Why do diesels have a tendency to have poor heater output? I have about 1/2 the radiator blocked off with cardboard. Shoulden't the thermostat keep the engine warm. I can drive for about an hour and the radiator is just warm. Is this because diesels have bigger blocks and have a large cooling system (30qts.)?

 

I have a 1987 F-250, 6.9 liter, 4X4, four speed manual, as far as I know everything is stock except the alternator. I do not plug mine up even on the coldest nights. I do let the glow plugs cycle twice on cold mornings and the engine turns about three seconds and it starts. I do check my antifreeze level about once a week. On cold days I do let it idle about five minutes before I drive. I do not know what kind of thermostat is in it. My girlfriends house is about six miles away, and on the cold days here (so far, this is the first winter I have owned it, or any diesel for that matter) mine is putting out plenty of heat by the time I let it idle and then drive straight to her house. About four miles is four lane highway, so I am going about 55 or 60 MPH for that time. So far the coldest I have run it has been about 14 degrees, you may be in a far colder climate. As it gets colder here, I will notice how it does. Actually she will notice it more than I will, since she freezes when the temperature gets below about 80 degrees. I'm sure as soon as it does not put out enough heat, she will let me know quickly, and I will report the results.
Are you running your truck in zero or below temperatures? I am curious how much different outside temp is for you and me. I am in Virginia, not far from Bristol. It is supposed to be about zero here tonight (Friday, Dec. 22).

 

I would suggest a new thermostat. Mine had the same symptons as yours and after installing a new one from International, it starts warming up with in a few miles. On the Powerstrokes, Ford only sells a 195, while International also stocks the 180.


Alan

_____________________________
95 C350-4x4,PSD,4-Door Bronco(Huh?),49K,auto,AIC,switched glow plugs,switched TC lock-up,4.10,Banks PowerPack,straight piped,Mobile-1 gearboxes,Rotella,BFG AT's 295/75/16

 

For what its worth, you may check your clutch fan to be sure it is freewheeling in cold weather. I don't know about the '86, but my on my '96, the fan "coasts" unless needed. Also, you may want to consider plugging in your truck, i've heard it is very beneficial to the longevity of the engine, not to mention the quicker cab warm-up. I use a timer to help my electric bill, the manual states three hours is suficient.Good luck.

'96F350XL,137"WB,4x4,PSD,SRW,5speed,4.10LS,aluminu m Pierce enclosed service body,Code 3 amber lightbar, SHO-ME wig-wags front and rear(hi-beam, brake and back-up sequencers), Cobra 148 CB, enough tools and material to wire a small Office LAN system on board at all times.

 

Went out and started my 1987 F-250 4X4 four speed manual 6.9 liter the other morning it was about zero degrees, I had not plugged it in. I let the glow plugs cycle twice and turned the key, it cranked for about four seconds and I let off the key about a second too soon, didn't start. I let the plugs cycle one more time, turned the key and the engine cranked about four seconds and started. I let it idle about five or seven minutes while I put my dogs in their pen, etc. I left the house and my road out to the state highway is just less than a half mile long, and I had to stop and close the gate. The four lane is only about another mile out. by the time I got to my gate, it was putting out some warm air. I have 3.55 gears as far as I know. On the four lane, at 60 MPH at about 2300-2400 RPM, it was putting out good heat within about three to four miles, I had to turn the heater fan down after about 10 miles, it was about to run me out of the truck.
I am not a mechanic by any means, and I may not be as cold natured as you are, but I can make some suggestions. If your anti-freeze level is good (and I would also suggest you actually take the lid off the COLD, NEVER HOT, radiator and check the level, not depend on the level in the resivor), check the freeze point, which should be OK on a new truck. DO NOT use the old anti freeze tester with the little round ***** that float in the tube. Get a good one that has a pointer and the boil and freeze temp protection levels, mine is a Prestone brand tester. If the level is good and the antifreeze itself is good, check the fan when the engine is cold and you first start it, if it has a fan clutch, the fan should not be turning yet, it will just turn very slowly if at all. If it is running fast, you may need a new fan clutch, but that is not likely on a new truck. To the best of my knowledge, about the only thing left is the thermostat, yours may be partly stuck or the wrong one for that engine. It shouldn't be the wrong one in a relatively new truck, I just refuse to believe the factory could ever make any mistake at all. Good luck, check around with several garages in your area, don't just go to one and take their word for what is wrong.

 

You just have to be patient. Plug in the truck, use a cold front, and idle the truck at 1300 rpm's until the temp[ gauge begins to rise. THEN turn on the floor or vent heater (not on high). These trucks have such a large cooling capacity plus being diesels will not warm up like a smaller gas engine.

 

Again, I am not a mechanic, but I thought of a couple of other things you may want to check. Try a new radiator cap, same pounds pressure, but this should not be your problem. Also, your heater core may be partially clogged. I have never looked at the one on my diesel, but all the others I have ever seen look just like a little radiator. It should be in the heater box under the dash of your truck. They can be taken out and pressure tested just like a radiator. You may want to disconnect your heater hoses from the engine first, careful about draining all your anti freeze out, then drain your heater core and take it to a good radiator shop, if needed, you should take the truck by there first and ask an experienced radiator man if he thinks that could be your problem. good luck, let us know if it starts heating better.

 

If using a weather front/or Cardboard, what percentage of the radiator do I want to block off? I am guessing about 80% for 15 degree weather. Any thoughts?

 

forddiesel, check your fan clutch, mine locked up and turned all the time and it wouldn't get warm at all when I changed the fan clutch it gets warm within 3 miles of my house in the morning (without plugging it in) they are not cheap but I would check it out to make sure that isn't your problem!
John

 

I may be wrong, but I think if everything is working as it should, you will not need to block off any of the radiator. My engine fan runs all the time, I know I need a new one, just have not had time to do it yet. But my heater will run me out of the truck after 10 miles or so, even on a day when the temp is zero degrees. And, I have about a one and a half inch hole in the fire wall on the drivers side I have been meaning to plug, from where the previous owner had a wire harness for a snow plow run, and my heater will still run me out. Have you checked the anti freeze level in the radiator? Put in a new thermostat? Had the heater core checked? Checked the heater hoses for pinched or crimped locations? Surely one of these things must be wrong, if you find the problem, let us know. (Also, my anti freeze is about two quarts low.) One other thing you may want to consider, ask someone that knows more about this than I know. You may have an oil cooler, or a transmission fluid cooler in front of your radiator, covering the front of it may have an affect on the other coolers, if you have one. You may want to check on that. Best of luck.

 

My major problem is that I make a lot of short trips during the winter. I usually plug it in and then I also warm it up until the cold advance/fast idle shuts off (About 10 minutes). For example <10 miles a trip and then it gets shut off for a few hours.

I have replaced the heater core, flushed the cooling system, refilled it with 50/50 mix and fw-16, checked coolant flow through the heater core, and all is good. I have not replaced the thermostat yet but it may be a problem. I have know were to work on it. But I know a lot of people with fords that suggest using a weatherfront/cardboard.

 

FD169. When you say "Heater" are you talking about the Hot air you should be getting out of the Heater Core in the Cab?

Those get blocked by 'Gunky Antifreeze' and should be replaced.

The engine heat is controlled by a Thermostat. Be sure you use the Ford or IH t-stat, and not the one sold by aftermarket parts houses. There is a little difference in construction, and the Aftermarket's might cause overheating in hard pulls during the Summertime.

Listen for the Fan. It should be intermittent.(the roaring sound) If it roars all the time, you have to replace it.

You dont say where you are, but they dont even have to cover the Radiators in Alaska.
In Ten minutes of Idling out in the Zero weather, it should be too hot to hold your hand on. (Hundred or more degrees)

 

IH diesel engines are cold blooded by nature they can idle 15 minutes and really not get to running temp.Go to Ford or IH and get a new thermostat. If you park your truck under a tree any time you might want to check your heater box it could be full of leaves.I found this out one day coming home from work when smoke came rolling out of my dash vents.I took the inside cover off the heater box and it was packed with dry leaves about half way up the heater core.

 

I also have a 1986 F250, and found the heater/ac ducts get restricted with leaves and pine needles. About twice a year, I remove the blower motor, and clean any accumulations of leaves etc. This also affects the ac performance. Let me know if this helps!
Big Mike