help with overheating

[dystynkt]

Please look at the post below for an update

i have an 85 325e and just did a lot of work to the car replacing all the belts/water pump/etc. today was driving and while driving the coolant light started flashing and i realized the car was overheating with the needle pegged. we immediately pulled over and shut the car off to find that one of the hose was not on all the way and had popped off spraying coolant everywhere

we got the hose fixed, refilled the car with coolant, let it run a bit to make sure it was cool and kept refilling, and it seemed fine. well we had about 20 more mins of driving back to the house after that and since then when i turned the car on the temp needle starts normal but slowly rises all the way til its in the red again (not completely pegged but in the red). i pulled over many times on the way home to check for low coolant or any blown hoses but everything seemed fine. drove the whole way home like that with the needle about in the red almost the whole time. never any smoke from the engine or no major signs of overheating. now i have to do a 2 hr drive tomorrow to get the car painted. what do you think my problem is? possibly the sensor that controls the temp needle got damaged and isn't reporting properly? Or am i actually overheating and just dont see it? is there any obvious way to tell if the engine is overheating besides the temp needle? Thanks in advance

[Liam]

For one thing Quit Driving It!

Replace the thermostat just for good measure (also look up bleeding the cooling system).

[Adrian_Visser]

okay first stop copy and pasting your posts from bimmerforums onto here all you get is a whole lot of URL BS second you probably have an air bubble in your cooling system vapor locking the water pump... bleed that shit. Third cross your fingers and hope you didn't warp your head or blow your headgasket.

[dystynkt]

i bled the cooling system and have a new thermostat which i am going to put in within the next couple of days. i also did a preliminary check to make sure that the head gasket wasn't gone. based on the flow in the upper radiator hose it seems as if the original thermostat is working and that the coolant is flowing.

now i have found a new issue, now that i finally got around to starting the car again, the temp gauge on the dash is somehow dead. by this i mean that when the car turns on the needle does not even budge at all. it just sits well below the cold line (where it sits when the car is off) and does not move at all. i am thinking that there is some kind of a temp sending unit that is now faulty. I need to get this fixed so that i can use that gauge to determine if the engine is still overheating or not. Looking up the part at pelican it seems that there are several different temp sending units, can anyone point me in the right direction here so i get the right one? thanks.

[Hallen]

i bled the cooling system and have a new thermostat which i am going to put in within the next couple of days. i also did a preliminary check to make sure that the head gasket wasn't gone. based on the flow in the upper radiator hose it seems as if the original thermostat is working and that the coolant is flowing.

now i have found a new issue, now that i finally got around to starting the car again, the temp gauge on the dash is somehow dead. by this i mean that when the car turns on the needle does not even budge at all. it just sits well below the cold line (where it sits when the car is off) and does not move at all. i am thinking that there is some kind of a temp sending unit that is now faulty. I need to get this fixed so that i can use that gauge to determine if the engine is still overheating or not. Looking up the part at pelican it seems that there are several different temp sending units, can anyone point me in the right direction here so i get the right one? thanks.

There are two temp senders on the thermostat. Make sure both of those wires got hooked back up when you replaced the thermostat.

You may have to repeat the bleed procedure a couple of times. Make sure you check your oil frequently for a while keeping an eye on the color. If it starts turning milky brown, you'll need to replece the head gasket as a minimum.

[dystynkt]

There are two temp senders on the thermostat. Make sure both of those wires got hooked back up when you replaced the thermostat.

You may have to repeat the bleed procedure a couple of times. Make sure you check your oil frequently for a while keeping an eye on the color. If it starts turning milky brown, you'll need to replece the head gasket as a minimum.

The wires on the thermostat's seems to be hooked up fine, so in that case could it be that one of the temp sensors are done for? I am going to be on top of checking the oil...trying to get everything good before bfest in 3 weeks!

[dystynkt]

bump, can someone tell me which of the two sending units should be replaced? or possibly a hint?

[thereisnoyun]

check on real oem. the more expensive one is the temp switch, the cheaper one is the sending unit to the cluster. I would jsut replace both. Get a temp light to determine the temperature of the cooling system, and see if you can figure out if hte thermostat is openign or not. Dont just keep changing part... DIAGNOSE THE PROBLEM.

[dystynkt]

i ordered what i thought was the right one. it got here today and turns out it is NOT the right one. here is a picture of exactly what it is that i need to replace (in the red circle). can someone direct me with a link to the one i need to order? i have gone through pelicans site many times and cannot pick the right one. thannnks

[Liam]

Woops, that's the thermotime switch (for the cold start injector)

Which one are you looking for?

[dystynkt]

Woops, that's the thermotime switch (for the cold start injector)

Which one are you looking for?

I think that one is failing. Does that switch have anything to do with the gauge? I went through testing things and came to the conclusion that it was failing, although at the time i thought that this piece was related to the temp

[Liam]

The gauge sender is brown and has only 1 pin in the socket, it's lower and coser to the intake tubes on the housing you have in that image, they don't go bad all that often.

But

There is a nut on the back of the cluster that holds the temp gauge in and also grounds the gauge. When they get loose the gauge will become erratic.

[dystynkt]

The gauge sender is brown and has only 1 pin in the socket, it's lower and coser to the intake tubes on the housing you have in that image, they don't go bad all that often.

But

There is a nut on the back of the cluster that holds the temp gauge in and also grounds the gauge. When they get loose the gauge will become erratic.

Ok cool I am going to check that out tomorrow. Thanks for the help I appreciate it.

[Liam]

Ok cool I am going to check that out tomorrow. Thanks for the help I appreciate it.

You're welcome and thanks for the appreciation ;)

[dystynkt]

ok so going out to the car today and finally getting it started again, the temp gauge seemed to be working fine. however, i bought a new temp sending unit anyways and want to put it in, i just want to be sure im pulling out the right thing. is this (circled in red) the temp sending unit? thanks!