Z3: I think the thermostat went out...

So the car is driving just fine, however I am looking at the coolant and its pegged in the middle like the idiot light it is.

However, the oil temp is pretty low. I would say 160 or so. That seems too cold, granted interstate driving right now is super cold, but shouldn't it be around 200?

This is all day, well warmed up since I drove the car 10 hours today.

I figure I need to replace the thermostat when I get home. Might as well do the water pump while I am in there. Belts too I guess.

How long does the Stewart water pump last?

Anything else I should replace on the M52TU while I am at it?

You're fine, little buddy. You don't have an oil cooler (presumably), and your coolant temp is fine. Oil temp really doesn't matter unless you're running a diesel.

Dive. Have fun. Don't waste the money.

You guys are having a cold spell down there right? Maybe you just aren't used to it?

So the oil isn't supposed to be 200 degrees? It warms up to about 200 when I stop at the gas station, but on the interstate at 80 mph with temperatures about 20 degrees outside its dropping down in temp.

I thought the idea was that the thermostat was supposed to keep the motor warm by keeping the radiator closed off.

I get the coupe up to 230-260 when I take it out on spirited drives...

I guess the Z3 is just a colder motor?

Originally Posted by Mpire

So the oil isn't supposed to be 200 degrees? It warms up to about 200 when I stop at the gas station, but on the interstate at 80 mph with temperatures about 20 degrees outside its dropping down in temp.

I thought the idea was that the thermostat was supposed to keep the motor warm by keeping the radiator closed off.

I get the coupe up to 230-260 when I take it out on spirited drives...

I guess the Z3 is just a colder motor?

Thermostat only monitors coolant temperature, not oil temperature.

Yes, engines with less displacement make less heat because they combust less fuel per cycle.

I have never seen the oil temp stay so low in 10 years of driving with an oil temp gage. I will never understand how people can live in such cold weather!

Originally Posted by Mpire

I have never seen the oil temp stay so low in 10 years of driving with an oil temp gage. I will never understand how people can live in such cold weather!

But haven't you ever noticed that your oil temps vary depending on outside temp and load? I've seen around 260 on the street -- bike on the roof, going up mountain passes at ~85, 100+ degree weather.

On the low side, here in the SF bay area I've had my oil temps hover around the 200deg mark on my freeway commute in the winter (maybe 45 degrees ambient).

Don't worry about it.

When my thermostat was stuck open the water temp was around 160 degrees, after replacing it I found the normal temp to be bit above 200 degrees. I used the Scangauge II which plugs directly into the OBDII port. The idiot gauge did show slightly below midway when the thermostat was stuck open, now shows midway.

Water temp idiot gauge is straight up and down.

I guess I need to go find a scangauge to test it.

160F oil temperature is normal for highway driving in 20F ambient temperatures.

Both my BMW's temp stays dead center. Thats actually a good thing.

Water temp gauge isn't quite as dumb as people say it is. It definitely has a dead spot on center, but it WILL reflect water temps outside of the normal range.

Originally Posted by Ron Stygar

Indeed.

Originally Posted by reidconti

Water temp gauge isn't quite as dumb as people say it is. It definitely has a dead spot on center, but it WILL reflect water temps outside of the normal range.

Not really, which is what annoys most of us. It's essentially an idiot light. The time below operating temperature is very short even in January in Michigan. At the high end, what really sucks about it is that 110C is above the boiling temperature of a 50/50 mix under atmospheric pressure. So how do you find out that you've sprung a coolant leak (and hence lost most or all of the the 25C or so of additional headroom provided by the cooling system's pressure)? By the fact that there's steam pooring out from under the hood.

Interesting. Thanks for the info.

I had my car begin to overheat on the autocross grid, thermostat stuck closed I believe. I shut the car down as the red light came on.

As we messed with it, running the car with an OBD-II scanner hooked up, doing my runs (it would be fine as soon as you started moving), burping the coolant, etc, I noticed the needle doing a fair bit of moving between halfway and the red mark (the light never came on again).

I was able to monitor the temp on the OBD-II scanner and watch the gauge. Coolant temps would be around 250-255, and the gauge was being quite active.

I agree that it would be nice if there was no buffering, or if it was a smaller range.

However, in a catastrophic cooling system failure, I question how much more notification you'd get on an un-buffered gauge. If the gauge lags time-wise, I'd be much more concerned (ie, reporting some kind of moving average).

If it simply starts moving at 230, well, if your car is heating up quickly, how much sooner would you catch it if there was no dead spot in the center?

Originally Posted by reidconti

Interesting. Thanks for the info.

I had my car begin to overheat on the autocross grid, thermostat stuck closed I believe. I shut the car down as the red light came on.

As we messed with it, running the car with an OBD-II scanner hooked up, doing my runs (it would be fine as soon as you started moving), burping the coolant, etc, I noticed the needle doing a fair bit of moving between halfway and the red mark (the light never came on again).

I was able to monitor the temp on the OBD-II scanner and watch the gauge. Coolant temps would be around 250-255, and the gauge was being quite active.

I agree that it would be nice if there was no buffering, or if it was a smaller range.

However, in a catastrophic cooling system failure, I question how much more notification you'd get on an un-buffered gauge. If the gauge lags time-wise, I'd be much more concerned (ie, reporting some kind of moving average).

If it simply starts moving at 230, well, if your car is heating up quickly, how much sooner would you catch it if there was no dead spot in the center?

Definitely true that in a sudden significant failure you're not going to get much (if any) notification from the gauge.

I can't speak for others, but I look at my gauges at regular intervals on every drive. Frequently in the first 10 to 15 minutes. The idea being to learn what's normal behavior in various conditions. I learn how long it takes for various fluids to come up to operating temperature. When one of the temperatures comes up faster than usual for the given conditions, I know something is amiss. Or in the case of the MINI Cooper S, slower than usual (the oil temperature wiring is very exposed underneath the car, hence gets severed almost every winter from snow or a chunk of frozen sludge that's fallen off of a car in front of me ).

That's why I don't like our water temperature gauge; it largely defeats this learning process and hence might as well be an idiot light (which would occupy less space in the cluster, making it easier for me to use a larger OLED in my latest project). It's also why I went with the ISSPRO EV 270 degree gauges with 100-280F range; I get useful information during the warm-up period.