Well here is the problem. I have a 86 300I6. The guy before me had purchased a rebuilt long block. The builder did a crappy job on the top end. The head had three un fixable leaks and the tappets were all concave along with flat spots on the cam. I tore it down to replace the head and cam. while I had the head off I noticed the block was bored .040 over. I replaced the cam with a crane cam new lifters new head and new carb. I initially replaced the thermostat with a 195*. While I was running in the cam and lifters the engine was getting too hot. I then pulled the thermostat and replaced the water pump. The engine runs great. Aside from the starter absorbing too much heat and cranking slow untill it cools. I need to know if there is anyone runninig the 165* thermostat. Since the temp runs in the perfect zone when driving without a thermostat I need some thing to keep it open at a lower temp. I believe this will fix the issue, however, i dont want to do this but once. Since the block is bored .040 over I believe that is creating the extra heat that the hotter thermo. cant remove. With a 165* thermostat in, it would open sooner and allow free flow at a lower temp. thus keeping the engine in the correct heat zone. Sorry for the long story. What say you?? just want to make sure I am not thinking out of the box here. The engine has very low miles since the last rebuild and the tranny is a C6 which was rebuilt about 2 years ago. thanks

Joe

 

It may run a little hotter until it's broke in. The engine needs heat to run efficiently...don't know what you mean by "correct heat zone". Unless you are running a real guage and not just the Ford "idiot" guage how do you know what temperature it is running at? A 180* would be more than cold enough for any place in the lower 48...TX included.

 

Its currently running at 185 W/O any thermostat. When I shut it off the engine block heats up as there is no more cooling. I would like to keep it at 180-190. Like I said right now it is full flow and maintaining that temp, of course in the winter months it runs cooler 160. I just dont want to have to take it apart more then once. More times coming apart increases the risk of messing some thing up. The old murphy law applies. Was just curious if anyone was running anything cooler then the 195 stat. It does get a bit hot here in South Texas but that should noty matter with a thermostat. It will only heat up faster. Once the stat is open and flowing outside temop shouln't have much of an effect

Joe

 

It seems to me that engine is producing more heat than it should be... OR maybe cooling system is not working as efficient as is supposed.

1º Check engine timing - 10º at hot idle no shorting plug at distributor.
2º Let the engine complete at least 20 running hours to finish break in period.
3º Are you sure you use a carby head? EFI head has higher compression ratio, leading in more knocking and heat when used in carby applications.
4º Did you check radiator core??
5º Transmission is shifting properly? early shifting schedule or not forced downshifts give more job to T-converter, producing a lot of heat which is transferred to engine through oil cooler at radiator

 

Maybe the 195 thermostat was defective.


If you do a search on thermostat temp or no thermostat discussions, youll find so much opinion, its not even funny.


If your getting expected mpg and everything works, why fix what isnt broken?