djb383

How/where is the mechanical gauge sending unit installed?

Zjcherokee

I installed it inline with the sensor that is in the t'stat housing.

Firestorm500

Is this the same head? Did you have it magnafluxed and checked for trueness?

Zjcherokee

Head was taken to shop for complete rebuild at a shop I have used and trusted for years. Can't fund any evidence of problem with head.

djb383

If the t-stat has been verified/tested opening at rated temp, rad and fan clutch are new, water pump impeller is good/firmly attached to shaft, system is burped, fan shrouds in place, temp verified with infrared gun and plenty of air movement thru grille/cond/rad, then I'm stumped.

Zjcherokee

Do not have infared gun, but is moving air good. Does have winch on front but it was on before head rebuild, fan clutch not new but is working correctly. t-stat has been tested and can see temp drop on gauge with first opening. Im also stumped. Guess I will replace hoses next even though I know they are not the issue. Thanks

Willys55

was the water pump replaced when the head was?

Zjcherokee

It was not, but I removed and checked it out when I installed rad.

thakmfb

Anything impeding flow can cause this...such as a blocked heater core, collapsed hose, check to make sure you have the belt routed properly so that it is turning the water pump and fan in the correct direction. I still feel like you may have a little air. With the engine cool take the temp sensor out that is on the drivers side rear of the head and fill the cooling system until coolant starts coming out the hole this should help ensure you dont have any air pockets...let us know how you make out

Firestorm500

And yet, you had a blown head gasket.

Did the shop know this? Maybe they did a routine build without checking for problems? Even the best places can drop the ball sometimes.

Did you use new head bolts?

Zjcherokee

Shop did know about gasket, head was resurfaced at time of rebuild as well checked for cracks. And yes I did use new bolts.

Firestorm500

Unless you really do have an air pocket in the system, which by now I doubt, you're probably gonna have to replace the head.

It sounds like there is something still wrong inside it.

djb383

Fan clutch performance slowly deteriorates from when 1st installed.

KennyG

This may sound stupid, but how about condition of A/C condensor or any aftermarket trans cooler. Any thing poised in front of the radiator that could hinder airflow when moving. I've traced mysterious overheats like that to plastic shopping bags and other such debris in between the condenser and radiator. Some thing to check for...