While trying to learn about this truck, i've read several times for the oil temp to not exceed the coolant by more than 15 degrees.. why?? I"m certainly not arguing, just trying to learn. I dont have this problem but what does it mean if i did. do i have a problem with the coolant system or a worst problem with the oil system. And does it mean that if it ever gets 15 degrees warmer,, i should be checking codes,, or does it have to maintain that differences.. thanks again.

 

It would be a sign that your oil cooler is plugging up and in turn cause your EGR cooler to have a melt down.

 

I agree
a little of track here but how do u like the scan gaugeII

 

I like it. Haven't used the scan feature yet, but its great for keeping an eye on the oil and coolant temperatures.

 

ya i kinda have been checking those out do you run a seperate fuel pressure gauge or does the scan gauge have a port for that??

 

You'll need a separate gauge for fuel and EGT

 

If you do not understand about oil & coolant temps, why do you have bullet proof stuff in your truck? I am not trying to be I smartaZZ! it just seems you know already!

 

most of this is covered in tsb 09-08-03.

 

Coming at it from a engineering stand point it would seem like ford wants to keep a limit on how hot the engine oil gets.
15w-40 has only 20% of the viscosity at 190 degrees compared to the viscosity at 100 degrees. So as your oil temp goes up, viscosity goes way down, engine protection goes way down and premature wear would seem to go through the roof.

and i agree with rick, one usually flows the other.

 

well, to answer your question. All I really knew was my truck was somewhere for the birds to sh.. for 6 weeks due to it not running.. and I was told it was the Egr cooler, etc, etc. Since that repair, i've been on this site and only then did i hear about the 15 degrees difference in the two temp. I was just trying to understand the mechanics of it. You know, ,someone said this and that,, but why? which one was at fault for this temp change,, oil.. or coolant... thanks again

 

Here's the way I understand it. The EGR cooler is downstream in the cooling path from the oil cooler. When the oil cooler plugs up due to casting sand/coolant precipitates the EGR cooler starves for coolant and whatever coolant DOES make it to the EGR cooler flash boils and starts to melt the EGR cooler guts allowing coolant into the intake. When this happens, blown head gaskets are the likely result. The reason for HG problem (credit to someone on here, can't remember who) is that the liquid coolant will NOT compress in the cylinder and the only place for it to go is out the head gasket.

 

Worse than blown HG's is you could hydrolock the engine and destroy it. Not a pretty picture.

 

When it hydro locks something has to give even if the head gaskets blow it might not be a big enough gap to allow the volume of fuild to push out and when it isnt something has to give and its usually a rod bending. Now your into rods, maybe mains and if you spin the bearing now your into pulling the crank and if it can be resurfaced great but now I would imagine between the labor for all of this and the parts its cheaper and less stress to just pull the dead round from the gun and put a new bulletin, maybe a re-man 6.0 better yet a cummin's.

 

Maybe I'm a masochist but I like my 6.0! Not for the possible problems but mine has never let me down and I love the way it pulls.

 

Dont get me wrong I love my 6.0 EXCEPT one thing. I dont think its a "real" diesel. Im not saying how come it doesnt pull my 30k trailer. Im not one of those guys. It is designed to do what it was designed for. But I am a diesel mechanic but not trained on this engine. I am a marine diesel tech and have done work with over the road truck and bus. Yes the engines I work on have problems also no engine is 100% trouble free however I have busses with 750k and they do have water pumps and maybe an injector as well. So dont shot to fast at me it just seems there is a decent amount of trucks with lets just say oil cooler problems and lets be honest how many people with 75K in the world dont have gauges and have no clue they need a cooler. To me in the "real truck or marine diesel" world oil coolers last longer than that. If over the road trucks with Acerts, Cat C9's or DD15's were blowing coolers at 75K or less we would have no frieght moving. Some real diesel's will have problems but most will jsut need valve adjustmest at 500K or so. Nothing like what we go through. Again I love me truck and I would rather push my Ford then drive a chevy but lets be honest a 5.9 is just a better built , designed, and tried engine. Its not all fords fault emissons play a big part trying to comply and all but whatever... Sorry to rant just gets me going when Im putting money into coolers and egrs and injectors with 108k on the truck and many have these problems with alot less.