*UPDATE* problem solved!! Coolant temp on hills GMC 3500

[NTORACN]

Hello everyone, just a quick update on how I fixed my2006 Tioga 24D on a 2005 GMC 3500 chassis from running to hot on long grades. My original post is below. I found that my problem was caused by several things related to my cooling system. Those 3 items were the fan clutch, thermostat and radiator cab. The radiator cap wasn’t able to build enough cooling system pressure (less than 5 psi), the thermostat was a little late in its opening temperature (195 degrees versus its 187 degree rating) and I think the biggest problem area was, the fan clutch never engaged even at 237 degree water temp. I installed a new 180 degree thermostat, a new 15lb radiator cap and a new Hayden (part#2786) severe duty fan clutch. The total cost of parts was $120.

On my test drive earlier today, pulling my same boat up the Cajon Pass with the dash A/C on max and generous amounts of throttle angle to work it a hard as possible, the highest temp on my Scangauge (and the dash gauge) was 207 degrees. The fan clutch only fully engaged once for 40 to 50 seconds during the whole trip and the temp came right back to 200 degrees while I was still climbing the grade and then the fan clutch disengaged. The normal operating temp on anything but long grades is the same 197 to 198 degrees as it was before.

Now I feel completely comfortable that anyone could hop in my motorhome and drive it even in Death Valley in August without it running excessively hot. So for anyone who is tolerating a motorhome that’s running hot, it’s not normal and it can be fixed. I hope this information is useful to someone out there in internet land.

By the way, I stopped by the truck scales on my way home to see what my motorhome and boat weigh. My 2006 Tioga 24D full of gas and water and me in the drivers seat, but no food or other passengers weighed in at 10,920 lbs (3320 lbs on the front axle and 7,600 lbs on the rear axle). My boat weighed in at 3,100 lbs. That brings my grand total weight minus food and 3 passengers to 14,020 lbs, well within spec.

(original post goes from here down)

Hi everybody,

I really like the 24D motorhome with the 6.0L gas and 4L80E trans. On both trips I took with the motorhome while pulling my boat, my motorhome temp gauge and scan gauge both read as high as 235 degree coolant temps on long hard climbs only. All other times it runs 197 to 205 coolant temps. It never boiled over, but runs to hot for my liking. My E350 5.4L Ford never got over 225 degrees on the same grades pulling the same boat. I put a new A/C DElco fan clutch in it and cleaned the debris out of the radiator and A/C condensor. My question for those GMC chassis owners is, how hot has/does your motorhome run on long hard climbs? My local GM dealer is telling me this is NOT normal. I wanted to hear from other GM chassis owners with the 6.0L gas engine, to see what your working temp is.

Thank You in advance.

Randy

[lonfu]

NTORACN wrote:
Just about everything Autozone is China made and will be questionable quality.

No kidding??????

So are the original parts that are installed on our engines. Both fan clutches that I bought, the napa part and the Autozone part were made in the big C. The last one, third one, I installed was too but from a different manufacturer in the big C. The good news is that it works!!!!

A couple of years ago, ok, so it was 5 years ago, I had to replace the alternator in my 96 Eldo. You know the one, heated leather recliner seats, black on black, Bose stereo, air suspension all at 80mph....

Any ways, dealer parts counter guy says $390 for the just the part. I tell him I don't need a 2000 watt gen set with a gas engine, just an alternator. Needless to say I like to replace with new parts when ever possible. I get on line and find a brand new alternator for $90 including shipping to my door with no core charge. Huh???? Who is making the extra $300? So I order this thing with a lot of reservations, it shows up in 5 days, and looks exactly like the original except brand new! I got out my magnify glass and spent an hour looking this thing over to find any differences, then I got out my meter and checked the diodes and such. No diff except it worked correctly. When on the vehicle it gave exactly the right charge voltages and amp production was just a bit higher than the original specs! (great) Now after 45k miles, it is still working perfectly.

Tech2 code readers from GM originally cost $4000.00. I just got one shipped from china for $260.00. Works just like the original. Who owns the rights to it? The Germans, Bosch. Huh??????

Do you believe AC Delco makes sparkplugs in the U.S.A. ????? how about other parts???? No, I don't think so.....

And I love this AC Delco blip about their parts, I did a copy and paste from an amazon listing, notice the country of origin!!!!!!

ACDelco 15823208 GM Original Equipment Power Brake Booster Vacuum Sensor

Technical Details

Brand
ACDelco

Item Weight
4 ounces

Product Dimensions
4 x 4 x 1 inches

Origin
China

Item model number
15823208

Manufacturer Part Number
15823208

OEM Part Number
15823208


Ok, so this is why all the doomsayers are running around crying "zombie apocalypse" , they don't have the courage to scream "Chinese apocalypse" if we don't get our car parts shipments from the big C!!!!! With the water shortage in Cali, where do you think our rice comes from???? It has become a world market and we are only the buyers....

[NTORACN]

Just about everything Autozone is China made and will be questionable quality.

[j-d]

It really seems, and sadly so, that aftermarket fan clutches just don't measure up to OEM a LOT of the time. This really bites when we need a replacement, are willing to spend on OEM and OEM is discontinued. That happened with the older 460 Fords. I count myself blessed that ours lasted the whole time we had that coach.

We had a fan clutch start to clatter in a Dodge van we used to have. 100 miles or so from home after 700 miles on a trip. Called my mechanic buddy and he told me this:

1. Climb under and take it off. What I did, was remove the assembly, fan and clutch, take the fan off the clutch, and put the clutch back on, to hold the water pump pulley in place.

2. I wouldn't need it at highway speeds. This was true. We could even use the A/C on the rest of the way home. But this was a van, not towing, not hills, not summer-hot out.

3. He warned me a failed clutch can pull the bearing out of the water pump, move forward, and tear the back out of the radiator. That was why he wanted me to remove it.

[lonfu]

Fan clutch update. So, I started out with a Autozone fan clutch, it failed afte 3k miles, so I put in a Napa unit that looked exactly the same as the Az unit. The napa unit failed just like the Az unit. Got a warranty unit from autozone and put it in and wallah!!! all works fine, the last unit does not look like the first Az unit or the napa unit. warrantied the napa unit and carry it onboard. So, with my 180 thermostat the hottest it runs about 210 on long up grades pulling a 3100 lb load, normal idle temp is about 192 with AC on. Tranny temps will climb to 160 on the long pulls, but on flat runs it is 150.

I switched over to the newer propane AC gas/coolant and the ac unit works perfectly too. the SC frigitte AC unit is junk. Had to tape over "out side air in door". The new AC coolant is amazing stuff, I actually get 42 degree air coming out of my dash air vents.

[lonfu]

Dang gone new fan clutch went out just as we climbed the last hill for home. Only 3k miles on it and the temp spiked to 220 and the clutch quit roaring I could hear when it went out. I hate changing that thing out. Good news is it the part is covered by warranty.

When it was working correctly, it would fully engage(roar) at 210 degrees(mechanical gauge) and bring the engine temp back down to 195 before reducing the degree of engagement. then it should slowly increase the degree of engagement as the engine temp rises to 210. (huge roar) If yours is not doing this it is defective.

I installed a 180 thermostat. It starts to open at 180 degrees and is fully open at 192 degrees. The OEM was a 195 unit and didn't full open until 210 degrees. I'd recommend changing out your stat with a 180 degree unit.

I found a huge crack in my SCS HVAC box when I changed out the fan clutch. Wouldn't have seen it if I hadn't been looking for it. this allowed hot air to enter the passenger side of the coach.

I also found that the when the fan clutch engages properly the ac works perfectly. When I turned on the factory electric aux fan it didn't help the cooling at all and it allowed the engine temp to go higher before full engaging the fan clutch. the only time the aux fan helped out was when I was at a standstill. So, when in doubt, suspect your fan clutch.

[rjstractor]

210 is not hot for that engine, I used to have a 2005 2500HD with the same engine and it ran around 210 all the time.

[ericsmith32]

Bumping a old thread versus starting another. So the first drive in hot temps last weekend. On the highway stayed around 205 on the highway. Stopping would go up to 210. After I stopped for a bit for gas went down to 195 on the highway at the same speeds. The AC stopped cooling a couple times when I stopped even though the temp didn't rise. I could hear the fan clutch a roaring on take off. Sure does drop fast once going. Starting to wonder if it's just the setup of the cooling system.

Debating if I should do the bleed procedure. The mechanic did burp the system but not sure how he did it.

[klutchdust]

Great! I love problems solved....

[IAMICHABOD]

A bit of update on my overheating problem. Just like NTORACN the only time that it overheated is on long pulls.I am not towing anything like NTORACN and scroller95969. But this test was done with it ready to camp with full fuel,water and food.

I had the Hayden # 2786 Severe Duty Fan Clutch installed and it seems that it has done the job.

I then ran a test on the same grade as the one that I had a problem with before when the temp went to 237. This time it kept the temp to about 215 then cooled down to 206. I then tried it again with the Tow/Haul on. Both times it was at full throttle. With the outside temp at 96.

With the Tow/Haul on the RPM was higher and the shift points changed and the temp hovered between 206-208.

So the new fan clutch worked and I will now use the Tow/Haul more.
Forgot to add ......Dash A/C on, running on high, man that thing gets cold!
Thanks Randy!

[IAMICHABOD]

Thanks Randy,I will be looking in it soon and thanks for the offer of the tool, I have a very good mechanic that has all the tools needed.

As I get older and less flexible I leave some of that stuff to others.....:B

[NTORACN]

Yep, the Hayden #2786 is the one you need. you will also need a tool to hold the water pump pulley as you unscrew the fan clutch from the water pump pulley. I made a tool to hold the pulley to save a few hard earned dollars. Your welcome to borrow mine if you need too.

Randy

[IAMICHABOD]

Randy
That is good to hear that it has fixed your problems with the severe test that you put on it.

As I said before I only had that problem once,but this last trip up over San Marcos Pass towards Lake Cachuma in 100 degree heat the temp did the same as yours did, sure like that Scan Gage.

So I think it is time to change mine out to the Severe Duty Fan Clutch.

Is the one that you used the Hayden 2786?

Thanks for the update, update...

[NTORACN]

update, updated. Took our coach on a recent trip up the Bishop grade where last year my temp hit 236 degrees pulling my boat. This time the Hayden fan clutch engaged at 218 degrees and brought the temp down to 206 degrees and never went higher. Confirmed my hot running on steep grade problem is solved. So for those with a hot running GM 6.0L on hills, go buy the Hayden Severe Duty fan clutch.

Randy

[ericsmith32]

Going to revive this thread to keep it simple for others. Ours like many of the others is also having the overheating issue. Overheated a bit in traffic last weekend, think around 215. Hasn't got any higher than that yet. The fan clutch roars at start up but spins freely when I shut it off hot. Ordered the Hayden fan clutch and dropped it off at mechanic we've used for years. Before installing it he checked the cooling system and I burped out a bunch of air. Sure would like to know how he did it! Didn't install the fan clutch yet.

I'll know here in a couple weeks... if it does maybe the Hayden is just band-aiding the real problem. I'll post updates in a couple weeks.