Engine Temp running cooler than normal (1 Viewer)

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My Land Cruiser has 265k miles and lately I have noticed the gauge is running cooler than middle, approx 3/8 point consistently. Only two major changes in last few months I changed PCV valve and added tundra brakes. The temperature issue seems to have started after changing brakes. I do have a slight pulley squeal when turning on LC sometimes.
 
Mine always sits at about 40-45% (left of center)

An OBD scanner will tell you the exact coolant temp. I use a Bluetooth ELM327 dongle and OBD Fusion. I find I run about 185F after idling a while, or about 195F when I'm actually driving. My temps will run a bit hotter than that on the highway (up to 200F) but that's a side-effect of 4.88 gears.
 
Modern thermostats are often designed to fail in the open position to avoid overheating the engine.

I agree with linuxgod an OBD module and app can give you the exact temp, but if it is actually running cool I'd start with thermostat.
 
Modern thermostats are often designed to fail in the open position to avoid overheating the engine.

I agree with linuxgod an OBD module and app can give you the exact temp, but if it is actually running cool I'd start with thermostat.
If the temp is below 180F once warmed up, then this is likely the culprit. It is possible the coolant temp sending unit isn't reading correctly though so if you find you can get up to a consistent operating temp (say... 165F) and the heater blows hot then you might try to swap the sending unit first as it's relatively cheap ($30) and most likely a LOT easier to get at than the thermostat.

The thermostat generally fails either due to build-up around the plate lip (rare) which causes it to not fully close or to the spring getting weak over time (common) and being unable to push the plate closed completely against the force of the water pump. If you have to replace the thermostat, you'll want to do the water pump too if you haven't done so as it needs to come out to get to the thermostat. Probably radiator too if you have the old style and any evidence at all of the hairline crack. Then new hoses, and maybe heater hose T's if you're at 265k. Expect that to run you in the $1000-1500 range.
 
I keep meaning to check whether these have a different sending unit for the gauge than the computer like older Toyota’s did. Time to do some digging i to the fsm
 
Mine always sits at about 40-45% (left of center)

An OBD scanner will tell you the exact coolant temp. I use a Bluetooth ELM327 dongle and OBD Fusion. I find I run about 185F after idling a while, or about 195F when I'm actually driving. My temps will run a bit hotter than that on the highway (up to 200F) but that's a side-effect of 4.88 gears.

Mine is sitting 40% left of center now. It was 50% for a long while. Chicago temps have cooled a bit but its been like that for weeks. It goes completely cold and it also increases if i start racing/slamming gas repeatably on open roads to 50% but comes back down quick.
 
I just experienced this with my cruiser, 2008 110k, was not getting up to operating temp, was only getting up to 1/4 of the gauge. Gas mileage had dropped 2-3 MPG's. I got a Bluetooth scanner and was seeing temps around 140 degrees. I called my mechanic and he said to make sure there was water in the radiator and to open the cap to check ignoring the overflow bottle. Well I opened the cap to find it had come apart. Spring was visible sitting inside of the fill hole. I had to use a pair of pliers to pull out the bottom rubber/plastic piece. I replaced the cap with a cheapy from the local auto parts store and it immediately went back to acting normal. Needle was back to near vertical with a slight lean to the left. Temps on the scanner where back up into the 180's while I was watching it. I am actually surprised this fixed it, I thought for sure my thermostat was stuck open or something.

So if your not getting up the temp, check your radiator cap

edit... seemed fixed initially yesterday, but on the way into work this morning it wouldn't get above 140 and then it through a code for the thermostat

so looks like my thermostat is stuck open...
 
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I just experienced this with my cruiser, 2008 110k, was not getting up to operating temp, was only getting up to 1/4 of the gauge. Gas mileage had dropped 2-3 MPG's. I got a Bluetooth scanner and was seeing temps around 140 degrees. I called my mechanic and he said to make sure there was water in the radiator and to open the cap to check ignoring the overflow bottle. Well I opened the cap to find it had come apart. Spring was visible sitting inside of the fill hole. I had to use a pair of pliers to pull out the bottom rubber/plastic piece. I replaced the cap with a cheapy from the local auto parts store and it immediately went back to acting normal. Needle was back to near vertical with a slight lean to the left. Temps on the scanner where back up into the 180's while I was watching it. I am actually surprised this fixed it, I thought for sure my thermostat was stuck open or something.

So if your not getting up the temp, check your radiator cap

edit... seemed fixed initially yesterday, but on the way into work this morning it wouldn't get above 140 and then it through a code for the thermostat

so looks like my thermostat is stuck open...
yeah, if you are ever driving around in the winter time, and you suddenly are not getting any heat out of the heater vents....stop! AND check the radiator to see if there is any coolant left in there
 

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