2008 3500 4x4 getting hot

[Matt42]

Here's the situation: I have a longtime friend in Wyoming where satellite internet is sketchy. She has a 2008 6.7 and tows a gooseneck 4 horse trailer. In the last couple of years, the temperature indication has been getting hotter year by year. We've discussed some fixes. But I have a question before I get into that. Do any of the later-year OEM radiators fit and also have a higher capacity (quarts, gallons) for coolant?

Here are the suggestions we've discussed, and we'd both like some advice. The truck has about 170K miles on it, with the 6 speed manual and regular gearing, not 4.11. The suggestions begin with the less expensive and go up.

• Remove the radiator and blow out from the back with high pressure water at a car wash. If R&R isn't possible, at least do it with the radiator installed. This has never been done.
• Replace the thermostat. Never been done.
• Flush and refill cooling system. Never been done. Service place says coolant is OK.
• Check water pump, but it is not leaking. Cooling system is tight, never has to add to it.
• Fan clutch has been replaced and is actively turning on & off. ("Sounds like a DC-8 taking off.")
• Check fan for excessive flex. (A long shot.)
  
• Installed EGT guage and drive by the EGT by gearing down. This was done recently (insert aha! moment here) and the coolant temperature follows the EGT. (Imagine that.) But it's not just an EGT guage, it's a system that adds fuel or some such on uphill grades. (Makes my skin crawl, kinda.)
  
• Replace OEM radiator with a bigger one. OEM radiator is not leaking. She has looked at Mishimoto aluminum radiators but is put off by negative feedback. It seems that her truck is a kind of orphan year and parts may or not fit, being more like a 2007 in some places and a 2009 in others. Any experience with IceBox radiators? I told her to not waste her money unless a new radiator adds at least a gallon of coolant capacity.

I've gone through similar issues with Utah friend's 2005 3500 4x4 automatic. Before he discovered the TDR, he had to R&R the engine because cylinders 5 & 6 fried. (The transmission followed shortly thereafter.) I have visions of similar things happening to my Wyoming friend's 2008 and we would both like to avoid this.

My gut tells me that the radiator fins are clogging with insects and dirt based on the gradual increase in heating. We all thank you.

 

[bcbender]

Coolant interval is 100k miles so its due for a change, Id go ahead and flush it and replace with new coolant, Cleaning the cooling area of the radiator of mud and insects also a good idea.. Im sure someone will chime in, my 3rd gen was a 5.9 and I never had cooling issues except the fan clutch went bad.

 

[sag2]

There are many that tow heavy with early 6.7 and do not get hot. I would start with making sure the radiator fins are clean, pulling and cleaning it would be best. Replace the coolant and thermostat since that has never been done.

 

[Darkbloodmon]

She has looked at Mishimoto aluminum radiators but is put off by negative feedback.

I missed the reviews by a long shot when I was shopping for a rad, I'm running a Mishimoto rad without issues along side their intercooler, large pipe kit, and hoses. I've got an issue with UPS their contracted carrier for delivery, as I've now got a small stock pile of warrantied out parts from shipping damage (two intercoolers and a rad)

I would start with a coolant flush, T stat, and hosing out the rad fins.

Have you checked if the brakes are dragging?

 

[AH64ID]

As mentioned she is overdue, by nearly 8 years, on a coolant replacement. At that age she need to have it flushed, not just drained and filled.

Before completing the flush go a good inside and outside inspection of the radiator to ensure that the it's not plugged, has too many damaged fins, or is otherwise not getting the airflow it needs.

The thermostat is also a great place to start and isn't going to break the bank. Get a genuine Cummins.

She doesn't need to spend the money on anything aftermarket, but she does need to get back to OEM cooling capabilities. I ran 415/850 to the ground with my 3rd gen cooling system and it was never an issue with heat, so her stock truck is fine with a stock cooling system.

The cooling system is the same total volume today as it was in 2008 (22qts) and the power output is significantly higher. There are differences in design due to cab/frame/EGR changes, but 22 quarts is plenty. The 3rd gen 5.9's did have a higher total volume due to the block holding more coolant. The radiators and plumbing are the same for 3rd gen, 5.9 or 6.7.

 

[bcbender]

Flush and refill cooling system. Never been done. Service place says coolant is OK.

Not sure if Id use that service place if they are saying a truck with 170k on the OE fill is "OK"... clearly stated in the OM to change by now.

 

[Diesel Gunner]

Here's the situation: I have a longtime friend in Wyoming where satellite internet is sketchy. She has a 2008 6.7 and tows a gooseneck 4 horse trailer. In the last couple of years, the temperature indication has been getting hotter year by year. We've discussed some fixes. But I have a question before I get into that. Do any of the later-year OEM radiators fit and also have a higher capacity (quarts, gallons) for coolant?

Here are the suggestions we've discussed, and we'd both like some advice. The truck has about 170K miles on it, with the 6 speed manual and regular gearing, not 4.11. The suggestions begin with the less expensive and go up.

• Remove the radiator and blow out from the back with high pressure water at a car wash. If R&R isn't possible, at least do it with the radiator installed. This has never been done.
• Replace the thermostat. Never been done.
• Flush and refill cooling system. Never been done. Service place says coolant is OK.
• Check water pump, but it is not leaking. Cooling system is tight, never has to add to it.
• Fan clutch has been replaced and is actively turning on & off. ("Sounds like a DC-8 taking off.")
• Check fan for excessive flex. (A long shot.)
  
• Installed EGT guage and drive by the EGT by gearing down. This was done recently (insert aha! moment here) and the coolant temperature follows the EGT. (Imagine that.) But it's not just an EGT guage, it's a system that adds fuel or some such on uphill grades. (Makes my skin crawl, kinda.)
  
• Replace OEM radiator with a bigger one. OEM radiator is not leaking. She has looked at Mishimoto aluminum radiators but is put off by negative feedback. It seems that her truck is a kind of orphan year and parts may or not fit, being more like a 2007 in some places and a 2009 in others. Any experience with IceBox radiators? I told her to not waste her money unless a new radiator adds at least a gallon of coolant capacity.

I've gone through similar issues with Utah friend's 2005 3500 4x4 automatic. Before he discovered the TDR, he had to R&R the engine because cylinders 5 & 6 fried. (The transmission followed shortly thereafter.) I have visions of similar things happening to my Wyoming friend's 2008 and we would both like to avoid this.

My gut tells me that the radiator fins are clogging with insects and dirt based on the gradual increase in heating. We all thank you.

Your list of things to do is pretty right on. I would suggest replacing all of the coolant lines at the same time the rest of the work is done. IF all of that does not resolve the overheating problem, THEN I would start looking for other causes. Don't forget to flush radiator and inspect internally as best you can to ensure that you don't have tubes clogged with corrosion, sediment, etc. I do not know if these newer trucks still use that catch bottle on the crankcase vent, but if id does lose it. I extended the vent hose down below the radiator so that the oily vapor does not get on it and attract dirt clogging it up. If the truck is operated in freezing temps care needs to be taken that it does not freeze and clog. Here in Kommiefornia freezing is not as much a problem.

 

[Ozymandias]

In the last couple of years, the temperature indication has been getting hotter year by year.

What temperatures are we talking about?
Numbers?

 

[BigPapa]

• Remove the radiator and blow out from the back with high pressure water at a car wash.
• But it's not just an EGT guage, it's a system that adds fuel or some such on uphill grades.

I wouldn't suggest the car wash to clean the radiator and CAC. High pressure can bend the fins which will block air flow much more than dirt and bugs. I'd use something like Simple Green or a coil cleaner and a water hose. You'll also want to clean the CAC and A/C Condenser.

This "EGT gauge system", sounds like a programmer. Can you tell us exactly what it is, brand and model?

 

[Jim W]

I have a 2008, 6.7L with an automatic and 3:73 gears, using a SMARTY S67 which adds about 60HP to the engine output. I have gauges on my truck EGT, Boost and transmission temp, reading is from the Transmission pan. With the EGR cooler still on the truck, but the air out output is blocked. The milage on my truck is 144K and counting. Since I am retired, I do not drive the truck very much in the winter now. My truck is now used mainly to pull our Cedar Creek 5ER in the summer. I am close to 20K when towing, been across a CAT scale several times checking weight numbers.

My cooling numbers in the summer run around 190F to 200F on the gauge in the truck. In the winter months I install a winter front around DEC1, and the cooling numbers run around 190F to 200F. The Cummins thermostat is 190F so, I am not worried about my truck temps. I have had my coolant changed and flush twice about ever 5 years to 6 years apart. I do not go by milage but by time, since I do not put that many miles on a truck in 5years. I do use air to blow my cooling system radiators out every spring and fall.

 

[Matt42]

I wouldn't suggest the car wash to clean the radiator and CAC. High pressure can bend the fins which will block air flow much more than dirt and bugs. I'd use something like Simple Green or a coil cleaner and a water hose. You'll also want to clean the CAC and A/C Condenser.

This "EGT gauge system", sounds like a programmer. Can you tell us exactly what it is, brand and model?

Well, PigPapa seems to have nailed the "information not given to me or not understood" aspect. It turns out that there is a programmer, and I think (but do not know for certain) that it's a Smarty. And there's more. It was installed at the same time as what seems to have been an EGR delete. (Insert sound of a heavy sigh here.)

Coolant temps being reported, using the display that comes with the thing that was installed, are circa 220F. The truck is not towing any heavier than similar trucks in the vicinity. There's good news. The EGT display has caused the owner to drive using the EGT as well as the speed and RPM. So in other words, when the EGT rises, she shifts down a gear. (This has been a longstanding, ah, discussion betwixt us.)

Your recommendation to use Simple Green and a garden hose is excellent. The danger of damaging the fins is real and I should have thought of that. I will pass that information along. Neither cleaning method would take place until spring, anyway.

Your list of things to do is pretty right on. I would suggest replacing all of the coolant lines at the same time the rest of the work is done. IF all of that does not resolve the overheating problem, THEN I would start looking for other causes. Don't forget to flush radiator and inspect internally as best you can to ensure that you don't have tubes clogged with corrosion, sediment, etc. I do not know if these newer trucks still use that catch bottle on the crankcase vent, but if id does lose it. I extended the vent hose down below the radiator so that the oily vapor does not get on it and attract dirt clogging it up. If the truck is operated in freezing temps care needs to be taken that it does not freeze and clog. Here in Kommiefornia freezing is not as much a problem.

I don't know if it has a catch bottle but I will check. Those are a known problem spot.

 

[AH64ID]

That doesn’t sound all that bad, nor does 220° depending on the load and terrain. The stock thermostat cracks open at 190°, goes full open at 207°, and has a max allowable temp of 225° from Cummins.

She is still overdue for a coolant flush and probably a radiator cleaning.

 

[Jim W]

I don't know if it has a catch bottle but I will check. Those are a known problem spot.

On the 6.7L engine there is no catch bottle instead there is a crankcase vent filter that resides under the 6.7L cover on top of the engine. This needs to be serviced at set intervals per the O&M guide. For our years of truck this needs to be done every 67,500 miles regardless of if the EGR is deleted or not. These can't be cleaned but needs to be replaced. Geno's garage sells them, part number CV520010. Last time I bought one my cost was $84.85 plus $7.50 for shipping.

 

[Matt42]

This "EGT gauge system", sounds like a programmer. Can you tell us exactly what it is, brand and model?

I'm traveling this week, so it took some time to find a hot spot and the time to actually use it. The programmer in her truck is a MiniMaxx. Didn't get a model number.

On the 6.7L engine there is no catch bottle instead there is a crankcase vent filter that resides under the 6.7L cover on top of the engine. This needs to be serviced at set intervals per the O&M guide. For our years of truck this needs to be done every 67,500 miles regardless of if the EGR is deleted or not. These can't be cleaned but needs to be replaced. Geno's garage sells them, part number CV520010. Last time I bought one my cost was $84.85 plus $7.50 for shipping.

Uggh. I would bet a steak dinner at a restaurant of my choice that this has never been changed. I'll look into it.

 

[hwebster]

Clean the Rad 1st... Towing an RV home for the first time - not particularly heavy - and the temps started going up quickly. Dropped down a gear and went home. Blew out the rad - seems it was quite dirty - and no issues since...

 

[AEdelheit]

I wouldn't suggest the car wash to clean the radiator and CAC. High pressure can bend the fins which will block air flow much more than dirt and bugs. I'd use something like Simple Green or a coil cleaner and a water hose. You'll also want to clean the CAC and A/C Condenser.

This "EGT gauge system", sounds like a programmer. Can you tell us exactly what it is, brand and model?

I have pressures washed hundreds of radiators from cars to heavy equipment with no issues, just need to use some common sense. Don't use a 0 deg tip and go straight inline with the fins and will be fine, I have found them to be far more effective then a garden hose.

 

[BigPapa]

I can't tell you how many cars and trucks I've seen come through the shop with the fins bent over in a very visible swath from the car wash wand. And I did say a cleaner AND a garden hose, not just a hose.

 

[Ozymandias]

Common sense, like said from Aaron.

 

[AEdelheit]

I can't tell you how many cars and trucks I've seen come through the shop with the fins bent over in a very visible swath from the car wash wand. And I did say a cleaner AND a garden hose, not just a hose.

I dont doubt it but I like to think members are a bit smarter then the average blonde, cleaner is great for grease but I have not found it to be effective for packed dirt. Maybe one day they will put reversing fans on these trucks to clean out the cooling package every so many hours of operation.

 

[Matt42]

Uggh. I would bet a steak dinner at a restaurant of my choice that this has never been changed. I'll look into it.

As it turns out, I owe the truck owner a steak dinner. The crankcase vent filter was changed in 2020 and has some 40,000 miles of life left.
(And I never thought I'd be quoting myself. I must be getting old.)