Changed water pump. Now running hot.

So my coolant reservoir kept emptying out, though never overheating. Ran 180-190 very consistently.

I noticed it was wet under the water pump...so I replaced it on Saturday.

It's not wet directly under the water pump anymore. Seems to be wet further down but I'm not quite sure because it was very wet outside today. I'll check again tomorrow.

My main concern though is that the coolant reservoir still emptied and when I drove to work today I was fluctuating between 200 and 228 degrees.

I'm not using Toyoyta pink coolant, but I did a flush about 10k miles ago and have had no issues until now.

Clearly it's related to something I did on Saturday...but I don't know what.

Appreciate any thoughts.

Edit: 1999 4cyl 2.7L

 

Did you change the thermostat? When you changed the water pump, did you make sure to run the motor and the heat to get rid of possible air pockets?

 

Negative on the thermostat. I ran it after I had everything put back together but have not run the heat. I will go run it right now.

 

It's not a bad idea to replace your thermostat when doing the water pump. Most likely the reservoir emptied because there was air in the system and ran hot because you didn't have enough coolant.

With the truck cool, heat to max, run the engine with the cap off. Burping process. I prefer doing this on an incline making the radiator the highest point so that the air is pushed out. Add coolant as necessary and close the cap when it starts to spill out.

 

Yea I definitely did not do that process. Thank you for the advice. I will let you know results.

 

Steady at 179 degrees. Thank you so much.

 

WIN!!!!

 

Happy to help.

 

Dumb question from a new Tacoma owner, how do you know specific temperature that your truck is running?

My '03 just has the gauge and it seems to run higher than my prior vehicles. If engine off is 0% and blown the eff up is 100% on the gauge then I'd say it runs somewhere between 70-80% on the guage.

I was thinking of changing the thermostat.

 

The coolant temp should be 190 degrees F with fluctuation of + and - of 10 degrees depending on driving style, ambient outside temp and what the truck used for (pulling a trailer?). The thermostat that is in you engine now is compatible with the OEM calibration of the computer. Changing to a different thermostat will mostly like cause the engines computer to think that is in the "warm up" phase which it dumps fuel to speed up warm up or overtemp phase which causes a engine light to come on signaling that the engine is critically hot.

In other words, leave the thermostat alone.

 

Buurrrrpp!

 

I run a ScanGauageII in all my OBDII vehicles. There are a couple of other options like Torque and UltraGauage as well. But you have to have something that interrogates the ECU for what the coolant sensor is sending. And certainly sensors can (occasionally) fail. But it's better than relying on faux gauge like most dashes have.

Of course you get lots of other good data too, as well as instant code reading and clearing ability.

 

i use an ELM327 and the Torque App to see my OBD2 info. 10 bucks total, maybe..... your temperature readings should show around 212f or 100c when warmed up. if higher when warm DO NOT DRIVE THE TRUCK. stuff begins to break down after about 220f/105c. and especially if you have an automatic. auto tranny fluid begins to break down around 240f. keep in mind your tranny uses your engine coolant to cool it down... it uses water at boiling point to cool it down....... that's bad as it is....

 

Even 212 is pretty warm. Im a 2.7 manual though, 2 of them, but ive never seen higher than 192°f and both run exactly the same temp. Via SG.
Just recently got a 3.4 runner. I have not yet put the SG in there to check out its running temp.

 

Operating temp with a moving vehicle should be just a bit above the tstat rating. On an idling vehicle it might rise a bit more, as fans don't move as much air as driving.

Mine have 180 tstats, and 186 is my normal on road temp. Idle/stop lights will be around 190-192.

 

T

thats excatly how my trucks run, on the money.

 

weird, my truck runs around 200, or that's what my sensor reports. tech buddy says between 190-210 is perfectly find.