Cooling System Pressure Test Results

[tbrumm]

Over the last six months, I have noticed that I have had to add a little coolant to the overflow reservoir every once in a while as the level has very slowly dropped. I replaced the reservoir (Thanks, Brian!) as mine was cracked on top. I have kept my eyes open for residue, drips, stains, puddles, etc. but haven't really found anything. The coolant system has been properly maintained by me and I have a newer Champion radiator. I happened to notice a few drips of something on the front drive shaft about 1 foot aft of the yoke. I smelled it and it did not have an antifreeze (Fleetcharge)smell. I took a flashlight and made a good inspection of the rear of the driver's side head. I noticed a couple of drips on the weld seam on the cab behind the head. Again I smelled this "moisture" but it had no odor. There is a little bit of white residue up behind the head though and the coolant has to be going somewhere. It isn't being burned (no smell in exhaust), no coolant in oil or vice versa. Anyway, to get to the bottom of this I purchased a pressure tester. I should note that I run a Motorcraft 7lb. radiator cap and not the standard 13 or 16lb. cap. I hooked up the pressure tester and pressurized the system to 15 lbs. I left that set pressured for a couple of hours. The pressure on the gauge had fallen to 13lbs in that amount of time. The only leak I found was the packing nut on one the coolant filter shut of valves (passenger side by fuel filter) was leaking. I tightened down the nut a bit as it was a little loose and that took care of that drip. Now, this valve "could" have been leaking all along, even with the 7lb cap, and I may not have noticed that. A slight drip would have just dropped onto the crappy fender sound insulation. That does not explain the drips on the driveshaft and cab seam (which didn't smell like coolant to me but maybe my sniffer isn't to good anymore). One thing is for sure: there was no coolant leak at the back of the driver's head while the system was at 15lbs. This was with the truck stone cold, so maybe the headgasket is only leaking a bit when the the truck is up to operating temp. Anybody experience anything similar or have any suggestions for additional testing? Thanks for reading! Todd

 

[riotwarrior]

Taste...

 

[tbrumm]

Taste...

Thanks, Al! Doh! I actually hadn't thought about that. I guess if it tastes sweet I will know. If we had any stray cats around I could have them taste it for me . Just kidding - no angry replies from cat owners now. I am a responsible antifreeze user. I could probably have my Wife smell the "moisture" as well. Her nose is more sensitive.

 

[riotwarrior]

Stick finger in pull it out taste....I do it

 

[MTKirk]

+1 on the taste, you're lucky it's not G05 , that stuff is insanely bitter.

Have a little Vodka on hand to rinse with. On another note, if I had a 7lb cap on my truck, it would be blowing steam all summer.

 

[tbrumm]

Thanks for the responses. I tasted the drips on the driveshaft. Ugh! not plain water - awful bitter taste. But, having never tasted AF before (I know, there is a first time for everything), I had nothing to really compare it too. So, I took a taste of some 50/50 Fleetcharge I have on hand. Stronger awful bitter taste (no wonder the cats won't touch it ) but still basically the same taste. Didn't have any Vodka but rinsing with Mttn Dew a couple of times did the trick. When the truck is running cold (or I have the system pressurized with the tester) , there is absolutely no coolant coming out the back of the head. It must only be doing it when fully warmed up and under load. Of course, when I crawl under there to look after a run, there are a few drips on driveshaft but the back of the head and everywhere else in the vicinity is completely dry. I am going to take the truck on a long run tomorrow and see how much it leaks. Seems more than likely though that a HG replacement may be in my future unless something else shows up.

 

[79jasper]

Don't forget to check the water pump, just in case.

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[riotwarrior]

Tighten hose clamps ..

Some bastions hqnflg hoses by lil nylon doohickys...needled through the hose...these PMO as it usually leaks there...

So check hose clamps...quick n easy...may want add some UV tracing dye and get a hold of UV light...see leak easy way.

JM7.3CW

 

[tbrumm]

I took the truck on a 200 mile run yesterday. More drips on the driveshaft and wetness on the back of the head - enough to be able to see that the coolant is coming from the "upper" rear of the head. I have attached a couple of pics to show the drips on the driveshaft and the wetness at the head.

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So, it looks like a HG project is in my future. I am not panicking as the leak is minor and the truck is still drive able, but obviously has to be fixed at some point. I have time to gather up my parts and this also presents the opportunity to install studs. The truck is N/A now, but at least I would have the studs in place for a possible turbo in the future. It would not have been all that long ago and I would have been panicked over something like this, but then i found OILBURNERS! Between Mel's writeup and Tim's writeup, I know I can handle an HG install(once spring gets here!). I picked up a new (well, used one time) 2 ton cherry picker for $35.00 off CL to use to pull the heads. Guess I will get some studs ordered out from R & D as he has the lowest price. I appreciate the help and suggestions, guys. Maybe I will do a write up when the time comes - hmmmmmm.

 

[icanfixall]

Please... Before you remove any bolts take pics. Then every part has a pic taken so if you have any questions how it goes back together you just look at the pics. Our cell phones are great for just this idea. When installing the heads its best to have 2 people. One to guide the head to the block and the other to lower the head by the cherry picker. I suspect you are doing the job with the engine in the rig. It will be tight on the passenger side if you don't remove the hvac cover. Also with the drivers head off its a great idea to change the oil cooler o rings. you will never get a better chance to remove and install the cooler. With the head out of the way its simple and you are working on top of the cooler. Not under it getting all that crap in your face. If there is one thing constant in this world.. Its gravity.. EVERYTHING fal down usually in you face, mouth or eyes... Gravity sucks....

 

[tbrumm]

Thanks, Gary - that is all great advice. While I won't be doing this until spring, I will certainly heed your suggestions when the time comes. Yes, I am doing this with the engine in the truck. I had already planned on doing an oil cooler reseal anyway even before this coolant leakage issue came up. While the head bolts are close to the AC plenum on the passenger side, the rearmost head bolt on No. 8 on the driver's side seems like it is almost right up against the cab - that one looks like it will be a real ******. Not so much for getting out, but for being able to get a torque wrench on it without a universal joint. And while I don't suspect there is anything wrong with the heads, I will do some research into shops in my area that are able to do a proper inspection on IDI heads and repair if necessary.

 

[OLDBULL8]

If your going to ARP stud it, the studs act as a guide when installing the heads, if not studs, just grind/cut heads off of about 4 bolts to use as guides, grind screwdriver slots on end for removal.

Why don't you re-torque the head bolts? Worth a try. Loosen one bolt at a time a half turn, re-torque to spec +10 ft lbs., do all just using the 1-2 sequence.
If using a torque wrench to loosen, set it 20 ft lbs above tightening torque, if it takes more than that to loosen, then it's an indication the bolt might be rusted in, remove, clean, reinstall, you will have to clean the threads if bolt is taken out, put a little grease on the tap, that will collect any rust on to the tap.

Edit: A pulley tap has a long length to go thru the head depth.

 

[79jasper]

I think we had to hold the studs in the head while setting it on, then put the rest in.
Wasn't room to slide the head on with the studs in place.
Definitely would've been nice to have just pulled the engine.

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[tbrumm]

If your going to ARP stud it, the studs act as a guide when installing the heads, if not studs, just grind/cut heads off of about 4 bolts to use as guides, grind screwdriver slots on end for removal.

Why don't you re-torque the head bolts? Worth a try. Loosen one bolt at a time a half turn, re-torque to spec +10 ft lbs., do all just using the 1-2 sequence.
If using a torque wrench to loosen, set it 20 ft lbs above tightening torque, if it takes more than that to loosen, then it's an indication the bolt might be rusted in, remove, clean, reinstall, you will have to clean the threads if bolt is taken out, put a little grease on the tap, that will collect any rust on to the tap.

Edit: A pulley tap has a long length to go thru the head depth.

Thanks for the suggestions, Bill. I guess it would be worth a try to re-torque the head bolts. Nothing to lose (unless I were to break a bolt) but trying to loosen them would tell me what I may be in for anyway. I may put that project on my agenda for next weekend. I'll have to pick up a set of valve cover gaskets before I make the attempt.

I know in both Mel's and Tim's write-ups, they had a few of the rear bolts/studs up in the head while the head was being set on, otherwise the bolt/stud was too long to install after the head was on.

EDIT: The head bolts on the 7.3 are 1/2-13 correct?

 

[typ4]

The dually engine has a random leak at the front top of head. I thought it was a stat gasket but nooooo. So I put a tube of silverseal in it and so far so good. may work for you.