You mean to pressurize the system and make sure it holds 16 PSI without venting? I don't have a problem with the pressure but the issue I can see is if I am at 14 PSI at 200* what is going to happen when I am towing and the coolant temp is 225*? I have to think that the pressure will climb and cause it to vent.

 

Yeah and I will be checking the level in a few more minutes when I leave work because it has finally been sitting on level ground long enough that I can get a good reading!

 

I read the level as a 1/2", either side of a line. It's up one day, down the next and I don't sweat a little change one way or the other.
If the bottle has coolant in it, I'm good, trucks good.

To pressurize the system, your removing the cap and replacing it with something to "pump up" the pressure, it won't vent unless you vent it. You most likely can rent the tool at AZ or Advanced Auto.

The cap will vent at 16psi, as long as your not over filled, it shouldn't blow coolant everywhere. Had mine at 225* while pulling a 6% grade that was 7 miles... no blow, fan on high. When your pulling that grade, are you down shifted to get RPM up? The ticket to keeping these trucks cool, down shift and let the RPM come up, that moves the coolant and puts the fan on high.

 

Well the coolant level was good, it was just below halfway between the lines. I hooked up my trailer and before I was even out of my neighborhood I was pushing 16 and easily got to 17.5 without even trying to push very hard and only on surface streets not the freeway or anything. What is weird is it is in the 17 PSI range and still hasn't vented so either my pressure sender from edge is reading high or the cap isn't venting at 16 PSI. I am going to put another cap it and retest tomorrow. If multiple caps are holding into the 17 PSI range I will be suspecting my pressure sender isn't acurate for some reason.

 

Some caps vent as high as 18 psig. The TSB below says a range of 15-18 psig.

http://www.phila.gov/fleet/Warranty%...sb09-08-03.pdf

Also, I am doubtful that the pressure sensors are exact. They are probably within 1 psig or so of being accurate.

That being said, with your numbers, it seems you have an issue.

 

And its to full, the min is the new maximum. I run about a 1/2" below the sticker.

If you got to 17psi and didn't get out of the neighborhood, I agree with Mark. You'll not get far without blowing coolant.

The gauge could very well be wrong.

 

I suspect that Ford caps will all vent closer to 18 than to 16 - simply for Ford to avoid issues. That being said, I wonder if 18 psig in the degas might be getting close to the point where the "crimped on" radiator tanks start having issues.

 

What's weird is I can get far. I've gone 450 miles of hard pulling without it puking since the first time puked and I didn't add coolant so it obviously isn't too low to puke.

 

Maybe, my stock radiator did start leaking from the crimps but that was 10,000 miles of mostly towing before it ever puked and some of that has been hard towing with ambient temps of 100+ and steep inclines and ECT over 225 and it never puked.

 

I'd lower the level to at least the bottom of the sticker or lower by 1/4" and then see what happens. Less water is less pressure as well, less to expand.

 

Ah I thought the sticker was the updated level and the plastic line was the old min. What's weird is that degas bottle is less than a year old and I bought it from Ford. I would've thought it would have been updated. I will drain some coolant out.

 

Have you vented off the pressure after your truck has come up to operating temps. Then see if it climbs back to 14 psi or if it hangs around 2-4 psi ?

That will tell you if it's pumping gases or just thermal expansion.

 

I run an Isspro 0-40 coolant gauge, tied into my bypass filter housing. I have blocked the filter supply line in and don't see any appreciable change in pressure, so I feel that the filter housing is appreciable to having it tied directly into the degas. I will see about a 1/2 psi increase when I give it throttle, but this will fall out when the tranny shifts and RPMs fall back down.


My level is just about where yours is. I think it is high and will lower it before my next tow. I'm running Ford Gold. I had the dealership replace the upper radiator hose not long ago and they put in 3 gallons of Gold and 3 of distilled. I feel like my mix ought to be close, but haven't attempted to verify.


Unloaded, I'll hang between 10-12 psig, and this is generally good from 190 ECT up through the upper 190s. Towing my 8K bumper pull, it is not uncommon for it to sit between 14-16 psig. It is very temperature dependent, and will fall back to 12-13 when the fan drives the temp below 207. It is not boost dependent. It has vented before - I think on a trip where it was about 88 F, with coolant temps hitting 220. I think the level was a bit higher than it is now.


I'm not convinced I don't have a small head gasket leak (or EGR). No smoke, no coolant loss. I don't see any boost correlation to coolant pressure, so I'm happy there. I also see a strong temperature correlation to pressure. Mine will rise from zero to 10-12 gradually (not linearly), but not the 5 psi spike you described earlier.


I'll be towing next weekend. Will lower the level and report back on pressure. It'll only be in the 50's so I may not even see the fan come on.


I do agree with the other guys that if you are seeing 16 psig before getting out of the neighborhood, you have something going on.

 

I agree it definitely just seems weird but I drove it hard all day on the freeway etc even though it was unloaded I cant imagine how unloaded pushing 26 psi of boost wouldn't cause me to see the 16-17 range all day but pulling my 3000 lb trailer 3 block at 20 mph caused it rise all the sudden. It just doesn't add up.

 

Subscribed