CLEANING REAR RADIATOR-FREIGHTLINER CHASSIS

[rossboyer]

PROCEDURE FOR CLEANING REAR MOUNTED RADIATOR

 

 

 

 

I have had trouble with overheating for about 10 years with my Caterpillar C-7 engine on Freightliner chassis. Several times technicians have checked, and no codes are indicated. Last year at the FMCA Convention in Gillette, WY, I again talked to the Freightliner service technicians. I explained my procedure for cleaning and was told I was doing everything correctly, but they wanted me to do two additional suggestions.

 

1.     First:  Using a 1.5-inch dia. hole saw, cut a hole in the lowest point of the fan shroud as close to the radiator as possible without hitting it. (If you do this, I suggest that you use about a 1/8-inch dia. drill bit first to create a pilot hole and then use the hole saw.) I will explain their second suggestion later.

 

2.      My cleaning procedure.

 

a.      If necessary, remove floor at rear of motorhome to gain access to the Charge Air Cooler (CAC) and Radiator sandwich.

 

b.      In a 1.5-gal garden sprayer, mix 2 cups of Simple Green Extreme (The Simple Green Extreme will not attack aluminum.) and fill with warm water to create cleaning solution. This is very close to a 1 to 13 ratio or Simple Green Extreme to water.

 

c.       Between the fan and CAC, spray the CAC with the solution from inside the motorhome.

 

d.      Let set for about 5-10 minutes, but do not let it dry.

 

e.       Start engine and with a small nozzle on a garden hose, spray the CAC until solution is washed out the rear of the radiator.

 

f.        Turn off engine and repeat steps c, d, & e until all the solution is used. The foam exiting the rear of the radiator should be white by now. (Takes me about an hour.)

 

g.      Place a bucket under the hole you cut in fan shroud.

 

h.      From outside the motorhome using a pressure washer (1,600-1,800 psi) set to a fan spray and about 18 inches away for the radiator (You don’t want to bend the radiator fins), start at the upper left corner and work across the radiator.

 

i.        Move down and do the next section and repeat until the water collected in the bucket is clear. (I had to do mine for 3 one-hour sessions before water was clear.)

 

 

 

Since doing the above procedure, I have traveled to several local rallies and to Arizona and back, about 4,000 miles. The highest temperature I had was on a five-mile 6% uphill grade between Phoenix and Flagstaff. The indicator was straight up on my non-numerical temperature gage. All the rest of my travel, the gage indicated about 10:00 or less. After a couple of weekend outings, I pressure wash from the outside as indicated above for about 10-15 minutes. I intend to do the steps to clean from the inside once a year before my trip to Arizona.

[dspalding1]

Had similar overheating issues with my Winnebago on a Frieghtliner chassis with a Cummins engine. Mentioned it to the Frieghtliner service manager in Rapid City while having other work done. They sent me to a local truck wash and they power washed the radiator until the waste water ran clean.  Apparently they do this a lot. $15 dollars and a half hour later my overheating problems were solved. The service manager recommended having this procedure done every couple of years. They were very careful to stand back far enough with the pressure washer as to not cause any damage.

[rossboyer]

You also need to clean from the engine side to clean the cac and transmission coolers. Be sure to use Simple Green Extreme which will not harm the aluminum radiator core. 

[wildebill308]

dspalding1, Welcome to the forum.

Yes using Simple Green Extreme is the preferred way. I have found driving through 10" per hour rain storms will do a amazing job of cleaning the CAC and radiator. The CR-V was covered in crud including the little chunks of oil/dirt from between/ in the radiator fins and CAC. If I had known I was going to run into that much rain I may have sprayed the CAC and radiator in advance. 

There was so much water spray coming through the radiator it looked like the car was in a wind tunnel.

Other than that a annuel (minimum) cleaning and learning how to manually downshift will keep your coach running cool.

Bill

 

[rossboyer]

Doing so was the time I got the whole sandwich of heat exchangers clogged the worst. The roadway had been coated with a chemical to prevent freezing. Packed in like mortar. 

[proost]

I think this is my issue.  The rig runs beautifully and cool on flatter terrain but when I hit just the slightest grade, I'll watch it come up.  Yesterday, I was stuck keeping the engine at 2500rpm min and 25-30mph going up a 4mi 6% grade to keep it from overheating.  I was the slowest guy around but had plenty of power otherwise.  

[wolfe10]

proost,

Welcome to the FMCA Forum.

Yes, the FRONT of the CAC (Charge Air Cooler) needs to be cleaned annually!

[40SC40QS]

My Cummins ISL 400hp was overheating on hills, radiator/cc were clean, turned out, fan clutch was faulty and not kicking into high, had a Freightliner shop replace and I'm makin' ice cubes now even on hills! 

[manholt]

Even so, I hope you take Brett's advice...I have experienced both sides of that issue!

[40SC40QS]

22 hours ago, manholt said:

Even so, I hope you take Brett's advice...I have experienced both sides of that issue!

Oh for sure! Got to keep that radiator and cc clean or all the air in the world will not keep 'er cool! 

[jaws2]

Thanks for the advise.  i reached overheat briefly near top of mountain this summer for first time ever in years with my c7 in Colorado.   Pulled over at top and let idle for a few minutes and it returned to normal.   I will clean as you suggest  and I should not have this issue again.

[wolfe10]

Yes, if overheating (and not because of loss of coolant) the best answer is to pull over, transmission in Neutral and idle around 1,200 RPM.

[luckydog1949]

Our CAT C7 overheated in 2013, not long after buying our '05 Horizon.  We didn't know anything about cleaning the CAC and radiator, then; so, we stopped at a CAT dealership on I-90, somewhere in Western SD.  It cost a little over $200 for them to clean leaves, crud, etc. out from between and off the surfaces of the CAC and radiator.  I believe that the leaves were brought in by squirrels wherever the previous owner stored the coach.  I did some research and found out about extending the slobber tube so there wouldn't be engine oil coating the front (inner) side of the assembly; so, I took care of that.  It did a lot toward keeping everything clean.  A good thing to check.

[rikadoo]

Also doing all that work is GREAT, however remember if you have a side mounted condenser for your a dash mounted A/C clean it too, you will really appreciate the difference.

[wildebill308]

2 hours ago, rikadoo said:

Also doing all that work is GREAT, however remember if you have a side mounted condenser for your a dash mounted A/C clean it too, you will really appreciate the difference.

Good advice rikadoo and welcome to the forum. 

Please take the time to enter your coach and other info to your signature. See mine and others as examples  This will save you time latter. 

Bill 

[manholt]

Bill is right about saving time, sometimes Posters get upset because we don't answer in time...if we had all the info, we could.

Again, welcome!

[urbanhermit]

Mother Superior, Cayman 36, Cummins 5.9, acquired in the Dallas area April 9, ran toward the high end of the normal range coming 760 miles home, mostly at night.  Had a general service done including flushing the cooling system.  Was told it took four cycles before exit water came out clean.  Afterwards ran near the middle of the normal range at a steady internet 65, rising only a little in urban traffic.  While considering radiator flushes, consider an internal cooling system flush.

[wolfe10]

Yup, a rear radiator DP is basically a huge "vacuum cleaner" of a fan sucking up all the dirt stirred up by 35'+ of coach moving down the road at hurricane velocity.  Oh, and the air goes past the hot rear axle, not transmission and hot engine on its way to the "cooling package". And, if anything is leaking oil, that gets sucked up as well.