Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: Shevretti on July 26, 2005, 04:56:22 PM

Title: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 26, 2005, 04:56:22 PM
Hello again!
I've decided to change cooland in my T-bird myself as I don't like if someone is working on my car. I found the engine and radiator drain plugs but I'm not sure if it's safe to unbolt the engine drain plug in 18 years old car. What do you think? Not sure if someone ever used (unbolted it)... hopefully someone did. Should I bolt it back on silicone?
The other problem I have is how to fill in the system to prevent from boiling coolant if it won't reach the thermostat at first. Is it a good idea to unbolt temp sensor (sending unit) so all the air would go up there?
Thanks in advance for help and any other advice!
Mariusz...
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Ifixyawata on July 26, 2005, 04:58:32 PM
To drain the coolant, you should only have to use the radiator drain plug.  I'm not sure what drain plug on the engine you're talking about.  However, when you refill the coolant, it would be a good idea to run the car and slightly open the plug on the thermostat housing, to allow any air in the system to escape.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: JeremyB on July 26, 2005, 05:08:01 PM
I wouldn't touch the engine drain plug unless you're prepared to tap a new hole when you strip the threads.

I'd recommend that you flush the coolant if you want to change it.
 (http://www.partsamerica.com/product_images/img/pt/PSTAFKIT.jpg)
Hopefully you can get something like that in Europe. Backflushing will get a bunch of crud out of your system that simple draining will not.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Tbird232ci on July 26, 2005, 06:40:05 PM
i pulled my lower rad hose off, had a bucket right under it, and i didnt spill a drop suprisingly

that drains the rad, and a good bit out of the rest of the system, then i filled it up untill it stopped taking more coolant, started it and let it warm up with the heat full blast, kept filling it, thermostat opened, filled it up when the fluid in the radiator dropped, once i refilled it, i put the cap back on, let it run, then filled the coolant resivoir to the full hot mark
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 27, 2005, 10:14:51 AM
Quote from: Ifixyawata
it would be a good idea to run the car and slightly open the plug on the thermostat housing, to allow any air in the system to escape.

What you mean by "the plug on the thermostat housing"? Could you please take a pic of what are you reffering to?
Thanks in advance!
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 27, 2005, 10:21:46 AM
Quote from: JeremyB
I wouldn't touch the engine drain plug unless you're prepared to tap a new hole when you strip the threads.

That's what I was aware of! I'll try to find flushing kit, wonder how do they call it here. It's sometimes hard to find stuff like this in Europe. If I won't find it, I'd simply take the lower radiator hose off as I do on my Granada. The difference is that Granada has cast iron head (I6), not aluminium heads. That's why I don't want to overheat them or something becouse of wrong cooling until the thermostat opens.
Mariusz...
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: JeremyB on July 27, 2005, 10:48:24 AM
Quote from: Shevretti
What you mean by "the plug on the thermostat housing"? Could you please take a pic of what are you reffering to?
Thanks in advance!

Neither of my CFI 3.8s have any plug on the thermostat. I've seen SEFI 3.8s on MN12s that have a plug to release trapped air.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 27, 2005, 11:26:42 AM
Quote from: JeremyB
Neither of my CFI 3.8s have any plug on the thermostat. I've seen SEFI 3.8s on MN12s that have a plug to release trapped air.

So what do you recomend to do to release trapped air after re-filling the cooling system in my T-bird? What about removing the temp sender idea I mentioned before? What do you think?

BTW. I'm wondering which coolant should I use. I thought of Valvoline MaxLife Coolant AF or Texaco Antifreeze Coolant, but maybe the New Prestone is better?
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: JeremyB on July 27, 2005, 12:44:12 PM
Quote from: Shevretti
So what do you recomend to do to release trapped air after re-filling the cooling system in my T-bird? What about removing the temp sender idea I mentioned before? What do you think?

I just fill the system up as much as possible. I crank the car, turn the heater on full blast, and start massaging the upper hose some if the thermostat doesn't want to open. This method hasn't failed me yet.
Quote

BTW. I'm wondering which coolant should I use. I thought of Valvoline MaxLife Coolant AF or Texaco Antifreeze Coolant, but maybe the New Prestone is better?

Any name brand coolant should do fine. Six one way, half-dozen the other. If you use an extended life (Dex-Cool) coolant, flush the system thoroughly to get maximum benefit from the new stuff.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 27, 2005, 02:11:09 PM
Quote from: JeremyB
I just fill the system up as much as possible. I crank the car, turn the heater on full blast, and start massaging the upper hose some if the thermostat doesn't want to open. This method hasn't failed me yet.


OK, so that's what I'll do!

Speaking of the heater. Is it OK that when I switch to "heat" like eg. defrost, the A/C turns on. Is it OK, or maybe something is wrong with heater control in my T-bird?
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: MexCougar on July 27, 2005, 02:21:07 PM
Only if you did not open the drain of the radiator, do it gently because with that age it can broke (i broke mine)....
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: JeremyB on July 27, 2005, 04:49:43 PM
Quote from: Shevretti
Speaking of the heater. Is it OK that when I switch to "heat" like eg. defrost, the A/C turns on. Is it OK, or maybe something is wrong with heater control in my T-bird?

That is perfectly normal. The A/C runs when you turn it to defrost to aid in the defogging of the windshield by drying out the air.

[complicated answer]
It boils to down to relative humidity (http://en.wikipedia.org/wiki/Relative_humidity).
Say you take in air at 68 deg F at 50% relative humidity (49 deg dew point (http://en.wikipedia.org/wiki/Dew_point)). When you pass the air over the evaporator (32 deg), the air will reach the dew point and dump out some of the water vapor in the air down the evaporator drain. Next, the air runs over the heater core, which heats it up to 100 degrees (>>25% RH). You now have much drier air passing over the windshield that helps to defog it quicker.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on July 28, 2005, 11:48:57 AM
Finally I've changed the coolant in my T-bird today. I've tried to find the flushing stuff but I couldn't find any in the stores. So I went the easier way and took the lower hose off. Than I've put everything back together and filled the system. It turned out that I couldn't pour too much so I had to take one of the heater hoses at the pump off to let the system get more coolant in. Than I filled the overflow tank to the full hot mark and started the engine. Temperature rose to the top of the NORM scale on the gauge and than the thermostat opened and it went down to the middle of normal operating temperarure. I refilled the overflow tank and took my T-bird for a ride. It seems to be OK. Think I haven't done anything wrong. Too bad I couldn't fill it up right to the thermostat.
Title: Re: Changing coolant in 1987 3.8V6 CFI engine...
Post by: ipsd on July 28, 2005, 10:14:37 PM
what has worked for me best is to park the car on a hill with the radiator up the hill. Then just start it up and let it get to normal operating temp and all should be fine. This way the rad is higher than the rest of the motor and all the air ends up in rad not the block.
Title: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on January 05, 2006, 08:07:16 PM
Quote from: JeremyB
I'd recommend that you flush the coolant if you want to change it. Hopefully you can get something like that in Europe. Backflushing will get a bunch of crud out of your system that simple draining will not.

JeremyB, finally I got the Flush 'N' Fill kit, but I'm not sure if I should put put the tee on the hose marked in red in this photo:
(http://www.americangranada.com/pics/tee_installation.jpg)
The installation instruction says I should put the tee on the inlet hose. Or maybe it doesn't really matter? I think it's the outlet hose, am I right?
Title: Changing coolant in 1987 3.8V6 CFI engine...
Post by: JeremyB on January 05, 2006, 08:14:42 PM
I put the tee on the outlet hose [the hose you highlighted in red]. It shouldn't make a difference where you put it.
Title: Changing coolant in 1987 3.8V6 CFI engine...
Post by: thunderblunder on January 06, 2006, 08:13:08 PM
Yes, it is good that AC comes on when on defrost.  The AC is designed to dry the air when attempting to defrost.  If you want heat but do not want AC to come on, leave lever on VENT and turn heat up.  That is, AC is designed to come on when heating or cooling.
Title: Changing coolant in 1987 3.8V6 CFI engine...
Post by: Shevretti on January 08, 2006, 05:18:25 PM
Quote from: JeremyB
I put the tee on the outlet hose [the hose you highlighted in red]. It shouldn't make a difference where you put it.

Does it release all trapped air up to the intake manifold when refilling? Hope it will work this way?