Engine overheating

[tantytpt]

I have a 2016 Ranger trawler with a D3 Volvo inboard diesel engine.
I've experienced this same problem last year. If my boat sits for a few weeks without use, the engine overheats with rpm increase. The boat has ablative bottom paint and a new inverter. Last season when this happened I had vessel short hauled with bottom cleaning. Is there another way to address this problem other than more frequent use. Any feedback would is appreciated, thank you

 

[fishheadbarandgrill]

Don't really see the inverter or the bottom paint playing a role in your problem. You may need to acid flush your raw water cooling system with barnacle buster or something similar.

 

[tantytpt]

Thanks, impeller was replaced. 27' Ranger trawler

 

[knotflying]

I will suspect that your raw water intake is getting clogged. It may have barnacle growth inside as well and just a little increase in the growth and your have restricted intake. Make sure the grill is clear and that there is no grouth built up past the grill. AND USE YOUR BOAT MORE!! :lol:

 

[tantytpt]

Thanks

 

[BB marine]

You have a few things that could be going on. Some of the issue stems from a poorly designed raw water cooling system. The D3 requires an 1 1/4" thru Hull and all plumbing no smaller than an 1 1/4" ID. Fluid motion decided that 1" is enough ! Does 1" work ? Yes if there are no Variables and the ambient sea water is cool like it is in the PNW. Think of the factory install as being about 20% restricted right from the start.

Add some debris in the strainer and the reverse gear cooler. ( yes the reverse gear cooler gets fouled very easily because of the course strainer screen that Marine Hardware uses in the strainer installed in the Rangers and Cutwaters powered with the D3 or Yanmar 150 Hp to 220hp.) Make sure the reverses gear cooler is clear of all debris anytime you experience an over heat.

Growth on the bottom will load the engine down. An engine operates in a higher temperature range because of a compromised raw water cooling system will easily start to run above temperature when a increased load is applied because of growth. You are trying to run at the same speed has when the bottom is clean and the engine is loaded down.

The other issue is the Ranger Tugs for the most part are not propped right. If your engine D3 200 hp will not turn 4000rpm WOT it is over propped. Now add some growth on the bottom and loose another 100 or 150 RPM you are loading an engine down that has a marginal Raw water cooling system to start with. Results higher operating temperatures. The D3 with a proper sized raw water cooling system should not have more than 10F variation between slow cruise and WOT. The range should be 178F to no more than185F at WOT. When I had my Cutwater(New) the range was 178F to 193F, as normal operating variables were applied, water ambient temperature, full fuel water and extra gear for cruising added, a little slime on the bottom and a small amount of debris in the reverse gear cooler. ( known good impeller with under 100 hours) My temperatures would rise above 200F. That is to Hot.

The cure, Get rid of that 20% restriction caused by the 1" thru hull, keep a clean bottom, confirm the engine turns a minimum of 4000 rpm at WOT as loaded. unloaded it should run 4150RPM, replace impeller every 200 hours, maintain the raw water cooling system if run in salt water by frequent flushing, replace the anti freeze in the cooling system everyother year.

 

[acdfpic]

As usual, Brian's information is right on. I found on my D3 that the reverse gear oil cooler was the cause every time this happened to me. It's probably the easiest thing to check first. Remove the hoses from either side of the oil cooler and using a hose, shoot water through from the starboard side to the port side. Have a strainer or something held at the port side opening to catch whatever comes out. Everytime I did, I had a small bunch of very wispy grass...looked almost like a chaw of chewing tobacco. The strainer helps keep it from going into the bilge and causing other issues.

One other thing to look at is the hose that attaches to the suction side of the raw water pump. Found the hose on another D3 had about a 2 inch split in it...it wasn't leaking...but the slit was allowing the hose to collapse as the RPM increased the suction and thus restricted the water flow.

Good luck.

Chris Boyd
Ex RT 25SCT
Destined Nomad

 

[batate]

We have seen overheating from 3 different causes:

- vegetation collected on the hull at the external strainer. Solution: jump in with a mask and clear it out. This intake is right beneath your raw water strainer. I have had to do this 3 different times on the loop.

- scaling in the raw water system. Solution: treat with Barnacle Buster. We did this once when we were running at 196 when fast (when the turbo was engaged). If you treat, change your anodes after you treat because it will dissolve them.

- sea grass collected right after the impeller. Solution: We were able to let it run out by pulling the anode and letting it drain out. We did this when we were running 196 at over 2800 RPM, but ok otherwise.

We inspect our impeller regularly. We also clear out the sea strainer regularly, but don't often get anything collected there. We never had to remove the hoses from the oil cooler as some have reported, but I can see how that could happen. We've also never lost an impeller.

 

[BB marine]

We inspect our impeller regularly. We also clear out the sea strainer regularly, but don't often get anything collected there. We never had to remove the hoses from the oil cooler as some have reported, but I can see how that could happen. We've also never lost an impeller.

You have a D4 Volvo which Fluid Motion uses a different strainer and larger thru hull pick up for raw water cooling. The strainer has a finer screen that does not let debris pass through as easily. The raw water cooling is better sized in the newer R29's and temperature fluctuation stays in proper range unless there is some major fouling. The raw water cooling installed in the Rangers and Cutwaters with D3 Volvo's is unquestionably undersized. Any water restriction, added load on the engine or impeller with normal wear will cause an increase in operating temperature. ( I changed my impeller every 100 hours) The impellers looked fine when removed but I wanted a strong pump to help keep the engine running as cool as possible.

 

[batate]

You have a D4 Volvo which Fluid Motion uses a different strainer and larger thru hull pick up for raw water cooling. The strainer has a finer screen that does not let debris pass through as easily. The raw water cooling is better sized in the newer R29's and temperature fluctuation stays in proper range unless there is some major fouling. The raw water cooling installed in the Rangers and Cutwaters with D3 Volvo's is unquestionably undersized. Any water restriction, added load on the engine or impeller with normal wear will cause an increase in operating temperature. ( I changed my impeller every 100 hours) The impellers looked fine when removed but I wanted a strong pump to help keep the engine running as cool as possible.

Makes sense.

 

[scross]

I know this seems obvious but is your coolant level full? The overflow tank won’t fill a cooling system that is significantly low.
Take the radiator style cap off the engine when it’s cool and make sure it’s full to the top.