I just finished an engine swap in my 94 Mustang. It now has a 306 in it with a TFS top end kit. Long story short, there were some issues getting it to run and idle properly which were finally fixed not too long ago. Before my last trip to the shop, the radiator blew up on the way there. So while it was at the shop, they replaced the radiator and put in a new thermostat (not sure what degree - I need to call them tomorrow).

I picked up the car today and drove it home. It ran fine, but I noticed that on the highway on the way home, the temperature was a little higher than normal. I figured it was fine b/c I had the AC running and it was a hot day, so I kept cruising home. When I got off the exit and started going through stop signs and lights to get to my house, I noticed the temperature starting to creep up. It was approaching the red line as I got home, so I turned off the AC and tried to park as quickly as I could so I could shut it off. When I shut it off, the radiator was gurgling and spewing out fluid.

I waited until the car cooled down again, started it up and drove it around town for about 5-10 min without running the AC. It ran fine and the temp didn't go up. At the end of the drive, I decided to turn on the AC to see what would happen, and the temp started going up gradually after about a minute of driving. I parked it before it got too hot, so it didn't gurgle and spit out fluid this time.

Anyone have any ideas as to what is going on? Like I said, I'm going to call the shop tomorrow to find out what degree thermostat they put in there. Does it sound like the thermostat isn't opening soon enough? Maybe it's the fan?

 

I would make sure all the air is out of the system and the condensor is not covered with grass or something like that. It sounds like it may have a compression leak if everthing checks good.

 

First I would check to see if the level of the radiator is full and then call the shop that did the work.

 

I checked the fluid level when I picked up the car and it was full. After overheating both times, I noticed that the fluid level was low once it cooled. I'll be calling the shop in a few min.

 

Shop thinks it could be any number of things (obviously). They mentioned that it could be the CCRM. The condenser looks fine - nothing covering or blocking it. I'm also going to try and burp the radiator when I have time.

Since the new engine is built and puts off more heat, should the stock radiator and/or fan be enough to cool it? Anyone recommend aftermarket parts?

 

If they put a new radiator on it, I doubt it would be the problem unless you have more mods than what I am reading. I have seen supercharged cars run fine with an old stock radiator.

Make sure the fan works good. If the air is working real good and the car is overheating, that is usually a sign that the fan is not the problem.

 

Ok, so today I tried to burp the system. I filled up the reservoir, left the cap open, started the car, and squeezed the hoses but I never saw any bubbles and the fluid level never went down. I ran the car for about 15-20 minutes to get it warm up while still squeezing the hoses, but nothing happened. After about 15-20 min, I decided to turn on the AC in hopes that it would get the thermostat to kick on and suck the fluid into the engine, but that never happened either. The fan kicked right on when I turned on the AC, the temp never rose beyond normal, and the fluid level never went down.

Thinking that the thermostat might be bad, I hopped in the car and took it for a 5 minute drive around town without the AC on and it never overheated... cool as a cucumber. I figured after running the car for that long (and with the AC on for about 5 minutes) and driving it in town it would do something. It was probably around 80 degrees or so outside, so I'm not sure if that had anything to do with it.

Any ideas?

 

if the temp never got to normal it sounds like your thermostat is stuck open

 

definantly would go back with a better thermostat than what the shop used.

I have seen thermostats go through sorta like a break in period to where they get a bit warmer than they should and then start working but, sounds like a bad one could be it this time.

 

Don't mean to hijack this thread but is there a bleeder screw to bleed the coolant?