S50 water temperature issue

[M3PO]

Hey guys, so I'm trying to sort out whether my water temps are good or not.

My S50 came from a car that appeared to be well maintained. It had 113k on it and seemed to have a new rad, hoses, water pump, and thermostat housing (thermostat also I am assuming, no clue if it's 80 or 88).

I used all of the stuff from that car. I added a Spal fan in front of the rad wired to the aux fan wiring utilizing the stock resistor. I put an 80/88 switch in the rad. To do that, I had to re-wire the plug because the early cars (mines an 84) used two separate switches.

Using a late model M20 bottle on the drivers side so it should be well bled.

E30 sensor for the cluster. For the first couple weeks it ran at about the middle of the gauge. It would creep up a little but until the fan came on (on high) and the fan would bring it back to the middle and shut off.

All of the sudden, it seems to run/operate exactly the same except now it's moved up a notch. Now it runs at 3/4 on the gauge. Is the sensor bad or what?

[M3PO]

I should also mention that the fan never comes on low unless I hit the AC button on the dash.

[M3PO]

Last night I went to a movie and the temp went almost to the red. Came out of the movie, drove it home and it stayed at the middle. Same thing this morning, right in the middle. WTF is going on here?

[328ijunkie]

sounds like coolant circulation problem

[M3PO]

So I installed a VDO aftermarket sender and gauge this weekend. It seems to be running around 195-205. That seems pretty normal right? OEM dummy gauge still running around the middle.

[burlmays9]

Your OEM gauge is probably right.

I also agree with 328iJunkie.

[mpowerful]

Mine runs between middle and 3/4 all the time in new orleans heat. It could prob be better as one of my heater hoses is pinched because i hacked em in due to not having the correct ones for the swap. I actually ordered new hoses and may put em in this weekend. Anyway so far 3/4 is what it says on heat soak when i turn the key on after sitting for few mins hot and before starting and recircing cooler coolant from radiator. Oem m20b25 late radiator. Euro fan/540 clutch. M52 water pump and oem thermostat.

[M3PO]

Your OEM gauge is probably right.

I also agree with 328iJunkie.

Thanks, so you think 200F is not okay? The E36 M3 forums suggest that 200 is normal.

[328ijunkie]

Mine runs between middle and 3/4 all the time in new orleans heat. It could prob be better as one of my heater hoses is pinched because i hacked em in due to not having the correct ones for the swap. I actually ordered new hoses and may put em in this weekend. Anyway so far 3/4 is what it says on heat soak when i turn the key on after sitting for few mins hot and before starting and recircing cooler coolant from radiator. Oem m20b25 late radiator. Euro fan/540 clutch. M52 water pump and oem thermostat.

Which 540 clutch are you using? Most of them lockup way too late as the v8s run ~215+ on average.

[mpowerful]

E39. Havent had any serious issue yet. I can put an e36 clutch on it. It seemed stouter than the e36 one i took off but alas it was a free new clutch.

[MyE30]

Thanks, so you think 200F is not okay? The E36 M3 forums suggest that 200 is normal.

FWIW, on my s52 I've never had the needle on the temp gauge go above halfway during normal operation. However, one time when the fuse for the electric fan popped, the gauge went to 3/4 while I was sitting in an In and Out drive through on a day when it was about 90 degrees outside.

S52
88c thermostat
80/88 thermoswitch
16" SPAL pusher

[nrubenstein]

The stock thermostat is 92C.

If your fan is not running at absolutely all times, you have an issue with your cooling fan circuit. (I like the flex-a-lite controller.) Also, if you still have the AC condenser installed, a pusher basically doesn't do shit.

[M3PO]

The stock thermostat is 92C.

If your fan is not running at absolutely all times, you have an issue with your cooling fan circuit. (I like the flex-a-lite controller.) Also, if you still have the AC condenser installed, a pusher basically doesn't do shit.

My fan doesn't run unless the car is at full temperature and sits still for ~5 mins (like in traffic). Then the needle goes a bit above the middle and the fan comes on. The fan is easily able to bring the temp down then shuts off.

No AC condenser. With the fan on and the door open, I can feel the fan pushing hot air under the car! :-D

[mpowerful]

So I got the pyrometer out today when I got to the shop. I drove about 3 miles to get there and measured with A/C on and off. I think off was probably the most important. Anyway I got 210 at the upper radiator hose actually on the radiator where it spills out. I got no more than about 185 on the aluminum housing for the thermostat. I got 195 on the upper hose. I got 155-165 on lower passenger side of radiator and hose. I let it idle for 20 minutes like that.