Hey guys.... new to the forum after lurking around for a year or so. Figured I'd jump right in with a curious problem my Powerstroke has been having since September. Sorry about the lengthy first post but I want to paint a complete picture.


About the truck:


2008 F250 6.4L FX4
123k miles


(All work below performed at 60k miles)
Elite Diesel H11 head studs
Ford headgaskets (dealer did not deck the heads.. said were in spec)
EDE EGR delete & wastegate/downpipe combo with manual boost controller
Dyno'd at 520HP/1103 lb. ft. torque on the "hot" tune (never used)
DPF delete
Banks 4" exhaust
Banks CAI
H&S XRT PRO tune on the mild setting
Spartan Dashdaq XL monitor (unused tunes also)
Transfer Flow 40 gallon aux fuel tank with TRAX II system
Open Country traction bars

(Despite all the mods, the truck doesn't tow over 6k lbs and that is on occasion, and the truck is not ran hard)


At 89k miles in 2013, the water pump and front cover were replaced with the new design.


I bought the truck in July of 2015 with 115k miles. In September I noticed a small coolant leak from the driverside front of the radiator. Replaced the radiator and bled the cooling system.


After three weeks, the lower hose blew off. I bought the new double o-ring lower hose assembly and replaced it. Re-purged the air from the system. Using Zerex G-05 btw....


I began to notice the degas bottle building pressure and the temps would no longer get over 184 ECT, 187 EOT.

I replaced the degas cap with the Murray cap from Oreilly next. Truck ran well for a few more weeks until it began puking coolant from the degas. Changed the cap for an OEM Ford cap and all was well for another week or so.


Three weeks ago, I noticed one morning that I had zero heat at idle. Temp would drop 10 degrees in about 30 seconds at a redlight. Heat worked while driving at 2k rpms.
I bought a set of thermostats and replaced them. Found that the 192 degree t-stat had cracked. Purged the system (Mac Tools vacuum refill tool) and pressurized the degas bottle using the Mac Tools pressure tester. The truck held 15 psi for 40 minutes with zero drop in temp.


The truck was perfect for about 5 days. ECT 194, EOT 197.5 consistently. Now, I'm hearing some bubbling in the degas bottle and see very slight signs of puking again under load.


This morning I noticed that even though I filled my coolant reservoir to the min line (usually expands right past the max line and settles back down after cooling off), it didn't settle back to the min line by this morning. It is still sitting almost at the max line. The coolant looks clean so not sure why the level is now higher.


The truck runs absolutely fantastic, doesn't smoke and doesn't seem to be using any coolant. I haven't had to add any since installing thermostats last Thursday.


I am going to build a pressure gauge to go inline on the return to the degas bottle tomorrow to see if the system is pressurizing (aka head gaskets), but is there anything else that could be causing this issue? I'm wondering if there is somehow still an air pocket in the system, but I don't know for sure at this point.

 

Its possible you have an air pocket, that wouldn't cause what you are seeing though. The likely cause is head gaskets or a cracked head.


You need to check pressure at wot to confirm this though. If they didn't machine the heads or check for cracks that might be the problem... 6.4s are known for cracking/warping heads when they blow hgs.

Either way, you need to check the pressure.

 

Yea I plan on checking it tomorrow morning. I'm putting the gauge together tonight.


Assuming it is head gaskets and the heads can be decked, is there anything else I need to go ahead and do while the guys are in there? Thinking about having them go ahead and slap a new set of rockers on since they're wear items. I really don't want to tear it down but this one time so I figured I should try and catch anything I can (that I can afford) while the guys are there.


Also considering having them install a new direct drive solenoid from Rudy's since I have the 4-5 gear flare and try to eliminate that.

 

If your wallet can handle it have them do lifters as well, but it adds quite a bit of cost because the motor is being removed completely. At that point you may as well rebuild and reseal everything. But yes definitely do rockers and push rods...


As far as the direct drive solenoid, its worth it... It doesn't completely fix the 3-5 shift flare if you run a hot tune, but most street tunes it will cure it. I also highly recommend traction bars...

 

I have traction bars already and run the 210 mild tune. Hoping the solenoid helps. I probably can't do lifters with everything else but I'm hoping to do all I can.

 

Heres the truck.

 

How many miles are on the current set of rocker arms? If they aren't worn too bad I wouldn't worry much about the lifters.




They get beat up pretty bad by the camshaft, but it is usually worn rocker arms that cause them to fail early. Those damn rocker arms are the reason we see more lifter failures in 6.4s than we do in 6.0s.

 

123k miles

 

123k miles

 

When were the hgs done?

 

60k miles.

 

I would do rocker arms... No questions asked.

 

So here's what's on my list for right now.

Headgasket kit - $600
6.4L Powerstroke OEM Upper Engine Gasket Set


Rocker Arms - $480
08-10 Ford 6.4 Diesel 6.4L NEW OEM Intake + Exhaust Rocker Arm Carrier SET ALL 8


For longevity, I'm thinking I want to add a coolant filtration kit too: $170
Sinister Coolant Fitration Kit Ford 6.4


I can probably forego the coolant filtration kit for now and put that money towards more engine work if needed, so trying to figure out where to put it.

I have a couple of questions:

I have some blowby in the CAC tube that I noticed when I removed it to replace the radiator. It's not that outrageous and I expected some blowby, but I also have noticed some oil residue building up around one of the lines running from the wastegate to the boost controller.

Question 1: How much blowby is acceptable before it's time for a rebuild? I can get the kits for $100 each... but don't know that the "issue" is really much of an issue at this point. I've had turbos with a lot more blowby that never gave me an issue.


Question 2: If I can eek out enough cash to do lifters and pushrods, do I need to do valve springs at the same time? I don't run the truck on the hot tune, and don't dog the truck so I don't think valve float should be an issue.


Question 3: If I do buy pushrods, is it safe to go back with the stock Ford pushrods? I was looking at a set of EDE chromoly pushrods but they are $300. I can get a set of OEM Ford pushrods for $82. I could go back with the OEM lifters for about $290.

 

The stock push rods are fine... ALL 6.4s have blow by, its the nature of the beast. If you can put the cap in the hole and it doesn't pop off you are fine. Part of that could be attributed to worn rocker arms and valves not fully opening/sealing as well... Most of it has to do with worn rings and the high cylinder pressures that our motors are known for. If the cap stays put when you set it in don't worry about it (make sure the truck is up to temp when you do the test).

Its always a good idea to do a CCV reroute as well...

The coolant filter is a good idea, but if you take care of your coolant you have nothing to worry about. Better yet... its apart do a full chemical flush and run the truck for a week or so after the flush with elc before you go in to have the head gaskets done. Then have them drain and fill with more elc and be done with it. Red elc doesn't break down like ford gold and won't have problems. it will cost you a little to flush but in the end it will solve the clogged cooler issues.

 

Heres the confirmation.