Radiator, Fan Clutch, Water Pump, EGT, OR My temp gauge is on the edge of insanity!
 

Howdy all,

Haven't been around here much since it's summer and I've been out doing "stuff!"

Here's what's going on. It's been hot hot hot here in Colorado (as I know it has everywhere else) and the old Dog Diesel isn't a bit happy about it when I tow my fifth wheel. It's been in the mid 90s, low humidy, and when you couple that with our high altitude it certainly makes the radiator less effective. I went over to the west side of the state last weekend. So I towed up and over 3 big passes. I'm able to keep my coolant temp just at the high side of allowable (NOT the high side of normal!). But it's always on the edge of insanity whenever I'm climbing. In fact, last month I towed up into Wyoming and had the same problem. I was bucking that good ol' Wyoming head wind! (Every see one of those wacky Wyoming Wind Socks? It's just a chain on top of a pole!)

Anyway, I've noticed a couple of things and I have couple of questions. You can check my signature for my bombs.

My first question is what sort of sustained boost are people able to maintain without overheating? With the temps in the 80s and 90s I can only maintain about 10 or 12 pounds of boost and still keep the temp gauge from climbing. My EGTs are under control (as much as they can be at this altitude with an H1C). It just seems like I should be able to put a little more pedal into it than this without overheating.

I'm quite sure my fan clutch is working. I can hear it come on at about 185*. I know it's very soon after the thermostat opens. Creates quite a ruckus. Oh, and I just replaced the thermostat this spring with a genuine Cummins part.

Do water pumps ever "wear out." I mean, I know seals and the bearings can let go. But do the vains ever really wear down so that the pump doesn't move as much coolant as it should?

I know my stock torque converter creates all sorts of heat. And this contributes to my problems climbing the passes on doubt. But I've come to think that the overheating begins really before the transmission system is hot. I think this because at the start of a climb, if I maintain, say, 18* of boost, the coolant temp will rise pretty fast while the transmission temp stays put for a while. The transmission temp will follow the coolant temp eventually. So I think my coolant is actually heating up the transmission fluid somewhat. When I crest the top of the pass the coolant temp will fall, but not a quickly as I'd like. The transmission temp will follow suit.

So...I really think my radiator needs some attention. I feel that this overheating problem has gotten gradually worse. Although bombing doesn't help the cooling issue, I know. I'm just trying to get a feel for what others may experience with their radiators and temp gauges. Next week I think I'll pull the radiator and get it rodded. This winter will be time for a different torque converter.

Anyone have any insight? I'm just tired of nursing my way up the passes with my foot only 1/4 they way to the floor! I got passed by a gol-dern Chebby gasser pulling a fifth wheel yesterday. I cried all the way home!

I was bucking that good ol' Wyoming head wind! (Every see one of those wacky Wyoming Wind Socks? It's just a chain on top of a pole!)

thats funny [laugh] .......but true :D


[b]Upgraded OEM Fan and Fan Clutch
Dodge has issued an updated Fan which has more twist on the blades and is lighter. If you plan on upgrading your fan clutch, I strongly suggest you also upgrade to this new fan. Again, this is an OEM component from MOPAR.

Fan- 52028653
Clutch module- 52028760




If you haven't replace the fan and clutch with these part numbers then i would start there.....do you still have the fan shroud on?

I can't give boost numbers what with all the variables. Radiator rodding helped some with mine, so it must have needed it. The stiff torque converter and valve body setup to handle it *really* helped. Under-the-bed fan-powered trans fluid cooler helped some more.

Since you live there, I'm assuming you know all the driving tricks, like keeping engine RPM up high (2k or so) even if you have to go to a lower gear.

I still had problems getting up over 60 on the flat into the wind in the Mojave desert towing the 5er last summer; I had the radiator rodded when I returned. I'll take a trip in a few weeks and see how much it helped.

The thing that helps most is late fall, winter, and spring. [laugh]

Regards, DBF

Flash - As far as I know the fan and clutch are still stock. I've heard of the upgraded units. Maybe I'll give them a go too. And, yes, I still have the fan shroud in place.

DBF - Yes, I know of the uphill "tricks." Shift down and keep the RPMs up. I took a trip last spring (March I think) to southern CA with the 5th wheel. Didn't have any problem in the Mojave, but I think we hit a cool day, too. It was only in the 80s and 90s. I can definately see some corrosion when I look down into the radiator from the fill cap. So there most likely is some blockage in the cores as well.

Thanks guys. Anyone else have some knowledge on this subject?

My thoughts -

At your altitude a 12 cm wastegated turbine housing is very helpful for EGT control.

I think you are on the right track with getting the radiator cleaned out.

It sounds like your fan and clutch are fine, you would do better spending money on the radiator.

The stock water pump is just a stamped steel impeller with an open back. The aftermarket unit I bought when my pump started making noise had a baffle welded on the back of the impeller. Seems to me that would be more effective.

Dave - I know that high(er) EGTs will produce more heat in the coolant, but I've never had a problem with EGTs. Only time they want to climb above 1250* is if I have it firewalled at 11,000 feet over the passes. Is there a 12cm non W/G unit? I have it in my head that some early trucks in 94 shipped with this housing. I guess I'm not too fond of modifying the downpipe. Although I certainly could if I needed to. That's why I'd like a non W/G housing. Sometime in the future I really really want to install an HX35. I think that would help move the air real nice.

There are non-gated units, but they will make too much boost even with minor pump tweaks. They are the same length as a wastegated housing so there's no reason to bother with them.

Oh, OK. I thought it would be the same length as my 16. Good to know!