goz40

Hello....I have a 1996 3.8 Mustang (150k miles) located in NJ. I am having the same problem with overheating and cold air blowing from heat duct. I had the head gaskets replacedand re-manufactured heads the being of summer 07'. Car ran fine no overheating problems all summer. As soon as it got cold and I needed to use the heat the problems began. It is a intermittint problem, I changed the thermostat , also the belt , had the system pressure tested (it was fine , no leaks). I checked the fluid level and it is also fine. The engine warms up to the N in normal range. I turn on the heat and it works fine then 10 miles later it is blowing cold air and I notice the temperture starts to rise. It raises to about theL in normal than a a mile or two it goes back down and the heats returns to hot. I checked the fluid level when I got to work and the fluid overflow bottle was overflowing. The radiator was to hot to check, I went out a few hours later and the fluid level is ok in the radiator and the overflow bottle went down to about 3/4 full. I started the car with the radiator cap off and warmed the car up and saw the fluid start to flow once the thermosat opened I checked the temp gauge and it was on the N in the normal operating range. Water pump does not make any noise so I am guessing the bearings are ok and no fluid is coming out the weeping hole. Does anyone know what the problem could be? Your help would be appreciated because I think the garage I take it too doesn't have a clue nor do I?

boltzy2006

having the same problem but not loosing heat but its driving me nutts cant figure it out and scared to drive it to far

stangdriver2007

have fun with the headgaskets again. ur losing coolant and ur gettin hot the reason why when its cool again the heat doesnt expand the aluminim heads until the car gets warm then the car will overheat again. u might not see antifreeze in the oil but it doesnt mean ur headgaskets arent bad. the bad part could be by the anitfreeze port and air is getting in and backin up the coolant therefore u are running on air instead of coolant. sorry to tell ya. another 1000 dollar job. have it pressure checked first if it drops u have a blown headgasket if there are no known leaks. buy a new engine since everytime ur car overheats it hurts the piston rings bad.

RyansQuick6

OKay, for a better more reasonable explanation;

Your years suck for head gaskets. it's a very easy fix if you have the know-how. Your coolant is leaking from the coolant passages into the combustion chamber, so there will be no signs of water in the oil. The head gaskets need to be replaced with the new style 01+ gaskets. This will fix your problems. If you have a machine shop available have them check the heads for warpage, if they are warped it'll be cheaper for you to buy a split port swap and you'll gain about 40hp. This is also the easiest time to this job anyway, if you have the funds available.

The rings rarely, rarely get damaged in this instance, unless you let it go for a while.

The reason you can't get heat is because the air in your system will not produce heat in the heater core the same as hotcoolant.

stangdriver2007

but he has overheated a few times in the begining of 07 too so id be carefull. the whole problem with the head gasket failure was the small coolant passages. the heads warp very easily too and even if they are slightly warped but still in specs MILL THEM. these engines are horrible for head gaskets 94-95 were the worst years for this problem

MantaDreams

guys guys guys
stop troubleshooting backwards from the worst possible answer.
start simple
1. thermostat installed in proper direction.
2. sufficient coolant
3. properly bleed air from hollow bolt on t-stat housing, while filling.
4. water pump not working
5. plug in hoses
6. if hoses replaced, were they the correct ones (one of the hoses has a special restictor built-in.... I guess to regulate flow.) were the hoses connected exactly back the way they were.
7. fouled rad

THEN start on the more complicated, deeper, threatening problems.

RyansQuick6

Or we can start fromt he proven point instead of having him waste time and money "replacing parts" instead of fixing the most common problem.

I am confident in recommending a head gasket replacement on all 94-95 3.8's due to the fact that it is what every single one of them suffers from. I understand what you mean by not wanting to jump the gun, but on this particular issue that all these guys have, this is what I will always recommend.

goz40

Guys,

I do thank you for your comments. My car ran fine all summer (re-manufactured heads and new gaskets in June and thermosat). Problem started End of November. In the shop twice since than. Pressure tested ,shop said it was ok. No antifreeze in oil. Changed radiator cap. These changes seem to work on morning commute to work. (30 miles). On my way home car overheated and no heat again? In shop again, changed thermosat. This change made it thru the morning commute and on my way home it overheated and lost heat again. When I got home I checked the overflow and it was half full and radiator was full when I removed radiator cap. I reved the engine the thermosat opened and the fluid level dropped to I could barely see it at the bottom of the radiator. I refilled the radiator to proper level. I lost heat and the engine overheated on my way to work this morning. It would overheat and lose heat, I work tur off the heat and the engine temp would drop after a mile or so. I would turn on the heat and the engine temp would remain ok for a few miles and than repeat again to lose heat and engine overheat. It did the same thing tonight on my way home tonight. Damn this really does s_ _ k.

goz40

oh I did find this on a site.

Two possible signs of a compression leak would be:
A. A sudden loss of engine power
B. Engine coolant that's being forced out of the recovery tank or
radiator.
C: Unexplained coolant loss.

MantaDreams

I am reading the classic case of insufficient coolant. What little you have surges through.

And I haven't heard whether you have ruled-out an air pocket (that is why you are supposed to loosen that top bolt on t-stat housing ... you add coolant until you see it come out through the side hole of that bolt, then resecure that bolt.)

Draining coolant during/after a head gasket jobrequires a lot more coolant than just your normal everyday flush.

Ryan I know you may be speaking from experience or maybe a lot of hearsay when you push the head/head gasket problem or reputation. But it was not my experience. I replaced the gasket with the year-model felpro and no problems. I don't understand how you would be so quick to suspect the head gasket so soon after it was "repaired." Everything we suggest is time and money. But I wouldn't be crackin heads loose unless I saw steam out the talpipe - or had a shop sample the emissions for coolant.

and geez, a problem with coolant only after turning on the heater for the first time. Uhhh guess what?!