99 Z3 Coupe - Engine Coolant Temperature

[ObeyThePoodle]

Hello all,
I did a search but could not find a specific answer.
I have been using the Torque app and my phone to monitor the coolant temp, amongst other things.
After reading around, it seems the temperature, in average, is 190F to 210F... Is that correct?


Anyway, the temp reading on mine stays pretty much at 204.8F in light city traffic, jumping to about 210F when I'm stuck in bumper to bumper traffic, and about 190-200F in the freeway.


I don't know if the water pump and related parts have ever been serviced/replaced 'cause I bought it used a couple months ago, that is next in my list.
My question is, at what temperature should I pull over to avoid a catastrophic failure?
TIA

[rf900rkw]

Any information you find on cooling temps needs to be M52TU or M54 specific. The systems are very different from the S/M52 or S54 (or *62 of that era). One point of difference that has high relevance here, the temp sensor is on the coolant intake side of the head, not the outlet like most every other car. This is the reason you show such large variations in temp as water pump speed and airflow cooling affects the inlet temp.

[ObeyThePoodle]

Thanks, I have a M52TU... So basically, no way to really know beforehand. Is that a fair assumption?
If the dumb needle in the cluster jumps over the eternal 12PM position, then I should just stop asap.

[wrench13]

EXACTLY !! You will have 20-30 seconds to do so, too.

[DuWop]

Does the check the check engine light come on if the engine is over heating on a 1998 Z3 2.8L??? I don't see a engine over temperature idiot light.

[vanne]

There was no CEL when my 2K 2.8 threw its belt.. Luckily I saw it in the first couple of secs...

[rf900rkw]

The MIL is an emissions control failure warning device, not a general fault warning.

[DuWop]

Looks like I'll be installing another gauge, cylinder head temperature with warning light. My two hole pillar mount is reserved for AFR and oil pressure. This one will go beside the windshield. http://www.autoanything.com/gauges/65A6805A0A0.aspx This one has a 0-5 V analog output connection that will be used to blink the oil light.

Does anyone know of a good 2 1/16 inch multi-gauge. I've spent a lot of time searching and found none I want.

- - - Updated - - -

Any information you find on cooling temps needs to be M52TU or M54 specific. The systems are very different from the S/M52 or S54 (or *62 of that era). One point of difference that has high relevance here, the temp sensor is on the coolant intake side of the head, not the outlet like most every other car. This is the reason you show such large variations in temp as water pump speed and airflow cooling affects the inlet temp.

Which end of the head is the coolant outlet?

When engines are over heated the valves/valve seats in the center of the cylinder heads are almost always (99.9% of the time) warped worse than the ones on the ends of the cylinder heads. The valves and valve seats on the rear of an engine are in worse condition than the valves toward the front of the engine. This happens when a water cooled engine becomes an air cooled engine. Perhaps the center of a cylinder head is the best location for a temperature sensor.

Over heated V6 engines mounted sideways, the rear head is damaged from heat and often the leading cylinder head is in relatively good condition. Again, air flow.

Maybe the ideal location for a heat sensor to see the highest temperature (due to coolant loss, coolant flow loss) would be under the valve cover, centered from end to end and side to side, however there would be problems with trying to locate one there. If there is a casting plug (steel, allen head type) in that location a small sensor could be installed in it without worry about cracking the casting, but then there is the wire routing and insulation to consider.

This gauge would be easy to install with the sensor ideally located under the number 4 spark plug. The Odyssey Series 11 is a pain in the a** to set the alarm set-point (300-600 F), and I’m not sure the area around the spark plug would normally be near 300 F but it's possible. This will not work. I think I remember the area around the spark plug is recessed but not sure and induced voltage.


http://www.dakotadigital.com/index.c...rod/prd347.htm

http://www.dakotadigital.com/index.c...rod/prd347.htm

[JayLynch]

Did anyone ever find out what the coolant temp for a M52 2.5i Z3 should be? I just picked up a 1999 Z3 2.3 and runs at between 190 and 200 degrees

[rf900rkw]

We know exactly what the temp should be on a M52. Also the M52TU like you have. The *inlet* temp is nominally 97C, but the computer has the ability to pull it down to approximately 85C as it deems fit. This is a modern constant inlet temp control system. The outlet temp will vary drastically depending on operating conditions. This is normal. Hanging a gauge on it and trying to make it stay at a single number pulled out of the air as if it was a '65 Impala has gotten many a person confused.