More overheating problems :(

[84blkstang]

ok well i was driving home from school today about 30 miles/ 5 city, 25 highway. I got home and was driving through town and my car started getting hot so i turned on the defroster. Well i get home and it spewed all of the antifreeze in the overflow, and then some. I changed t-stats three times 192, 180, 180, had the radiator professionally reworked, new waterpump and it has a shroud, and a new radiator cap. What doesnt make since is that i can drive for a week and it be fine then one day it does this, WHY? Also it runs cooler in stop and go traffic then on the highway doing 70+. To me this is ass backwards but i am no professional mechanic, anyone have any general idea. We also burped the system but there was no bubbles.

 

[84blkstang]

also there is a brand new clutch fan in there

 

[Michael Yount]

You say it tends to overheat at speed not in traffic. Most Stangs have a plastic air dam under the front end. It's there to create a low pressure area behind/below the radiator which allows air to move across the radiator and exit the engine compartment from the bottom. Have you removed that air dam or is it missing? That can cause one to overheat at speed.

As for it working fine, and then not, is it possible it's losing coolant when you drive, and gradually as it loses more and more, it gets to the point where it overheats - causing you to refill it - and then everything is fine for a while. Have you been refilling regularly?

Do you have an aftermarket/accurate temp. gauge in the car?

 

[84blkstang]

Yes i have a o rileys mechanical gauge it runs about 185-190 normally, this time it shot up to 200-210-220ish-215 and kept fluctuating(sp). If i am losing coolant then where is it going? it is a brand new motor, the antifreeze is green no brown or orange color. When i switched the front over i didnt get the air dam i guess, where would i get one of those? Thanks for the input mike.

 

[Michael Yount]

Hard to believe that little piece of plastic can make such a difference. I guess you have to hit the junk yards for one.

If the gauge is fluctuating, that often means you've got air in the system - that it's not completely 'burped'. That possible?

 

[84blkstang]

well i "burped" it like hissin said to, jack up the driver side and start it and let it run until it lets the t stat open the squeeze the hell out of the radiator hose, over and over, is there another way do this and how do i know if i got all the air out of it.

 

[jd351]

Three ideas here.

One, there is air in the system. Likely, as this can run fine untill the air pocket gets near the t-stat and then t-stat will not open due to a combination of a vapor lock and the fact that steam does not transfer heat very well. This will be worse at high engine/water speeds that force the air down against the back of the t-stat. To clear this problem you will need to do a good bleed of the air, and it is hard to do in a 5.0. First, remove a coolant line going to the T/B and run untill water comes out, then run with the rad. cap off until the t-stat opens, once it does, raise engine speed to 2000+ and add all the water you can and replace cap before lowering the engine speed down, then cool. Also, make sure the overflow is properly filled and the hose is connected. It may take a few heating and cooling cycles to fully fill, but this will work.

Two, it could be a weak head gasket that only gives under heavy load. This would cause it to overheat more on the highway too, and once it does, so much water is displaced it can not cool. This has happend to me once., not likely with a new motor though.

Three, The water pump is a POS. Many of the off the shelf replacements are not very good. I have had a bad one and so has a friend of mine, and both were new from Napa. Sympoms are also simular. I have resorted to using only Edelbrock pumps, never had a problem with them.

 

[JB66]

Does your car have a serpentine belt and a reversed direction water pump? I can imagine the pump fins cavitating the coolant at speed but still working good in traffic. Possibility?

 

[Michael Yount]

The Stang guys will have to help you with 'burping' the system - see jd's remarks above. My car has a 'proper' cooling system with an overflow resevoir higher than the radiator and an air bleed valve in the t'stat. It fills completely up the first time with no air pockets.

What kind of t'stat did you use? The proper types have a little air-bleed valve in the body. Best way I can describe it is 'the little jiggly thing'. It allows air to work it's way past the t'stat when filling the system with water. If yours doesn't have one, you can simply drill a small hole in the body - be sure the hole is positioned at 12 o'clock when placing the t'stat. This will help remove the air pockets. Did you test the t'stat with a thermometer and a pan of coolant on the stove? I've seen brand new ones be bad...

In 35 years of playing with these things, the only way I've ever seen a water pump fail/not be effective on a street car is because the shaft seals start leaking. I don't think replacing the water pump is gonna change anything regardless of the make.

 

[mackey]

To burp mine i took out my ECT sensor, let the car get to temperature and sprayed water in the radiator until it was a steady stream coming out of the ECT.

 

[JB66]

Used to be the water pumps always turned in the same direction as the crankshaft. Times are changing!

 

[84blkstang]

i dont know what brand of t stat it was. no it doesnt have the little air bleed thing the 192 did but the 180 doesnt, i am going to order a new ford t stat from the dealer. I will re "burp" the system again today and i will let you know how it goes. Yes i tested the t-stat with a candy thermometer it popped at 178 ish. I have the resivor and everything else also, i cant undo all of the ect sensors and stuff because mine is carbed thanks guys i will give it another shot

 

[Michael Yount]

No need to buy a new one unless you just want to - a small drilled hole will work just fine...I've done many that way.

 

[84blkstang]

well here is the deal i ran the car sitting in the driveway cap off for 45 miuntes and the t stat never opened it never got any pressure on the system
so i refilled it and drove it all day and it ran 185 ish everywhere i went

 

[Michael Yount]

Well, hold your breath and hope....

 

[84blkstang]

i was on a date and it got hot it was embarrasing, oh well the chick was cool so anyways i am going to bash this t-stat to pieces for my personal satisfaction.

 

[Michael Yount]

I can remember when getting hot on a date was a good thing, nothing to be embarassed about....

 

[Maryland Stang]

What are you using for a radiator? I know you had it professionally reworked but is it the right rad for your engine? Too small, not enough rows? Also, did you put the engine together and do you know for a fact that the head gaskets are correct and installed right?

 

[84blkstang]

It is a two row radiator out of an 84 lincoln that is all i know about it. What doesnt make sense is that i can drive it for a week and it will be fine until one day it decides to get hot. I drove it to school today and it ran around 185 even lower somtimes, i ordered a new Ford t-stat and it will be in tomorrow well see if this fixes this problem. Oh yea Mike it still is good to get hot on a date..... i wasnt embarassed about that part

I put the head gaskets on and they were put on correctly also.

 

[ratrapp]

you need to have your cooling system pressure tested to make sure it doesn't have a small leak somewhere,heater core,hoses,etc.also you could have a cracked block where the headbolts go in.my engine would run for 3 or 4 days and not lose a drop of coolant,then it would overheat like crazy.no coolant or oil mixed together anywhere.finally one day it started missing so i took it apart and found the headbolt holes were cracked all the across to the cylinder bores.