Cooling System Bleed Issues?

[XCRN]

My 93 overheated yesterday and I pulled over immediately and had it towed home. The PO shortly before I bought the car apparently replaced the radiator, water pump, thermostat, and hoses so he did have the system open. The car acted normal until I was 7 miles away from home and the needle pegged. There was no heat at all for the last 4 days. When I pulled over I looked under the hood and I did not see steam or hear any bubbling in the reservoir. When I got home after work and the car was sitting for awhile, I checked the coolant level, and it was only about an inch below the cold line.

I was a little worried it could have been a head gasket since there was some milky residue on the oil cap, but it has been cold out and the cap seal is shot so it can just as easily be condensation since my drive to work is only 10 miles mostly city streets and I doubt that is enough to get the oil hot enough. Plus the no real change in coolant level does not point to a head gasket either.

Is is possible for a cooling system bleed issue to cause overheating after a few hundred miles of driving after having the system open? A lot does point to the thermostat not opening being the culprit here but I figured I should ask about the potential bleeding issue first.

[Jblue200]

Try to bleed the system first. My money is on a thermostat.

[fo3]

Order/buy thermostat, replace, test old one for curiosities sake, bleed system. Air can cause an overheat of course, but in this case it's an extra worry because you may have run your engine even hotter and even longer than you thought.
T/stats are cheap so why even over think it?
My previous owner got my car for next to nothing due to a over heat and did a thermostat delete with replacing radiator and head gasket. He thought the original problem was his PO not bleeding or having a bad fill cap but he still went the extra mile with head gasket, valves, rad, electric fan to replace mech fan etc. E: though he was still and idiot and did a t/stat delete because he didn't trust them.

Bonus points: while the cooling system is low replace all heater o rings under the dash, plus expansion tank, manifold hoses, heater parts, water pump etc.
While you're there this is a good time for inlet manifold gaskets and chain guides

[ross1]

My 93 overheated yesterday and I pulled over immediately and had it towed home. The PO shortly before I bought the car apparently replaced the radiator, water pump, thermostat, and hoses so he did have the system open. The car acted normal until I was 7 miles away from home and the needle pegged. There was no heat at all for the last 4 days. When I pulled over I looked under the hood and I did not see steam or hear any bubbling in the reservoir. When I got home after work and the car was sitting for awhile, I checked the coolant level, and it was only about an inch below the cold line.

I was a little worried it could have been a head gasket since there was some milky residue on the oil cap, but it has been cold out and the cap seal is shot so it can just as easily be condensation since my drive to work is only 10 miles mostly city streets and I doubt that is enough to get the oil hot enough. Plus the no real change in coolant level does not point to a head gasket either.

Is is possible for a cooling system bleed issue to cause overheating after a few hundred miles of driving after having the system open? A lot does point to the thermostat not opening being the culprit here but I figured I should ask about the potential bleeding issue first.

The smoking gun is highlighted above.
Contrary to what you are seeing in the reservoir it sure sounds like low coolant. That or no circulation, BMW water pumps have been known to fail with a loose impellor

[GregT53]

You could check to see if you have a head gasket problem. Pressurize the cooling system to about 1.5 Bar overnight, pull all the plugs, crank engine and note if coolant spits out of any cylinder. You can borrow a pressure tester from most auto parts stores. It's helpful to have another person to either crank or observe.

[XCRN]

The smoking gun is highlighted above.
Contrary to what you are seeing in the reservoir it sure sounds like low coolant. That or no circulation, BMW water pumps have been known to fail with a loose impellor

Not sure what brand but he said it was a plastic impeller pump he bought. I am a little worried it was URO stuff he used for it to fail this soon.

You could check to see if you have a head gasket problem. Pressurize the cooling system to about 1.5 Bar overnight, pull all the plugs, crank engine and note if coolant spits out of any cylinder. You can borrow a pressure tester from most auto parts stores. It's helpful to have another person to either crank or observe.

I will try that this weekend and see what happens. Might as well do a compression check too since I have never really checked overall health of this car when I bought it since it has been so cold out.

[XCRN]

Hopefuly bled the system right. Heat is working after awhile. Lower hose is cold upper is hot. Is that normal? I have heard a few conflicting things about a cold lower hose.

[Jblue200]

Yup thermostat isn’t functioning if you have a upper hot and lower cold. Change the thermostat