So i just replaced all the freeze/soft plugs on side of the block while i had the intake and header off, wrapped the header, and now i cant get past the second mark on temp gauge, Before it stayed right around 210 but would bounce between second and 210 mark. One of the plugs was leaking, thats why i replaced them all, Now my main reason for asking this is because i have read that if the engine does not get to proper operating temp it will stay in open loop and will consume more gas, which would make sense since i am getting worse gas mileage with a brand new exhaust versus a cracked header and dented downpipe, But i have read elsewhere that the lower temps done affect that much, So would it be a good guess that either my t stat is stuck open or am i just being stupid, 90 cherokee 4.0

 

replace the stat and go from there... would be my advice
Good job tho :} people hate puting in freezeplugs..

 

Going to replace the t stat today, and as far as freeze plugs go, yeah i understand why, it took me two sets to get one good block, the front one kept falling out every time i started the dam thing, But now i have peace knowing that at least those are new, now got to worry about one on head and one in bell housing,

 

Could u have bumped something on the temp sending unit thus getting a false temp reading? It's possible that the t-stat picked this time to stick open but removing the intake and exhaust means u disconnected a bunch of stuff also. I'd start looking at the stuff u removed, disconnected, reconnected and re-installed before suspecting something that wasn't touched.

 

i checked everything, i label and right down everything i disconnect, so that way i have a checklist to make sure its all back, and my thermal gun is agreeing with the temp gauge radiator is reading about 167.4 degrees

 

Do u know what temp t-stat is in it? Is one in it? With cool ambient temps, a 160 t-stat could easily allow 167 temp reading. If u have a 180 or higher rated t-stat, then it sounds like the t-stat may be stuck open.

 

no i do not know what is in it, as its from po, its been about 60 and before it would go right to 210, and stick around there, i got thermostat and forgot gasket so thats on order be in friday, then we see. reason i think it might be thermo is becuz it did reach 260, becuz the front freeze plug started to leak when i went in basement to get more antifreeze, i shut it off, turned on electric fan to cool it down and then replaced plug

 

Sounds like a large air bubble in the system.

 

nope it was the thermostat, it was a 195 but the spring was actually cracked, u could push it open with ease no tension what so ever, so when it was just bypassing the whole time, put new one in, started her up, added coolant and 5 minutes later sitting right before 210, before i could let it idle for 30 minutes and not get over the 160 mark