Where to find Thermostat on Volvo Penta D4 260 Engine?

[tzaddi93]

Yes, I feel like a total noob for asking this - but I'm stumped (or blind). :?
Anyone have a diagram showing where the thermostat is located on a D4?

Engine started over heating while cruising this weekend. As soon as I got above 2k RPM, would jump from 180deg & climb above 200+. Received a system response that auto lowered RPM, ran fine under 2k RPM until I could get back home.

Figured it might be the impeller, so swapped that out yesterday but it looked fine and still having the issue. Moving on to the thermostat - if I can find it...

Appreciate any pointers, photos, or alt suggestions.

 

[glider4]

An additional thing to check is your coolant level. Check the coolant level at the yellow fill cap located at the bow end (front) of the engine, not any capture reservoir you may have. A low coolant level can cause your symptoms. If the coolant is low, and after filling, the next step is to look for coolant leaks.

 

[tzaddi93]

Thanks glider4, that was actually the 1st thing I checked. No issues there, so started moving down the list
1) coolant level
2) change out impeller
3) change out thermostat (if I can find it)
4) hopefully don't get this far
5) take it to the shop...

😀

 

[Cutwater28GG]

couple of other things to check.

raw water intake is clear. (check water coming out of exhaust as well)
The strainer is clear.

I've seen posts like this before where the heat exchanger needs to be cleaned. This is I understand a more involved piece of maintenance but does need to be done.

how old is the boat and how many hours?

 

[CaptT]

Check the through hull intake as barnacles can block this, it happened to me twice in the Keys. Also make sure the raw water intake hoses, basket, etc isn't obstructed. A good flush out of the cooling system/heat exchanger with Barnacle Buster may help as well.
The thermostat is located on a housing connected to the heat exchanger, Marinepartsexpress.com has schematics of this on their website. They also have the parts you may need at a fair price. I believe this link will get you to the schematics you need.
https://www.marinepartsexpress.com/VP_S ... 287%29.pdf
Hope this helps.
Terry

 

[tzaddi93]

couple of other things to check.

raw water intake is clear. (check water coming out of exhaust as well)
The strainer is clear.

I've seen posts like this before where the heat exchanger needs to be cleaned. This is I understand a more involved piece of maintenance but does need to be done.

how old is the boat and how many hours?

Thanks Cutwater28GG
- yes, left intake / strainer off my initial check list but that was done right before checking coolant.
- heat exchanger cleanout would be my next step after thermostat, hopefully not the issue as I'd rather deal with that while winterizing.
- She's a 2014 R29. Just purchased her a couple months ago and has been running perfectly between Bainbridge, Whidby & San Juan Islands. This just popped up after gassing up in Brownsville.
Thanks for the suggestions.

 

[tzaddi93]

Check the through hull intake as barnacles can block this, it happened to me twice in the Keys. Also make sure the raw water intake hoses, basket, etc isn't obstructed. A good flush out of the cooling system/heat exchanger with Barnacle Buster may help as well.
The thermostat is located on a housing connected to the heat exchanger, Marinepartsexpress.com has schematics of this on their website. They also have the parts you may need at a fair price. I believe this link will get you to the schematics you need.
https://www.marinepartsexpress.com/VP_S ... 287%29.pdf
Hope this helps.
Terry

Thanks Terry - that's exactly what I was looking for, much appreciated!

 

[Just Right]

Pull the hoses off the the transmission cooler and back flush. Debris will accumulate on the inlet side off cooler.