Overheating .. surprise..

["Jeff Phillips" <jeff.phillips@xxxx>]

Since I have had the DeLorean I've experienced the common overheating 
woes. The car runs extremely cool most of the time, rarely going 
past the second temperature gauge mark. It usually will only begin 
to overheat after highway driving and I return to the regular 
streets. I've had "spectators" point out that I have antifreeze 
running or at times they say "pouring" out the back, and after 
driving the fluid is very low and the car is wet around the overflow 
hose. It seems that when driving I'm blowing a lot of coolant out 
the overflow before the engine begins to overheat. Loss of coolant 
seems to be the cause of my overheating instead of the by-product. 
I've checked the overflow cap and it vents at or slightly above 15lbs 
and will hold fine at pressures below that. I do have the plastic 
overflow tank and it appears to be in good shape. I've also 
installed the self-bleeding kit to the system. Also there are no 
leaks elsewhere in the system (via visual inspection). I have two 
suspicions and I'd like some advise:

1) Is it possible/probable that the plastic tank is deformed an not 
allowing the cap to seat properly? (Is there a pressure testor that 
doesn't use the overflow tank opening to attach?)
2) I have a head gasket leak allowing blow-by to enter the cooling 
system at the head. (This wouldn't necessarily show up in a cooling 
system pressure test as the cylinder pressure is much higher and the 
blow-by may only go one way)

Any help or experience in this area would be appreciated, we all know 
how important/fun it is to have a reliable car to drive!

Jeff
#10544