Ok here we go, I got an 04 F250 with 03 engine, a few years back prior to a tuner or a gasket failure i did a cab off full FCDP egr and cooler delete, Head Studs, and head gaskets, as well as checked heads for flatness according to fords TSB, Oil cooler, stainless oil screen, blue fuel spring, coolant filter, and full distilled water coolant flush, refilled wih ford gold coolant

This fall truck developed a coolant leak only when cold, would seal when hot, didnt leak all summer just started when temps dropped in Upstate NY. Found it to be the FCDP aluminum U pipe that bypassed coolant from intake to oil cooler housing. Noticed i was low on coolant when i lost heat in parking lot at idle.

1.) Replaced tube last weekend, used VC-9, flushed system with 5 rounds of distilled water, new thermostat, installed snow plow fan clutch, then refilled with Final Charge Cat EC-1 certified coolant. I had alittle puking but figured i over filled it, now it has stabilized but while ideling i can hear degas cap blow off air every few min. I have issapro guages, and also monitored it with autoenginuity and coolant and oil temps are spot on. issapro guage usually stays 180-190, never above 190, did alot of towing and temps all seems fine except for air blow off. When i get on it good coolant temp seems to drop to 180-185 from 190 on issapro guage located in driver side head drain port.

2.) Also i loose heat when stopped and as soon as i increase rpms it is to hot to hold your hand infront of vents.

When i removed coolant filter at the start of the weekend project the top was covered with a thin rusty film, enough was in filter that it restricted flow.

I was thinking low flow thru heater core was the famous 03 water pump but engine temps stay low, maybe plugged heater core?

Today i stuck pressure guage on hose running to coolant filter, goes up to 14 then blows off, at 1500 rpm, pressure recovers to 14 in a min or two, sounds like cap is a little weak but what should pressure be and how quick should it get their.

No rough Running, No white smoke on cold, hot start, or while driving.

Sorry for the long post.
Thanks Alot
and Happy Holidays

 

Oil cooler clogged up could cause the no heat at idle...

 

Thanks

Newer cooler and oil and coolant temps are within a degree of each other, looks like heater core is its own loop, comes out of waterpump thru heater core and returns to Y pipe on bottom of degas bottle. and its not a crew cab so i dont have the vaccum ooperated valve to shut the coolant flow to the heater core off during a/c operation. i imagine their is not much pressure in heater core loop if some trucks have a valve that stops flow during ac operation, so maybe i have a particial plugged heater core, but more worried about the pressure?

 

Are your temps taken ffrom the OBDII Port???? they should be

Now Dont take Offense but Aftermarket gauges are only a Close Guestimate and are generaly in the wrong Spot to begin with so the Reading is Biased

Once you notice a Problem Factory sensors should be used to resolve the problem

An Aftermarket ECT sender screwed into the Block drain IMO is Biased because its at midway point in the block and hasnt picked up all it heat yet


The only Aftermerket gauges I would put on a 6.0L would be Fuel Pressure and a LPO gauge thats just me though



Moving on tell us about you Headgaskets are they OEM??? the BO HG SUCK

How About the Fan what RPM is it Running at with ECT 190* at Idel A/C Off

Whats the Spread between ECT & EOT on the FACTORY Senders

 

Id be a little leary of a head gasket issue if your degas cap keeps releasing pressure.

 

I feel the same towards aftermarket guages, i like the range compaired to the factory temp, oil temp is located in oil sample/test port in oil cooler return side so i get really accurate reading compaired to the ecm readings, For obd2 reading i am using my laptop with autoenginuity to show and record ect and eot
I have recorded an average of 1-2 deg. difference between oil and coolant temp just crusing no big loads and not towing, previously when towing up a large grade i see oil temp rise above coolant temp maybe 5 deg for a short time on the aftermarket guages, used for quick referance.

Head gaskets are Black ONYX, ARP head studs.

Today at running temp believe fan was running 900 rpm while engine was at 1000.

 

I know and that is the first thing on my mind but with head studs, black onyx gaskets and all the time and care i put in it i am hoping it could be something else but cant rule out bad gasket or crack in head, but no white smoke, smooth running, and no coolant loss, even used stant tester to pressure test unit and no loss in pressure, truck can sit for a few days and still hear pressure when i remove cap,
Is cap blowing off at 14 too early or should pressure not get that high anyway

 

<p>You try a new degas cap? I believe they are set to lift at around 16 psi

 

Current one says 16 on it but releasing at 14lb, going to get a new one at dealer tomrrow, i magine as it heasts up and expands it has to release some air right?

 

[quote=vlietracer64;12632504]

Head gaskets are Black ONYX, ARP head studs.

quote]

Those BO HeadGaskets have had Alot of problems for folks

Does it still PUKE?????
Or has it stoped since the Coolant leval dropped down some???




I still think to High PSI in cooling system Plus its always venting from what I gather I can maybe see venting 1-2 times as truck heats up but Not Continual vent

Optimal Coolant press is 6-10psi


Its Really starting to sound like Bad HeadGaskets because

1. Its Always Venting Press out hte Cap
2.Coolant press Stays High (14psi)
3.Puke
4.No Heat at Idel (Combustion gas in cooling system is Messing with the Flow)
5.EGR Has already Been Deleated (EGR Cooler Gone)
6.Its Been rebuilt with Black Onyx HeadGaskets Before and lots of problems with this Brand HG

Small Chance the Water Pump is Bad and/or Cavitated front cover

If it was Me the Next step I would take is to get the Exhaust Test strips and Dip a Test strip into the Coolant and see if it comes Back Positive for Ehaust Gases in the Coolant

 

[quote=BLADE35;12632756]Where is the best place to get test strips?

 

im not a fan of test strips. follow tsb 09-08-03. you way want to check the water pump for damage being an 03

 

What should I look for, what generally fails on the 03 water pumps.

 

The impeller. It's plastic and undersized from what I remember.

 

they crack and fail to spin on the shaft, or break off sections