5.4L overheating

[TheFellaFella]

Recently swapped my old rod knock 5.4L with a good running one, put a new water pump, a 180 T-stat, and even tried a new fan clutch, still overheats. It actually overheated more w the new fan clutch so I placed the old one back on, some how my gauge got fried so it’s always reading a high temp, live data on scan tool gives me the accurate temp so the ECT sensor is still good, I’ve seen someone say the motorad t-stat is the REAL correct part, and others say it needs to be burped, but can’t find the motorad part or anything on how to burp this engine coolant system, some say heater core but my heat comes in fine… should a drill holes in t-stat? Or how can I burp it? I live in California so summer gets hot as hell. I’m close to letting it run with the garage door closed if you catch my drift

 

[99WhiteC5Coupe]

Recently swapped my old rod knock 5.4L with a good running one, put a new water pump, a 180 T-stat, and even tried a new fan clutch, still overheats. It actually overheated more w the new fan clutch so I placed the old one back on, some how my gauge got fried so it’s always reading a high temp, live data on scan tool gives me the accurate temp so the ECT sensor is still good, I’ve seen someone say the motorad t-stat is the REAL correct part, and others say it needs to be burped, but can’t find the motorad part or anything on how to burp this engine coolant system, some say heater core but my heat comes in fine… should a drill holes in t-stat? Or how can I burp it? I live in California so summer gets hot as hell. I’m close to letting it run with the garage door closed if you catch my drift

If I read correctly, you put an non-OEM engine thermostat in?

I would use an OEM Motorcraft engine thermostat.

 

[TheFellaFella]

If I read correctly, you put an non-OEM engine thermostat in?

I would use an OEM Motorcraft engine thermostat.

I haven’t been able to find the OEM thermostat, every link I follow just takes me to a similar but non oem part

 

[TheWildMechanic]

I actually had the same issue on mine, and I did a coolant flush on it as well as a new thermostat from AutoZone, and mine seems to work. I'd suggest trying to flush the old coolant out and replacing it with new stuff. A hydrometer/coolant tester may help as well to get that balance just right

 

[lonestarjeff]

I went through the same overheat problem a few years ago on one of my 4.6 trucks. I chased the problem for a couple weeks and went through two new t-stats in the process before I realized the new ones were junk. No problems since I put my old motorcraft back in. On the bright side, the truck has a nice new cooling system now(pump, radiator, hoses, and coolant).

 

[Hamfisted]

How old is your radiator ? If you spray the radiator with a garden hose does it still overheat ? The cooling system will de-gas in normal operation. You should be able to see it circulating through the reservoir if you have the cap off and look in there. If the radiator is more than 10 years old and you're having engine cooling issues ( not a blown head gasket case....), and you've replaced the pump and T-stat, I'd look at replacing the radiator.





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