cold blooded CTD's?

[jaynes]

Are our engines cold blooded? I don't know bout y'all, but in the winter my engine runs really cold. Hard to get the heat working. In the summer, it runs really hot. I had the pedal to the medal one day at about 88 degrees, and if I didn't let up on the pedal and slow down, I would bet $100 that the thermostat gauge would have just kept climbing. I probably would have over heated. Is this normal or do I have a bum thermostat? Would flushing the radiator do anything for cooling?



jaynes

 

[DKasper]

By "cold blooded", it sounds like you mean cold running in the winter, as opposed to hard to start. I've never had problems with winter starts with any of the 3 I've owned. But then I almost always plug 'em in too.



The two 1st gens I have experience with always run a couple of needle-widths colder in the winter, that's why I always fashion a cold front out of cardboard and stick it between the AC condenser and the radiator. That helps tremendously to keep things warm.



In the summer, my temp gauge never goes up unless I'm towing and it's hot outside, then it will climb a couple of needle widths above normal, but I almost never hear the fan go on - unless I forget to take the cardboard out in the spring.

Are you hearing your fan engage?



Dave

 

[bgilbert]

jaynes, is your fan clutch locked up? Sounds like it is, you should be able to turn the fan freely with no resistance with truck off and cold. Clutch locked up will keep the truck from reaching operating temps in winter. Junk thermostat will do the same in winter and summer. Buy only a updated thermostat from Cummins or Dodge, stay away from the parts stores. I dont know the part number off hand, i know it can be found in a search though. Plugged up heater core will not push out much heat too.

 

[JLEONARD]

After my engine warms up the needle goes to the same place on the gage... winter (0 F) or summer (90 F). . city or highway... . within a needle width.

 

[jaynes]

You know, when the engine is cold (hasn't been started yet that day) the fan is kinda hard to turn. I mean, there is resistance, and quite a bit of it! When the engine is warm, it's easier to turn. I can hear the fan when the engine gets hot. Especially when I've come to a stop the gauge is getting high, then I take off, and I can hear the fan blowing away. It's like the only way to cool it down in hot weather is to drive about 35 miles an hour around town for about 20 minutes. I think there is something wrong with it.



Josh



PS: The squeek I was talking about in my "mouse in wheel" post I've determined to be bad ujoints. Replacing those Friday before anything bad happens

 

[jaynes]

forgot something

I also forgot to add that when i've come off the highway and the engine is hot, the idle drops WAY down. I have to have one foot on the brake and the other on the diesel idling it up just to keep the oil press. light off! That ain't normal, is it? I can drive it around town fine, but after being on the highway at 80+mph, the temps really climb on the thing and I have to do as stated above. I don't like it. Can you guys think of anything?



jaynes

 

[cerberusiam]

Do you have the cross flow radiator or the older chrysler style? There were some problems with the older radiator and they went to the cross flow to solve them. The older radiators had a tendency to plug and not cool under load and circulate the water to fast.



If the only time the idle drops is when it is good and warm it might be the fan pulling hard to cool that is causing the idle drop but you should be able to set the idle up up to compensate. You need to verify the oil pressure is dropping as the electric gauges for oil pressure and coolant are a bit flaky. The oil could also be getting really hot and thin if the coolant system is pooched. In a word oil pressure dropping at an idle when warm is not a good thing.

 

[bgilbert]

Fan clutch is shot, you test it when cold. A defective clutch will turn easily once warmed up. A new one will help you get heat quicker in cold weather. I'm not sure how a defective clutch will affect temp in hot weather if at all. Maybe someone else can enlighten us on that. Are you running AC when you talked about your idle dropping and oil press light coming on? Sounds to me like your idle maybe too low, even if you're not running AC. Something about the warm engine pulling down the idle. I think its normal to a point. But you may benefit from bumping the idle up a bit.

You do a good fan shroud don't ya? Its not broke or missing? Being non-intercooled we don't have a good cooling system to begin with, non cross flow radiator, we need every thing to be in top shape. Shroud, good fan clutch, non bent fan, antifreeze up to 50% no more or less it will affect cooling, both radiator and coolant overflow jug fillled to spec, t-stat working correctly, no obstructions in front of the radiator to affect air flow.

 

[Niki]

My early 91 runs hotter than my late 91 did. I think the earlier radiators are smaller too. At least it looks that way when I compare my 91 and 92.