Strange heat problem

[SVTDanny]

Having a hell of a time getting this figured out. Wondering if anyone else has had the same issue and can shed any light.

Backstory -

Bought truck in September with 112k miles on it. DPF/cat delete, intake, and H&S tuner. Had signs of puking out of the degas bottle and was low on coolant, but the price was right so I bought it. Didn't have any issues with the truck except that if coolant was filled in the bottle to the "Cold fill mark" lines, it would puke out. After a while of getting annoyed with that, I set out to fix it. The first thing I did was replace the coolant cap - that did nothing. The next thing I did was flush the coolant system and replace the thermostats. I flushed the system with Cummins Restore, tons of water, and refilled with EC-1 coolant. Didn't have any issues afterwards, but it still puked. The next thing I did was delete the EGR coolers.

After I deleted the EGR coolers, it was still puking, but my heat started acting weird. It would blow hot a few minutes after starting, then would stop, then would start again after a while - like air was trapped in the heater core. I tried putting a funnel on the degas bottle and just letting it run to get the air out, driving it for a few days to get the air out, and no change. Finally I took it to a friend's shop that had a vacuum filler. We drained the radiator, drew a vacuum on the system (Held 15 inches solid, no leaks), and filled it back up. Had to add another half gallon of distilled water to bring the coolant back up in the bottle so I thought we were good to go. That was this past Sunday. Since then, I tested the "new" cap I bought from Ford a while back and found that it doesn't hold pressure. I went to Advance Auto two days ago and bought a Stant cap - that has completely solved my puking issue. However, this morning, the heat acted up again. Was blowing hot at the end of my road, but then I got on the highway for a couple miles, and when I stopped at the gas station it was blowing cold. Shut it off, went inside, came back out, and it was blowing cold until I was another couple miles down the road.

It's acting like there is air in the system, but I have done everything to bleed it. My next step is going to be to drain, vacuum, and refill one more time if nobody here has any ideas.

I thought maybe a headgasket was popped and causing pressure/air to be put into the coolant system, but I tested the coolant for combustion and the test came back good. The truck runs great and returns great fuel mileage, I just can't seem to figure this heat issue out after the EGR was deleted.

Thanks

 

[MrMike2010]

I know u checked the coolant for combustion but have you put a gauge on the coolant system to check what your pressure is? Theres a video on youtube that explains this much better and can show you how to doit if your not familiar. Reason why im asking tho, back when i blew the headgaskets on my 6.0 i would have the same problem. I seemed to lose heat at idle but after a few min cruising around it would be hot then when i stopped it would be cold again. Not exactly sure why this happens.

 

[Gary]

Probably the first thing I would do is "T" a pressure gauge in the cooling system and watch what happens.
It sound like maybe air is accumulating in the heater core, so if that's the case then where is it coming from? first guess would be a head gasket, but then you said the no combustion gasses are present. Maybe if the air is being pumped in on the compression stroke that could explain the lack of combustion gasses.
I would also fill the heater core with CLR and let is sit for about a hour, then flush it out with water both ways and see if that helps.
Also is it possible that there is a blend door or heater control valve problem?

 

[SVTDanny]

I know u checked the coolant for combustion but have you put a gauge on the coolant system to check what your pressure is? Theres a video on youtube that explains this much better and can show you how to doit if your not familiar. Reason why im asking tho, back when i blew the headgaskets on my 6.0 i would have the same problem. I seemed to lose heat at idle but after a few min cruising around it would be hot then when i stopped it would be cold again. Not exactly sure why this happens.

Hmm, interesting. Maybe I'll try watching coolant system pressure.

Sounds like mine, but the heat doesn't come and go. This morning it blew warm/hot until the temperature gauge reached the middle, then was blowing cold air, then a few minutes later started blowing hot again and kept blowing hot the rest of my way into work. Once the heat comes back, it blows hot as can be whether I'm cruising down the road or sitting at a light.

It also only does this from a cold start. Say I run to the store and back, when I get back in the truck to come home it'll blow heat the whole way without issue. The problem only happens after the truck sits overnight and is completely cold.

Probably the first thing I would do is "T" a pressure gauge in the cooling system and watch what happens.
It sound like maybe air is accumulating in the heater core, so if that's the case then where is it coming from? first guess would be a head gasket, but then you said the no combustion gasses are present. Maybe if the air is being pumped in on the compression stroke that could explain the lack of combustion gasses.
I would also fill the heater core with CLR and let is sit for about a hour, then flush it out with water both ways and see if that helps.
Also is it possible that there is a blend door or heater control valve problem?

My first thought was headgaskets too, but the coolant system holds pressure and vacuum, there aren't any combustion gasses, and it isn't losing coolant or blowing it out of the bottle since I replaced the cap. Also doesn't overheat, run hot, smoke, or show any other typical signs of a head gasket failure. I suppose I could still have a headgasket problem but I just have a hard time believing that at this point. I also thought about the blend door causing the problem, but since it only happens when the truck comes up to temperature from a cold start it seems like a coolant issue. That may be worth exploring if nothing else works.


When I drained the coolant and refilled with the vacuum filler, I still had the old, faulty cap (Didn't hold pressure at all, had an audible hiss coming from it once the truck was warmed up) and I think it let the system suck air back in. I hand bled a good bit of air out of the system last night when I got home from work. I'm going to drain the coolant and refill with the vacuum filler again now that I have a good cap and see if that fixes it. If it doesn't, then I am truly stumped. :shrug:

The part that I'm hung up on is that when I flushed the Ford Gold coolant to switch to the EC-1, I filled it without a vacuum filler or anything - just dumped the coolant in the bottle, and didn't have any issues. This only started after I deleted the EGR, and I drained the coolant and refilled the exact same way. That would lead me to think there is an issue with one of the EGR block off's, but the system holds 15 inches of vacuum like a rock. :shrug: Also, I deleted the EGR 3 days after flushing the coolant and all I did was drive to work and back, I have a hard time believing that I developed a headgasket issue in 3 days of commuting.

 

[MrMike2010]

The blend door actuators on these trucks have been known to fail. Assuming u have a lariat (don't think the manual temp controls use blend doors) there's an easy way to rule out the actuators. With the key on engine off play around with the temp settings, a bad actuator will click. There's a thread at the top of this section that explains everything and shows how to change them if that's your problem.

I'm still curious if your pressurizing the cooling system. The vacuum test is only 15psi these trucks build boost quite quickly, cruising around can hit 20-30 psi easily. I would just like to rule that out before we get into anything else.

 

[SVTDanny]

The blend door actuators on these trucks have been known to fail. Assuming u have a lariat (don't think the manual temp controls use blend doors) there's an easy way to rule out the actuators. With the key on engine off play around with the temp settings, a bad actuator will click. There's a thread at the top of this section that explains everything and shows how to change them if that's your problem.

Yes it's a Lariat. Thanks I'll try that just to rule it out.

I'm still curious if your pressurizing the cooling system. The vacuum test is only 15psi these trucks build boost quite quickly, cruising around can hit 20-30 psi easily. I would just like to rule that out before we get into anything else.

I have a mechanical gauge I can try tee'ing in tonight or tomorrow. My gut feeling is that if it was pressurizing, it would continue to blow coolant out of the bottle with the new cap, but who knows. :shrug:

 

[SVTDanny]

Guess I'll concede that it is indeed a headgasket issue. Heating issues were more pronounced with the cold temperatures this morning. The heat would get weaker for a few seconds after every time the boost saw 20-30 pounds or more without fail. I guess it is only pushing past on the compression stroke which seems strange. Oh well.... time to figure out the best way to tackle this job.

 

[6.4strokin]

Pulling the cab is easiest. Check heads for cracks maybe do some bottom end upgrades pistons are known to crack maybe do some valvetrain upgrades also. My truck is doing the exact same thing lol


Sent from my iPhone using Tapatalk - now Free

 

[SVTDanny]

Pulling the cab is easiest. Check heads for cracks maybe do some bottom end upgrades pistons are known to crack maybe do some valvetrain upgrades also. My truck is doing the exact same thing lol


Sent from my iPhone using Tapatalk - now Free

I do have access to a lift but I think once I do the gaskets I'll do it cab-on. Doesn't look too bad to do it that way, and I'll have the ability to stretch the project out over a couple days in my garage. A friend runs his own machine shop so the heads will definitely be gone over.

http://www.441diesel.com/post/2013/01/14/64L-Powerstroke-head-studs-CAB-ON.aspx

 

[B585Ford]

I do have access to a lift but I think once I do the gaskets I'll do it cab-on. Doesn't look too bad to do it that way, and I'll have the ability to stretch the project out over a couple days in my garage. A friend runs his own machine shop so the heads will definitely be gone over.

http://www.441diesel.com/post/2013/01/14/64L-Powerstroke-head-studs-CAB-ON.aspx

Did you ever measure the coolant pressure to confirm the coolant is being pressurized? When you go to do the HGs, make sure you look over the cracked block threads. Also I would do the lifters while doing the HG job.

 

[RedRice589]

I blew head gaskets 3 times and never had a heat problem. Not always head gasket related LOL

 

[SVTDanny]

Forgot to update this.

I did a 'poor mans' pressure test - threw it in 4WD and brake boosted with the hood up so I could see the coolant bottle. Once the boost hits 20 pounds, the coolant starts to come up in the bottle, nearing the top. I did the same thing with the cap off and coolant came pouring out of the bottle. Combustion gas test was repeated several times and still never returned positive, but it's pretty obvious that the coolant system is getting pressurized. Still going to drain/refill coolant to see if I can resolve the heat issue but I'll be doing the gaskets after it's warmer out either way.

 

[B585Ford]

Forgot to update this.

I did a 'poor mans' pressure test - threw it in 4WD and brake boosted with the hood up so I could see the coolant bottle. Once the boost hits 20 pounds, the coolant starts to come up in the bottle, nearing the top. I did the same thing with the cap off and coolant came pouring out of the bottle. Combustion gas test was repeated several times and still never returned positive, but it's pretty obvious that the coolant system is getting pressurized. Still going to drain/refill coolant to see if I can resolve the heat issue but I'll be doing the gaskets after it's warmer out either way.

See my previous post. Pay real close attention when doing the studs and don't get in a rush.

 

[sootie]

A: get the heads decked
B: Get your tourque wrench calibrated
C: make sure the stud holes are clean
D: Dont over-torque the studs-i daresay 250 lb ft is ample.

 

[SVTDanny]

Thanks guys - sounds like a plan to me.

 

[WILD_PHIL]

Get any further on this issue?

Sent from my SM-N900V using Tapatalk

 

[Fordtrucks]

Be prepared to buy new heads. Mine were cracked beyond repair and so is most everyone elses.

 

[Dieselfever]

I have a customer truck with similar issues; 2008 F450 6 speed Lariat, has had overheating problems on and off since new and it's had the thermostats. I did the DPF delete with gearhead tunes on a MM to try and help fuel mileage(he usually just leaves it on stock anyway).

A local dealership said his overheating problem was either EGR related or water pump cavitation, since it already had the tunes we did the EGR delete. That made the coolant temps be erratic and also the heat in the cab would not work correctly as described by the OP. Now recently it is having issues with Puking coolant. I'm in the same boat, I don't want to say 100% that it's a headgasket issue but not sure what else could be making pressure in the cooling system now. Not trying to steal the thread but sounds like this truck and the OP's are having similar, if not the same issue

 

[SVTDanny]

Get any further on this issue?

Sent from my SM-N900V using Tapatalk

Popped a Mishimoto radiator and intercooler in my truck. Vac'd down the coolant system and refilled. Still seeing the same symptoms. I can guarantee it's my head gaskets or heads at this point.

Be prepared to buy new heads. Mine were cracked beyond repair and so is most everyone elses.

I'm planning on buying a set of heads before I do the job. Talked to too many people lately that say 6.4 heads are cracked 9/10 times. If mine turn out to be fine then I'll just resell the new ones.