I hope you guys are willing to help me with my truck. I swapped a junkyard TBI454 into my K5. She has a massive quality 4core in her.
The junkyard motor came with a 195* stat and ran at about 240*. I replaced the stat with a new 195* and got the same results. I put a 180* in her and she runs at 180*. I suppose I should try a 195* stat but why would she act like this? Also what temp should I aim to maintain? Thanks

Charlo

 

you sure you ran the truck the same way? like you didnt drive on the highway when testing teh 180 stat right?

that is a wierd problem though.

 

not sure when the ECM would put things into closed loop mode, maybe it's like 190°, so you're not reaching it. this could affect things like fans, etc.

also, the temp gauges aren't very linear. are you measuring temp with a real gauge, or just on the dash?

 

Only measuring temp from the dash.
The weirdest part was after first installing the 180* stat she ran between 205* and 210*, not till a couple hundred miles later did she run at 180*. I never left the 195* in that long but dont want put that many miles on her at 240*.

Charlo