96 Maxima GLE - is it running cool?

All:

I live in the midwest - ambient temperature was 20 deg.F yesterday morning (probably cooler overnight - car is not garaged). Drove to work - highway onramp is < 1/2 mile from home (so there is not much low-speed driving or traffic lights that allow the car to warm up before I get to the highway). The car took 10 miles (~10 minutes) of highway driving to get to operating temperature (and therefore engage the torque lockup converter).

I saw the same behavior last winter, so this past summer I did the following, since I assumed that the car was running cooler than it should, or taking longer than it should to reach operating temp.

1) Replaced thermostat and gasket (with Nissan parts) 2) Checked upper and lower radiator hoses (they were fine) 3) Replaced ECTS (with Nissan part) 4) Flushes/refilled radiator with 50/50 Prestone Coolant.

The warmup behavior has remained unchanged.

Is there anything else I can look for that would cause the car to take a long time to get to operating temperature?

Also, has anyone noticed at which point their car finally allows the torque converter to lock up? i.e. my temperature needle (not accurate

- I understand) is just below the mid-point of the guage before the lockup occurs... when locked-up - I run at 72mph at 2500rpm - when not locked - I am at 68mph at 2500 rpm. Not shifting overdrive gear is a concern since my gas mileage is suffereing (10%) as a result of being stuck in a lower gear for 1/2 my commute.

Once I reach operating temp. the engine temperature remains consistent (i.e. doesn't vary with speed/heat etc), the shifts in/out of overdrive as expected, and I have no problems getting heat, etc. So it is just the initial time required to get to the operating temperature that seems to be too long... (this is of course relative to other cars I have owned/own).

What else could could I check? (No codes are stored in the MIL).

Thanks, Nirav

96 Maxima GLE, 98k
Reply to
Nirav J. Modi
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Did you check the heater hose valve? On the 3rd gen, it's on the firewall with 2 vacuum hoses going to it. When you changed the engine coolant temp sensor, are you sure you replaced it and not the coolant temp sending unit? Just a thought. My tranny is doing the same thing your's is with the slow to lock-up, etc. When I get a chance, I'm going to check and maybe changeout the transmission temp sensor that's in the valve body. There's a test procedure in the manual that allows a test using a multimeter to test voltage without opening up the trans.

Chris

90 & 94 GXE's
Reply to
Chris H

Chris, I'm not sure how the heater control valve would affect the engine warm-up time... are you suggesting that this valve could be stuck open

- thus having the overall effect of a larger coolant pool to heat on start-up?

Yes I am sure I replaced the ECTS -> since thats the part I ordered from a nissan dealership and I did it per the Haynes manual...

I had asked a question relating to this same issue last winter and had basically asked "Does the ECU use anything other than the ECTS signal to detect whether the car is warm enough to shift into OD?"... I didn't get any answers - if indeed the transmission computer and/or ECU use the transmission temp sensor readings - this could be the culprit in my case. Would the transmission control computer post an error code via the OD light if the trans. temp. sensor was not working correctly?

Thanks for your response, Nirav

96 GLE, 98k
Reply to
Nirav J. Modi

I doubt there is anything -wrong- as it's normal for them to not shift into OD until the engine temp is up to normal range. Given the car is not garaged and is in sub 20F temps, 10 minutes to warm up sounds about right. Some nissans have a temp sensor in the trans, some use the engine temp sensor but it sounds like it's working like it should to me and the 10% lower MPG could easily be caused by the warm up enrichment too. If you only have a 20 minute comute, I wouldn't waste a bunch of money trying to save on some gas! :-)

Reply to
Steve

Steve, thanks for your feedback... the only reason I posted about this warm-up problem again this winter is that I took the wife's car one morning (after leaving it out overnight) and it was warm enough for the OD gear to engage within 2-3 miles of being driven... but then again its a different car, different engine and perhaps the warm-up characteristics can be that drastically differently engineered. For now I'm not going to do anything at all.. :) maybe I'll try extract the codes from the transmission computer and see if anything is stored (per the procedure in the Haynes manual)... and then maybe its time to clean out the garage and make room for my car!

Cheers, Nirav

Reply to
Nirav J. Modi

Was her car garaged? Yes cars are very different in their warm up time. My mitsubishi truck is warmed up an a couple of minutes, my 77 280 takes a while. Larger engines take longer than smaler ones. And yes I'd clean out the garage!

Reply to
Steve

Steve,

her car was also left outside the garage overnight..

cheers, Nirav

Reply to
Nirav J. Modi

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