to those with aux water temp gauge - cluster vs aux readings??

[pandaboo911]

to those with aux water temp gauge - cluster vs aux readings??

The gauge hardly moves because it's located on the head, even though the temperature in an engine is in constant fluctuation, the gauge is steady because it has very good thermal contact to the head.
I have an autometer ultralite mechanical gauge and it's reading temps coming out of the thermostat. the temperature fluctuates 10-15 degrees F as the engine heats up and cools back off with the fan. It does this every few minutes. The needle moves very fast as things get hot

The gauge seems damped because there isn't much coolant flow in that location. They use that as a location because even if you lose all your coolant it'll still read hot.

I found that out the hard way when I built my lemons car. The coolant temp was measured at the heater core hose. A wrench from the trunk of the car in front of ours flew out and went clean through the radiator, the coolant temp didn't register any change because the coolant was draining so fast, so we kept racing for 2 laps on no coolant and the race was over.

[Sh3rpak!ng]

The gauge hardly moves because it's located on the head, even though the temperature in an engine is in constant fluctuation, the gauge is steady because it has very good thermal contact to the head.
I have an autometer ultralite mechanical gauge and it's reading temps coming out of the thermostat. the temperature fluctuates 10-15 degrees F as the engine heats up and cools back off with the fan.

The gauge seems damped because there isn't much coolant flow in that location. They use that as a location because even if you lose all your coolant it'll still read hot.

I found that out the hard way when I built my lemons car. The coolant temp was measured at the heater core hose. A wrench from the trunk of the car in front of ours flew out and went clean through the radiator, the coolant temp didn't register any change because the coolant was draining so fast, so we kept racing for 2 laps on no coolant and the race was over.

Yes, thanks for that. I have been wondering about the quality of the head location as a source for temp. Do you use that aluminum splice in the radiator inlet hose for the sender? I want to see TRUE engine coolant temps, and I want to see those changes and fluctuations reflected on the gauge.

[pandaboo911]

to those with aux water temp gauge - cluster vs aux readings??

Yes, thanks for that. I have been wondering about the quality of the head location as a source for temp. Do you use that aluminum splice in the radiator inlet hose for the sender? I want to see TRUE engine coolant temps, and I want to see those changes and fluctuations reflected on the gauge.

Yeah I used the adapter that goes on the radiator hose. Knowing your coolant temp is actually rather useless because it changes so fast. I had 240 degrees showing at coolant temp but the head was only slightly hot. on top of that, there is way too much coolant flow in the radiator hose to come to any conclusion on how hot the engine actually is. I wish I could move it but the mechanical sensor is just too big to fit into the port on the head.

I run an external temp sensor on my lemons car. It bolts onto the side of the block. It's way more reliable and steady than the coolant sensor I was running. I also moved my coolant sensor so it has good contact with the aluminum on the head. The coolant temp always made drivers unsure whether they should come in or not. Now it's very clear that if the block temp goes anything over 110 C there's a problem.

BMW knew what they were doing when they put it there. The aluminum head is ultimately what will cause engine failure when your car overheats, so knowing the exact temperature of the head is the best measurement.

Block temp is a backup in case the cooling system explodes again. (Which is rather hard to notice at 100mph and 7000rpm)

Just for reference my supercharged s52 sits right at 200F. Goes up to 210 when the fan turns on. Running the e36 koyorad and Stewart waterpump. 88C thermostat I believe. When I ran the s54 z3 rad it was at 205 and 215 respectively

[pandaboo911]

And to answer the original question.. Your temps look exactly the same as mine. I was expecting it to be around 185-190 but I guess the engine coolant runs a bit hotter than the engine itself.

As long as you don't go over 230 you should be golden.

[Sh3rpak!ng]

Yeah I used the adapter that goes on the radiator hose. Knowing your coolant temp is actually rather useless because it changes so fast. I had 240 degrees showing at coolant temp but the head was only slightly hot. on top of that, there is way too much coolant flow in the radiator hose to come to any conclusion on how hot the engine actually is. I wish I could move it but the mechanical sensor is just too big to fit into the port on the head.

I run an external temp sensor on my lemons car. It bolts onto the side of the block. It's way more reliable and steady than the coolant sensor I was running. I also moved my coolant sensor so it has good contact with the aluminum on the head. The coolant temp always made drivers unsure whether they should come in or not. Now it's very clear that if the block temp goes anything over 110 C there's a problem.

BMW knew what they were doing when they put it there. The aluminum head is ultimately what will cause engine failure when your car overheats, so knowing the exact temperature of the head is the best measurement.

Block temp is a backup in case the cooling system explodes again. (Which is rather hard to notice at 100mph and 7000rpm)

Just for reference my supercharged s52 sits right at 200F. Goes up to 210 when the fan turns on. Running the e36 koyorad and Stewart waterpump. 88C thermostat I believe. When I ran the s54 z3 rad it was at 205 and 215 respectively

And to answer the original question.. Your temps look exactly the same as mine. I was expecting it to be around 185-190 but I guess the engine coolant runs a bit hotter than the engine itself.

As long as you don't go over 230 you should be golden.

Thanks for all the details. So I guess I might just leave it as is for now. I mean, obviously it's not overheating, it just bothers me that the cluster gauge and the aux gauge don't seem to agree. And the aux gauge seems to read too high. I might eventually try another gauge/sender.

On my supercharged e36 with spal fan, mishi aluminum rad, 80c tstat and oem water pump it stays down 185 while cruising and will climb to ~210 while stopped in traffic but the fan drops it back to ~190. It's just driving me crazy that on that car with almost identical setup the temp readings seem appropriate, but on the e30 they don't.

[TobyB]

we kept racing for 2 laps on no coolant and the race was over.

I DO love my level sensor on the tank-

when the heater hose bypass popped off,
the housing temps DROPPED- so I looked over, the
level sensor was on (DOH!),
I braked- and the braking
sloshed coolant over the bulb,
causing it to spike up to about 240.

Which was where my heart rate was as I switched off...

I find that the housing location's pretty sensitive- I can watch
temps overshoot in warmup, rise slightly when drafting, overcool just
a touch afterwards- signs of an ever- so- slightly sticky t- stat...

t

[Sh3rpak!ng]

I DO love my level sensor on the tank-

when the heater hose bypass popped off,
the housing temps DROPPED- so I looked over, the
level sensor was on (DOH!),
I braked- and the braking
sloshed coolant over the bulb,
causing it to spike up to about 240.

Which was where my heart rate was as I switched off...

I find that the housing location's pretty sensitive- I can watch
temps overshoot in warmup, rise slightly when drafting, overcool just
a touch afterwards- signs of an ever- so- slightly sticky t- stat...

t

So you have your temp sender on the thermostat housing on the m20?

Ugh I don't know what to do.

One thing I am sure of is that this will drive me crazy until I find a suitable solution :hitler::hitler::hitler:

[Sh3rpak!ng]

FIXED :D

So I was very stupid. I had chained all of the gauges onto the same 20awg wire. So there was a single 20awg wire for power, and a single 20awg wire for ground for all three of them. Also, I tapped the power supply to the radio to supply power/ground which I also tapped to hardwire a phone charger my god I feel stupid. I have NO idea what I was thinking. That kind of work is not even close to my usual standards...

Anyway, I have been wanting to clean up and organize the behind dashboard/under cluster/steering column wiring for a long time since the PO hacked it all up to install an alarm.

Solution: I ran a large gauge power line straight from the under hood power terminal which split to 2 12awg wires into 2 80amp relays (yea I know way overkill) which feed a 10 slot fused power distribution block. The relays are switched from ignition power (tapped a larger gauge purple/white wire which came straight from the ignition cylinder). I also added a ground distribution block which is supplied with 2 12awg wires from a factory ground near the top of the pedals. Each gauge is now individually wired with a 14awg ground and 14awg power and fused with 2 amp fuses. Additionally, I got a new water temp gauge just in case it was faulty since I didn't want to have to take anything apart again (I returned the old one via amazon).

I am now showing a solid 180-190 during normal conditions and haven't seen it pass 195 :D :D :D

Power distribution block makes it so much easier to add auxiliary items. I already wired up my radar detector, hardwired my usb phone charger and a volt meter

[CorvallisBMW]

Nice work! Yes, gauges like these are very susceptible to errant power from either wires that are too small or wires that feed other sources. I did the same thing you did with a power distribution block and 14awg wires for power and ground; mine are dead accurate!

[Varinn]

Bump from the dead!

Does anyone have any input on what size wire needs to be run between the gauge and the sender? Could I get away with 20awg between the two and doing something like the distribution block with fat wires for the + and - part of the gauge circuit?

[CorvallisBMW]

I think you could use 20AWG for the signal, backlights, and +12VDC, but VDO recommends at least 14AWG for the ground wires.

[Sh3rpak!ng]

Pretty sure vdo or whatever gauge manufacturer specs that out in the installation instructions. I'd follow their requirement.

[Varinn]

I ended up running a 10gauge from the positive post to a distribution block/relay under the dash then 3 separate 14gauge feeds to the gauges and a 14ga ground from each gauges to a ring terminal on the chassis under the dash. 20 gauge wire is running the 3 bulbs in parallel and 20 gauge is also used on each sensor, everything so far is rock solid and appears very accurate.

Only downside is now I'm very aware of how the engine is behaving. I'm finding that the stock 5w40 at cold start temps (+5c ambient) is about 50-60psi at idle, it drops progressively and hovers around 12psi idle when the oil gets hot (100 celsius). In stop and go traffic my pressure light flickers off and on somewhat frequently but I've replaced the oem switch with a double pole VDO that has a 10psi warning contact. I seem to never drop below 8-9 psi by the gauge reading.

I'm thinking it's worth switching to something more like a 5w50 or 10w50 oil to try and bring my hot pressures up some without effecting cold much.

[JRKOUPE]

what engine????....3.2 s52?


and yes..w/ gaUGES U WILL BECOME HYPERAWARE OF ENGINE STATE OF HEALTH..LOL...youll get over it


oops sorry bout caps

[Varinn]

what engine????....3.2 s52?


and yes..w/ gaUGES U WILL BECOME HYPERAWARE OF ENGINE STATE OF HEALTH..LOL...youll get over it


oops sorry bout caps

Right, yeah car has an S52B32 in it. OBD2 with m50 manifold.