I have a big prob with my 93 dodge. I need to know if its the guage or if my truck is over heating? What it does: the guage will rise slowly then fall fast it will keep doing this till it gets all the way to the H. also the heater will get warm when the guage goes up and cold as the guage goes down. this has been going on for a week and tonight the heater just started blowing cold and the guage went to hot and stayed there so I pulled over looked under the hood felt of the hoses and i could feel water flowing thru, and they didnt feel to hot. Also im leaking rad fluid from some where. if you guys can help it would mean alot cus i have to leave for a 6 hour drive tomarow...

Agin any help would be great!!!!

 

if you know you're leaking coolant, low coolant level could cause some of the symptoms you describe, otherwise the thermostat may be sticking.

 

Im keeping a very close eye on the coolant levels

 

sounds like a t stat our trucks tend to do that

 

would that make my guage move that fast up and down

 

Yes, the t-stat cycles open and closed causing the gauge to rise and fall. New t-stat for you and all is good!

 

Hey Guys
Mine cycles up and down in cold weather but the heater works all the while.
Do not have any coolant leaks and it never gets hot, well warm when she's workin'. Would a new ts stop (help) mine from cycling?
GW Cooke

 

how far up and down does it cycle?

 

Some say Yes, others say No. I put a new Cummins t-stat in mine. It helped the cycling quite a bit, but it still does cycle some. The colder it is the more cycling it does. Although I had it out last week in the 0*F temps and I didn't notice much cycling. I'm not sure it every got warm enough for the t-stat to open up! The t-stat is cheap and easy to install. It really only takes about 20 minutes from cracking the toolbox to recycling the beer can. You may as well...

 

Not quite cold start to 2nd mark on gauge, which is summertime running temp. Here in SC we don't get teens much but I'm going to Mi. in March so it will be cold there(for a southern boy). This has not been a problem so far but I think that I'll change it anyway.
GW

Ain't figured this computer stuff out yet, will post pics and info when I do.

 

Would a NAPA ts work or ONLY Cummins ts?
Napa is 4mi. Cummins Atlantic is 70mi.

 

THe NAPA one will work fine however it is slower to open than the Cummins one. I run a NAPA t-stat in the winter for more cab heat and a Cummins one in the summer for better cooling when towing.

 

my truck does that sometime only if the coolant levels are low. But i have notaced with my truck the block is not that hot when it does that. I was scared the first time it happend so i got out and touched the block and head and it was cold. When i added coolent the problem goes away. So i would start there if i was you

 

I got a new T-Stat, but it didnt work... the gauge now will rise slowly no till it goes to the H side then when I stoped at a light the gauge darted to the C side then started to go up slowly from there??? WHATS GOING ON WITH MY TRUCK!!! I dont get it

 

Time to start eliminating more variables...you've got to find that coolant leak. If you can't physically see it leak, you've more than likely lost the headgasket and are pumping air into the cooling system. FWIW, get a mechanical temp gauge and plumb it in right where the factory sender is.