98 5.4 coolant level issue!

[ARiley23]

Lower rad hose was replaced about 2 years ago not sure about all the others no dry rotting on them and they do not swell and go back down. There is good pressure in the upper main hose when I squeeze it

The fluid is going somewhere and then coming back to bottle. How old are the hoses? Are they swelling when hot and contracting when cool?

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[1955moose]

Try parking on a steep grade, or Jack front end. Theirs many videos on how to purge air. I hope your problem is that simple.

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[ARiley23]

Try parking on a steep grade, or Jack front end. Theirs many videos on how to purge air. I hope your problem is that simple.

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I've tried that before when I knew for a fact I had air in the system and it did not work! Ill give it a shot in the morning i guess


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[ExplorerTom]

Is 165 as warm as the engine gets? That's about 30 degrees too cool.

The thermostat opens at 190 or so. For some reason the first time I run the engine after draining the coolant (replacing thermostat, radiator or intake manifold) the engine will go up to about 215-220 before opening the thermostat. Then it cycles between 190-205 just like it should.

 

[ARiley23]

Is 165 as warm as the engine gets? That's about 30 degrees too cool.

The thermostat opens at 190 or so. For some reason the first time I run the engine after draining the coolant (replacing thermostat, radiator or intake manifold) the engine will go up to about 215-220 before opening the thermostat. Then it cycles between 190-205 just like it should.

No, it gets up to 190 195

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[Rich_007]

I would fill the reservoir to the cold line, start it up and turn the heaters on for the front and the back, let it warm up with the reservoir cap off or loosened. It might bubble out a little but it might get rid of any air pockets in the system.

 

[bobmbx]

You know come to think of it the other day I was gonna top off the coolant to the max line took the cap off (was cold had been sitting over night) and it made a hissing noise like letting air in or out. Did not have coolant to add so I just put the cap back on . Maybe I got some air in the system?

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That hissing from a full radiator is normal. Over time, all those tiny bubbles that didn't get burped out eventually make their way to the top of the radiator. Most of them get expelled into the overflow tank when the pressure in the system opens the vent on the radiator cap. If you top off, and I mean right the rim on the radiator every time you open it, eventually you won't have any air at the cap. Which is how the system is designed to work.

As to the observation you made....if your system isn't leaking, I'd forget about it. But, you might try replacing your radiator cap, it sounds like the spring relief valve isn't working right.

 

[Rich_007]

bobmbx
I think he said in an earlier post he didn't have a radiator cap.
My 2000 5.4 is like that too. Everything has to be done thru the reservoir, unless you want to take the top rad hose off the radiator.
I had a similar but diff problem. Would stop putting out heat at idle. I figured there was air in there. I was already at temp and when I cracked open the res cap i heard it hissing and a little bubbled out, then it sucked down the entire contents of the res.
It is funny, (if i understand his post) the levels in the reservoir are backwards from what you would expect: higher when cold and lower when engine is at temp.

 

[ARiley23]

Well today I added coolant to the cold fill line and drove about 50 miles and had no issues with temp or the level fluctuating. not sure what the issue was?

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[Rich_007]

Sounds good.
Like someone was saying earlier, if its just air in the system, it usually sorts itself out after a couple cycles of bringing engine up to temp and cooling back down. Between my own experience, what I have read on here, and the fact there is no rad cap and the res is teed in to the lower radiator hose, it seems to take longer sometimes to purge itself.