I recently had my truck in for service to fix an overheating problem. When it would heat up, the Temp gauge would go from normal to hot in 2-3 seconds, and when the ignition was turned off for 5 seconds, it immediately went to the normal range again. The service tech couldn't replicate the problem (as normally happens) so they said it sounded like a thermostat problem and changed that out. That seemed to work for about 3 weeks, and the same thing started happening again. When it heats up, it is fairly cool outside and not pulling a load and it's on level terrain. I've had cars get hot on me before, but this one doesn't smell hot when this happens, and the radiator doesn't seem to be boiling over??. The computer dials down the power when it heats (or think it heats), and it does turn on the service engine light, and when I turn off the ignition and re-start (which immediately fixes the problem) but the service engine light stays on until it gets re-set. Has anyone heard of anything similar to this before..... I'd like to be able to give the service gang a heads-up when I take it back in.

Thanks,

Gremlin

 

Sounds like a bad temp sensor.

The CHT (cylinder head temp) sensor can fail, and cause the computer to think the engine is overheating. The computer will dial down the power by running on 5 cylinders (note: I'm not sure about the 3-valver doing the "limp home" mode on 5 cylinders, but I know the 2000-2004 did).

Could be a bad ground, could be lots of things.

But it doesn't sound like the engine itself is hot.

 

Well.... my truck has been in to the Ford dealership 3 times now to fix this false overheating problem. 1st time, they changed the Thermostat, 2nd time they changed out the Computer Module, 3rd time they installed a new Crossover Pipe (that caries the anti-freeze) and installed a different Thermostat. This was all done with guidance from the Ford Staff. Now I'm faced with a problem. I understand the Lemon Law in California... I fairly certain that I can get Ford to either buy this truck back, or get a replacement. Problem is... there are no more '06's and the '07's are not available in California. I like this truck and hope/d that a solution can be found to fix the problem, but so far no luck.


You know, the suggestion that the cause could be a bad Temp sensor (as suggested earlier in this thread) is not even being considered by the Ford boys ?

Any ideas ?

 

Either go back to that dealer and say "change the cylinder head temp sensor" or find another dealer.

It definitely sounds like the sensor. Someone else had the same problem once. And the fix was the sensor. It was going into "limp" mode for no reason, thinking the engine was overheating.

 

You know, come to think of it, I think it was the computer itself, thinking the cyl temp was too high...

There was something wrong with the computer causing it to think the temp was too high.

It could still just be the sensor. They should be able to read the computer and see what it thinks the temp is.

 

On the last four new vehicles I owned I always do a complete front to rear test of EVERY electrical connector...You would be amazed at how many connector I push together and hear the final "CLICK" indicating the keeper is now engaged... I also find several fasteners that are "finger tight" and I did fine a braided "ground" strap that was not even bolted in place

This sounds like an electrical problem... the water temp sensor and cylinder head temp sensor should be changed with "Known good" parts...every electrical connector must be checked, the battery ground needs to be checked.

If the cluster Temperature Gage is reading HIGH and the Check Engine light is coming on then the PCM should be commanding a "limp home" mode...if it is NOT commanding the Limp home mode...(and you would know because it really looses a LOT of power)...then the fault is between the PCM and the Instrument cluster.... if this is the case insist on a new main cluster. This item is also a computer and can do weird things... do NOT forget to drop the Main Fuse Panel and disconnect every electrical connector and then reinstall them in the sockets..... I don't really think the GEM can cause this but some of the circuits going to and from the PCM-ABS flow through the GEM on their way to the Main Cluster

Generaql Electrical Module (GEM) is on the back of the main fuse panel below your left knee... Generaly speaking this is the main brain for all the non-automotice circuits like security system, windows, door a jar logic etc..

I bet it ends up being a loose or bad electrical connector

 

I would agree with Fred ,
Also if the tech at this dealership is any good ! He would have hooked up a WDS analyzer to your vehicle and did a wiggle test.
Also would have grabed the codes.
This is common MO for dealer techs they get you to come back ,therefore they get more warranty $$$$$$$$$
A infra red temp instrument would verify your overheat condition also.

Rich

 

Well....... it's settled. Ford could not figure this one out and agreed to repurchase my truck from me under the California Lemon Law. I ordered an '08 yesterday. On the last visit, they worked with the FSE's and the hotline, but couldn't isolate the cause of the false overheat. There was a TSB out on this that they had already performed, but that didn't fix it. Looking forward to the '08, I test drove a couple and decided to stick with a new V-10 again (although the new deisel was pretty slick). The ride on the '08's are incredibly smoother than the '06 & '07.

 

Hate to see it come to this. I would love to know what Ford is going to do with the truck. Would make an excellent investment and a great project. Bet you will love the new truck. Keep us posted and send pictures of the new ride.

 

You are in CA? I thought the V10 was not available in the GREEN States? Which '08 V10 did you get (F250, F350)?


biz

 

The V-10 is available in CA for '08. It was not in '07. I got the 250 Lariat

 

When you get it, check to see if it has an EGR valve... and take pics!

It's weird that that one little bug was unfixable...

Unless it had an internal problem, and just couldn't find it. Weird. Very weird.

But congratulations anyway! Post pics in your gallery when you get it.

 

WOW! That is GREAT news...

I would certainly like to know what makes it compliant for '08...when it was not for '07???


biz

 

The one glaring thing that CA wanted for '07 was an EGR valve up to 14000 lbs GVWR or so. That's why a properly setup F350 could be bought in CA with the V10 for '07.

I suspect Ford didn't see it cost-effective to certify the V10 until '08.

After going through CA's emissions regulations, it's all I can find that would do that.