176* engine temps on my 1FZfe? (1 Viewer)

[midfat]

As background, I am running an OEM thermostat. Unsure of the exact temp rating, but assume it’s 180* (actually thought it was 185*). I ordered it through @cruiserdan back when I bought the truck and overhauled the cooling system. That was about 75k miles ago. I also run a blue fan clutch with a new fan and just replaced the cowl a few months back. Foam gasket around the radiator makes a solid seal. It sounds like all of this adds up to a new engine finding it’s center, and a well functioning cooling system. All good stuff.

 

[LongDuck]

Just a sidenote, but your baseline temp (*over summer) was with a new factory short block, which I can attest seemed to raise my engine temps during the break-in phase of the first 4-5k miles. Like you, I did an OEM new block with rebuilding the head, new TYC1918 radiator, new water pump and new thermostat and was still seeing 200-205F running at highway speeds with ambient at 105-110F (AZ & NM deserts). That seemed high to me, and would occasionally bump higher with grades, but I kept a close eye on it.

Over time, and with the subsequent oil changes, the temps have dropped slightly - both ambient and engine, as to be expected with the piston rings, timing chain, and all the other new parts that got added during the engine refresh breaking in. Nothing substantial, but 180-185F on my OBD2 reader (96-1FZFE) are normal now with daytime temps in the 80F range.

I actually stopped looking at the scan temp, as it made me a little neurotic for the first 2k miles or so...

Practically speaking, if it's not overheating on your scangauge, i.e., 215+, and you're not seeing any other signs of overheating, you're probably just fine.

 

[midfat]

Just a sidenote, but your baseline temp (*over summer) was with a new factory short block, which I can attest seemed to raise my engine temps during the break-in phase of the first 4-5k miles. Like you, I did an OEM new block with rebuilding the head, new TYC1918 radiator, new water pump and new thermostat and was still seeing 200-205F running at highway speeds with ambient at 105-110F (AZ & NM deserts). That seemed high to me, and would occasionally bump higher with grades, but I kept a close eye on it.

Over time, and with the subsequent oil changes, the temps have dropped slightly - both ambient and engine, as to be expected with the piston rings, timing chain, and all the other new parts that got added during the engine refresh breaking in. Nothing substantial, but 180-185F on my OBD2 reader (96-1FZFE) are normal now with daytime temps in the 80F range.

I actually stopped looking at the scan temp, as it made me a little neurotic for the first 2k miles or so...

Practically speaking, if it's not overheating on your scangauge, i.e., 215+, and you're not seeing any other signs of overheating, you're probably just fine.

This is almost exactly the same experience I’ve had. My old engine ran a hyper reliable 185. The new engine was closer to 190 for the first few thousand miles. Under almost any load, it was nearing 200 on the freeway in SoCal summer temps. But this has definitely settled. I’ve been watching temps over the past week and 176 seems to be my new mild ambient temp (<70F) resting spot. In gridlock traffic, it warms up to 181.