coolant need is flucating. VIDEO INSIDE!

[jamg]

https://www.facebook.com/photo.php?v...type=2&theater

my coolant needle is going crazy... it's reading in the middle, then getting to hot, and coming back down.

just now on my drive back home, it went to hot, and stayed at full hot.

my auto meter water temp gauge reads 100*F the whole time.

on my way, it actually fluctuated from 100*F, to 150*F, back down to 100*F

This problem recently started happening. I bled the system already when i swapped in a new rad, and it has been operating at normal temps for a while, until now...

any idea what's wrong?

[blksylv]

Have you changed the smaller CTS on the water neck that goes to the oem gauge cluster? I'd also try bleeding the system again as well.

[jamg]

i have not. this roblem happened literally today.

[blksylv]

Ah gotcha. I'd try changing the sensor and check for leaks in the coolant system if your aftermarket gauge is doing the same thing. Might wanna check grounds as well to make sure none have come loose since it could also be an electrical problem. Does it just happen when you hit bumps? Do you smell burning coolant?

[jamg]

i bled the system today. there was so much air inside... some how i lost coolant, and it needed to be filled up.

or it just went into the overflow tank and didn't go back in.

[anti tyler]

It's an overflow tank... not an expansion tank. It's not meant to go back into the system...

You need to replace that sensor. There are 2. One is for the ECU and one is for the dash gauge.

[Kallixtos]

I agree on replacing the sensor. Should be the one with the spade connector if im not mistaken. Verify the wiring is ok also.

[racepar1]

Originally Posted by anti tyler

It's an overflow tank... not an expansion tank. It's not meant to go back into the system...

That is NOT true. It is an expansion tank and the coolant will be sucked back into the system when it cools down. I don't know of ANY OE cooling system that does not have an expansion tank.

[Primo's Silvia]

And remember nose up of the car to help get those evil bubbles out easier!

[S13HB]

Originally Posted by jamg

i bled the system today. there was so much air inside... some how i lost coolant, and it needed to be filled up.

or it just went into the overflow tank and didn't go back in.

Then there is a leak somewhere.
Check the obvious places
Radiator
Radiator cap is holding pressure
Cracks in overflow tank
Radiator hoses.
If those check out, look towards the back of the head and play with those water lines and see if they are leaking. (More than likely your problem if everything else checked/ checks out okay.

[toyyxvoy]

I agree on replacing the sensor. Should be the one with the spade connector if im not mistaken. Verify the wiring is ok also.

[Def]

Originally Posted by racepar1

That is NOT true. It is an expansion tank and the coolant will be sucked back into the system when it cools down. I don't know of ANY OE cooling system that does not have an expansion tank.

Every BMW made in the past 30+ years...

They have a true expansion /surge tank, and when the cap pops the coolant goes all over the engine bay. It doesn't pop because there is air space in the tank for coolant to expand into.

[blueshark123]

Also i know for a fact early 240z dont have a coolant/expansion tank either.

Also 100f or 150f is rather low. something doesnt add up

[Def]

Originally Posted by blueshark123

Also i know for a fact early 240z dont have a coolant/expansion tank either.

Also 100f or 150f is rather low. something doesnt add up

It's seeing air because he has a major coolant leak. Then it sees really hot coolant, then air etc.