Overheating

[doug13c]

So I have a 01' xlt with a 5.4l and a rebuilt 4r100 trans and it has over 250k on the clock and I have had this for about 6 months now but recently it had overheated while I was going down the freeway so I got it home and started doing the basic checks on it. it was full of coolant/water when I left and obviously had spit some out but for the most part it was still full so I went and checked the thermostat and I had found a bolt that was not seated down all of the way yet there were no signs of it leaking from there and the thermostat opens and closes as it should so I drained the coolant/water out to see if it was nasty and needed a flush had about half a second of brown stuff then clear water the rest of the time so I'm not even sure if it had antifreeze/coolant at all in the system and if it was straight water yet I never really bothered to check it at all in the winter time since I had good heat and it was not overheating. I did not have any coolant with me at the time so I replaced it with water for the time being until I could get coolant. I had at least flushed the rad out fairly well and I had to what I had believed to have burped the system out well too and it really hasn't overheated since yet today once I got done driving it (had been driving around the city for about 30 min at 25-40 mph) i had decided to check my coolant reservoir and I found that the water was quite literally boiling in the reservoir and it was puking some out naturally. I went back out and checked the fluid level once it had cooled down and it was still in between the lines. The only reason I ask is I don't want to put a bunch of money into putting coolant in the thing if it is sill going to overheat and need parts replaced that were apparently bad. Do keep in mind it has been 100+F outside temp both of these times it has gotten hot no idea of the actual coolant temperature tho needle was in the middle the second time. So what should i do diagnostic wise or am I just stupid and need to put actual coolant/antifreeze in the thing. I used to race cars and we were only allowed to use water in them, with my coolant temps commonly getting 190 to 200+ with no problems in 90F weather hence why I'm running water at the moment with the intent of putting coolant in it once it is fixed yet I could be confused/stupid upon the differences of running a racecar on straight water versus running this vehicle on straight water for a bit.

Side note: if it is even important it has the aux rear heating and cooling system with a single pass radiator. Also if you guys know of any good and easy ways to burp the coolant system out please let me know.

 

[ManUpOrShutUp]

quick version since i burned one hand and cant really type

- any sign of coolant in oil and vice versa?
- pressure test coolant system (free loaner tool at Advance)
- test for compression gases in coolant (Harbor Freight, Advance, etc)
- run a real temp gauge on the obd port
- rad cap ok?
- make sure no air in system. raise front end and run engine w heat on and rad cap off. add fluid as level drops until level stops dropping

 

[Hamfisted]

Do you know any of the maintenance history for the Expy, other than the replaced trans? How's the waterpump look ? It's a quick and easy change if you suspect any issues with the WP. But definitely test the coolant for exhaust residue. It'll smell like exhaust and probably have soot particles or traces in the reservoir. Since you've only had it 6 months and it didn't have any coolant in it, I'm just wondering if it had a blown head gasket and somebody put some goo seal in the coolant system just to sell it and it's started leaking again.

 

[doug13c]

Just looked at the service history and it has a pretty good service history it went to a dealership for servicing all the way up untill 187k and then from there on it has only gotten oil changes from various shops untill I got my hands on it, I do remember that when I did the plug they all looked rusted but I called that up to when I flooded the engine out once before I changed the plugs out which I felt like they were the original plugs from the factory wich probably accounted to the rust on them from age but idk. There was no water in the oil and vise versa and I haven't had any power issues with the engine along with it has never leaked any fluids at all. My only complaint so far from the engine is the overheating now and I have never gotten above an average of 10mpg, is this common.

Edit I found a photo of one of the plugs I pulled out of it and they all pretty much looked similar

 

[Hamfisted]

Yeah, that plug has a huge gap, it could be original. Hopefully you'll see much better gas mileage with your new plugs. My 2wd '03 gets about 18 mpg on the highway and I don't know what around town, stop and go. Gas mileage drops off if you go over 70 mph very often. I'd be looking for a blown head gasket. It's not uncommon at all. I just did mine at 200k miles about 6 months ago. Had the heads rebuilt, with new springs and rocker arms at the same time. I did the labor and had about $500 in parts, and $350 in the head work.
Runs like new again now.

 

[Trainmaster]

Like ManUp says, check your head gaskets. The First Generation 5.4 blocks have a known machining problem on the right side that sometimes shows itself after 200K miles. Mine gave me 230K miles before developing a leak right above the starter.

 

[doug13c]

Well I kinda feel like an idiot I went out today to make sure the coolant system was fully burped and from what I could tell it was and when I got home I checked the coolant tank and it was still at proper coolant level and not boiling (I had been driving for about an hour in the city) so fully knowing it was under pressure I cracked the cap and it instantly started boiling and when I went to tighten the lid back up it wouldn't seal and stop boiling I started the truck to get the boiling to stop and to be able to remove the cap and when I looked at the cap the sealing ring was junk went to autozone and got a replacement cap and lone and behold it no longer was boiling when I shut the truck off. So I believe it was the junk cap that allowed the hot water to escape and overheat since the system had basically run low on water.

The attached images are of what the water in the system looks like now after flushing the rad and the engine block along with the junk cap.

 

[Hamfisted]

Keep flushing until you get clear water. Then drain the radiator again and add a couple of gallons of Zerex G-05 anti-freeze to the system. But keep an eye on it just the same. The system is "self burping" in normal use. If you see it continue to "burp" you have a head gasket issue.

 

[doug13c]

Keep flushing until you get clear water. Then drain the radiator again and add a couple of gallons of Zerex G-05 anti-freeze to the system. But keep an eye on it just the same. The system is "self burping" in normal use. If you see it continue to "burp" you have a head gasket issue.

May I ask why the zerex is it because it is the only coolant that can be found with the matching for standard because I was running straight water after I replaced the rad cap and my Temps were fine at 190 but I went to my dad's place and flushed out the rest of the system blew out as much of the water as I could and added in my coolant (it was the prestone all vehicles mix because I'm cheap) and ever since I have been hitting 220 on Temps and I have confirmed multiple times that it was all burped out and the head gasket is not blown with no temp change could that be because it don't say that it meets fords spec or not?