Is it water pump time?

[jmo69]

Your E46 has an electrical fan, which seems to function perfectly.
The E36 has the mechanical fan, which very probably isn't working well.. And the aux fan will only turn on very late with the original temp switch..

I would first replace the mechanical fan, or do a proper fan delete mod (at least the 80/88 deg. C temperature switch).. Then test again. And go from there.

On the other hand checking the 10+ year old radiator isn't bad of course, but I doubt there is any problem there. Otherwise it would have shown on the highway.. There is nothing wrong with 204 degrees F (95 degrees C). But with the bad mechanical fan (and the aux fan starting way too late) it will rise when you're idling or in stop-go traffic.

My e46 has a mechanical fan and the electric auxiliary fan just like my e36. The e46 has a newer fan clutch but I did run a 700 mile trip one summer with no mechanical fan on the e36. Had no cooling problems on that trip. Never got near 200°F.

[ed323i]

Ah, okay.. I thought all manual E46's, especially the later ones with the M54, only had the electrical fan and no mechanical fan. Or perhaps your 325xi is an automatic?

The M52TU and the M54 in your E46 do have a way more complex thermostat that is electronically controlled by the DME.. So, it's normal that it's running on other temperature ranges than the "dumb" thermostat in the M52. (for example, under high load, the thermostat will open a lot earlier/cooler, and while cruising along it will open a lot later/hotter)

Like several other people say in this thread, the 205 degrees F seems perfectly fine with an 88 deg C thermostat. But to be absolutely certain nothing is wrong, you could inspect and clean the radiator, check for flow issues, and swap another thermostat and/or water pump.. High risk of wasting money and time though. If the temperature remains stable at 95 deg C, or in the 200-210 F range, even under high loads, then I seriously doubt anything is wrong with your cooling system (except for the mechanical fan clutch). If you want lower operating temperatures, then you can install an 80 degrees C thermostat and it will probably run at +/- 85 deg C (unless in stop&go traffic, as the bad mechanical fan will not be able to keep temps there, and the aux fan, with the stock temp switch, will only turn on at +/- 100 deg C head coolant temp, as the 92 deg C of the temp switch is measured on the output/cool side of the radiator).

Let us know what you find.

[jmo69]

I'll try to flush the radiator tomorrow and see if anything comes out. I'll pull and inspect the pump, but I would think a pump wouldn't have varying degrees of failure. Either it would leak or impeller blades would fail or break.

[jmo69]

This is what I did today. Back flushed the radiator and didn't see any sediment come out. I found the fan clutch I took out of my e46 a few years ago. Lastly the pump seemed to have some play in it so I put the original back in. This may have been a waste of time, everything is working but it is noisy. There is a definite knocking sound. I took about a 5 mile ride and the temps were lower but it is only about 80° out today. Screenshot_20180702-135714.jpg
I think tomorrow I'll pull the fan off and see if the noise level changes, my guess is the knock is the water pump. Strange considering this one felt tighter than the Graf that I took out.20180702_120251.jpg20180702_110804.jpg20180702_110753.jpg

[jmo69]

Actually I bit the bullet and bought a new Graf pump, Behr Fan clutch and Wahler 88° thermostat. If those don't help I'm just going to have to live with it.

[MIKYZZ4]

Not exactly,
you're neglecting the only other possible obstruction to flow-RADIATOR!

[jmo69]

Not exactly,
you're neglecting the only other possible obstruction to flow-RADIATOR!

I flushed it the other day and it flowed just fine.

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[MIKYZZ4]

Yes, I understand, but it's 109,000mi. & 11yrs. old,
and since you're so anal retentive about the temps,
that's the last thing left to replace, as you've replaced the rest of the system,
so just make it 100% sure!!!

[jmo69]

Yes, I understand, but it's 109,000mi. & 11yrs. old,
and since you're so anal retentive about the temps,
that's the last thing left to replace, as you've replaced the rest of the system,
so just make it 100% sure!!!

Gives me something to do seeing as every day is Saturday for me lol.

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[MIKYZZ4]

I understand, believe me I'm the same,
enjoy the rest of the holiday week/weekend!

[jmo69]

I understand, believe me I'm the same,
enjoy the rest of the holiday week/weekend!

I may have spoken too soon. I did an oil change this morning and as I was pulling the drain pan out I noticed a drip from the radiator. The drip came from the aluminum crimp forward of the drain. I was able to tighten the upper hose clamp so I'm hoping that was the source. Put some new O-rings on the oil filter stem while it was out.
I hope the video works to show the knocking and what seems to be the fan wobbling
https://cloud.tapatalk.com/s/5b3fb9a4...706_112010.mp4

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[jmo69]

Try this link https://youtu.be/wOwXyrYJFHc

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[jmo69]

If it isn't one thing it's another! Put in the new pump, thermostat and fan clutch, bled it and without a drive the temps are a little better. BUT, now I have a leak, not bad but I haven't been able to pin point it yet. Retorqued all the fasteners but it's still dripping off the front of the motor. I think my next step is to pull the thermostat and put a bead of RTV around the housing. Oh well, tomorrows another day.


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[jmo69]

Redid everything today, a little RTV on the sealing surfaces and no apparent leaks. I still have to drive it to make sure but the temperature is down. This is what I got while doing the bleeding process.


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[ed323i]

Great that you managed to fix the leak and installed all new parts. Should be very reliable now for the coming years (except for the radiator, but with some luck it will last a few years more).

It seems like the thermostat hasn't opened yet, during the bleeding, because temp (178 deg F = 81 deg C) is a few degrees C below the thermostat temperature of 88 deg C.
So, either the engine needed a bit more warming up time, or the thermostat is opening a bit too early..

Let us know how it works out while driving.

An update for my car: I received the 6 new coils today which I will install soon, and then I'll hopefully be able to run INPA while driving the car (old coils are probably causing too much electromagnetic interference, causing INPA to lose the connection with the engine on). Then I can monitor the temperatures while driving and let you know what temperatures I see with the stock thermostat.

A question: What do you use to measure the temperatures, speed, fuel trim and rpm, as in the screenshot you sent? Some sort of OBD2 device?

[jmo69]

Great that you managed to fix the leak and installed all new parts. Should be very reliable now for the coming years (except for the radiator, but with some luck it will last a few years more).

It seems like the thermostat hasn't opened yet, during the bleeding, because temp (178 deg F = 81 deg C) is a few degrees C below the thermostat temperature of 88 deg C.
So, either the engine needed a bit more warming up time, or the thermostat is opening a bit too early..

Let us know how it works out while driving.

An update for my car: I received the 6 new coils today which I will install soon, and then I'll hopefully be able to run INPA while driving the car (old coils are probably causing too much electromagnetic interference, causing INPA to lose the connection with the engine on). Then I can monitor the temperatures while driving and let you know what temperatures I see with the stock thermostat.

A question: What do you use to measure the temperatures, speed, fuel trim and rpm, as in the screenshot you sent? Some sort of OBD2 device?

Took the car for about a 5 mile ride and the temperature from my OBD Fusion app held at 199° F until I let it idle in my driveway for a few minutes and then it went to 203°. I'm happy with these numbers, the ambient temp was in the mid to upper 80's so I think it was a fair test. No stop and go traffic but mostly country roads and speeds above 25 mph. Tomorrow after work I'll drive a little further.

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[jmo69]

More info on the app. As I stated it's the OBD Fusion app for my Android phone. It cost me about $15 with the Veepeak device that plugs into the OBDII port under the dash. It does more than just show the temps and speeds. It shows and clears fault codes and also records drives so you can email them via drop box. I don't understand all that but its helpful for people that do. It is available for i products too.

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[MIKYZZ4]

Very similar to the Torque Pro APP, it seems.

[1215]

You have two choices: You can drive it as-is and the second you hear even a small belt squeak then stop everything, do not pass go, do not collect $200, do the water pump... Or proactively change it. If you are asking then yes, just change it. (and the expansion tank) There are a couple different types of failures. If you are asking if it's time --just do it. The $ you spend on the tstat and pump will be cheaper than a head gasket (or worse). I'll probably get flamed for saying that but it's true.

[jmo69]

Very similar to the Torque Pro APP, it seems.

More info here https://www.obdsoftware.net/software/obdfusion

- - - Updated - - -

You have two choices: You can drive it as-is and the second you hear even a small belt squeak then stop everything, do not pass go, do not collect $200, do the water pump... Or proactively change it. If you are asking then yes, just change it. (and the expansion tank) There are a couple different types of failures. If you are asking if it's time --just do it. The $ you spend on the tstat and pump will be cheaper than a head gasket (or worse). I'll probably get flamed for saying that but it's true.

2 days ago I installed a new water pump, thermostat and fan clutch, temps are better and I'm satisfied. With any luck I'll never have to do this again lol.

[jmo69]

Took a longer ride this am, about 10 miles. About half were on secondary roads with speeds from 35 to 55 mph and the temp held at 199.4°F. The return trip was at freeway speeds of 65 to 70+mph and I maintained the 199.4° until I turned on the AC and then it jumped to 203° and stayed there even after I turned it off. Ambient temp was 84°F. I'm satisfied with these temps, I still need to figure out why the auxiliary fan only comes on with the AC. Have to find a way to jump the pins on the connector at the switch or just get a new switch.

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[ed323i]

Great! Seem like very stable coolant temps to me.

Thanks for the info on the OBD App.. I'll look into it.. Alas, the European E36's don't have the OBD2 connector (not even the very late ones have it), but I think the DME internally is OBD2, so it's just a matter of installing the connector and finding the right DME wires to connect to..

Aux fan will virtually never turn on by itself if your viscous clutch is okay. The stock one, that is.
I can recommend installing the lower temperature one, which turns on at 80 (normal/low speed) and 88 degrees C (high speed). Note that the temperature is measured on the cold side of the radiator.
While driving you'll probably see 5 to 10 degrees C difference between hot side (driver side, high) and 'cold' side (passenger side, low) of the radiator. So, the stock one with 91/99 degrees C will only turn on when the head coolant temperature gets near/above 100 degrees C, and high speed another 10 degrees later. The stock temperature switch is very late (normal speed fan), and extremely late turning on the high speed fan, almost unable to prevent any damage from happening when you really need it. High speed fan, with stock temp switch, only turns on just before hitting the red zone in the temp gauge.

[jmo69]

I know there is a 16 pin OBDII to 20 pin round like the underhood cable. I have one to connect my Peake tool to the OBDII on my e46. Somebody must make the opposite cable.

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[ed323i]

I already have the 16 pin OBDII to 20 pin BMW diagnostic plug convertor cable.. It works fine with INPA, so it should probably also work with the tool you're using. I'll probably give it a try some day, as it's more convenient than connecting a laptop..

[jc43089]

Ed is right, if you still have the mechanical fan and it is turning at all you will probably never have the aux fan come on. Especially if you still have the 91/99C switch. You can use a scrap of wire or paperclip to jump the pins in the connector to test it. One wire is brown, jump that to either of the others. One will trigger normal speed and one will trigger high speed.