1993 Ford Taurus - HVAC and Exhaust issues

The car:

- 1993 Ford Taurus sedan
- 3.0L GL
- 110k miles
- Auto trans
- A/C

Issue #1:

Very low heat inside cabin, even with windows up and heat on high. While some heat does come into the car, it feels like it does it in waves. For a couple of mins it will feel mildly warm, and then it will get much colder for a couple of mins. I thought this was the cycling of the thermostat, but I've never felt it like this before. Even when the air coming in is "warm" it's still very cool compared to what it should be.


What I've done:

- Thermostat has been replaced less than a year ago.

- These tests were done from a cold start, and with the HVAC controls all turned to "Off" - I first checked the feed lines going into and from the heater core. After letting the car run for 5mins, the passenger-side line felt warmer than the driver's side line. After another 5mins, the drivers side was *very* warm, and the passenger's side didn't feel much warmer than the first time I checked. After another 5mins, the passenger side caught up with the driver's side, and they were both *very* warm and about the same temperature - the driver's side felt about the same temp as it did the second time I felt them.

- To see that the doors for the HVAC were working properly, I turned the car to Acc. and turned the HVAC knob all the way from hot to cold several times. I was able to hear the motor (on the HVAC door) working, and it sounded like foam was being seated when set to completely hot or cold.


Issue #2:

White smoke from exhaust, and *lots* of moisture leaking from muffler and other parts of the exhaust. After letting the car idle in one place for a couple of minutes, there was already a puddle the size of a dinner-plate from whatever is leaking from the muffler.

Car at times also runs rough, and sometimes bogs down during acceleration (not sure if this is related).


What I've done:

After running the car for 5mins, I moved the car to another spot on the driveway, I looked over all leak spots, but it seems like anything coming from the car was from the exhaust.

I checked the engine coolant, and the reservoir is nearly empty. I could not see any other leaks on my driveway (note: this was only for a couple mins, so it doesn't mean there are no other leaks, I may have just not seen them) so this leads me to think one issue. I'm hoping not to say anything, to see if you guys come to the same conclusion as well.


Any input, advice, or things to look for would be GREATLY appreciated! Thank you all in advance!
- Woody

Welcome to the forum, and great posting format!

I have a few questions. Was the thermostat replaced looking for this problem, or just out of maintenance? Did the problem begin shortly after replacing the thermostat? Have you checked the level of the coolant in the radiator? Have you tried filling the recover tank to see if it continues to use coolant? Did the moisture from the exhaust just start as the weather got colder?

For the cyclic heat I suspect you might just have an air pocket in the cooling system, especially if the issue began after the thermostat was replaced. I don't recall if the 1993 uses a heater control valve in the input to the heater core or not. If it does, then you need to determine if the valve is functioning the way it should be. If you think there might be an air pocket, you should top the system off (radiator and overflow tank) and drive the car to get it up to temperature a couple of times. Check the radiator when cold to make sure it is staying full since if the coolant level is not to the cap it won't effectively pull coolant from the recover/overflow tank. Your 1993 might also have a bleed screw on the cooling system to bleed the air, but you should be able to get by with topping off the system.

As for the moisture in the exhaust, if it just started as the outside temps cooled, it only happens after the car has sat for quite some time (overnight, all day at work, etc.) and the exhaust doesn't have a distinct sweet smell to it, I would not be too concerned about it being a head gasket or cracked head/block issue. The colder temperatures overnight will cause condensation, so water from the exhaust is not uncommon with a cold car.

-Rod

Dang, I forgot to check the coolant level before I made this post. I topped it off (it was 2 gallons short of full :shakehead ) and the heat now works great! That issue seems to be solved, however, I checked the coolant level again after a couple days, and had to add another 1/2 gallon to top it off again. For a car that has no visable leaks, this makes me think more and more that it's a head-gasket that's gone bad. Especially when losing so much coolant over just a couple of days of normal use, and not seeing any puddles other than the exhaust. I also took a look at the dipstick, and it looks pretty normal - not thick or foggy like a milkshake. However, this was just the dipstick, I haven't actually drained the oil to get a good look at it.

My fiancee often complains that the car smells like 'burning chemicals' so maybe that's the anti-freeze she's smelling? I noticed the exhaust has cleared up a bit, and isn't as 'foggy' as it was, but it's still got quite a bit of white smoke and moisture coming out of the muffler. Any other ideas? Does this sound like a head-gasket to you guys? I don't mind doing the work, but if there's any possibility it could be some other issue, I'd love to try those fixes before having to replace the gasket :uhoh:

Thanks again for the help everybody!

Is the passenger side floor wet? Maybe it's a heater core that's leaking and your fiancee is smelling the heater core leaking.

You could put a pressure tester on the system to see if it's filling a cylinder with coolant or creating a puddle on the passenger side floor.

-Rod

We haven't noticed anything at all, but next time I have the car (Wednesday) I'll be sure to pull back the carpet, and check out both passenger and driver's side for any moisture.