OBC 19.7.00 - Watcha' go? doityourself

[derbo]

Mine read 95C on the freeway tonight with ambient temp at 48F


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[Oli77]

Oli77: 96
Dane: 97 (give us the real one; whenever you're ready )
Telijah: 88
edlvrt: 96
MrMaico: 97
Spencers: 90
Livesnearcoscto: 95 (will check).
derbo: 95

[MrMaico]

About your comment, I too notice a drop when (I think) you accelerate and push more air onto the radiator, then when you slow down or come to a stop, temp rises.

I would think the thermostat would react faster than that, that's a pretty big temp drop. I really have no good idea what it might be though.

Okay. Finally got around to this today

90

I wonder if it's the fact that your car is a 2001 that would explain the cooler temp. I've always heard that newer cars are designed to run hotter to help meet emission and fuel economy regulations.

[spencers]

I wonder if it's the fact that your car is a 2001 that would explain the cooler temp. I've always heard that newer cars are designed to run hotter to help meet emission and fuel economy regulations.

Hmmm... Good point. I'll have to test this again sometime soon.

The car was fully heated up and the reading was taken/monitored during city driving. Maybe it would be different highway driving.

[MrMaico]

Hmmm... Good point. I'll have to test this again sometime soon.

The car was fully heated up and the reading was taken/monitored during city driving. Maybe it would be different highway driving.

I've been monitoring mine for over a year now and I don't see any real difference between city and highway. I see 205 (96.1) most of the time but have seen it vary from 188 (86.6) up to 212 (100). 205 seems to be the average though.

[Oli77]

I wonder if it's the fact that your car is a 2001 that would explain the cooler temp. I've always heard that newer cars are designed to run hotter to help meet emission and fuel economy regulations.

Good point. Need more data...

[LivesNearCostco]

I monitored mine today on a drive, maybe 14 miles round trip. I never saw it go above 92C, which is weird, as I was sure it went higher than that last summer when I first discovered how to monitor it with the OBC. Weather was 55F and as I drove to then on the freeway, it never got higher than 72C. Once I exited the freeway and stopped at a light, it climbed into the low 80's and after some parking lot action it got all the way up to 90C. I stepped (motor running) to unload something and when I got back in the fan had come on and it was back down to 88C so am not sure how high it got.

Going back to the freeway ranged from 86C to 91C, then on the freeway dropped into the 70's (71-77C). Exited freeway and it went into the 80's. Finally I stopped in front of my garage and sat with the motor running. It climbed slowly up to 91 then dropped to 88, back up to 91, dropped to 88. My theory is my fan is turning on at 91C and turning off at 88C.

This all seems kind of low. Maybe my thermostat is stuck open? It has ~85,000 miles on it. But the buffered temp needle stays in the middle. Mods include EMP Stewart pump (more flow) and underdrive pulleys (less flow). I will try to monitor again on a hotter day.

[derbo]

my bone stock car on the freeway is around 95. During traffic (40mph) on the freeway the car dropped down to 90-92. But overally stock new composite waterpump and stock pulleys for me was done 20k ago.

[MrMaico]

I monitored mine today on a drive, maybe 14 miles round trip. I never saw it go above 92C, which is weird, as I was sure it went higher than that last summer when I first discovered how to monitor it with the OBC. Weather was 55F and as I drove to then on the freeway, it never got higher than 72C. Once I exited the freeway and stopped at a light, it climbed into the low 80's and after some parking lot action it got all the way up to 90C. I stepped (motor running) to unload something and when I got back in the fan had come on and it was back down to 88C so am not sure how high it got.

Going back to the freeway ranged from 86C to 91C, then on the freeway dropped into the 70's (71-77C). Exited freeway and it went into the 80's. Finally I stopped in front of my garage and sat with the motor running. It climbed slowly up to 91 then dropped to 88, back up to 91, dropped to 88. My theory is my fan is turning on at 91C and turning off at 88C.

This all seems kind of low. Maybe my thermostat is stuck open? It has ~85,000 miles on it. But the buffered temp needle stays in the middle. Mods include EMP Stewart pump (more flow) and underdrive pulleys (less flow). I will try to monitor again on a hotter day.

How old is your thermostat? In your other post you mention you changed it last year.

What year is your car? M54? At any rate, that's way too cold. Do you have any hidden codes? At those temps I would think it would light a CEL though. I would have to think it's the thermostat.

[LivesNearCostco]

My car is a 2003 (August 2003 build) and if we believe the indie shop that once serviced my car two owners ago, my thermostat has 85,000 miles on it and was changed around 2008. I did put in a new aluminum bodied one 10 months ago but it stuck shut, throwing a code and overheating my car, so I put the old one back on.

This morning I drove the ZHP to work (instead of the beater car) and conveniently got stuck in street traffic. Air temps 45-48F. OBC coolant temps cycled same as yesterday... rose to high 70's while driving, 80's at stoplights. When I got stuck in slow traffic, it cycled as follows
88 to 90 to 88 to 90 to 88 to 91 to 88 to 92 to 88 to 91 to 88 to 92.
On the freeway it went back down to the high 70's, and when coasting down a long off-ramp with zero throttle went as low as 73C. When parking got back into the high 80's.

Maybe my thermostat is stuck open. I have a new Wahler thermostat leftover from the warranty replacement of the aluminum one. Maybe I should put that in.

When my coolant temp cycles between 88C and 92C does anyone know if that is the thermostat opening and closing or the fan turning on and off? Are these thermostats set to open at 90C? 95C?