The overflow saga continues...

[JJM_Stanger]

I recently had a post about a problem I’m having with my Stang. To make a long story short I had it out Sunday for about a 2 hour drive and when I got back I saw it was dripping antifreeze. I popped the hood and it was overflowing from the overflow. After the first post I did a compression test to see if it blew a head gasket, here are the results:

# 1: 150 psi
# 2: 149 psi
# 3: 150 psi
# 4: 148 psi
# 5: 147 psi
# 6: 150 psi
# 7: 149 psi
# 8: 150 psi

So everything looks good there, right? Can someone tell me what the compression is stock? 1990 GT..? So the compression test did not show a blown head gasket what else could it be? I don't see any obviouse leaks?

Any ideas?

 

[JJM_Stanger]

Can someone at least tell me what the stock compression should be?

 

[tjm73]

I think it's 8.8:1 if I remember correctly.

If you're puking coolant check your radiator cap. I had the same problem and I put a new radiator cap on and changed the thermostat and it hasn't done it since.

 

[jerryD]

check your rad cap. it may not be releasing the pressure built up, and the pressure has to go somewhere. as long as you aren't over heating the thermostat should be fine.

 

[ALMOSTFINISHED]

I have almost the exact same problem. If I drive nicely the temp stays around 185, (autometer guage and 180 t-stat). Once I start to drive a bit "spirited" the temp will go upwards towards 200. Not that I beat on the car or anything, just a full 3/4 throttle passings or other cars. I have a newer be cool aluminum rad, and a new cap. My car does the same as yours tho, overflows outa the tank. Almost like the car boils over but never gets to that temp. Maybe we have the same problem. ?

Nick

 

[Curse]

You guys sure the T-stat is working? My car did something similar, changed my cheap 180* T-stat to a Mr. Gasket 180* never had another problem with it.

 

[ALMOSTFINISHED]

I've thought about changing the t-stat out to a mr gasket one. I should tackle that this weekend and see where it gets me. Thanks for the suggestion.

Nick

 

[Curse]

No problem, good luck!

 

[iapexl8r]

try drilling a 1/8 th hole at the top (12:00) pos on the thermostat its called a burp hole. chris

 

[ALMOSTFINISHED]

I'll give ya a bump.

Nick

 

[JJM_Stanger]

I replaced my t-stat and water pump last year, so I wouldn't think it would be those. I'll try the radiator cap and maybe another t-stat.

ALMOSTFINISHED - If you find the problem let me know, I'll do the same.

 

[1989MustangLX]

try drilling a 1/8 th hole at the top (12:00) pos on the thermostat its called a burp hole. chris

Does anyone else recommend doing this? I've heard of it before, and it sounds like a good idea.