Problems With Cooling System

~Mike~

~Mike~

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Hello all. I have a problem with the cooling system. Not on my 97 lsc but on my dads 98 lsc.

He had a mechanic working on the car and he has changed practically most of the cooling components. Originally the problem was that the coolant began overflowing from the reservoir with the cap on while driving. The low coolant indicator light would come on due to this.

Parts that have been changed:
water-pump, thermostat (changed twice), reservoir, all hoses, radiator, overflow plug and coolant sensor.

The guy that he hired suggested changing all these parts without pin pointing the exact problem. (horrible idea) It cost my father a small fortune after the mechanic finally gave up and said that the head gasket is bad and there's nothing more that can be done and he wants no further involvement. I advised my father to just get the car home and i would come by and take a look. I have a 97 lsc and have a great deal of experience with this cooling system. My first guess was an air pocket in the system. Any time i have done work on my own car, i was always able to get the air out on the first or second try (i know most of the tricks). I'm quite familiar with the procedure and i even made a special funnel that clamps down on the cross over tube and extends up about 2 feet. Ive had the car running with the crossover open for 45 minutes, jacked the car up, dropped it back down, rocked the crap out of it, removed the bypass hose connection in rear (thinking that maybe air was trapped up there). I saw a ton of air come out over the course of 30 minutes and then it would seem to stop. I also, dropped all coolant out of system twice and started all fresh all over again after failed attempts and about 5 hours in. We have driven it lots in-between attempts and everything else i can think of . There are absolutely no visible leaks and the car builds up solid pressure with the system closed. I can also confirm that the thermostat is opening and it was changed twice and i checked to make sure its installed correctly.

My indications that a problem still persists are:
coolant keeps overflowing out of reservoir while capped after driving (that was the original problem). Eventually all coolant leaks out of there and he gets the low warning light again and the car will start to run hot of course. Ive checked the oil and there is no indication of a milky mix from a bad head gasket that i can see. Also no smokey exhaust. Does this sound like more than just air in the system or another cooling component? Are there any other possibilities other than the ones I have mentioned? I'm at a loss and i don't know what else i can do to help. Thanks
 
It never ceases to amaze me that all these mechanics out there and they don't know how to properly fill up a burp a Mark. Save yourself some money and do it yourself. Coolant must be filled at the crossover tube, the engine must be on and the temp all the way to 90. Keep filling until you see coolant flowing across the tube. The mechanic must be a moron. Air is in there.
 
Did you replace the cap? It could be busted, causing the cap to relieve at less than the desired pressure. Check the cap and make sure it's completely flat on top. If it's domed, replace that sucker. That fixed the problem on my 97 a while back.
 
Yeah i know what ur saying, i mentioned it to the mechanic and he didn't know what i was talking about and really didn't wanna hear it either. Towards the end of his failed attempts to fix the car, he started looking into it and according to him he tried over and over again.
However, i did fill at crossover tube and have had it running and forgot to mention that i did have the heat on 90 while running too. I will have to keep trying it. I know its a stubborn system but was just curious if there's any possibility of internal engine damage as a root cause. I was 99% sure it was just air before today. Now im 50/50. I will keep trying at it though. thanks
 
98lincmk7lsc said:
Did you replace the cap? It could be busted, causing the cap to relieve at less than the desired pressure. Check the cap and make sure it's completely flat on top. If it's domed, replace that sucker. That fixed the problem on my 97 a while back.
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The cap is brand new along with the reservoir
 
You dont have to have the heat on to fill/test the system. The Mark VIII uses an "always on" heater core. So its always flowing. Once you know that it makes it a bit more comfortable testing it.

Jack the front end of the car up to be sure you have all the air out and into the crossover. Even, once filled properly, take it around aggressively and on some bumps to get any air pockets out of the back of the heads.

If after all that there is still an issue then I would certainly look into there being a head gasket blown. After all, everything else is new.
 
unity said:
You dont have to have the heat on to fill/test the system. The Mark VIII uses an "always on" heater core. So its always flowing. Once you know that it makes it a bit more comfortable testing it.

Jack the front end of the car up to be sure you have all the air out and into the crossover. Even, once filled properly, take it around aggressively and on some bumps to get any air pockets out of the back of the heads.

If after all that there is still an issue then I would certainly look into there being a head gasket blown. After all, everything else is new.
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I'm starting to think that's one possibility but i will continue exhausting the burping option before coming to that conclusion. If so, how might the head gasket be the problem with no visible indications from leaks? Might it be sucking air into the system or something else? On another note, is it possible to fill the system too much where it would over flow from cap?
 
~Mike~ said:
I'm starting to think that's one possibility but i will continue exhausting the burping option before coming to that conclusion. If so, how might the head gasket be the problem with no visible indications from leaks? Might it be sucking air into the system or something else? On another note, is it possible to fill the system too much where it would over flow from cap?
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mine over flowed from the cap from filling it to much. i did my thermostat and over filled it and it started spewing from the cap so i just drained some from the bottom of the rad.
 
You can have a compression test done to check and set your mind at ease to wether it's the head gasket or not, it's fairly inexpensive at the right shop. Here in FL it's about $65.
 
My guess is this idiot that calls himself a mechanic put in just any old brand of thermostat. These cars need a factory motorcraft thermostat. And the cheapest easiest way to test that is to remove thermostat housing, remove thermostat, reinstall housing fill with coolant which is easy to remove air with no stat. If it pukes out coolant like that then you have a blown head gasket.
 
chargerxr said:
My guess is this idiot that calls himself a mechanic put in just any old brand of thermostat. These cars need a factory motorcraft thermostat. And the cheapest easiest way to test that is to remove thermostat housing, remove thermostat, reinstall housing fill with coolant which is easy to remove air with no stat. If it pukes out coolant like that then you have a blown head gasket.
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I told him he needs to put in a motorcraft but not sure if he did.
 
compshmoe said:
You can have a compression test done to check and set your mind at ease to wether it's the head gasket or not, it's fairly inexpensive at the right shop. Here in FL it's about $65.
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Gonna take your advice and ask my dad to take it to a mechanic that i know and do just that. :)
 
You can over-fill. And only an idiot mechanic would fill the Mark VIII form the over-flow tank. That tank on the side MUST be closed when filling. Period. Coolant only goes in the crossover. I bet he filled it at the tank, or tried to.
 
unity said:
You can over-fill. And only an idiot mechanic would fill the Mark VIII form the over-flow tank. That tank on the side MUST be closed when filling. Period. Coolant only goes in the crossover. I bet he filled it at the tank, or tried to.
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At first he was until i told him how to fill and then he understood :eek: My father had it towed to a mechanic friend. So basically we are waiting on the news but im fearing the worst. I gave the mechanic the direct link here so that he can review all that's been done thus far.
 
So he had NO CLUE how to fill a modern car?? The cross-over tube is not a "Mark VIII" thing. Its pretty dang common.

If anything he may have caused more problems!
 
Not a clue at all... I know we share the same necessary methods as other cars. TBO, I wasn't aware of burping either before i got my mark viii about 3 years ago but figured it out with about 2 minutes of online research before repairs.. And im a carpenter...... So how a mechanic isnt aware of this is beyond me... :eek:
 
head gasket is shot These heads are difficult to remove? Possibly its a good chance the heads are warped anyway... Is it worth gettin into?
 
Much easier and cheaper to slap in a new JY motor.

Sapperfire has the same problem and thats why his new motor is sitting on a stand in my carport.
 
Its very, very rare a head gasket goes. You can replace them. But if you do the heads come off.... so... C HEADS!!! :D Slap on an 01 and up Cobra/Mach intake and you will have a beast!



or not...
 
I am surprised it took 10 posts to get there and your mechanic didn't
Do right away but +1 on a leak down test
 
I should back up a little.. The mechanic who we took it to, looked it over, drove it (i dont know how far) and claims he did a pressure test. He states that the pressure held steady for over an hour. He said that he saw no issues. Now i don't know how far he got into this. I asked him about possibly air in the lines and he said 'no way' all of the air comes out when you fill the car up. (Obviously i know that's wrong) So here we go again, another mechanic who is not familiar with burping the system. This is getting frustrating and i cant stand incompetence. We left the shop and my father followed me back to my house and i wanted to check compression. As soon as he got to my house, (10 minutes away) there was a puddle of antifreeze under the car. It was leaking out of the coolant reservoir cap that was changed twice (and the mechanic claimed he drove it 3 times and even got on the parkway and all was fine). Taking it to the mechanic was a complete waste of time and im not even sure if i can take his word on checking pressure in the coolant system.
I checked compression in all cylinders and everything looks fine. We rented a pressure tester for the coolant but the caps don't fit the reservoir on our cars. Im guessing this one was designed for a radiator cap only. I did notice, most times when i remove the crossover cap, a little smoke comes out. Almost looks like exhaust smoke so im guessing that could indicate the head gasket?? i dont know anymore and my father is ready to junk the car. Every time he drives it, the coolant will drain out of the cap which tells me its exceeding 16psi.
 
Pull spark plugs 7&8 and I bet they are wet. Shine a flash light in the hole and I bet you see water. Its not often a 4.6 DOHC will pop a head gasket but when they do that is where the go, 7&8.
Smoke in the coolant bottle and excessive steam out the tail pipes is a sure sign there is a leak in or around the combustion chamber.
 
LaserSVT said:
Pull spark plugs 7&8 and I bet they are wet. Shine a flash light in the hole and I bet you see water. Its not often a 4.6 DOHC will pop a head gasket but when they do that is where the go, 7&8.
Smoke in the coolant bottle and excessive steam out the tail pipes is a sure sign there is a leak in or around the combustion chamber.
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7 and 8? i will take a look tomorrow. didnt notice a smokey tail pipe but did see it more than once coming out of the coolant reservoir and the crossover. After i finished compression on one side, i put all back together, i started it for about 10 seconds just to make sure all was back together right before moving on to the other side and there was smoke that came out of the crossover. that quick. So that's why i thought def head gasket. Gonna do like u say and check 7 and 8. thanks
 
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