Volvo D4-260 Cooling System - explain please?

[kennyh]

Hi all

I've a question re the Volvo Penta D4-260 cooling system for you....

But first, the reason why I'm asking.....

The coolant temperature on my 2007/2008 D4-260 normally sits around 85C when underway and crushing at 3200rpm.

Now if I push it to full throttle it will come up to circa 3450rpm with the temp sitting at 85C for a few minutes and then it jumps to 95C in an instant. If I throttle back, it will sit at 95C and then jumps back to 85C and stays there.

So, I'm trying to understand how the cooling system works to deliver that type of jump.

Can someone explain to me how the cooling system is configured; how/when the thermostat opens to the raw water side, and why it would "jump" from 85C to 95C?

Of course it could be the instruments/ sensor that is causing the jump!m and not the actual coolant temp.

Any comments advice would be very welcomed.

 

[spannerman]

When I was on a D4/6 factory course the instructor told us that Volvo have designed the software to display 85C on any temp between 80 and 90C to eliminate all the questions they get where people complain that their engines don't have identical temps, which is a very unrealistic expectation seeing as they are two independent power plants that just happen to be sitting side by side in the same hull, but we get the questions all the same. So if yours jumps to 95c then it has gone into the next (electronic) temp zone and is obviously running hotter than 90C so should be investigated. The engine temp will increase gradually if you use an IR thermometer but the software measures it in steps. The best thing is to check the raw water side is OK, then the freshwater system, it could be the coolers are needing a clean going by the age. There is no thermostat on the raw water side it is on the freshwater side it starts to open at 82C and is fully open at 92C.

 

[julians]

Yep as above, mine did the same. Fixed by removing the various heat exchangers/coolers and cleaning them out.

 

[kennyh]

Yep as above, mine did the same. Fixed by removing the various heat exchangers/coolers and cleaning them out.

Thanks guys (Spannerman, Julian's) that would certainly explain it.

I assume removal / cleaning of the coolers is a big job?

 

[julians]

Thanks guys (Spannerman, Julian's) that would certainly explain it.

I assume removal / cleaning of the coolers is a big job?

If I remember correctly it cost about 1000 euros for a single engine

 

[kennyh]

If I remember correctly it cost about 1000 euros for a single engine

Ouch!

I have done some quick digging on the heat exchanger cleaner product called Rydelyme that attempts to dissolve and flush out fouling / deposits.

I may give that a go first as it should be a lot cheaper to do before processing on to an overhaul of required.

Any thoughts anyone on whether that solution actually works?

 

[GrahamHR]

I can't comment as to the ease/ cost of cleaning intercoolers etc. However, I had a boat with a V8 petrol engine. From first use, it had a "closed" cooling system with a heat exchanger. I kept it for 9 years use in salt water. I was flushed with fresh water every time after use. ( a simple OEM fitted T piece on the inlet to the raw water pump). Never a problem with overheating, I removed the heat exchanger end caps after 8 years; no build up at all,, absolutely nothing.

Based on that experience, I fitted a T piece in the raw water intake hose of my current D4-300. They should have fitted one as standard in my opinion.

 

[frothblower]

Ouch!

I have done some quick digging on the heat exchanger cleaner product called Rydelyme that attempts to dissolve and flush out fouling / deposits.

I may give that a go first as it should be a lot cheaper to do before processing on to an overhaul of required.

Any thoughts anyone on whether that solution actually works?

Yes it works a treat with minimal disruption.

I haven't used Rydelyme but used a similar method (brick cleaner containing hydrochloric acid) and cleaned both my D4-260's. After use heatexhanger, intercooler and oil cooler were immaculate and I could once again run at max revs while maintaining a steady 85 degrees.

 

[kennyh]

Yes it works a treat with minimal disruption.

I haven't used Rydelyme but used a similar method (brick cleaner containing hydrochloric acid) and cleaned both my D4-260's. After use heatexhanger, intercooler and oil cooler were immaculate and I could once again run at max revs while maintaining a steady 85 degrees.

Thanks frothblower, can you advise how you applied the stuff? Did you just pour it into the hose connections or did you rig up a circuit for the cleaner to flow through the coolers?

 

[Mike k]

Thanks frothblower, can you advise how you applied the stuff? Did you just pour it into the hose connections or did you rig up a circuit for the cleaner to flow through the coolers?

Hi I sat up a circulation system:

A plastic bucket placed low down in the engine bay, a small whale pump laid in the bucket and connected to bilge hose http://www.asap-supplies.com/marine/bilge-pump-hose
then attached a stepped hose tail something like http://waterways-direct.com/index.php?main_page=product_info&products_id=906 to the bilge hose and the main cooling water inlet hose to the cooler, then another stepped connector to the hose leaving the cooling system and into more bilge hose then drop into bucket. Filled the bucket with rydlime ,connected the pump to the battery and left circulation for a good few hours.

 

[frothblower]

Thanks frothblower, can you advise how you applied the stuff? Did you just pour it into the hose connections or did you rig up a circuit for the cleaner to flow through the coolers?

Remove the anode from bottom of the heat exchanger, then remove the end of the heat exchanger (4 bolts) which allows you to peer in the end and see how badly clogged they are, Lightly refit the end of the heat exchanger upside down with the anode hole now facing upwards (note only 2 bolt holes line up), Repeat process for the intercooler, then tip in solution down the anode holes, let it fizz away and do its stuff until it stops fizzing, remove exchanger ends to see immaculate looking exchangers, refit properly and run engines to flush out any remaining solution then enjoy full revs at nice constant 85 degree temperature.

 

[CharlieAlpha]

Thank you Spannerman I had wondered why my D6's always read exactly 85 once warmed up - guess that software is common on newer green lumps.

 

[kennyh]

Was there enough room to remove the bolts from the heat exchanger without fouling other parts of the engine? I've heard some folks say you need to strip other components out first to get access to the heat ex?

 

[frothblower]

Was there enough room to remove the bolts from the heat exchanger without fouling other parts of the engine? I've heard some folks say you need to strip other components out first to get access to the heat ex?

Only thing I removed was the pulley off of the water pump held on by a cir-clip.

 

[kennyh]

Only thing I removed was the pulley off of the water pump held on by a cir-clip.

Perfect. Thanks frothblower.