Diesel Bombers SIGN UP NOW

National Association of Diesel Motorsports
Go Back   Diesel Bombers > Dodge Cummins > 12 Valve 2nd Gen Dodge Cummins 94-98
Sign in using an external account
Register Forgot Password?
Search
Welcome to Diesel Bombers


Registered Members don't see these ads. Register now it's free!

12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 10-02-2010, 01:46 PM
Diesel Enthusiast
Status: like a crazy cat lady but collecting vehicles... and I'm a man

   
View Member's Albums View Member's Youtube Account

Default Installed new cummins thermostat...

I just put in a new thermostat from cummins (part # 3928499), and I'm getting huge temperature fluctuations. I read that this was a problem for unloaded trucks because of the large radiator, but I thought the new thermostats from cummins would fix the problem?

When the truck is warmed up and I'm cruising down the hi-way the gauge jumps from the halfway mark down to under a quarter and then climbs back up and repeats. I drive most of the time unloaded or very lightly loaded so I would like to fix this problem if possible

jpfiero's Sig:'96 Dodge Ram 2500, cummins 5.9l 12v, ext. cab, long box, 5spd 4x4 - lightly bombed
'55 Caterpillar #12 motorgrader - unbombed
'86 Pontiac Fiero GT - Highly Bombed
'69 AMC Ambasador SST - future bomb
'01 Yamaha YZ 426F - unbombed
Reply With Quote
  #2  
Old 10-02-2010, 01:58 PM
wildbill's Avatar
BOMBARDIER
Status: Being Twisted In the Wind

   
View Member's Albums View Member's FaceBook Profile View Member's Youtube Account

Default

You may have gotten a bad t-stat, or there is some air still in the system.

wildbill's Sig:
2006 Ram Cummins
"RAMPAGE"





Reply With Quote
  #3  
Old 10-02-2010, 02:10 PM
Diesel Enthusiast
Status: like a crazy cat lady but collecting vehicles... and I'm a man

   
View Member's Albums View Member's Youtube Account

Default

Ok thanks, what's the best way to bleed the cooling system on these trucks? Might as well try that first before I try to get warranty on the thermostat
Reply With Quote
  #4  
Old 10-02-2010, 02:14 PM
wildbill's Avatar
BOMBARDIER
Status: Being Twisted In the Wind

   
View Member's Albums View Member's FaceBook Profile View Member's Youtube Account

Default

Drain about one gallon from the radiator. Remove the upper hose and neck together, then pull the t-stat out. Pour coolant into the block where the t-stat sits until the block is full. Tighten the neck back down, then fill the radiator, squeezing the upper hose until you purge all the air, and the radiator is completely full of coolant. Also, be sure the recovery tank is at or just above the max mark. Drive the truck and see if the problem still persists. If it does, need to get a new t-stat.
Reply With Quote
  #5  
Old 10-03-2010, 11:44 PM
tltruckparts's Avatar
Diesel Bomber
Status: Trucks gettin body/Paint!!!

   
View Member's Albums

Default

i dont think you necessarily have any problems the thermostats are notorious for doing that from cummins. mine did the same thing. replaced thermostat with 4 different ones and same thing every time. i just gave up and dealt with it

tltruckparts's Sig:1995 Chevy K2500, 1993 Cummins P Pumped 12 valve Turbo Diesel IC, Getrag 5 speed w/ southbend clutch, NP205 Transfercase, SAS w/ GM Dana 60 front. custom fabbed coil suspension, AAM 11.5 rear, BFG MT 35's. SDX 5x14 injectors, PhatShaft 62, airdog II 165, Autometer EGT, Boost, & Fuel Pressure, hydraulic steering. and a few moore goodies
Reply With Quote
  #6  
Old 10-04-2010, 11:33 AM
Diesel Fan

   

Default

its normal!!
Reply With Quote
  #7  
Old 10-04-2010, 11:35 AM
Dr. Evil's Avatar
BOMBARDIER

   
Default

I believe so. You are seeing the actual temp. Be thankful - the later trucks have a dummy guage.

Dr. Evil's Sig:
98 12V quad cab 4X4 AND 2001 24V quad cab 4X4


SEEN IT ALL, DONE IT ALL, CAN'T REMEMBER MOST OF IT !
Reply With Quote
  #8  
Old 10-04-2010, 06:54 PM
Diesel Enthusiast
Status: like a crazy cat lady but collecting vehicles... and I'm a man

   
View Member's Albums View Member's Youtube Account

Default

I read that it was normal, but I also read that it had been fixed by an updated thermostat. I guess I just don't like the thought of the engine being heated and cooled so drastically all the time. But I do like having a real gauge

Quote from geno's garage:

# Wide fluctuations of the temperature gauge

* the result of a large radiator, it is relatively harmless and normal
* Cummins has released a revised T-stat that does fix the "problem". The revised T-stat Cummins part number is 3934373. (The old T-stat Cummins Part number is 3928499. )
So according to this cummins sold me the "old" thermostat, I guess it's my fault for not asking for the new part number specifically, I assumed they didn't sell the old one anymore . Has anyone tried the "new" thermostat, how does it work? I would think it just opens slower?
Reply With Quote
  #9  
Old 10-04-2010, 07:56 PM
godblessmud's Avatar
Diesel Enthusiast
Status: Burnt my brakes, stripped my gears gunna have to ride 'er down I fear. Diesel smoke dangerous curves

   
View Member's Albums

Default

The temp changes used to drive me crazy to the point of watching the guage paranoid something was wrong but after 2 t stats and a full coolant flush ive learned to live with it.

godblessmud's Sig:-1994 2500 5 speed, 120 marines, no fuel plate, 40psi, a few shenanigans in the AFC, 16.5*, bhaf, 4" fender stack, Centerforce stage 2, turbo silencer gone, Yukon gearing...etc...
-1990 "F150" 351w, ZFHD 1 ton 5 speed, 1 ton T case, 6"all spring lift, 36x13 pro comp MTs, Sterling 10.25 1 ton rearend 4.10 posi..in need of Dana 60 front
Reply With Quote
  #10  
Old 10-04-2010, 08:02 PM
wildbill's Avatar
BOMBARDIER
Status: Being Twisted In the Wind

   
View Member's Albums View Member's FaceBook Profile View Member's Youtube Account

Default

Haven't had an issue since I changed over to a NAPA heavy duty.
Reply With Quote
 
 
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


 
All times are GMT -5. The time now is 01:03 PM.

Copyright And Legal Notice Links Of Interest

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.5.2
Diesel Bombers ® - All Content Protected Under Intellectual Property Rights Law of Registered Trademarks
Reg. No. 3,494,401 Cls. 100, 101 & 104 Under Int. Cl. 38
USE AT YOUR OWN RISK WE HOLD NO LIABILITY FOR ANY CONTENT RIGHT, WRONG OR INDIFFERENT

Protected by Copyscape Duplicate Content Check


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233