98 Expedition - air in cooling system?

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I have a 98 Expedition 5.4 in which I just changed the heater core.
All seems to be working fine, but when I shut it down, it makes a running water sound at the heater core. It sounds like a babbling brook or as if you turned a water bottle upside down to empty it.
It makes the percolating sound for about 30 seconds, almost as if the coolant is settling, or emptying from the core itself.
There are no leaks anywhere and my fluid level remains constant after running many heat cycles.
It seems to me as if air may be trapped.
I have done many burping techniques, but the situation remains the same. It is more noticeable if I shut down while the heater blower is running, than it is if I shut down with the fan off. With the fan off, the sound is still there, but it is slight and subtle.
 
Did you replace the hoses as well? The factory hose has a flow restrictor in it and some of the cheaper aftermarket hoses don't have the flow restrictor built into them.
 
Yes, heater works.
My biggest concern is electrolysis, I can live with the sound upon shutdown, but it does not seem normal.
I replaced one heater core years ago in the same vehicle (with aftermarket core, this one is from dealer)
I had the same symptoms last time and after some time, the outlet tube developed leaks, upon removal, I see pinholes on 1 tube where quick connect fitting was. Not sure if electrolysis was to blame, or cheaper construction of heater core from after market source.
Anyone have a burping procedure for this vehicle that works, most videos on line have a radiator cap, this one just has reservoir bottle
 
I only replaced 4" of hose from where previous mechanic bypassed heater core to the heater core connections.
I used a coupler from the factory existing hoses and used factory ends to complete the install
All is the same as original with regards to hoses, except for the connectors
 
Try jacking\lifting the front end about 3 feet with the expansion tank cap off and the engine running. Give it 20 minutes with the stat open while you have it in the raised position. Should clear right up.
 
I understand the concept, but can't quite figure out how to get a 3 foot front lift at home.
I live in Florida, everything is flat our biggest hill is the garbage dump.
 
Can you expand on the electrolysis testing procedure?
That is my biggest concern, since I don't ever want to have to change this heater core again plus I don't think my plastic dash parts can handle any more, as it is, I spent days at the junk yard salvaging dash parts to replace all the cracked and broken pieces from removal...age is making it too brittle
 
I dont' think you need to lift it 3 ft in the air, but if you could get a pair of ramps like rhino ramps or something that get the front up high enough that the air would work itself out.


or you could always drive it up on ramps and let some air out of the tires for a little extra incline.


I replaced a heater core on my brother's 02 f150 a few years back and i guess i didn't recall hearing any noises afterwards i just filled it up the top and drove it around and rechecked the level etc and the core has been good ever since.
 
Originally Posted By: Fitz98
Can you expand on the electrolysis testing procedure?
That is my biggest concern, since I don't ever want to have to change this heater core again plus I don't think my plastic dash parts can handle any more, as it is, I spent days at the junk yard salvaging dash parts to replace all the cracked and broken pieces from removal...age is making it too brittle
https://youtu.be/6rc9t3Ve_bI
 
Cycling rpm up and down could help. I'm surprised they don't have the high point piping vent on this engine as they did for the 4.6l engines of that same era. I agree with the rhino ramps, then running the engine with the radiator cap off for a while, while cycling rpms. The car being on level ground with a reservoir about the same height as your upper coolant/heater piping makes for inefficient venting.

Expedition gurgling problem following heater core/radiator replacement
 
I tried again today, should the reservoir bottle coolant get warm? I would think it should.
Upper hose is hot, heater core hoses warm, but reservoir bottle is cool.
I tried reving up for 10 minutes, still no hot fluid in bottle.
Car is jacked up on drivers side with fluid level higher than heater core hoses
 
Can you unhook the heater core hoses at the firewall and flush water with a garden house thru to get air out then hook the hoses back up? Be sure to add a quart or so of straight antifreeze to rebalance the mixture.
 
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I have seen guys on ford forums use copper wire to ground the heater core to the vehicle ground to reduce electrolysis.

It was a big problem and a big job in the tbirds to do the heater core, and I put a ground strap on the last one I had.
 
Originally Posted By: Fitz98
I tried again today, should the reservoir bottle coolant get warm? I would think it should.
Upper hose is hot, heater core hoses warm, but reservoir bottle is cool.
I tried reving up for 10 minutes, still no hot fluid in bottle.
Car is jacked up on drivers side with fluid level higher than heater core hoses


Reservoirs don't really warm up. Now a degas bottle which has a recirc line connected to it like the Ford 4.6L will get hot (ie 2 lines). In this case your reservoir is only a place that collects some air (hopefully) or allows for a small amount of fluid to move for makeup/excess.

The reservoir won't usually get hot if the rest of the system is close to full. But when the car is up on ramps it is the highest point in the system for improved venting.
 
Originally Posted By: Fitz98
I have a compressor, how do you do that vacuum filling?


You are in luck ECS has the tool on sale right now, if you are going to do this grab it. It is a good tool.

https://www.ecstuning.com/b-schwaben-par...ASABEgJkLPD_BwE

Drain the radiator, save the coolant if its in good condition in a clean bucket add a little to it so yopu have engough to fill the system then use the tool to vac it down. This video may help.
 
Looks like a good tool. Do you know if it fits the Expedition bottle? Fitment specs looks like it is mostly for German cars
Also cooling system is full, when pulling vacuum, will this suck out the fluid in the head and hoses and areas that won't drain from the radiator?
 
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