Engine over heats

[Roadrunner351w]

I told everyone about the water in cylinder 1 problem well it never stopped so I returned the Edelbrock intake and got a Offenhauser intake with the 16 bolts so there will be no more leaking but now the problem is it over heats we replaced the thermostat and still over heats it acts like the thermostat is stuck closed. The water pump is also new.With the Edelbrock intake it never overheated, the problem started with this new intake.The sending unit will jump to about 300 degrees in about 3 minutes time and the radiator is still cold and the water at the heater hoses is very hot. It acts like it is not flowing through the engine almost like their is a air pocket in there somewhere. Has anyone had any problems with offenhauser intakes for the 351 windsor? Any help on this matter would really be appreciated.

[fordman]

if i remember the engine ran fine before all of this started was that right? or was it a water leak that promped this intake change in the first place? can you run the engine with the radiator cap off and see if it belches bubbles out o f the neck of the radiator?

[floyd67]

do you have the thermostat in backwards possibly

[Roadrunner351w]

The engine has always ran fine except for the water in cyl 1 That is what promted the intake change. all the parts are the same except the thermostat which we replaced this morning and the problem stays. No the Thermostat is not backwards that was the first thing I thought of.

[fordman]

it is sounding like a bad head gasket or a possible cracked head. check the rad for air bubles. and get a pressuer checker fo rthe radiator and see what pressure it gives you when pumped up or whatever. i forget how those are used to check for bad head gaskets or heads.

[Roadrunner351w]

It may be possible of a bad gasket but this is the second set of head gaskets on this motor and it has less than 150 miles on the rebuild. I know for a fact there is nothing wrong with the heads.The cylinder 1 water problem was coming from the bolt holes there around the intake because edelbrock only uses 12 bolts on the 16 bolt heads and I could never get it to stop leaking around the bolts and it did not matter which gaskets I used I have tried them all even the ones for a 302 and it would continue to leak. Everytime I torqued the bolts it would stop leaking for a couple of days and then start again. so we know the leaking problems is definately from the intake. I will try the pressure test and then maybe look at the head gasket again.
but for some reason the thermostat will not open up almost like the water pump ain't pumping.

[fordman]

without reading too much o fyour last thread . the thought came to me that a head gasket could be put on upside down. i think i remember reading that. this si about all the info i can give on over heating and what has happened to this. take the thermostat out completly and see what happens. it could be worth a try.

[swinn]

Backwards head gasket does sound possible. When you installed the head gasket, there is a hole in it for a water jacket that has to be placed in the back of the motor. If it is in the front the flow of coolant would be blocked by the gasket.

[Roadrunner351w]

OK, I pulled the heads today the gaskets were fine but replaced them and the intake gaskets and also had to replace the Water sender unit it was also bad after I accidentally broke it when the intake slipped. So far everything is working fine so don't really know what the problem was but it works great now after replacing all the gaskets.Thanks everyone for there input.

[willowbilly3]

Did you burp it?
I always run an engine until the t-stat opens and the coolant circulates good before installing the the pressure cap. If you don't there can be trapped air which may cause problems.

[Roadrunner351w]

When it was running hot the T-stat would not open at all. But anyway I have got it fixed now. don't know exactly what it was but I replaced the Head gasket and the intake gaskets and the T-stat. So now everything is good to go. Thanks everyone for your input.