New engine running warm

[dirtyred11]

ok i just rebuilt a new motor for my mustang and it seems that it is hard to keep cool. I have replaced my water pump and put in a 160 thermostat. The fan is straight wired to stay on all the time, it ran good on low speeds bt if i wired it up to be on high speed it would burn up the fuse or burn up the switch i had on it. I wired it back to the original wires today and it stayed a little above middle on the temp guage. I was concerned because my previous motor didn't run that warm so i'm wondering what it could be. ANY HELP AND COMMENTS WOULD BE GREATLY APPRECIATED....

 

[1997gtRioRed]

what temperature is it running at? highest it has gotten?

 

[dirtyred11]

i drove it around town today and it was around the R and M then it started to get a little farther so i parked it.

 

[1997gtRioRed]

the stock gauge is worthless. get a temp gauge to get actual numbers.

 

[Javi]

Factory gauges become dummy gauges as they get old
If you want to get true readings get a mechanical temp gauge and report back

 

[dirtyred11]

ok, so what about new engines running warmer. Is that true?

 

[1997gtRioRed]

i thought the stock guage was a dummy to begin with?

It should start moving off center after 20+ seconds of ECTs over 220F and should be all the way over after only a few seconds at 230F+

from another mustang forum

 

[Javi]

Unless it wasnt build properly it could be true
How many miles are on the new engine?

 

[dirtyred11]

i would assume none, i broke it all the way down and took it to the machine shop and had it cleaned up and the cylinder walls honed. wouldn't that put it back to 0 miles on it? and whur could we have gone wrong in building it?

 

[CC'S95GT]

Try stepping up to a 180* stat. You might think a 160* would run cooler but if the coolant doesn't stay in the rad. long enough then it will run warmer. Especially in traffic with no airflow. How old is the fan motor? As motors get old and worn they pull more current and the extra current is blowing the fues on Hi speed. If your going to run the fan manually then you need to install a relay.

 

[Venom351R]

I'm with 95GT on this. A 160 T stat will keep it in constant open loop, it will always be trying to cool down the coolant but wont be able to do so. The thermostat will stay open and just keep cycling coolant through the radiator and not allowing it to stay in long enough to get cool. I would not put anything lower then a 180 in a 5.0 based engine.

 

[dirtyred11]

ok thanks for all the help guys, im gonna put in a 180 and let you all know how it goes

 

[evilcw311]

first 100 miles on a "new" motor that has had no break in time ran can run a little hot. all bearings and pisting rings are running at the tightest tolerance they will ever be ran which in turn can cause a little extra heat in the first few runs. if it keeps up past that then id worry.

 

[dirtyred11]

ok, thanks for all the help and comments guys

 

[ScottyDsntKnow]

Depending on what mods you did to the motor could affect the temp greatly. When I did my HCI the car went from 180 degrees normally to almost up to 240 at points before I got it tuned. After the tune it was back at 180-190 and rock solid. And the stock gauges... they are idiot gauges from the beginning. At the very least, aftermarket oil/water gauges should be a requirement, mechanical if you can. The stock idiot gauge will tell you nothing worthwhile...

 

[miss2slocoupe]

to be honest alot of people over look little things. When i was having problems with my 95 overheating I replaced everything as well and then i had to replace the radiator (which was the problem to begin with) and when i did it still ran a lil hott. What i did wrong was when i filled up the radiator i didnt wait for the thermostat to open all the way and allow me to fill it up completly. just something little to look at, even though it most likely isnt it