Loss of Power in my 330 Cummins - Country Coach

[RevRV]

I am wondering if anyone here might be able to help... here's the question: Will a leak in the engine cooling system create a situation for lost engine power?

My speed has been slowing to about 35 at the tops of hills... very frustrating. I noticed a pretty good leak in my cooling system yesterday... antifreeze in a puddle around the heater core area. Any ideas?

Thanks.

[Jeff]

If you coolant level has dropped the fan will have to run harder to control temperatures. Our side-facing fan on a 330HP Cat is 38 HP at full RPM, over 10% of the available power. Our fuel mileage improves about 1 mpg also when temps drop into the high 60's because the thermostat will keep the engine within allowable temps without the fan turning on.

[RV Roamer]

The fan will run more/longer, robbing power. And the intercooler (aka charge air cooler) may be partially cooled by radiator coolant as well. If so, the air intake will be hotter and that reduces power as well.

[Rex]

Check and tighten the hose clamps on the firewall outside under the hood and see if the leak at the heater stops.  Had that problem.

[RevRV]

If you coolant level has dropped the fan will have to run harder to control temperatures. Our side-facing fan on a 330HP Cat is 38 HP at full RPM, over 10% of the available power. Our fuel mileage improves about 1 mpg also when temps drop into the high 60's because the thermostat will keep the engine within allowable temps without the fan turning on.

Makes sense thanks.

Wow, 1 mpg! I have done several things to try to get 1MPG.

Looking forward to winter now. 

[RevRV]

Check and tighten the hose clamps on the firewall outside under the hood and see if the leak at the heater stops.  Had that problem.

I did this today... I hope it fixed the problem.

Thanks for the reply.

[Ron from Big D]

If the cooling fix doesn't do the job, change your fuel filters.  You could be having a fuel starvation problem.

[RevRV]

If the cooling fix doesn't do the job, change your fuel filters.  You could be having a fuel starvation problem.

I had it changed in July. I think I started to notice some power issues at that point... but I have just been in NC and WV in the mountains, so the issues are much more noticeable. Is it possible that the filter was faulty, or installed wrong, or an o-ring not seated correctly? Anything? One guy I talked to said it was a work/no work issue, but I think I need a second opinion. 

I also just changed my air filter about 45 days ago.

[RV Roamer]

According to Cummins, the top causes of power loss are fuel filters, air filters, and air leaks in the charge air cooler.  Weak fuel/injector pumps is probably next.

Diesels need only fuel and air to run, so it seems evident that poor performance is lack of one or the other. The difficulty is figuring out what is causing the lack. The fan thing is a separate issue that robs the power from the drive train. Not all chassis have a thermostatically controlled fan, though.

[RevRV]

Thank you all for the help... I think, based upon the input here - I just need to take it into a Cummins shop.

It's just money... 

[Jim Dick]

A bad turbo charger will also cause a dramatic loss of power but I would expect it would be bad all the time. I had that happen twice when I had a CC Intrigue. A sensor mounted on the engine had a threaded nipple that came loose and wasn't providing the correct information for the turbo charger. The second time it happened we were in the bottom of the first tunnel crossing the Chesapeake Bay. I barely made it out at 35mph and could only get up to 45 once back on the bridge.

I would suspect your problem would be along the lines of what has already been suggested

[Ron from Big D]

Thank you all for the help... I think, based upon the input here - I just need to take it into a Cummins shop.

It's just money... 

Even though you changed the fuel filters of late, it could be that there was algae building in your fuel tank and this would immediately clog a new filter.  Try it, you might like it.  Treat your fuel with a fungicide.

[RonPatt]

Thank you all for the help... I think, based upon the input here - I just need to take it into a Cummins shop.

It's just money... 

I don't know where you are located, but the Cummins Atlantic service center in Kenly, N.C. does
great work.  Call Mrs. Pearce in service and she will fix you up.

Ron