So the stang starts overheating and I think it is because my old radiator isn't up to snuff anymore. so I replace it with a High efficiency 3 row from NPD and put in a new 180 thermostat. After filling up the system and starting the car with the fill cap off the car begins to get hot very fast. the gauge sists at about 3/4 the way hot while idling on a cool night in the driveway. It also only takes about 2 gallons of coolant (qapacity is something like 15 quarts). So I drain the system and refill it with the heater on and the heater hose off the intake. same thing. I can look down the fill neck and coolant is flowing. my question is what can cause this. if its airlock how do I bleed the system. if it is not why can I only put in 2 gallons. Also I checked the temp with an ir gun and the temp of the coolant is 208 at the outlet hose and the block is about 220.

 

whats the temp of the bottom of the rad and lower rad hose about 7" from the fitting on the rad?

-Gun

 

I'm not sure about the temp at the bottom of the rad or the hose. i will check tomorrow morning. I am more concerened with the fact that I can only fit about half the coolant into the system. less water = less heat exchange = hotter engine. Right?

 

Unless you pulled the block plugs you didn't drain all of the coolant when you replaced the rad. Water is a better conductor of heat than A-Freeze is so a 60/40 mix is a good really the best ratio for cooling. If you run the engine with the cap off and visually confirm t-stat opening, you have bled the air out of the system. Service the rad level to just above the tubes and you're set. Now if your still overheating, check your timing first, too much advance or typically, too much retard will make the engine run hotter (so will a lean fuel mixture) You may also have a water pump malfunction,

 

my guess is water pump too. but its rare that the fins inside the pump go bad, maybe unless it was sitting in standing water for years?

 

Could be the lower radiator hose is collapsing and restricting flow. Did you change hoses lately? does the lower radiator hose have a spring coil in it now to prevent collapsing?

 

ok its a new water pump and the tstat is opening and at the right range. I drained the system again this time draining the block. same problem, it just creeps up at idle. I am begining to think I have a bad radiator. I will put my onld one on tomorrow just for kicks and giggle and see if that makes any difference.

 

are you sure your not reading into this too far?...maybe its just a faulty sending unit or old gauge.

208 at the top of the rad is a good thing that's about normal. 220 at the block is a bit high but that could be "skin" temperature maybe header heated up the outside...where on the block did you measure that?

Did you bother to check temps at the bottom of the rad? Lower rad temps are the important thing. If the water entering the rad is 215 but the lower rad temp is 160 then your golden. If lower rad temps are nearly equal to upper then its not cooling well.

Do you have a fan shroud? Stock fan or electric?

-Gun

 

Just off hand, what is the "normal" operating temp? also the temp at the lower rad is lower but steadily climbs the longer the car idles. I drove through taco bell last night and the gauge jumped from around a quarter to around two thirds to pegging out. it was 180 at the lower hose when I got home and 210 on top one. outside temp was 60 degrees. too me that spells overheating when outside temp is 90.

 

and no I am not sure if I am reading too much into this. but I am concerned that the temp never stabilizes at a certain temp. it keeps climbing untill the car moves.