Community Forums

chunker · 06-25-2019, 05:58 PM

So it's a Freightliner chassis, Cummins ISL engine, in a Winnebago/Itasca motorhome with a side radiator. Who has established the proper procedures for draining, flushing/cleaning the cooling system? I also wonder if I should change the thermostat? Engine temps run in the 190 range based on the analog dash gauge and digital readout. Might run up to 205 climbing mountains when warm outside so I figure it's OK and "if it ain't broke don't fix it".

Mainly where do I find the specified maintenance procedures for this item?

Gary RVRoamer · 06-25-2019, 07:39 PM

The thermostat opens lower than that - the engine ECU controls the cooling once the thermostat is wide open, which occurs around 160 if I remember correctly. The ECU controls the fan on/off/speed as needed to keep the temperature in the proper range.

Milford 47 · 06-26-2019, 03:10 PM

Quote:

Originally Posted by drwwicks

So it's a Freightliner chassis, Cummins ISL engine, in a Winnebago/Itasca motorhome with a side radiator. Who has established the proper procedures for draining, flushing/cleaning the cooling system? I also wonder if I should change the thermostat? Engine temps run in the 190 range based on the analog dash gauge and digital readout. Might run up to 205 climbing mountains when warm outside so I figure it's OK and "if it ain't broke don't fix it".

Mainly where do I find the specified maintenance procedures for this item?

A couple threads a few months ago about exchanging coolant and using distilled or RO permeate to flush with. Seems most don't quite get it all out so you need to compensate for that.

At least tow flushes if the coolant is old or dirty.

I always change the thermostat if getting into the cooling system and some of my engines had dual thermostats. They are fairly cheap and that is the opportune time to change them unless they or it are fairly new.

Are you going to OAT?

CountryB · 06-26-2019, 05:50 PM

I changed mine to ELC (OAT). I bought the concentrated (not the 50/50 mix) and a couple of cases of distilled water. It's cheaper that way and makes getting the correct mix easier. Walmart had the best prices.

1) Drain the coolant. if you can find a block drain, drain from there too. If not, don't worry about it.

2) Then I removed my thermostat and reinstalled the housing. That makes the coolant circulate without needed to warm up the engine each time to get thermostat to open for circulation. And I planed to install new thermostat as part of job.

3) Fill with the cooling system regular tap water and run the engine. Put dash heater on Hot. If you have the AquaHot with Engine preheat, turn that on. Run the engine for ten minutes. Then drain that out.

4) I added cooling system flush and refilled with tap water. Run engine for ten minutes and drain that out. Water should be 95% clear by now.

5) Fill with distilled water now, run engine, drain that out.

6) Repeat step 5. After draining there will still be some distilled water left in the cooling system (probably a couple of gallons).

7) Install the new Thermostat(s).

8) Put in the concentrated ELC coolant in now. Put it all in. You will have bought enough to enough to equal 50% of capacity. So if total cooling system holds 20 gallons - you bought/add all 10 gallons now.

9) Then add in enough distilled water to fill system (since there will be some distilled water remaining in the system from step 6, you will not be able to add 10 gallons - however much water it takes you will end up with a 50/50 mix since you put in a full 10 gallons of ELC and the total water (what's already in system plus what you add will equal 10 gallons).

I hope this makes sense.

Dutch Star Don · 06-26-2019, 06:01 PM

When I flushed mine, I did it similar to "CountryB" (who did a good job). The only difference, I flushed mine once with house water, then once with distilled. I bought the OAT coolant, ELC or Final Charge, in the 50/50 mix. I also bought one gallon of concentrate. I added the concentrate first, to bring the water left in the system to 50/50 and then added the rest with 50/50. This way, there is no guessing how much your system will take.

lwmcguire · 06-27-2019, 06:03 AM

Quote:

Originally Posted by CountryB

I changed mine to ELC (OAT). I bought the concentrated (not the 50/50 mix) and a couple of cases of distilled water. It's cheaper that way and makes getting the correct mix easier. Walmart had the best prices.

1) Drain the coolant. if you can find a block drain, drain from there too. If not, don't worry about it.

2) Then I removed my thermostat and reinstalled the housing. That makes the coolant circulate without needed to warm up the engine each time to get thermostat to open for circulation. And I planed to install new thermostat as part of job.

3) Fill with the cooling system regular tap water and run the engine. Put dash heater on Hot. If you have the AquaHot with Engine preheat, turn that on. Run the engine for ten minutes. Then drain that out.

4) I added cooling system flush and refilled with tap water. Run engine for ten minutes and drain that out. Water should be 95% clear by now.

5) Fill with distilled water now, run engine, drain that out.

6) Repeat step 5. After draining there will still be some distilled water left in the cooling system (probably a couple of gallons).

7) Install the new Thermostat(s).

8) Put in the concentrated ELC coolant in now. Put it all in. You will have bought enough to enough to equal 50% of capacity. So if total cooling system holds 20 gallons - you bought/add all 10 gallons now.

9) Then add in enough distilled water to fill system (since there will be some distilled water remaining in the system from step 6, you will not be able to add 10 gallons - however much water it takes you will end up with a 50/50 mix since you put in a full 10 gallons of ELC and the total water (what's already in system plus what you add will equal 10 gallons).

I hope this makes sense.

Great overview

chunker · 06-27-2019, 06:11 AM

Thanks, when I've been under servicing things I recall seeing a block drain, left rear of engine, I believe one on the radiator but didn't look for others. Don't recall if the overflow tank has one or just remove hoses. I have internet searched for a specific maintenance procedure that one finds in an authorized service manual but have been unsuccessful. I plan to do the cooling cleaning/servicing after I get it back from the suspension work in a couple weeks. After that I'll take the pressure washer, using lower settings, to the engine and trans underside and clean it up. Going to do my own oil and fuel system servicing this year.

skypilot_1 · 06-27-2019, 02:25 PM

On a Cummins IS series engine you will never get 100% of old coolant out by gravity draining. Truck shops use air pressure to move the lower passages. Start engine and make sure dash heater control valve is open (heater on) before draining coolant. After coolant stops draining I use a 1/8 inch alu tubing about six inches long brazed to air chuck fitting. Loosen house clamp and insert into coolant hose. Set air regular to no more than 10 psi. Shoot air in 2 or 3 different hoses, till you get no more coolant flowing out of block and rad petcocks. I can easily get more then a gallon out this way. Even pulling lowest engine coolant hose wouldn't get it all by gravity.
If you use coolant flush, be very careful who's you use in a wet sleeved block. And it must be totally flushed out.

https://www.cumminsfiltration.com/so...ystem-cleaners