fix for this campaign is to simply unbolt the wire and turn it around, providing more space between the cable and the alternator. If looking to inspect this wire yourself, there is a black plastic cover that will need to be removed by unscrewing the single bolt holding it in place. You can then visually inspect the wire and connection. Once we received notice of the campaign we have been inspecting every D4 that comes through the factory, and reporting our findings to Volvo so they can remove the campaign from those engines. This is why some will experience the campaign, and other's will not. The serial number range for engines affected is: A191179 to A957200. If your engine has been recently into a certified Volvo Penta service center they should have inspected this at no charge. For all others, you'll want to go to volvopenta.com to locate the nearest service center.

I will say that out of the 90-100 engines I've personally inspected, there has not been one that needed anything more than an inspection. Please feel free to reach out directly to my email listed below with any additional questions.

-Tim
Tim Bates
Ranger Tugs & Cutwater Boats
timbates@rangertugs.com

 

[S@LTD]

Al,
When I took mine in for the 400 hour service I needed a coolant sensor replaced as mine went bad. I figured might as well change the coolant. Up to this point I have only added less than a pint in the five years we have had the boat. Even though they changed the sensor they talked me out of doing the coolant (someone else here might remember the way they can test the coolant). Based upon this not sure I would spend the time/money changing the coolant unless this test shows it needs it. Just my 2 cents.

 

[knotflying]

So I have a new recommendation for everyone on this forum: Check your service protocol periodically. You can do that by going to this link and putting in your engine serial number. https://www.volvopenta.com/en-us/service-and-support/your-engine/manuals-and-handbooks/

Another benefit is that you can get the latest versions of several manuals in pdf form. In my case, I can get pdfs pf the Operator's Manual, the Service and Maintenance Manual, and a data sheet explaining the emergency procedure for shifting the transmission out of gear. The fact that Volvo changes the service protocols from time to time (apparently without notice to registered owners!) makes me wonder if the Owner's Manual or Service and Maintenance Manuals also get changed or updated. Guess I'll have to download new copies just in case.

Gini

(Note: Addition to my original post. I've already discovered one change to the Service and Maintenance Manual that differs from the one I've had since I got my boat. The change is to the torque specs for tightening the tension on the drive belt and the bolts that hold the tensioner in place. I decided to make a separate post about updating service protocols and getting newer manuals via Volvo's website since that may be a topic of broader interest to members of the forum).

Spot on! Yanmar is a bit worse than that. They change things and don't update their manual. The thermostat I spoke of was not located where the manual indicated. At first I thought it was totally missing. When I called the tech at Mack Boring he told me that he "seemed" to remember that they moved it! He told me where to look for it and I found it. Some crazy stuff. I think this is what happens when they marinize an automobile engine. Then add to that, that you have Japanese engineers talking to German engineers! That is why I think they stopped the BY engine and went with a Toyota.