Has anyone had any issues with boring out a 5.3 to a 5.7? I ask because I just had this done and now it runs much hotter than it did before.(203-225) Specs are 5.3 bored .125 to 3.905 with 317's. (The rest is in my sig) I know there are several people who have done this but I haven't heard of any issues...

 

Uhm, did they sonic test the block or did you have them just ream it out? A friend of mine went through 4 blocks until he found one that was good enough to bore out to a 5.7L. The rest were too thin and would have ran into overheating issues.....

 

Usually boring will cause more heat. Is it boiling over or just running a little hotter.

 

Yep, they sonic tested it and everything looked good for the operation.

It's not boiling over but if the ambient temps are 95+ and I'm in stop and go traffic, temps will climb pretty quick up to 230-240.

 

sounds like a head gasket is on backwards

 

My iron 5.7 has been in since feb. And all I did was put ls1 fans on it. Everything else is stock cooling and I haven't had a problem. Check sensor? Maybe the temp sensor is bad?

 

The engine was assembled by the shop doing the machine work and it was running hot. Then another shop removed the heads to replace some bad lifters and put new head gaskets on and it still ran hot. Not sure if both shops would have put the gasket on backwards....but who knows....

We replaced the temp sensor before installing the new motor back in the truck since it broke in the transportation process. It also has a brand new water pump. I'm lost.....

 

try 160* T-Stat may be it will work with you fine

 

here's the crap that I went threw with my build . . . . and having 2 people assemble it.

https://www.performancetrucks.net/fo...d.php?t=386801

try the coat hanger . . . pull off the water pump

 

Sounds like the same kinda fun I'm having! Mine is a little different, though. When I first start it, I don't have any issues and it takes a while to warm up. If the ambient temps are cool (low 70's) it may only run 180-190. Once the trans gets warm (150's) and the turbo is hot and pushing air through the FMIC, temps start to rise. For example, on the way to work this morning cruising 70-80mph it was staying around 195-199. After a 40 minute trip, and I stop at a light, the temps jumped up to 210. When I accelerate and begin building boost, temps climb even more. If I have a long stretch of road to just cruise, temps will slowly come back down to the 203-206 range. Stop & go traffic in the heat of the day is killer since I have seen temps in the 240's!!