cooling / heater questions.

[BHerring]

Hey all,

What I did this weekend.



1. Replaced all radiator hoses including hearter and transmission cooler hoses.

2. Replaced the clutch fan.



(Im doing all this because of a big trip I am taking and its been a long time since these were replaced)



Today I took a drive and the truck got a bit warmer than normal, so I added more coolant to resevior, took two hour nap, took the truck for the same drive and now temp is cooler than normal. too cool for my likeing. Anywasys what would cause this? Could I have a vapor lock in the system if so how do I get rid of it?



Any comments or suggestions will be great

Cheers

Brad

 

[monkeyman]

Did you check your thermostat? It can stick open.
Rick

 

[BHerring]

Monkeyman,

No I havent I figured the first drive was working ok, and the thermostat was working before I changed the hoses so I dont suppect the t-stat just yet, I think I need to make sure I get rid of all the air pockets and I dont know how to do that? How can I check my t-stat without haveing to pull the t-stat off the truck?

 

[monkeyman]

If you have a defective radiator cap, it will allow air to enter the system. If you drive around a few miles to purge the air, check upper radiator hose for warmth. If thermostat is a 190 lets say, you should see needle go to approx. middle point then a hair over and drop

when thermostat opens. If you have never replaced it, I would. Mine is a 190, and today with outside temps below zero, my water temp while driving was about 190. Of course at idle it will run cooler. A cheap test is to put a piece of card board in front of radiator and do a test drive and watch temp. I don't know what area you are in, but if its cold outside that will show you something. If heater gets warm and temp goes up fast, replace thermostat

Rick

 

[BHerring]

Rick,

I will try that, I live in San Diego, so it should get a bit warmer than what it is now, the needle is not at is "normal location" I will replace the t-stat and rad cap and try again. I tried to remove the bolt right about the t-stat to let some air out but I striped it, so go figure on that. I even used a t-60 socket and it just spun in side the bolt.

 

[BHerring]

Update,

I replaced the thermostat and the dodge is getting warmer, just like you said Rick, the needle goes just past the 2ne tick mark on the gauge and then "BAM" the temp drops to the mid position between the first and second tick mark (this is the norm for my truck and the past). Anyways now I noticed fluctuations in the temp as it goes up and then back down, up and down, the temp won't say steady. Should I worry about this? In the past the temp never fluctuated at all, it stayed in the mid range between the 1st and 2nd tick mark, now it would get warmer if I was climbing a big hill or mountain. Any suggestions or comments?

 

[Paychk]

Sometimes it will take a couple of heat/cool cycles to completely purge all of the air out of the cooling system. I would watch the coolant level at the overflow tank for a couple of days, I think it will settle down with time.

PS Mine does the same thing, when ever the cooling system gets air in it from maintenance.

 

["Mad Max"]

next time the t-stat is out, one easy trick is to drill a small (1/8") hole in the t-stat face to allow air to escape out when re-filling the coolant system. Also allows some water pump pressure release when the truck is warming up (before the t-stat opens). I think the 2nd gens have an actual t-stat bypass line (1/4" steel line) to aleviate the pressure. I've noticed the upper rad hose trying to 'collapse' just slightly during warm up with a blip of the throttle.

- M2

 

[Bob Beauchaine]

My coolant temp varies widely on the factory guage - what would appear to be 20 or more degrees. My after market guage will fluctuate may be 2 to 5 degrees at the same time. BTW I've got the latest "no-swing" Cummins guage. Sounds fairly normal to me.



Bob

 

[matches]

I got tired of the stock guage, so I put in a water temp guage to really know what was going on. The stock guage moves all aver when my analog stays firm, once she warms up.