Thought id get some input quick. Im going this weekend to pick up a 1998 24V truck that dont currently run. I dont have gauges yet and im not sure i should tow that heavy beast home? Its a 2 hr drive one way with a few good hills in between. Also i will be parting the truck out. If  anyone has requests let me know.

15 hours ago, Mopar1973Man said:

 

Actually, it does impact the final ratio to the ground. Your final would be 3.42 to the ground. Like myself with 245/75 R16 my final to the ground is 3.69. Yes, the 1 inch does impact towing abilities and EGT's...

 

 

Yes, I understand that. Smaller tires will help my 1st gear launch under load, acceleration and part throttle towing. I don't have heat problems here. I need the help at WOT, when the grade/load won't allow acceleration and or causes a drop in speed. This is where my truck gets hot. With smaller tires and the same WOT, my temps will be the same.

 

I seem to have lost some cooling performance with my new radiator. I can't figure out why, it looks identical inside and out. I understand the 2nd gen 12 valves had three cores but the oem Mopar replacement, is two. My oem is two, the new one (Spectra), is two. Some guys are using the 3 core aluminum radiators off E-bay, they look pretty good and the ones using them are happy.

 

Keep in mind I live at 5800' elevation, the Mogollon Rim is 7800' elevation (route to Phoenix), Phoenix is 1300'. Between there, are several mountain ranges and canyons to cross. Miles and miles of 5-7% grades that seem to go forever. I am pretty sure your truck will get hot on a 105* day here. I bought my last heavy duty dump trailer in February, I have not unhooked it yet. Everywhere I go I am loaded. My tare weight with this trailer is 14,500lbs, so I am loaded empty.

First off Riggins, ID can reach 115*F in the summer this is normal. Steep grade are plentiful. There are few unmarked 20% floating around. Elevation ranges from 800 feet to 9,000 feet at Heaven's Gate. Even New Meadows, ID this summer was 105*F.

 

 

2 hours ago, NIsaacs said:

his is where my truck gets hot. With smaller tires and the same WOT, my temps will be the same.

 

 

Actually no not true. You be cooler. EGT's will drop and the engine load will be less. I've enjoyed towing my RV and trailer with the new tires. I can stand on the throttle and never reach 1,200*F. The only thing I did was turn off the wire tap. Still running Quadzilla CanBus fuel and timing. The RV I can slowly accelerate on 6% grade still gain speed but slowly. Coolant temps only rose to 208*F, locked the fan then dropped to 195*F continue to hold the lock till I reached the top.

 

Just for weight specs. These tires were my 235's I did have EGT's issues with these and had to slow way down to prevent overheating on some grades.

 

 

15 minutes ago, Mopar1973Man said:

First off Riggins, ID can reach 115*F in the summer this is normal. Steep grade are plentiful. There are few unmarked 20% floating around. Elevation ranges from 800 feet to 9,000 feet at Heaven's Gate. Even New Meadows, ID this summer was 105*F.

 

Actually no not true. You be cooler. EGT's will drop and the engine load will be less. I've enjoyed towing my RV and trailer with the new tires. I can stand on the throttle and never reach 1,200*F.  The RV I can slowly accelerate on 6% grade still gain speed but slowly. 

 

 

 

I understand Idaho has extremes, I have hauled there. But how often do you haul in those extremes?

 

I also understand that if you can accelerate, you are not using all your wot power. I am talking about when you cant accelerate or when you loose speed, that's full power. What happens on 7% or 8%, that's what I am talking about. On level 2 with RV275's I am only at about 335hp/800tq, my cooling system should handle that.

On 11/21/2018 at 2:51 PM, NIsaacs said:

 

Yes and no, with modified power the system is not up to the task, brand new. On hot days, long grades mine don't have a chance. Your system is way better than mine. Part of the problem is the rectangular radiator, not good. Cummins says it needs to be as square as  possible to keep the un-swept area at a minimum. Our radiators suck.

 

Your fan is a 26" 9 blade unit, ours is a 7 blade 22". We have a viscous fan clutch that may or may not kick on before the ECT is off the chart. You have a more positive clutch, a square radiator and a little bigger overall.

 

 

Yeah the fan is great on the 3rd gens, especially where I can control it's engagement temp and speed. 

 

I didn't realize there was that much of a change in radiator design. 

 

On 11/23/2018 at 5:18 AM, NIsaacs said:

 

 

I understand Idaho has extremes, I have hauled there. But how often do you haul in those extremes?

 

I also understand that if you can accelerate, you are not using all your wot power. I am talking about when you cant accelerate or when you loose speed, that's full power. What happens on 7% or 8%, that's what I am talking about. On level 2 with RV275's I am only at about 335hp/800tq, my cooling system should handle that.

 

 

I mostly tow between 3K and 7K, but will  get up to 8K on occasion. It's rare to be high, hot, and needing full power as the roads don't allow for it. 

 

Yes, I would think your system could handle that power. 

 

The new 6.7's have more power and a smaller total cooling system size than your 2nd gen. 

 

What water pump are you running? 

 

Is the water temp gauge accurate? Does everything indicate the same after sitting overnight?

1 hour ago, AH64ID said:

 

Yeah the fan is great on the 3rd gens, especially where I can control it's engagement temp and speed. 

 

I didn't realize there was that much of a change in radiator design. 

 

 

 

I mostly tow between 3K and 7K, but will  get up to 8K on occasion. It's rare to be high, hot, and needing full power as the roads don't allow for it. 

 

Yes, I would think your system could handle that power. 

 

The new 6.7's have more power and a smaller total cooling system size than your 2nd gen. 

 

What water pump are you running? 

 

Is the water temp gauge accurate? Does everything indicate the same after sitting overnight?

 

This may or may not be exactly correct because I am using Napa, but...

 

1st gen. 523 sq in core

2nd gen. 720

3rd gen. 796

early 4th gen. 861

 

I have a Napa pump. Are there flow differences in the brands? I know some have a ring around the impellors and some don't.

 

I am sure the gauges are accurate. The oem is real close to the CTS and the CTS ECT is within a hair of the IAT and fuel temp on cold start. 

I know there are 5.9 vs 6.7 pump differences, but they are interchangeable. A 6.7 pump on a 5.9 generally makes it run hot as the coolant moves thru the radiator too fast. 

 

I’ve personally never had good luck with NAPA parts so I don’t use them anymore. 

23 minutes ago, AH64ID said:

I know there are 5.9 vs 6.7 pump differences, but they are interchangeable. A 6.7 pump on a 5.9 generally makes it run hot as the coolant moves thru the radiator too fast. 

 

I’ve personally never had good luck with NAPA parts so I don’t use them anymore. 

 

Yes, I have heard that about the pumps, and since the 2nd gen radiator is so much smaller it would stand to reason. One of my complaints on the radiator is the raised outlet. In my mind that seems wrong but maybe it is not an issue. In theory, it would loose some performance I would think.

 

I have used Napa for 40 years and like you, have had some bad experiences, but overall I would say they are fine. The warranty is good and the manager of the local store I have known since he was a kid selling parts in his dads store. And on the road they are everywhere. 

They are everywhere. 

How are your intercooler and a/c condenser? 

12 hours ago, AH64ID said:

How are your intercooler and a/c condenser? 

 

They are both clean. In the spring I am thinking about going to one of these, there are several 3 or 4 core aluminum radiators out there now for cheap...the cheap part kind of puts me off tho, but there are some guys running them and like them.

https://www.ebay.com/itm/3Row-Aluminum-Radiator-For-94-02-Dodge-Ram-2500-3500-L6-5-9-Cummins-Turbo-Diesel/282687210889?fits=Year%3A2001|Make%3ADodge&hash=item41d1788589:g:hCQAAOSw7m9bHRrY:rk:2:pf:0

 

I am also looking at this plastic fan from Geno's, they claim 39% more flow but it is pricey.

https://www.genosgarage.com/product/dodge-ram-cummins-replacement-cooling-fan-fan9402/fan-clutch

 

While we’re talking about gauges I have been questioning whether or not my oil pressure has been sufficient lately. WhT are oil pressure specs for our trucks? 

Just now, Marcus2000monster said:

While we’re talking about gauges I have been questioning whether or not my oil pressure has been sufficient lately. WhT are oil pressure specs for our trucks? 

 

Oil pressure by Cummins specs.

 

Require at least 10 PSI at idle (800 RPM)

Require at least 30 PSI at 2,000 RPM.

4 minutes ago, Mopar1973Man said:

 

Oil pressure by Cummins specs.

 

Require at least 10 PSI at idle (800 RPM)

Require at least 30 PSI at 2,000 RPM.

What are ideal specs?

Like I see roughly 60-65 PSI on the highway. Idle at about 35 PSI fully warmed. 

 

2 minutes ago, Marcus2000monster said:

What are ideal specs?

 

Anything about the stated minimums.

 

Excessive high oil pressure is not good either being you take the risk of blowing out the plastic oil cooling jets for the pistons. This is one reason that cold startups Cummins suggest to allow the oil warm a bit before rolling so the oil pressure doesn't get too high starting out in the morning. Mind you the block heater does not heat the oil or the oil pan at all. All that is the same temperature as the outside air. The block heater only heats the coolant jacket. So the first minute or so the engine oil will pass there the oil cooler and rise to the coolant temperature.

I monitor oil pressure in the cam journal so it's likely a little lower than the oil filter head where many monitor it. 

 

Warmed up (oil temp 195-200°)

idle: 18-20

1600: 40-45

2000+: 55-60

 

Hot (oil temp 225-230°)

idle: 15-18

2000+: 40-45

There is a high pressure relief valve in the oil filter head that opens at 75 psi to avoid excess pressure. Even with that valve open I can see pressure as high as 85 on cold oil. 

 

4 hours ago, Mopar1973Man said:

This is one reason that cold startups Cummins suggest to allow the oil warm a bit before rolling so the oil pressure doesn't get too high starting out in the morning. Mind you the block heater does not heat the oil or the oil pan at all. All that is the same temperature as the outside air. The block heater only heats the coolant jacket. So the first minute or so the engine oil will pass there the oil cooler and rise to the coolant temperature.

I have to say I've never seen a Cummins bulletin about oil temperature, only coolant temperature. 

 

 

Between my IAT (off block), IAT (intake manifold), battery temp sensor, and MM3 pyro junction block temp sensor I can without a doubt state that the block heater indirectly heats a lot more than coolant. 

 

The block heater may only directly heat the coolant, but the radiant heat from the coolant does, and will, heat the oil in the pan and the block. It's very obvious on my oil pressure gauge that the oil is much closer in temp to the block than the ambient air. 

 

The oil temperature rises much slower than coolant temperature, and more-so on cold days without any block heater operation. The coolant is generally 25-30° warmer than the oil on cold soaked start and warmup. It takes a lot more than a minute to get the oil to temp. It might take me 12 miles to get the coolant to operating temp and then another 5 miles to get the oil to the same temp on a 15° morning without a load. 

 

Well I managed to pull to long steep grades with another 24 valve on a trailer in 6th gear and never pass 1100F! 

I picked up my truck recently. It was the test truck for 2nd gen Cummins at calibrated power in Marengo Illinois. After testing they rebuilt the engine and transmission. Truck runs very strong and runs well. After reading posts about exhaust temp while pulling grades, I'm not sure if my truck will pull a fifth wheel at all without melting down. I can hit 1100-1200 degree exhaust temps buy just planting my foot on the fun pedal for a few seconds. That is on the low tune. If I have a load like a trailer on, I can't imagine what it'll do to exhaust temps. However, maybe it won't make much of a difference towing or unloaded.....

 

Sometimes I think ignorance is bliss. Guages tell you alot of information, however, sometimes you have to rely on technology and testing built into what you drive and just enjoy your vacation..... I'm not one of those people, so here I sit and worry about hurting a truck built for work, afraid I might work it too hard and break it......

 

 

I need help......

On 11/19/2018 at 3:27 PM, Marcus2000monster said:

Thought id get some input quick. Im going this weekend to pick up a 1998 24V truck that dont currently run. I dont have gauges yet and im not sure i should tow that heavy beast home? Its a 2 hr drive one way with a few good hills in between. Also i will be parting the truck out. If  anyone has requests let me know.

You won't have any problem, towing that truck you won't even know its behind you, even on a trailer. They didn't come with gauges from the factory.

21 minutes ago, Max Tune said:

I picked up my truck recently. It was the test truck for 2nd gen Cummins at calibrated power in Marengo Illinois. After testing they rebuilt the engine and transmission. Truck runs very strong and runs well. After reading posts about exhaust temp while pulling grades, I'm not sure if my truck will pull a fifth wheel at all without melting down. I can hit 1100-1200 degree exhaust temps buy just planting my foot on the fun pedal for a few seconds. That is on the low tune. If I have a load like a trailer on, I can't imagine what it'll do to exhaust temps. However, maybe it won't make much of a difference towing or unloaded.....

 

Sometimes I think ignorance is bliss. Guages tell you alot of information, however, sometimes you have to rely on technology and testing built into what you drive and just enjoy your vacation..... I'm not one of those people, so here I sit and worry about hurting a truck built for work, afraid I might work it too hard and break it......

 

 

I need help......

You are ready for head studs and twins for openers.  A bigger or more efficient intercooler and intake would help as well, not to mention a 5 inch straight pipe or mildly muffled exhaust.  A low restriction air filter like a BHAF would also help a good bit.  EGT's in that range are a solid indication to downshift to the next lower gear to keep rpms and airflow up.  

Heck just good fuel management will do more that all the bolt on mods you can buy.

 

3 hours ago, LiveOak said:

You are ready for head studs and twins for openers.  A bigger or more efficient intercooler and intake would help as well, not to mention a 5 inch straight pipe or mildly muffled exhaust.  A low restriction air filter like a BHAF would also help a good bit.  EGT's in that range are a solid indication to downshift to the next lower gear to keep rpms and airflow up.  

 

 

It's running a firepunk Trans, fleece Cheeta turbo, blue Chip pump, edge comp/MM3 tuner, head Studs, 7x11 SAC injectors, 4" exhaust, BHAF.

 

Runs and drives incredible. Wife nicknamed it BEAST.....it fits....

 

I've just read alot about EGTs and mine seem high empty. I have two EGT guages, one in manifold at #4 cyl and one in exhaust pipe about 6" after turbo. There is consistently 100-150° difference between the two. The 1100-1200° numbers I'm referring to are the manifold temps. So I guess if what I'm reading in various posts is exhaust pipe temp rather than exhaust manifold temp then I'm in the ballpark.

Edited November 29, 20186 yr by Max Tune