: New motor runs a lil hotter?

11-16-07, 03:05 PM
Just got my baby ETC back. Man , what a difference a new motor makes. So smooth, so quiet. So powerful! woohoo! One thing though. Seems to run a lil hotter than the motor that came out. Most the time it runs in the middle (2001) but since i got her back, under some acceleration, the temp climbs to just a lil past the next line after the middle. Also, while I was at lunch today, under normal city driving, started to climb past the middle make about halfway. Dotn know if it would have kept climbing up because I got to work and shut her off. Is this normal for a new motor to run a lil hotter? I plan on taking it on a leisure trip up the coast this weekend to break her in more(say 200 miles or so) but just curious about the temp.

11-16-07, 03:31 PM
Probably nothing to worry about, but let me spend some of your money.....:rolleyes:

Before you do the coast run, load 2 jugs of 50/50 DEX-COOL (I assume that's what's in it now...) in the trunk. Just for security if you have to top it up to the mark on the surge tank, no more......

Go to Radio Shack and buy a little IR thermometer ($25-28 ?) so you can shoot temps at the thermostat housing and here and there while you watch for fan cycling and hose temps.

Have a nice trip !!

JN in CA
11-17-07, 12:20 AM
Submariner, do those IR things really work? I've gotten some false (too low) temps with those?

As for why a new motor would run hot. Well, it's possible it sat long enough (waiting for the new engine to be installed) that the thermostat is sticking now. However, I would suspect it is just added friction until the rings smooth out the cylinder honing. After all, why do you think they want you to change oil so often, and avoid synthetics, during the break in phase? So you'll have the right amount of friction to smooth out the honing.

11-17-07, 12:24 AM
When the engine in my 2000 STS was replaced, the new engine ran a little warmer than the old one for a few thousand miles. Now the temp gauge is straight up, unless it sits in traffic.

11-17-07, 10:34 AM
Submariner, do those IR things really work? I've gotten some false (too low) temps with those?
Mine seems to be very accurate from what I can tell.

11-17-07, 03:41 PM
IR thermometers are a good tool, and mine (all 3) from different marketers give very similar readings, BUT the Radio Shack unit has a 1" window at 6" distance, so you need to "shoot" the desired temperature spot at close to 90 degrees to the surface, fairly close, less than 6".

The best temperature and pressure gauges are mechanical units using capillary tubing. Very sensitive and indicate the slightest changes. An electric gauge, however, relies on a variable resistor moved by a diaphragm or expanding wax pellet in the sending unit which changes electrical voltage/current across the coil of the gauge, which is nothing more than a voltmeter calibrated in lbs. or degrees or whatever. SO, if the car is idling at, say, 13.8 V and you accelerate to highway speed, the charging and system voltage goes to 14.5V (+ or -) and therefore, the gauge will tend to move in response not only to the changes in mechanical engine conditions, but also to electrical system changes. Not much, but very measurable.

We never use electric gauges in our boat engine installations because they are so slow and relatively inaccurate. As I posted some time ago in an engine building discussion, electric gauges are nothing more than idiot lights with a needle BUT they're easy to install.......

11-17-07, 03:46 PM
On the engine temp running a little warm, I found that if I am down even a quart of anti f, my temp goes up several degrees (5 to 10 perhaps). Make sure you bleed system of air bubbles. That made a diff for me.

Re rings, that makes sense, but I ain't no engine mechanic.