Overheating issues with S50

[havand]

Wouldn't the higher temp thermostat just make it stable at a higher temperature? Maybe you finally got a good bleed? I have had nonstop issues with my swap and m42 rad too. Every time I think I got it, it goes whacky again.

[e30austin]

Ended up going with a Graf water pump and 75c tstat. Found out I had two 88c tstats in a row (never bothered to check, my fault.) Explains my issue. Now it's all nice and new and ready to go! Sits right between 1/4 and 1/2.

[e30austin]

Got a new Stewart water pump and a 72c Tstat today. Let's hope this fixes this slut!

[edsel1134]

Ok as I've stated I've owned 7 e36 m3 all of which had this symptom and every time it was water pump.. Good luck

[e30austin]

Word up. Looks like that's tomorrow's project. I get good heat so I think heater core is probably fine (no water on carpet now, idk? lol)

[golde30]

hmm, if it was running cool before, then its another issue. replace the water pump, and figure out if your heater core is plugged up. Water pump is like what, $80? better than rebuilding the head...

[e30austin]

which Tstat are you running? the e36 spec Tstat runs hotter than the e30 spec Tstat, so at operating temp its about 1/2 way between 1/2 and 3/4 on the e30 gauge cluster. I had this same issue the last time i swapped from s50 to s52 using all new everything. installed a new m20 Tstat with a hole drilled at 12o'clock and bled it out. now it never goes over 1/2 on the gauge, unless i forget to turn on my fans in traffic.

E36 80c tstat. Should I go get an M20 tstat and see if that changes it? It only ran between 1/4 and 1/2 before I was having issues, which is weird that it will run that much warmer now.

[golde30]

which Tstat are you running? the e36 spec Tstat runs hotter than the e30 spec Tstat, so at operating temp its about 1/2 way between 1/2 and 3/4 on the e30 gauge cluster. I had this same issue the last time i swapped from s50 to s52 using all new everything. i went through 2 brand new water pumps thinking i got a bad unit, then I installed a new m20 Tstat with a hole drilled at 12o'clock and bled it out. now it never goes over 1/2 on the gauge, unless i forget to turn on my fans in traffic.

[edsel1134]

Again.. All symptoms of water pump

[e30austin]

Got enough motivation to fuck with this damn thing again today.

Drilled/tapped a hole for a bleeder valve on the thermostat housing. Not the most orthodox way of doing it, but I thought it would get the job done and I wouldn't ever have to deal with it again.

Put it all back together, pulled off the upper radiator hose, filled it with coolant until it was full, installed upper radiator hose, started the car up and parked it on the hill at my shop. I added coolant as needed (roughly 1/2 gallon) while the car was running. It took a long time to get to temp. I had the cap off, fan on, and heater fan on. It got most of the air out within the first minute. It kept getting warmer and warmer until it got to the 1/2 mark. After that, it stayed there mostly, but would creep up a ways. I went out and drove it for about 5 min and it stayed mostly at 1/2 mark, maybe a little below if I was getting a fair amount of speed built up.

I got it back to the shop after realizing it wasn't going to get any cooler than that. It was still doing the same thing as before, where I could hold it at 3k rpms for 20 seconds or so and the temp would drop a bit, but come back up within a minute's time. It very slowly kept creeping up, would rev it, and it would come back down.

Here's the weird part- when I took the cap off, there was very little pressure (if any,) it wasn't overflowing and bubbling like it was before (which leaves me hope that the head/head gasket is not compromised) and wouldn't just immediately overheat (like it had been doing.) I let it idle with fans on for about half an hour or so and it appeared to be doing fine, but would slowly creep up a bit (concerned me enough to reply to this thread.)

I'm about ready to give up on the damn thing. I don't see what else I could be doing wrong?!

[edsel1134]

Pressure leak? From air? Who knows start with pump it's cheap and easy to do.. And idk what the swap intells but check the fan clutch or what ever is used

[e30austin]

I fucking despise cooling system issues, too. Only used OE coolant in this motor.

Water pump was nice and quiet at the time of install and showed no signs of failure. Since I'm working on basically an unlimited budget at this point, I guess I'll just replace it.

Also, another thing to note...heater core appears to be leaking. The carpet does feel pretty damp. Wonder if it's clogged and caused the orings to start leaking? Sure would explain a lot.

[butters]

Agree on coolant. I also add some water wetter.

Hate to say it Austin, but I would probably be moving towards replacing the water pump at this point just to be sure.

[edsel1134]

Sorry helps prevent not stops lol
And it's worth the inflated price.. This is why I've had trouble debating the s50 swap myself.. They are sensitive that's why I got rid of my m3 lol

[edsel1134]

Agreed the BMW coolant stops warping of the heads from extream heat.. I seen what the BMW coolant bs others does inside these motors it's crazy.. Good luck op keep us posted