Cooling system questions

[guyhaz]

I took the family up to the Rim (Arizona) for our first family camping trip pulling a toy hauler which weighed about 8k loaded down. I left in the middle of the day and the outside temp was about 105 degrees. Pulling a big hill the ECT touched 225 briefly and never did it again on the trip, but I watched it to make sure it didn't. This is the first time pulling anything with this truck that I got last year. So when I got home I decided it might be worth giving the cooling system some TLC.

I have recently put a CTS 2 to monitor things.

I bought a new serpentine belt and tensioner that I haven't gotten around to installing, so I figured I might as well replace the water pump and thermostat since I will be in there. Radiator cap and hoses too since I don't really know what the previous owner had done to the truck.

The truck currently has 128k miles on it, mostly stock with an S&B air box and a rebuilt transmission.

Which thermostat would be best, the 180 or 190?

Should I replace the water pump or is a truck with these miles due for one anyways?

I will purchase the parts from Geno's most likely and want to get everything ordered together.

Thanks!

 

[Tuesdak]

That's NOT a hill. I have blown engines on that mountain grade! 225 isn't bad, but, I hate going over that. Only the best cooling systems can ignore the "Turn off AC" signs and remember it takes 2 min or more for the condenser to stop dumping heat in the stack. In this heat, yeah, the AC is going to stay on...

How old is the coolant? What condition is the condenser fins - all bent up restricting air flow? Bugs and other junk clogging the radiators?

Gearing can also make a difference.

When it hit the 235 was the fan screaming?

T-stat should be a Cummins part and stock temp. Unless it sticks a T-stat is not the reason for running hot.

 

[Mark31]

I replaced my hoses a couple of years ago with hoses from Geno. I was so unimpressed with them (I forgot which brand) that I started to put the originals back on. They were much softer than my new-looking, feeling 12 yr old OEs. The bottom mopar hose had a spring to keep it from collapsing. If I get to go on a trip pulling a load in hot weather, I going to get some new mopar hoses. Having had 2 parts house water pumps leak with less than 20k on them, I encourage you to get a Cummins water pump. Definitely use a Cummins thermostat. JDoremire told that right!

 

[cerberusiam]

You might want to check the CTS readings, they could be as much as 10% off form actual. If it never got near that again and the cluster gauge never went high it is probably normal.

You are due for a coolant change and flush, but, if the WP is not leaking leave it. Anything you get now will likely be lower quality. Just check the hoses for bulges or wear and leave them if they look good. Thermostat is your choice but if you aren't seeing consistently high temps all the time I would leave it and flush the system.

 

[Motorhead]

The last water pump I got from Cummins Pacific was a CONCENTRIC made in USA part. That was a few months ago. If you use a heater much in winter where you live, a 180 thermostat cuts the heater a bit. I run a 190 which is stock. Did a 3000 mile trip in June pulling 9000 pound 5th wheel and through lower Utah and Las Vegas where the outside was 111*-113*. The cooling fan ran plenty but I also had the AC on full speed too. The dash temp gauge sat just above 1/2.
We all have suggestions. You are asking so here is mine.
Do a complete job! I always pull the radiator out so I can carefully clean the cooling fins of the radiator, AC condenser, inter-cooler and if you have an automatic, the external cooler. I spray the fins with Purple power or Castrol Super clean. Be careful not to bend the cooling fins with the pressure from the water hose. Back flush the radiators so the debris goes back out the way it came in. Check for any play in the water pump or seepage. If any then replace it. Water pumps are a fickle beast. Some last 50,000 miles and some last the life of the car. I completely flush the engine block with a garden hose and hose nozzle. I remove the heater hose from the back of the head and CAREFULLY, watch the pressure, rinse it out too. I have seen lots of crap come out of heater cores. I use compressed air to remove as much rinse water as I can get out. With the water pump out, more drains out. I replace the thermostat with a Cummins part with a new seal. I replaced ALL of my heater and radiator hoses with a set from Mr Bob's silicone hoses and I always keep the OE style spring hose clamps. Replace the fan drive belt unless it is relatively new. Check the fan clutch for any fluid seepage. Seepage indicates that the clutch might be failing. Make sure the wiring to the fan clutch is in good shape and that the little conduit is replaced properly so it doesn't tangle with the cooling fan. Look up the cooling system capacity for your truck and fill 1/2 of the total capacity with the OE Mopar diesel coolant CONCENTRATE first and top off with distilled water. There will be some residual rinse water remaining in the block so the amount of distilled water won't be as much as the coolant concentrate.
My saying is "Do the job right and complete and only do it once."

 

[guyhaz]

Thanks for the all the reply's so far, I really appreciate it.

Do any of you have a good online source for Cummins parts and Mopar parts?

I don't have much history on the truck in regards to what the previous owner (bought from original owner) did to the cooling system, so I am thinking it's cheap insurance to just replace/clean those parts that are likely to fail so I am not left stranded on the side of the road with the family in the Arizona heat.

It touched 225 briefly and I could hear the fan roaring, I had the A/C off and pulling the hill out of over drive.

Condenser fins are in good shape.