Again, thanks for the previous help.
My temp gauge goes all the way to the red line.
So I just installed a new radiator and 180* thermostat.
Gauge still goes to the red line.
I checked the thermostat in boiling water. It's fine.
The new thermostat is fully open at 190*.
Reinstalled Tstat and bled all the air.
Still goes to the red line.
Temp probe reads as high as 206*at the top of the radiator
BUT I DON'T SEE fluid flowing across the cap opening.
Upper radiator hose is hot.
Lower radiator hose it NOT hot.
The upper and side Tstat hoses are HOT.
Auxiliary fan is NOT coming on.
(Yes, I have confirmed that the Auxiliary fan actually works.)
Here is what I think is wrong.
I think my water pump is not working (but it's not making noise either).
That makes sense because:
I don't see coolant flowing across the cap opening.
The thermostat probably opens but that won't help because fluid isn't flowing into the top of the tank.
The auxiliary fan switch never comes on because the coolant in the lower half of the tank isn't getting hot.
What do the experts think?
2001 Boil Tstat.jpg2001 radiator outlet.jpg2001 switch.jpg2001 lower hose.jpg2001 bushing.JPG
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If your lower hose is cold typically that is a bad thermostat however since you tested it I would bet money the water pump is bad.
more pics
2001 new tab.jpg2001 lower clip.jpg2001 shroud clip.jpg2001 Old Tstat.jpg100_1481.jpg
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I agree but I have never had a bad water pump that wasn't making some sort of bad noise or fan wobble.
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Can't you ground out the temp gauge to see if it is working:?
jm
Visit my 1977 320i Build and BLOG page HERE.
Probably have a rusted water pump impeller that's where I'd start
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Did you set the heater control valve on 'full hot' when you refilled/bled the cooling system?
This may be irrelevant to the issue, just thought I'd ask...
Last edited by epmedia; 10-20-2016 at 06:14 AM.
Tbd
My dash heater controls are jacked up. I don't think they work at all. I think the water pump impeller is the problem.
Water temp sender switch is good? I guess you could check resistance on that or they're $7. You can jumper the aux fan just like the fuel pump to see if the relay works but, I think it's 87 to 30 (instead of 15 on the FP) don't quote me on that but, when looking at the relay, it's the top one and the one to the (ccw) left of it.
I would have to guess water pump too because, down here my car has never got hot enough to need the fan.
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Unless you had a leak or blew the head or something. You can strip it down to the water pump and turn it over (someone else) real quick to see.
I see coolant flowing across the top of the radiator on all the other vehicles I own. But not on this BMW radiator. I've ordered a new water pump. Just another adventure.
I've never been able to look in my e21 radiator and confirm water pump in this car but yeah, sounds like the right thing to do.
Lugnutz: You can actuate the heater control valve from the engine bay. (or at least you can on the 80's models).
"The most important thing is balance." - KT
Something went well today. I actually fixed the overheating problem. I just don't know for sure HOW I fixed it. LOL!
I had decided that the old water pump had failed. WRONG! It was fine and looked pretty nice actually. The only thing I can figure is that I had a major air bubble trapped somewhere inside the engine and it was preventing the old water pump from moving any coolant.
Anyhow, it's fixed. Gauge never goes above half now. The day was frustrated by sheared off alternator bolts that wouldn't budge. The pictures show some of the differences between the water pumps. Different impellers. Rock Auto probably has me on their Christmas card list of people who buy parts but don't really need them.
Thanks again for all the help.
IMG_0446.jpgIMG_0449.jpgIMG_0450.jpgIMG_0453.jpgIMG_0456.jpg
Visit my 1977 320i Build and BLOG page HERE.
^ Is it fixed, or not?
Your other thread says otherwise...
fyi: it's best to keep the same topic in the same thread to avoid confusion
Tbd
I clearly say that I fixed the overheating problem. What other thread are you referring to? I started this thread with the topic of "a possible failed water pump". I stayed on topic since this is my follow up message.
Last edited by Lugnutz77; 10-24-2016 at 07:01 AM.
Ummmm, . . . . this is Lugnutz77.
Visit my 1977 320i Build and BLOG page HERE.
Last edited by SilverPuddle; 06-11-2018 at 08:57 PM.
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