Author Topic: 2004 Cat C7 Overheats on Hills  (Read 22216 times)

0 Members and 1 Guest are viewing this topic.

Offline ncrowley

  • Newbie
  • *
  • Posts: 6
2004 Cat C7 Overheats on Hills
« on: June 22, 2016, 05:44:19 PM »
I have read other posts on this but I cannot find what I need. I have a C7 with 40K miles. I had the radiator flushed last year and the thermostat replaced. I extended the slobber tube when I got it and clean the CAC once per year the best I can and I have the rear radiator steam cleaner once per year. I am on a trip and the engine temperature went very high for the first time. I have had the RV for 3-1/2 years and this has never happened before. Yes, it is very hot for this time of year. It was on the mid 90s when I was driving. I am driving out west and it happened while going up a long hill. Everything would be fine for a while and then the engine temperature would climb quickly and the alarm light in the panel would go on. It happened twice on the way to our destination. The first time, I pulled over and let the engine run and the temperature dropped very quickly - within one minute. The second time I coming to the top and it dropped as soon as the road leveled out.

The second time I forced it into a lower gear while climbing the hill but it did not help. I was fine and then started climbing fast.

I had both belts replaced last year as well.

I drive all the time out west on steep and long hills and this is the first time this has happened. Does anyone have any idea what could be the problem? I have to drive home and I am not looking forward to the drive.

Offline Brett Wolfe

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 2554
Re: 2004 Cat C7 Overheats on Hills
« Reply #1 on: June 22, 2016, 07:02:17 PM »
Start with the basics:

Water pump belt (the small V belt, not serpentine belt) tight?  New belts can stretch.

Thermostats are a wearing item (metal on metal).  Not hard to replace them.  Caterpillar calls them regulators. 

Visually check the front of the CAC (access from bedroom or closet).  Make sure the perimeter, particularly the lower perimeter is as clean as the center (the fan slings the dirt to the perimeter).  Sucking up a Walmart bag can have a significant impact on air flow.

Offline ncrowley

  • Newbie
  • *
  • Posts: 6
Re: 2004 Cat C7 Overheats on Hills
« Reply #2 on: June 23, 2016, 05:01:26 AM »
I really cannot see a lot of the front side of the CAC. I have an access port in the closet and I can see some of the CAC through the fan blades but that is about it. I purchased a scope and looked where I could but seeing the edges is not possible. I have crawled under and tried to look the best I could from there but the view is very limited there. I take a wand and reach as far as I can and saturate with Extreme Simple Green and then rinse with hot water. I get a very fine silt when I do that. I know the fan blades are not clean and I have done my best to clean them off but there are areas I just cannot reach except with the wand, and the wand does not get everything off.

I will get it home the best I can and have the Freightliner dealer look at the belt and the thermostat. If they cannot find anything, do I need to resort to have them remove the CAC and clean it that way? That sounds like a very expensive task.

Offline Brett Wolfe

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 2554
Re: 2004 Cat C7 Overheats on Hills
« Reply #3 on: June 23, 2016, 06:14:21 AM »
Don't know your schedule flexibility, but if you have even a little time, I would not risk engine damage or being stuck on the side of the road.

Replacing thermostat(s) and checking water pump belt tension should take less than 2 hours. 

And, yes, if the front of the CAC is clogged enough that it can not be cleaned in place, removal of radiator  and CAC is not inexpensive.

Brett

Offline WILDEBILL308

  • Full Member
  • ***
  • Posts: 106
Re: 2004 Cat C7 Overheats on Hills
« Reply #4 on: June 23, 2016, 06:45:42 PM »
I have read other posts on this but I cannot find what I need. I have a C7 with 40K miles. I had the radiator flushed last year and the thermostat replaced. I extended the slobber tube when I got it and clean the CAC once per year the best I can and I have the rear radiator steam cleaner once per year. I am on a trip and the engine temperature went very high for the first time. I have had the RV for 3-1/2 years and this has never happened before. Yes, it is very hot for this time of year. It was on the mid 90s when I was driving. I am driving out west and it happened while going up a long hill. Everything would be fine for a while and then the engine temperature would climb quickly and the alarm light in the panel would go on. It happened twice on the way to our destination. The first time, I pulled over and let the engine run and the temperature dropped very quickly - within one minute. The second time I coming to the top and it dropped as soon as the road leveled out.

The second time I forced it into a lower gear while climbing the hill but it did not help. I was fine and then started climbing fast.

I had both belts replaced last year as well.

I drive all the time out west on steep and long hills and this is the first time this has happened. Does anyone have any idea what could be the problem? I have to drive home and I am not looking forward to the drive.

What was your RPM after down shifting? I had a simular problem on long grades that were not steep enough to make you downshift at the beginning. You may find that going down a couple gears eve more as necessary will cause your engine to run cooler. A good rule is, if you can't accelerate in a gear you should downshift till you can. Higher rpm = higher fan speed and more coolant pumped through the system. Yes for a while you may have to reduce your road speed to keep your rpm under max. The lower gear also reduces the load on your engine. The fact that it cooled down rapidly when you pulled over/ took the load off, indicates to me the method I suggested will help fix the problem.
Keep us informed on how your trip home is.
Bill
2003 Bounder 38N,300 HP 5.9 Cummins
Allison 3000MH Trans.Towing 2014 Honda CRV. Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

Offline ncrowley

  • Newbie
  • *
  • Posts: 6
Re: 2004 Cat C7 Overheats on Hills
« Reply #5 on: June 27, 2016, 04:25:21 AM »
I took the coach to a local mechanic. They checked everything - belts, etc - and all looked fine. They washed the CAC the best they could - no big chucks came out but the fan shroud and blades were really greasy. We left very early in the AM when the temperature was in the high 60s and did not attach the Jeep (4500 pounds) until we got to the top. It ended up the grade was less going back. The grade was 8% to 12% going there. Well, no issue at all.

Now that I am home, I am going to do a number of washes on the CAC with Simple Green Extreme and see what I get out. I am also going to look at the front of the CAC (what I can see) with a scope I purchased. I do not know if this will solve the issue or not. If there is a lot of gunk on the side of the CAC I cannot see, the scope will not help. I will try and blow the simple green through using the fan. Wish me luck.

Offline Brett Wolfe

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 2554
Re: 2004 Cat C7 Overheats on Hills
« Reply #6 on: June 27, 2016, 06:19:37 AM »
With your description of "really greasy" on the fan shroud/blades and if there, most certainly on the front of the CAC, you need to verify that your crankcase breather has been extended to BEHIND the fan shroud.

There are two normal by-products of combustion that exit that hose: moisture and oil vapor.  Both, if sucked into the fan/CAC/radiator will markedly increase dirt accumulation.

Easy and less than $10 to do.

Parts list:
4' of 1" ID hose.  Oil resistant is fine, but even the clear reinforced hose will last for many years.
1 nylon 1" barb to barb fitting
2 hose clamps for the 1" ID hose
Couple of zip ties

Locate the crankcase breather-- it will be the 1" ID OPEN (the only open hose) on the passenger side of the engine.  If not already cut off straight, cut the end off straight.  Insert the barb to barb fitting and then the new hose.  Secure with hose clamps.

Now, the important thing-- route the original and new hose (now one unit) so that it only goes DOWNHILL from engine to the end of the new hose behind the fan shroud.  Said another way, no "drip loop".

Cut off the end of the new hose where you want it to end.  Secure in place with the zip ties.


Offline ncrowley

  • Newbie
  • *
  • Posts: 6
Re: 2004 Cat C7 Overheats on Hills
« Reply #7 on: June 28, 2016, 03:50:32 AM »
I made that modification when I first got the coach and it is still there and working. I made the modification based on your posts - thanks.

Offline vrodboy

  • Newbie
  • *
  • Posts: 5
Re: 2004 Cat C7 Overheats on Hills
« Reply #8 on: June 28, 2016, 12:55:19 PM »
Our 2005 C7 CAT overheating too........I spoke with our Fleetwood service manager here in Sacramento, a really good and honest fellow, and he said the radiator needs to come out and be steam cleaned due to the cooling fins clogging up.......$2,000 job!! HOO-WEE!!!!

He said too this would include replacing all the belts since the engine is accessible during this process......

We have no problem overheating until we start climbing, especially in the California heat. We climbed into Yosemite Park a month ago, a serious climb and had to stop twice to let the C7 cool down.....it worked and we made it.

It has been suggested that I should spray the back (from the rear of the RV) of the radiator with Simple Green then a water rinse (not using a pressure washer). I've done this twice and it seems to help, but apparently not as good as pulling the radiator and steam cleaning.

For our engine experts out there:I'm thinking of using brake cleaner instead of Simple Green. Is this a good idea or not? It's OK to call me a dummy, I'm just looking for a good solution to the overheating problem and avoid $2,000 service bill!!!

Thanks in advance for any help or advice you can offer.

Ed & Debby


Offline Brett Wolfe

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 2554
Re: 2004 Cat C7 Overheats on Hills
« Reply #9 on: June 28, 2016, 02:09:23 PM »
First, do NOT use brake cleaner.  Simple Green EXTREME is the aluminum-friendly choice.

And you are not going to clean much off spraying anything from the back.  The dirt is on the FRONT of the CAC (Charge Air Cooler).

I would sure try cleaning it from the front (access from under bed or closet) before paying to have it all pulled.  But, it dirt has been allowed to build up for 10+ years, you may have to take it apart to clean it adequately.

Cleaning from the front needs to be done annually. 

Also, verify that your crankcase breather has been extended to behind the fan shroud.

Brett

Offline vrodboy

  • Newbie
  • *
  • Posts: 5
Re: 2004 Cat C7 Overheats on Hills
« Reply #10 on: June 30, 2016, 08:38:26 AM »
Thanks Brett for the advice! Greatly appreciated.......

ed

Offline Jim

  • Newbie
  • *
  • Posts: 2
Re: 2004 Cat C7 Overheats on Hills
« Reply #11 on: July 13, 2016, 04:32:12 PM »
Put a new radiator cap on the expansion tank.  It's an overlooked part of the cooling system and cheap to replace.   Make sure the cap pressure is correct.

Offline Gadget Man

  • Full Member
  • ***
  • Posts: 139
Re: 2004 Cat C7 Overheats on Hills
« Reply #12 on: July 22, 2016, 04:22:20 AM »
I have been fighting this same issue for a long time. In addition to rad/CAC cleaning, I've re-calibrated my oil dipstick, extended my slobber tube and added a collection can. I've replaced my surge tank cap, all of my belts, hoses, t-stats and coolant, but the problem still exists.

I have done over 25 thorough cleanings over the past eight years using Simple Green Pro HD. The condition has improved but it still comes back to haunt me on long hard pulls during summer months. I am throwing in the towel and plan to have the rad/CAC pulled and steam cleaned this winter, when I am due for a coolant change. I give up!

Craig
2005 Fleetwood Providence 39J
Cat C7 350, MP-8 Tuner
Freightliner XC Chassis

Offline ziggyh

  • Full Member
  • ***
  • Posts: 248
Re: 2004 Cat C7 Overheats on Hills
« Reply #13 on: July 22, 2016, 11:00:21 PM »
Have you tried running with out the mp8 tuner to see if there is a difference.
ZiggyH

2007 Revolution LE
C9

Offline antiqueclockservice

  • Full Member
  • ***
  • Posts: 133
Re: 2004 Cat C7 Overheats on Hills
« Reply #14 on: July 23, 2016, 04:55:03 AM »
Hi, 

What is an mp8 tuner?

Best,
Phil
Best,
Phil

Offline ziggyh

  • Full Member
  • ***
  • Posts: 248
Re: 2004 Cat C7 Overheats on Hills
« Reply #15 on: July 23, 2016, 10:17:28 AM »
Phil, it's a performance chip, they claim more hp,torque an fuel economy.
ZiggyH

2007 Revolution LE
C9

Offline antiqueclockservice

  • Full Member
  • ***
  • Posts: 133
Re: 2004 Cat C7 Overheats on Hills
« Reply #16 on: July 23, 2016, 12:47:03 PM »
Hi Ziggy,

Thanks!

Best,
Phil
Best,
Phil

Offline boundertom

  • Newbie
  • *
  • Posts: 11
Re: 2004 Cat C7 Overheats on Hills
« Reply #17 on: July 25, 2016, 03:25:42 PM »
I too have fought the overheating battle with my Cat C-7 in a 2006 Fleetwood Expedition. We bought it new in May of 2005, and fulltimed in it for 10 years. Almost 6 years ago I broke down and removed the radiator/ CAC. It was a lot of work, but worth it. I found a considerable buildup of oily dirt on the front of the radiator. My cleaning had kept the front of the CAC in fairly clean condition, but was not getting to the front of the radiator. The heaviest buildup was around the corners of the radiator. I did not know about extending the breather tube for about the first 3 years of ownership. Since that time, I have been cleaning the radiator/CAC  once or twice per year, depending on mileage. On the last trip I was having significant overheating problems again. On returning home, I found that I had a pretty bad exhaust leak. so, there was a significant amount of 1000 degree exhaust going through the radiator, which I am sure did not help! I now have an inspection camera, and looking at the front of the CAC I saw very little dirt. Thinking about the radiator/ CAC removal episode, I figured I might again be getting a buildup on the front of the radiator. That of course is impossible to see or access without removing the radiator/ CAC. I decided to do another cleaning, but concentrating on the radiator. I used a 50/50 mixture of Extreme Simple Green and water in a garden sprayer. I sprayed through the rear of the radiator with the nozzle very close to the radiator (low pressure garden sprayer), going carefully across every row of fins. I was trying to get the cleaner through the fins to the front. I let it set a few minutes, then rinsed thoroughly with water. There was a lot of dirty water! I then ran the engine for about 20 minutes to blow out the water. I repeated this process 2 more times. By the third time, the rinse water was clean. I also cleaned the front of the CAC, even though it looked pretty good. Based on what I saw today, I do think it is useful to clean from the rear of the radiator. I won't be going out for a couple of weeks, so I don't yet know if my problem is solved. I really think that the exhaust leak was a major part of the problem this time.  I also have new regulators on hand to install as my next step.

FWIW, I also have an MP8. I keep it set at about 50%. Any more and the EGT goes too high. When I was having overheating problems on the last trip, I tried dialing it back, but did not see a significant difference in coolant temperature, which surprised me a bit. The only way I got by was by downshifting (sometimes to a lower gear than required to climb the grade) and keeping the RPMs over 2000.

Tom (in sunny Arizona)

Offline ncrowley

  • Newbie
  • *
  • Posts: 6
Re: 2004 Cat C7 Overheats on Hills
« Reply #18 on: July 25, 2016, 07:41:10 PM »
Just an update. I had an issue where the coach was not responsive to the throttle and while the repair shop was diagnosing the issue, they saw that even though I had extended the slobber tube, it was still being picked up behind the radiator behind the fan. We had run it past everything but there is a backdraft that picked some of it back in. He took the end of the extended slobber tube and pointed it downward.

The issue was the high pressure pump was going bad. Had to have the pump and the injectors replaced.

I have had the shop steam cleaning the radiator from the back. I am going to do another cleaning of the front of the CAC using Simple Green Extreme tomorrow. I will run the engine to try and drive the Simple Green through. The shop said they are getting through the radiator but it is hard to say how much of the steam cleaning it hitting the back of the CAC. I can only hope that my cleaning will help. The front of the CAC looks fine.

It did not overheat on the last trip or even come close but the weather was not as hot and the hills were 6% and not 12%. Only time will tell if the cleaning from the front and back will do the trick.

Offline WILDEBILL308

  • Full Member
  • ***
  • Posts: 106
Re: 2004 Cat C7 Overheats on Hills
« Reply #19 on: July 28, 2016, 09:10:17 PM »
I have been driving under some challenging conditions on this trip I have driven I-15 from Shelby MT to Idaho Falls Idaho. I have found if you aren't manually downshifting to reduce the load on your engine you are going to overheat.
I recommend going back and reading what I posted earlier. If you can't accelerate in any given gear you are driving the EGT and water temps up to seriously high temperatures.
Bill
2003 Bounder 38N,300 HP 5.9 Cummins
Allison 3000MH Trans.Towing 2014 Honda CRV. Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

Offline ncrowley

  • Newbie
  • *
  • Posts: 6
Re: 2004 Cat C7 Overheats on Hills
« Reply #20 on: July 31, 2016, 01:06:58 PM »
Thanks for the information. I am going to change my driving habits and downshift on the hills. I have not been doing that.

Offline WILDEBILL308

  • Full Member
  • ***
  • Posts: 106
Re: 2004 Cat C7 Overheats on Hills
« Reply #21 on: July 31, 2016, 07:46:30 PM »
I have found that a Exhaust Temperature Gage (EGT) is a good tool to tell how you are doing. When the temps get high you can downshift to reduce the load. The important thing is EGT go up much quicker than water temps.  Something I have found is when running on cruise the computer will crank up the boost and fuelling to try and maintain the set speed. I was on I-15 headed south and had to watch my water temp as there are several long slow climbs and several pretty good pulls.
Bill
2003 Bounder 38N,300 HP 5.9 Cummins
Allison 3000MH Trans.Towing 2014 Honda CRV. Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-