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Hi all. I'm towing a 25' travel trailer that weighs about 6500lbs loaded and ready to go . I live in Calgary and just took a trip out across the prairies and was surprised to find that on moderate climbs (shorter steep hills coming out of Drumheller) that the temp gauge spiked very quickly. It hit one mark back of the red zone on the temp gauge. I was watching the oil temp and watched it hit 118 C or 245 F. I am nervous as I will be going camping through the Rockies and know the passes will be far more demanding. Anyone have experiences like this? Will the temp hold on a long climb for 10-15 min?
 

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Hi all. I'm towing a 25' travel trailer that weighs about 6500lbs loaded and ready to go . I live in Calgary and just took a trip out across the prairies and was surprised to find that on moderate climbs (shorter steep hills coming out of Drumheller) that the temp gauge spiked very quickly. It hit one mark back of the red zone on the temp gauge. I was watching the oil temp and watched it hit 118 C or 245 F. I am nervous as I will be going camping through the Rockies and know the passes will be far more demanding. Anyone have experiences like this? Will the temp hold on a long climb for 10-15 min?
There are a lot of threads and posts on this subject both here and in the Jeep Garage Forum. We had the experience you describe pulling a 21 foot TT (about 4500 loaded) from Denver up to the Eisenhower Tunnel, which is a very challenging grade for towing anything. We made it, but I was worried the whole rest of our trip about coming back over Wolf Creek Pass. But when we climbed up to Wolf Creek Pass, I was careful to hold rpm's to 2000-2500, and I found the oil temp held when it reached 246 and the coolant temp gauge stabilized at the halfway mark of the third quadrant, short of the hot zone. There was plenty of power, and the car did not struggle or lug at that level of rpm's. There is a YouTube video of a diesel GC climbing to the Eisenhower Tunnel in a test run pulling max weight-- just google "Diesel Grand Cherokee Ike Gauntllet challenge". The driver floored it all the way up, and the oil temp got to 272, but did not overheat. Not that I would try that. BTW, I had the oil changed right after the trip, and the dealer said it looked fine.
 

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Thanks emersonjeep for your experiences and the pointing out the video. In the video it looks like it was still cool outside. I wonder how it would fair in hot summer conditions doing the same test? It makes me fell a bit better but I hate to see the temp gauge crawl over that high. As long as it stabilizes there I guess all will be good. Does anyone know if these jeeps will start to de-fuel or shut down to protect themselves if they get too hot?
 

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There are a lot of threads and posts on this subject both here and in the Jeep Garage Forum. We had the experience you describe pulling a 21 foot TT (about 4500 loaded) from Denver up to the Eisenhower Tunnel, which is a very challenging grade for towing anything. We made it, but I was worried the whole rest of our trip about coming back over Wolf Creek Pass. But when we climbed up to Wolf Creek Pass, I was careful to hold rpm's to 2000-2500, and I found the oil temp held when it reached 246 and the coolant temp gauge stabilized at the halfway mark of the third quadrant, short of the hot zone. There was plenty of power, and the car did not struggle or lug at that level of rpm's. There is a YouTube video of a diesel GC climbing to the Eisenhower Tunnel in a test run pulling max weight-- just google "Diesel Grand Cherokee Ike Gauntllet challenge". The driver floored it all the way up, and the oil temp got to 272, but did not overheat. Not that I would try that. BTW, I had the oil changed right after the trip, and the dealer said it looked fine.
I was out this weekend to the mountains and got to try towing up the Highwood pass on hwy 40 which has some longer steep climbs. I tried your suggestion of holding it in the 2000-2500 range and had very similar results. Have to say it freaks me out a bit. I stumbled onto something while playing with the paddle shifters. I found that while climbing if I kept the rpm's hovering around the 3000 Mark and feathered the throttle (not foot to the floor) I could come very close to maintaining the speed limit and the engine temp would drop back down to almost normal at the half way mark to the second quadrant. I have a lot more confidence in it after this last trip. It makes me wonder if the water pump doesn't have enough capacity at the lower rpm's.
 

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I was out this weekend to the mountains and got to try towing up the Highwood pass on hwy 40 which has some longer steep climbs. I tried your suggestion of holding it in the 2000-2500 range and had very similar results. Have to say it freaks me out a bit. I stumbled onto something while playing with the paddle shifters. I found that while climbing if I kept the rpm's hovering around the 3000 Mark and feathered the throttle (not foot to the floor) I could come very close to maintaining the speed limit and the engine temp would drop back down to almost normal at the half way mark to the second quadrant. I have a lot more confidence in it after this last trip. It makes me wonder if the water pump doesn't have enough capacity at the lower rpm's.
Very interesting, Parry. You appear to be on to something here! How did you build up to to 3000 rpm's on those inclines without flooring the accelerator? I admit that I just let the auto transmission do its thing while I used the accelerator to hold the lower rpm level. It sounds like you used the paddle shifters to hold to a lower gear while the rpm's increased at that lower gear. We won't be attacking passes like that for awhile (we are Minnesotans), but more trips to the Rockies are on the drawing boards for the future! Thanks for this helpful and encouraging report.
 

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Emersonjeep - I would build revs without flooring it by just hitting the downshift paddle without changing the throttle position. As I approach the hill I would drop one or two gears until the revs are around 3000 and then lightly work the throttle and downshift again if necessary to hold rpm and speed. I found I could maintain 80-90 kph or 50-55 mph on the inclines this way. It made a massive difference on the engine temp and I carried better speed.
 

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Emersonjeep - I would build revs without flooring it by just hitting the downshift paddle without changing the throttle position. As I approach the hill I would drop one or two gears until the revs are around 3000 and then lightly work the throttle and downshift again if necessary to hold rpm and speed. I found I could maintain 80-90 kph or 50-55 mph on the inclines this way. It made a massive difference on the engine temp and I carried better speed.
I live in Colorado and have had similar problems going over the passes. The dealer says that the temperature gauge misrepresents the actual engine temperature and that there is no problem. We are going to install a gauge that actually gives the engine temperature rather than guessing where in the red zone we will fail. I will let you know what we find. In any event, even though there may be work arounds such as maintaining hi rpms, this car shouldn't have these issues. I am still very nervious going over the Eisenhour and Vail passes.
 

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Emersonjeep - I would build revs without flooring it by just hitting the downshift paddle without changing the throttle position. As I approach the hill I would drop one or two gears until the revs are around 3000 and then lightly work the throttle and downshift again if necessary to hold rpm and speed. I found I could maintain 80-90 kph or 50-55 mph on the inclines this way. It made a massive difference on the engine temp and I carried better speed.
You are using the correct technique. A turbo diesel can generate tremendous heat if lugged under heavy loads. EGT goes down as RPMs go up. The engine is a heat pump and moving more air through it prevents heat buildup. I tow heavy with a Powestroke and it behaves the same way. The GC cooling system is not sized to handle lugging at max torque like it is on diesel pickups. Use the paddle shifters. Get a ScanGuage2 and watch the EGT, transmission, and coolant temps when towing. Let these parameters determine the power limits. Use the paddle shifters, not the dummy gauge and standard shift points on the tranny to keep everything in check. This is all basiv diesel towing 101.

It has been reported that the thermostat fully opens at 225 and 235 is the red zone on the dummy guage. This was done to run the diesel engine hotter for better emissions and economy.
 

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Discussion Starter #9
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I live in Colorado and have had similar problems going over the passes. The dealer says that the temperature gauge misrepresents the actual engine temperature and that there is no problem. We are going to install a gauge that actually gives the engine temperature rather than guessing where in the red zone we will fail. I will let you know what we find. In any event, even though there may be work arounds such as maintaining hi rpms, this car shouldn't have these issues. I am still very nervious going over the Eisenhour and Vail passes.
That makes a lot of sense to me. I've had the chance to use mine going over the Rogers Pass in hot weather and the gauge will run right up to the high mark and then come down and settle at one mark back from the red. I keep thinking it will overheat but it doesn't. Made me nervous as hell. Let us know what happens when you install the real gauge. I decided to change things up and move the jeep to the back.
 

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Don't waste your money on a "real gauge"! The coolant temp is available via ODB2 and a ScanGuage2 can give you EGT, Coolant, and numerous other readouts configured on a readout. It also reads and resets DTC codes if the engine light comes on.
Is your scanguage2 running on a diesel GC?
 

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Is your scanguage2 running on a diesel GC?
Yes sir. I routed the cabling through the back of the cubby. I normally watch EGT, DPF, and CAT temps and PSI Bòost. Water temp, fuel flow, and tons of other stats are available. You can enter custom PID code info to read additional data. I have the codes for EGT, DPF, and CAT temps.

Bought mine at Autozone.
 

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I was out this weekend to the mountains and got to try towing up the Highwood pass on hwy 40 which has some longer steep climbs. I tried your suggestion of holding it in the 2000-2500 range and had very similar results. Have to say it freaks me out a bit. I stumbled onto something while playing with the paddle shifters. I found that while climbing if I kept the rpm's hovering around the 3000 Mark and feathered the throttle (not foot to the floor) I could come very close to maintaining the speed limit and the engine temp would drop back down to almost normal at the half way mark to the second quadrant. I have a lot more confidence in it after this last trip. It makes me wonder if the water pump doesn't have enough capacity at the lower rpm's.
Does anyone know that the overheating issue has been fixed? I am considering to buy a GC primarily for towing an RV trailer to the national parks with some serious uphill climbs.
Thank you
 

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Does anyone know that the overheating issue has been fixed? I am considering to buy a GC primarily for towing an RV trailer to the national parks with some serious uphill climbs.
Thank you
What overheating issue? The problem is that the gauge is truthful unlike the majority of temperature guages in other vehicles. The guage raises to near red then stops unless you punish the motor by lugging it hard at low RPMs.

Most light duty high output diesels will produce power near or beyond their thermal limits and get hotter than normal if lugged. The key to towing with our vehicle is to avoid lugging on steep grades. Paddle shift to keep RPMs above 2500. This allows the engine to remove hot exhaust, and the water pump and radiator to have enough flow.

Due to their torque curve and lack of turbo, the gas engines don't have enough torque to maintain speed on a grade so they CAN'T overheat from lugging at low RPM. They end up pulling hills at higher RPMs which is exactly what we should do with the diesel unless it's a short pull. Extended climbs are where lugging will heat soak the motor.
 

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Would a simple solution be to keep it in Sport mode when towing up hills? On my other car (gasoline powered Audi) the Sport mode locks out the 6th gear and will cruse in 5th at a higher RPM. Maybe same approach with the Jeep?
 

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Would a simple solution be to keep it in Sport mode when towing up hills? On my other car (gasoline powered Audi) the Sport mode locks out the 6th gear and will cruse in 5th at a higher RPM. Maybe same approach with the Jeep?
Sport mode raises the shift points so definetely use Sport mode in the hills. On long grades, I would still recommend paddle shifting. It is simple and effective, and the difference it makes in engine and coolant temperature is substantial.

I would recommend that anyone that tows heavy invest in a Scanguage2 and monitor the exhaust gas temperature. The real killer on any diesel is high EGT. Once you start monitoring EGT, you will see what lugging is doing. Our motors are heat pumps and keeping the hot gasses moving fast enough to prevent buildup is the name of the game. This is common knowledge with diesel pickup owners who tow heavy. They drive by watching the EGT (pyrometer) gauge...and thats just as applicable for us.
 

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What overheating issue? The problem is that the gauge is truthful unlike the majority of temperature guages in other vehicles. The guage raises to near red then stops unless you punish the motor by lugging it hard at low RPMs.

Most light duty high output diesels will produce power near or beyond their thermal limits and get hotter than normal if lugged. The key to towing with our vehicle is to avoid lugging on steep grades. Paddle shift to keep RPMs above 2500. This allows the engine to remove hot exhaust, and the water pump and radiator to have enough flow.

Due to their torque curve and lack of turbo, the gas engines don't have enough torque to maintain speed on a grade so they CAN'T overheat from lugging at low RPM. They end up pulling hills at higher RPMs which is exactly what we should do with the diesel unless it's a short pull. Extended climbs are where lugging will heat soak the motor.
I was looking to the similar other brands like VW Touareg TDI. To be honest, I drive tested Touareg. It does not feel like an SUV but like a sedan. My only concern is overheating during towing. I did not find any complain about the overheating issue for Touareg. I am trying to convince myself to lean towards GC, since I like the appearance of this car much more than Touareg. But all discussion in this forum and other Jeep forum make me skeptical.
 

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ExcursionDiesel - any tricks to running the cable through the cubby? You have to cut anything?
No cutting. Here's how I did it.

I used a stiff piece of solid core copper wire about 3 feet long to fish it through the back.

1. With the cubby door open, tilt it closed just a bit and reach inside and you will feel an opening in the cubby roof just behind the top edge of the tilted door that goes from left to right. The drivers side of that opening has an open path down to the area where the transmission tunnel meets the console....near where your right shin is when driving.

2. Tape the ODB2 cable to the copper wire and make sure there are no edges to snag.

3. Use the copper wire to pull the ODB2 cable through to the gas pedal area and then you can route it the rest of the way high on the firewall to the ODB2 plug.

Tip: The path is narrow fishing it through the back of the cubby. Take your time and pre-bend the wire to get it to go down. The hole in the cubby roof goes up so the wire has to be bent in a gradual arc. It took me maybe 20 minutes to figure it out.
 
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