Hello all. New owner of my first diesel – an 04 F-350 PS 6.0 w/ 140k miles on it. And as I’m finding out, a poor purchase in respect to how much I paid and how much I bit off with it. But setting aside my personal shortcomings on the purchase, I’m trying to get the truck in shape while taking a crash course in diesel maintenance.

In short, I’m looking for some insight. It’s an early 04 I believe – the valve cover (pass side) says 2003 on the sticker. Presently I’m 99% sure of a blown head gasket. I believe I have lots of supporting data on that: it has factory bolts; the cooling system goes to max pressure in under 2 minutes from starting cold and holds steady at max thereafter. No white smoke that I can detect on start or otherwise. When running, the cooling system level raises from "min" to above “max” almost immediately and the cap (which I tested OK at 18 lbs.) dribbles a small amount of (red/gold?) coolant. Coolant is very clean. It loses a small amount of coolant along the way, probably due to the loss from the cap. So at present I’m planning on changing the head gasket and replacing the bolts with studs. A local place said they would do it (and other stuff along the way) for 6k. I’m sure they’d do an awesome job, but I just don’t have 6k after buying it and can’t see spending that much in addition to what I have into it already. Other local garages either don’t inspire any faith or just flat out reject the job. I’ll have to do the job cab-on in my own garage, and I’ll have to knock out the back wall of my garage to fit the truck in. I’m really committing to a lot here, but I don’t see a way around it.

Since I’m going in for gaskets and studs, I figure I also will:

• Magnaflux and mill the heads. I don’t think I can afford o-ringing, but I will get a price on it. I also would like to sleeve the valves if I can afford it. If the heads are bad, the project might stop at that point because I’d really be getting into a lot more money at that point.
• Replace the oil cooler
• Test the oil pump – replace if needed. I’m not sure how you test it but will research.
• Delete the EGR (I don’t think it’s deleted yet. Most of the truck looks OEM except exhaust and a coolant filter)
• Rebuild the turbo

Maybe other things would make sense too; I’m open to suggestions. Considering my already large investment, there are some limits I’m up against; but I really don’t want to dig into the engine again to this extent.

I haven’t put over 100 miles on it since I got it. Codes it has now are:

• P0275 – Cyl 5 Contribution/Balance
• P0404 – EGR Control Circuit Range/Performance
• P0500 – Vehicle Speed Sensor (this is new – wasn’t there a day ago – might be from my testing)

During a testing run using a Bluetooth OBDC2 dongle and Torque Pro, I came up with few readings - not as much data as I would have liked to get, but I was having issues with the Bluetooth dongle. But here’s what I did get:
@RPM :764 @Temp :134F InJPW:1088 IPR:26.7% HPOP:915.4 ICP-V:1.2 FMP47.5

I made a video with good audio on it of the pre-start, cold start, idle, running at 2k RPM, and a warm(er) restart. I’d be interested in knowing what people familiar with the PS6 can glean out of hearing it but alas I can't post links yet. So I'll do that the future maybe or perhaps there's another way to post it.

If anyone would be so kind, please throw me your opinions. As I prep my garage, I’m trying to get together as much data as I can to efficiently do this.

Thanks,
-Jeff

If you dont have a mix of coolant/oil you havent blown a HG, yet.

I say you have two options, one is to go all in and strip it down pulling the engine and resealing it top to bottom hoping that the heads arent cracked and can be reused.

the second is to focus on the maintenance, read the threads about monitoring the truck and understanding the deltas, and drive it to base line the issues you have beyond the signs of a gasket failing.

Thanks for the reply. If there was a gasket leak between the cylinder and the cooling jacket, wouldn't the result be the compression from the cylinder getting pushed into the cooling system - so bubbles, but not necessarily contamination other than gasses? For this to not be a head gasket it seems like the only other option would be the EGR cooler, but I assumed that wasn't the case because of the lack of white smoke. My oil and coolant is clean (of course - they both have filters, but still).

Is there a definitive test I can do that doesn't involve digging in too far so I know what I'm dealing with? I took it to one mechanic (who admittedly was non-diesel) who was sure it was head gasket. My own internet-based-diags agreed.

I did the cooling system pressure check as mentioned ('T' into the cooling line to monitor the pressures). I see there's a bubble test but it doesn't look extremely definitive on the surface (cork the cooling cap with a plug and hose sticking out of it - watch bubbles in a 2 liter bottle). Would I need to pull the EGR tube to know for sure?

Since you have already put in a gauge into the cooling system, that should have told if the head gasket is blown or not/ cracked head

what you are looking for is a sudden pressure rise under load -- so brake torque or pull a hill at wide open throttle
I prefer the engine to be cool/warm -- not up to temp

The EGR cooler can act as a steam generator if the EGR valve is not closed all the way -- with cool engine that is less likely to happen

The bubble thing works to a point -- still need to load the engine for best results

Putting it under load while the engine is cold is logistically difficult for me to do, unless "cold" is just less than normal operating temperature. By the time I could first do WOT without breaking too many laws the coolant temp had started to come off the "cold" pin on the gauge. In my testing, starting with a cold system, at 25 seconds after starting it's at 5# pressure. After a minute it's at 10#. That's the point I can start driving (slowly). Before 2 minutes, it's at 18# pressure and fairly stable, and the coolant gauge is still on the cold pin. Another minute or two before I can add any load, but it relaxes at 17#-18# but can crawl (slowly) sometimes up to 19# or 20# just regular driving. Then during WOT (up a moderate hill, coolant temp starting to go up a bit but still not to normal) it goes more rapidly up to 21#. With as hard as I could push it in my area, I could get it to 22#. As soon as you level off the throttle it smoothly moves to 18-ish again. The needle doesn't move with the speed of a RPM needle. More like the MPH needle, if you get my meaning. Not super sudden. I videoed the whole thing so I can refer back to it for times/readings.

I just want some definitive way to see what I have going on. What do garages use to say for sure on diesels?

if you have to wait till it's warm, fine -- just loose the cap and relieve the pressure

should not build pressure again -- cap relieves at 16psi normally

so under if you have relieved pressure -- then WOT, and the pressure spikes to 16 or more

there is a leak

Cool - when I get back home on Monday I'll retest it that way. I stopped driving it except for testing when I suspected the head gasket leak. I really miss driving it, and I'm not fond of riding the bus to work, even though it's a diesel too

I want to do oil/oil filter/fuel filter changes on it as soon as I can, but was holding off until I diag this issue. No sense in doing all that just before tear-down. Oil looks clean though, as if it was just changed.

I'd like to somehow identify the type of coolant in the system so I know what to add. It's not what I'd call "Gold" color. More "Red". But very clean looking. I don't know what Ford Gold coolant looks like exactly. My auto parts store is not at all helpful with that question.

Ford gold =death for the oil cooler -- do not use that stuff

There are several threads on here discussing coolant -- one of the favorites is a red color

unfortunately there is no good way to know what is already in the truck

Once the motor and coolant is warmed up (with the cap off)......put the cap on tight. Since the coolant is already warm and has expanded....there will be little to no pressure increase as you drive the truck around. If you start getting pressure in the system (showed on the gauge)...and it just keep creeping up and up and after few minutes up over 12psi..and eventually hits 16psi......YOU HAVE A HEAD GASKET LEAK!! It's a simple test.

My truck has a very small HG leak. When I warmed up my truck and then went for a drive...the gauge started at 0, then would creep up to 4, 5 + Then when I would get on the gas, it was up over 10psi...and then up to 15psi.....and then the cap would start venting at 16psi.

After my new head gaskets and studs....I repeated the same test. I let the truck warm up with the cap off, and then tightened it down and went for a drive. I romped the hell out of the truck.......I never saw the gauge climb up over 2psi during the entire drive....and that was just from heating up the coolant more. After it idled for a bit, it dropped back down to 0psi.

The fact that you are getting well over 16psi means you have a HG leak.

Why? Then you can't really tell if the increase in pressure is from the coolant temp rising and expanding....or from a HG leak. At least when everything is up to temp, you have a pretty good idea that the coolant isn't going to heat up much more and expand and cause the pressure...it's all coming from the HG.