OVERHEATS AFTER I SHUT IT OFF

[Boston]

Crazy as it sounds my 91 Ford 250 with the international 7.3 IDI diesel in it overheats, when its off. I run it for a while till the temp guage says its warm and when I shut it down and wait for say 20 minutes it wont start, temp goes to the top and its got all the signs of classic overheating no start.

Its got oil, got coolant, got belts, got a mind of its own

I've never heard of a mechanical system doing this before.

Any idea folks cause all I can think of is to change the thermostat but I'm not sure how that could be screwing up if its not overheating when I drive or stuck open.

Thanks
B

 

[rhkcommander]

could be worn ip. some say to pour cold water on it bad idea as the shock can stress/crack things.

IDK how else to tell though. but rough hot starting is a sympotm of seals in the IP or something

 

[Boston]

IP ?

 

[itsacrazyasian]

injector pump.

I can't imagine how the motor would overheat sitting as there is no "heat" or energy being converted into heat.

Pour a bottle of cold water over the injector pump like said above and see if it;lkl start. Does sound like a worn IP

 

[Boston]

Not the injector pump, or it wouldn't run for jack even if I could get it started, or at least I wouldn't think it would. the engine is actually overheating as it sits after its run. I'm thinking it must have something to do with the thermostat, but I'm baffled as to how its screwing up. Maybe its closing without the pump pressure against it and something about a lack of convection that is causing the issue.

I"m all ears but the injector pump seems like it would cause a lot of more problems than the occasional trouble restarting after a run.

 

[itsacrazyasian]

Not the injector pump, or it wouldn't run for jack even if I could get it started, or at least I wouldn't think it would. the engine is actually overheating as it sits after its run. I'm thinking it must have something to do with the thermostat, but I'm baffled as to how its screwing up. Maybe its closing without the pump pressure against it and something about a lack of convection that is causing the issue.

I"m all ears but the injector pump seems like it would cause a lot of more problems than the occasional trouble restarting after a run.

Take a point and shoot and see what the temp at the thermostat housing and see what it is vs the heater core lines. Should tell you if the stat is open or closed.

No hot starts are usually a classic sign of a worn injector pump though. How many miles are on yours?

 

[icanfixall]

Sounds to me like the pump has a heat soak issue. This happens on high mileage pumps. The internal tollerances get so worn and then the shut down heat makes them larger. Then the pump can't make enough pressure to pop the injectors. About the ******* of the dash gauge. Just lift the wire off the drivers side head temp switch. Thats the large switch in the front of the head. Its supposed to close when the temp reaches 242 degrees. It then pegs the dash gauge. So remove the wire and see what happens. Then ground the wire and watch the dash gauge. It will peg way over past the "L".....

 

[Boston]

About the ******* of the dash gauge. Just lift the wire off the drivers side head temp switch. Thats the large switch in the front of the head. Its supposed to close when the temp reaches 242 degrees. It then pegs the dash gauge. So remove the wire and see what happens. Then ground the wire and watch the dash gauge. It will peg way over past the "L".

The no hot starts thing came on really suddenly, I'd think that a wear issue would come be gradually slowly getting worse and worse. But hey I can't figure it out so you guys could just be nailing it. I'll try the thermostat first thought cause its a lot cheaper than a fuel pump.

the quote above ?
what does this accomplish ?
its possible that simultaneous failure occurred but it seems more likely that the issues are related, no?

 

[rhkcommander]

The no hot starts thing came on really suddenly, I'd think that a wear issue would come be gradually slowly getting worse and worse. But hey I can't figure it out so you guys could just be nailing it. I'll try the thermostat first thought cause its a lot cheaper than a fuel pump.

the quote above ?
what does this accomplish ?
its possible that simultaneous failure occurred but it seems more likely that the issues are related, no?

We call them idiot lights for a reason. engine off pegs the gauge as he said above...

 

[Boston]

well I'll check the switch and see if its working but the likelihood of a random simultaneous failure is pretty low, it seems far more likely that the two issues are related. or are you saying that the temp gauge does this anyway and I just never noticed it before

The millage is an unknown, truck says 90,000 but that can't be right cause the body is in such bad shape, thing had to have been driven to near death, remember I got it free when it wasn't running at all and hadn't for about a year or so. I looked up that part and its not all that expensive but still I'll check the thermostat first before I go spending $300 or so on this part.

 

[Compu Doc]

It sounds like your thermostat is only partially opening. Their are two things yo could do and that is replace it out right or test the old one. To test it put it in a pot of water on the stove. Heat the water and using an instant read thermometer in the water see what temp it first starts to open and see what temp it fully opens is at.

If you replace the thermostat do the above with the new one also to make sure it works properly before installing. Also only use a Motorcraft or IH thermostat. Do not use any other brand or you will have problems.

 

[Agnem]

STOP!

First question. What year is your truck. You have no signiture, so shame on you. IF you have an 83-86, be advised there is a high probability that your temperature gauge is doing what it does due to a faulty IVR. Secondly, do you have an aftermarket temperature gauge installed? If not, GET ONE. The factory gauges are not trustworthy, and a second opionion is always needed. As was mentioned before, get a thermal imaging thermometer and verify your engine is actually hot. I think your going to find that your mind is being decieved. Now, the hot start issue, that is not a lie. Try running some waste motor oil in your fuel, up to 50 % This may negate your hot starts for a while, but the truth is, your pump is on its way out.

 

[Boston]

Crazy as it sounds my 91 Ford 250 with the international 7.3 IDI diesel in it overheats, when its off. I run it for a while till the temp guage says its warm and when I shut it down and wait for say 20 minutes it wont start, temp goes to the top and its got all the signs of classic overheating no start.

Its got oil, got coolant, got belts, got a mind of its own

I've never heard of a mechanical system doing this before.

Any idea folks cause all I can think of is to change the thermostat but I'm not sure how that could be screwing up if its not overheating when I drive or stuck open.

Thanks
B

I typically run WMO and recently built a rather large fuel tank for just this purpose however I've been held up waiting for a controller for the pump motor so I went back to diesel. Truck just started doing this but when it does I have to wait for it to cool off before it will start. Starts great cold.

I"ll try the IR test but something tells me its the thermostat and if the pump is effected by residual heat then you are right in that the pump is not long for the world. I'd also think that WMO would being a thicker fuel would prolong its life.

whats up with this "switch" isn't this a simple mechanical thermostat? its an older truck "91 as mentioned in my original"

anyway thanks guys I'm learning enough to probably track down the cause and get it fixed properly which is always the goal. I turn all my own wrenches

cheers
B

 

[icanfixall]

Boston. My posting about the dash gauge ******* after you shut down the engine is going to be the "check engine" switch or sender if thats what you want to call them in the drivers side head at the front. All it does is peg the dash gauge when the coolant reaches 242 degrees. Run the engine till its warmed up. Then do as you have done. After you shut it down and let it sit try to restart. See if the dash gauge is pegged hot. If so remove the wire to the head temp sender. I'll bet the dash gauge goes down to a normal level.
Now about the heat soak issue with the pump. So you have already been running wmo but reciently stopped for reasons. So now your fuel is much lower in viscosity.. Your pump is now really worn internally so it can't make enough pressure to pop the injectors. To prove this add some cheap engine oil to around 1/4 tank to increase the fuel viscosity. See if the next time or two the truck restarts easier. If it does your pump is shot. Agnem is on the right path. He knows these fuel systems very well and is highly respected here. All that I have suggested here is not going to cost you anything. Just lift a wire to prove the switch. Then add oil to the fuel to prove its the pump worn out. You still can replace the thermostat if you really feel that will "fix things". I would do that as about the last resort concerning the coolant system because all the things I have suggested are easy things.

 

[redneckaggie]

what they are trying to say about the gauge is that it could be lying to you the stock gauges in these trucks are junk. I dont even have the stock water temp sensor connected anymore. that is the reason for everyone suggesting aftermarket gauges. overheating should not stop the truck from starting but heat soak on the ip will. good luck.