Hey guys before I start throwing parts at my truck I want to ask if this is the symptom of a bad thermostat. This morning my fuel filter gelled on the way to class(college) and I think my fuel heater is bad. But anyway when I came home i started my truck and let it run for about a half hour. when I went back outside it was running rough and I think that it gelled or the filter was still plugged. I shut the truck off and noticed my temp gauge(the crappy factory one but its all i got for now) was higher than normal. I popped the hood and the radiator was not warm at all. The motor didnt fell extremely hot either but felt like operating temp. I removed the radiator cap and coolant shot out and it relieved pressure. The coolant that came out was cold and the overflow bottle by the fender was almost full with some of it returning when i opened the cap. Stuck thermostat? or something worse? My first thought was a bad thermostat but after i thought about it I wondered if it was something worse.

 

Aside from the gelled fuel, my thermostat got stuck closed last week. Similar symptons. Add some cold weather diesel treatment to your tank and filter.

Remember only replace it with a motorcraft or navistar thermostat.
(the one i removed was a crap aftermarket one)

 

Thanks, i was hoping it was just the thermostat but just wanted to make sure. yes i was planning on getting a motocraft one. Ya i havent tackled the fuel yet. i need to check and see if i am getting voltage to the heater first. I had put a dose of the white bottle of powerservice in the tank but maybe i didnt get it mixed in well. A new filter and a dose of anti gel i should be good. Well other than replacing the thermostat.

 

your diesel should be treated to about 0 or 10 above in your neck of the woods, it should say on the pump ware you buy it. however CFFF, (cold fuel flow factor) affects the filter flow, when was the filter last changed? and is it a factry 10-12 micron, or is it 6-4-or2 micron? after market? having a operational fuel heater will fix this problem, and if it is cold enough to gell (thicken) the fuel, you should have the block heater in play...In 15+ years over the road in big rigs, we just don't shut them off

 

Diesel17,

At what temps are you experiencing your fuel problems? Some will say that with today's low sulfur diesel fuels and winter mixes, fuel heaters are no longer necessary. I have experienced problems of my own, but not until around -10* anything over 0* and it should't be an issue. the heating problems you have could very well be a t-stat. FWIW, the t-stats in these trucks are not real easy to get to, so if you are going in, it would be a good time for a coolant flush, and checking all of your hoses and such.

Good luck,

Mac.

 

I think we were at -5 this morning with windchills around -25 or so. This is only the second time I've ever gelled. I didn't get a chance to check the heater tonight to see if I got voltage there. My dads 94 idi fuel heater works and it's never gelled (yet, hehe) so that's why I'm leaning towards mine being out or a no power situation. Is the fuel heater powered by the fuse block under the dash or elsewhere?

Speedwrench I get my fuel from our bulk tanks on the farm so I don't know exactly what the blend is but it should be for winter. They just filled the tank the first week of January after they let us run out... I think the last time I changed the filter was in May?? Maybe. It's a napa filter. So I think 10-12 micron. I did have the block heater plugged in last night. I'm not sure it would have fired if I wouldn't have.

 

it sounds to me like your radiator was partially frozen from improper coolant mix, not a bad t-stat.
have your coolant tested to see how low it is good for.

 

I think I tested it a week agoa and it was -30 or -35. Though it wouldn't hurt to check again. Thanks tjc.

 

Wow that's cold...cardboard in front of rad block off no more than 1/2 and all of the grill to keep hard wind off rad, my van takes forever to warm up, to get heat from heater needs to run 10 mins even when plugged in depends on provider on the fuel you could call them, but most racks up north treat their full in winter, diesel 911, wouldn't hurt, get her going and keep her plugged in.

 

That's the plan for now anyway. It's supposed to be a balmy 24 tomorrow instead of close to zero. So we are planning to pull it in the shop and take a closer look at it. Thanks for all your help guys. I appreciate it!!

 

Update: I've been driving the truck again for about a week now and think I got everything fixed....well for now I ended up having to replace the water pump and the thermostat(a cheap aftermarket one) and all seems to be ok. I also replaced my fuel heater because I think the old one was burnt out. Thanks for the advice that everyone gave. Now I dont have to keep borrowing my parents vehicles.