so the new 3.4 engine is in, sounds good, have driven her 70 miles already, bled coolant system 2x. the temp gauge wont go above the second line (not sure the actual temp that would be). when it sits for over 15 minutes it does raise up to normal temp but has NOT gone past that yet. my heat in the car is very toasty warm. could this be a sensor issue or thermostat?

 

oh and i forgot to add that the hose coming off rad to the t-stat housing doesnt seem to have that much pressure. it can be squeezed

 

I'm thinking it's a sensor messing up, the hose can be squeezed but is the hose hot? I'm assuming it is because if not then coolant isn't circulating which would cause over heating issues.

Didn't realize your that close to me lol

 

my dad thinks its the thermostat. which i do too in a way. the hose gets really warm..but not hot hot. haven't checked the rad cap yet. what im thinking is that the t-stat is sticking open enough to let a steady flow of water thru to keep the engine cool, but its closed enough that it gives me heat. if the coolant is constantly flowing thru, it wont build up enough pressure to harden the hose. this is only in theory tho. i was in South side Pittsburgh today and sitting in all the dreadful city traffic on 51 the gauge did finally go up to normal temp, but as soon as i start going again at a steady speed above 35 she drops back down again.

i dont pay any attention to where anyone is located myself. but yeah your only 35-40 min from me

 

hubby changed the thermostat, i lost all my heat and temp began to rise. it was a brand new one too. i told him to put the old one back in. the hose did get more pressure tho with the new thermostat...sigh. if it was any bad sensors i would think that the obII scanner would pick up on that.

 

First, looks like your temp is riding about 170 degrees. Operating temp is roughly 180-200 (give or take).

If you have an air pocket (about 1-2 quarts of missing anti-freeze) you will notice while driving you seem to have some heat, come to a stop and the heat fades away, get going again and it comes back.

If you have access to a tool that can read the temp reading from the PCM, you can find what the PCM is reporting the temp at (see if it aligns with your gauge). If it doesn't, trust the PCM reading over the gauge (as the gauge is attempting to display what the PCM is reporting). If they do match, then the lower temp is either:
- Not enough coolant
- Bad OR lower temp t-stat (as mentioned)

You can test the t-stat by having it out of the car, take a pot of boiling water and drop the new and old ones in, see if they open about the same time.

If the car appears to be running cool (and confirmed by the data off the PCM) and your heat is blowing plenty warm/hot, I would not mess with it any further.

 

well he put the old one back in and still no heat temp began to rise again. im going to try to bleed the system out again today. maybe he didnt do it enough. i didnt have problems with this t-stat before except for over cooling and ill take that over overheating anyday lol. my heat was good and stayed good thruout the entire time driving.

 

Was the temp sensor from the old engine swapped into the replacement engine? Sensors have different calibration (even for the same CID engines) depending on the model the engine is in.

If the sensor came with the engine replace it with one for your model of car.

Another possibility is the radiator cap. Have it tested to make sure it is holding pressure.

 

That was my thinking, a radiator cap.

 

ill check on the sensors. my rad cap was replaced 2 years ago. and before my hubby changed the t-stat back to the old one it had pressure. so now i have pressure and no heat. we havent had the chance to bleed the system out again. gona try after dinner tonight. there may still be an air pocket in the system., plus my hub said i may need more coolant.