Stang 5.0 Overheating Issues

Ricky B

Ricky B

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Joined
Mar 20, 2005
Location
LKN - Tha Dirty Mo (Mooresville, NC)
Ok so this technically isn't a 4x4 so pretend I have swapped a 5.0 into a rig and am asking about it :lol:


My Dads DD is a 95 Mustang with the 5.0, we are having overheating issues and can't figure it out. Daily driving its fine but if you turn on the AC at all it will immediately overheat. Or if you drive on it hard it will overheat but I'm talking like high rpms for an extended amount of time.

We have replaced the thermostat and had the radiator flushed, there was no gunk in the system its clean, also replaced the radiator cap.

Now here's the part that has me worried - you can smell antifreeze all the time when its running, like no terrible bad but if you come to a stop light or something you can smell it. However there is no lack in performance in the engine whatsoever which you would assume if a headgasket was blown it would run bad.

This isnt a new problem, its been going on at least a year if not longer it just has been ignored since normal driving doesn't make it overheat and it hasn't been a primary DD vehicle till recently usually served backup for everyone kinda car.


I don't know if this is related but for some reason even thou its stock unless you run 93 octane in it it sparkknocks, but it has done that since we bought it like 7 years ago so thats nothing new.

However if it does heat up bad it will shut itself off and not let you start it again untill it cools off (computer failsafe maybe?)


Anyway anyone have any ideas? I guess my next step is to just replace the water pump and see if thats the issue it just is a pain on everyone cause its my Dad's DD right now and we don't have an extra car anymore since my lil bro is DDing my Z71.
 
Intakes on those were notorious for busting at the back of the engine and leaking coolant.

But its not as nice as it sounds, BOHICA when you price that puppy.
 
Any weeping around the freeze plugs and WP seal? I would stab at WP or thermostat hung shut
 
Is you fan clutch working?

also if you have mixed macthed fords part make sure you have th correct fan for the direction that it is spinning
Some of the other ford 5.0 had the fan tha spun the other direction.
I bought a 5.0 mustang once that was overheating only at High speeds and that was the problem.

it could be a failed water pump and the anti freeze is comming from the drip hole. I kno most of the time the will leak first and then fail but I have seen the intenals fall apart and not leak much at all
 
My 93 was the same way, extended driving at higher rpm or ac on it would run hot. Fan clutch was good and tight, radiator was good, etc.

Tore it down to install Trick Flow top end kit and found head gasket failed. Wasn't blown, just leaking into the combustion chamber. There was no sign of coolant on the plug, obviously no coolant in the oil or vise-versa.

You need to use a combustion gas tester to check for combustion gas presense in the coolant. You can find them on tool trucks like Mac or Snap On. Your better parts stores may have them.

I would definately make sure there is air flow accross the condensor as well. Make sure the air dam in front of the car is properly in place also.

I have been into many, many 5.0's with overheating issues in the past. PM me as needed.
 
Thanks for the tips guys,

yea it is Efan and it does run, and its stock so I'm pretty sure its blowing the right direction, this vehicle hasn't been modded at all except for exhaust and a mild lowering kit.

I've spent a good bit of time under the thing over the last year or so (like I said problem has been around and ignored for quite a while) looking and have never been able to find a leak anywhere.

So from what I'm hearing its a toss up between intake gasket, head gasket, and water pump

I guess my first step to take would be try and get ahold of that exhaust gas tester thing? Otherwise I would just have to replace the water pump and see if that fixes it?

I've assisted in a 5.0 intake swap before in a buddies car and it was not a fun mod to do so i know what you guys are sayin with it bringing the suck :shaking:
 
Hey guys i did the coolant pressure tester thing (hooks on where the cap goes) and It never showed a leak i don't think, if i put it on at zero psi it would only rise about 5 or so psi before the fan kicked on and it drop back, then if i pumped it up to 16 psi (which is what the cap was rated to) it would drop to like 10 when the fan turned on, then rise back to bout 15/16 then drop again just like it did with no initial psi.


does that sound normal, the instructions said to look for an increasing build in pressure or the needle to be jumpy on the readings to indicate an internal coolant leak and it did neither.
 
jrraw23 said:
Hey guys i did the coolant pressure tester thing (hooks on where the cap goes) and It never showed a leak i don't think, if i put it on at zero psi it would only rise about 5 or so psi before the fan kicked on and it drop back, then if i pumped it up to 16 psi (which is what the cap was rated to) it would drop to like 10 when the fan turned on, then rise back to bout 15/16 then drop again just like it did with no initial psi.


does that sound normal, the instructions said to look for an increasing build in pressure or the needle to be jumpy on the readings to indicate an internal coolant leak and it did neither.
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I'm no mech engineer, but it would seem a head/intake leak/crack could go 1 of 2 ways. If it was forcing coolant into exhaust passage I could see a situation where it would never build pressure in the cooling system.
Honestly, I need to wrap my head around this a bit, Im not sure why its dropping that much when the fan kicks on, I understand temp lowerieng but that seems a bit drastic.
 
SkyHiK5 said:
I'm no mech engineer, but it would seem a head/intake leak/crack could go 1 of 2 ways. If it was forcing coolant into exhaust passage I could see a situation where it would never build pressure in the cooling system.
Honestly, I need to wrap my head around this a bit, Im not sure why its dropping that much when the fan kicks on, I understand temp lowerieng but that seems a bit drastic.
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Yea I mean the temp sensor in it doesn't actually have numbers it just says "normal" and has a range on the dial, but you can see that the temp will go to like not quite 3/4 of the way then when the fan kicks on it drops back to just below 1/2 and back and forth. Thats sitting at idle, driving it normally stays at almost 3/4, especially on the interstate it'll stay high.

If it gets much higher than that 3/4 range it'll start acting funny if you drive it hard, and if it gets too high it will automatically cut itself off but the only time its done that was in the garage when I force it to go too high or one time when we were trying to drive up the mtn and my truck was struggling to pull the jeep at like 20mph wide open and the stang was following me it overheated and cutoff.

But I mean, turn on the ac its over, she immediately heats up.

I need to figure out where I can get ahold of one of those exhaust gas tool things WNC Custom Jeeps was talking about.
 
The water pump should be ok as long as the weep hole isnt leaking. Im sticking with the intake or head gasket. If it gets to hot and pops let me know I have something to lower in its place!!!
 
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