The Nissan Path

Newer to this forum, but I posted the other day regarding the same issue at hand: hard shifts. I haven’t had much to work with in diagnosing the cause of concern because nothing’s throwing any codes currently. However, I’ve recently noticed my engine temp gauge never exceeds approx 40% and is also noticeably slow to warm up. Did some research, began connecting some dots, and wanted to present my findings to see if I could be correct. I believe my problem is the thermostat being stuck open, thus allowing for an influx of coolant to circulate. In term, my ATF isn’t reaching proper levels of temp/maintaining its heat for smooth gear shifts/downshifts. As being too cold for ideal transmission performance. Any ideas, ways to help diagnose the cause(s) on my own, and/or possible solutions??

Notes: replaced valve body two weeks ago, ATF and radiator fluid levels are good (and no worries of pink sludge), no leaks underneath car but occasional leak by glovebox/passenger foot area, roughness of downshift seems to be dependent on how quickly I accelerate or brake/come to a stop, engine temp gauge is all the way on C upon starting and takes quite some time to rise (yet doesn’t exceed ~40%), some loss of power to an extent, no dash lights nor codes of any kind are presented or picked up on my OBD2 reader

'Stat stuck open would be a good guess, and yes, trannies like to be warm to work right just like engines do. That's entirely plausible.

VStar650CL wrote: ↑

Wed Jul 20, 2022 3:50 am

'Stat stuck open would be a good guess, and yes, trannies like to be warm to work right just like engines do. That's entirely plausible.

Thanks for the reply! Planning on replacing the thermostat tonight. Any insight on how long of a process this may take though?

Also, what causes a thermostat to be stuck open?

It's not complicated but 'stat isn't in an easy spot, maybe a 2 hour job with proper tools. Be prepared to jack the front end to bleed the air out, and either have a no-spill funnel on hand or be prepared to make a mess.

It's more common for 'stats to lose their wax and stick closed. But it's a mechanical movement, so sticking open can happen too, especially as the return spring gets older and fatigues.

VStar650CL wrote: ↑

Wed Jul 20, 2022 10:55 am

It's not complicated but 'stat isn't in an easy spot, maybe a 2 hour job with proper tools. Be prepared to jack the front end to bleed the air out, and either have a no-spill funnel on hand or be prepared to make a mess.

It's more common for 'stats to lose their wax and stick closed. But it's a mechanical movement, so sticking open can happen too, especially as the return spring gets older and fatigues.

Will I need to drain the radiator of fluid in the process of replacing the thermostat? Though before I even go about it, are there any for sure ways to check/confirm that the thermostat is stuck open (as being stuck closed isn’t a concern due to the symptoms of that not aligning with my car’s current conditions)?

No, there are good ways to pin down a 'stat that's stuck closed but not one that's stuck open. The only symptom will be what you're seeing, prolonged warmup and possibly never reaching temperature.