College student's m42 repair

[salvuhdor]

I'm done bleeding the system but hot air does not blow out! And temp gauge slowly rises to this point at and stays.
I think I might of switched up the temp sensors.

Hoses are hot.
Heater core hoses are not hot at all

[Vivek]

How'd you bleed it, did you jack the front of the car up? Does your heater valve work (they rarely break but worth checking)?

[salvuhdor]

How'd you bleed it, did you jack the front of the car up? Does your heater valve work (they rarely break but worth checking)?

I barely had it lifted up. just enough for a little tub to fit under the car. Then right now I took it to fill up on some fuel and got home with the marker on 3/4's mark and took off the bleed screw while car was not jacked at all and only coolant came out.

what's the proper way? I need it jacked up higher or not at all?

[salvuhdor]

oh and my heater valve works I believe, I took it off to clean it. But I touch those hoses in the engine bay and they are not hot at all and my air conditioning does not blow hot at all. Even when warm

[RCtheRed]

I'll take a look at my hoses and sensors and upload a pic. Jacking up the car like 4 inches on the front driver side helped me. Check that your upper and lower radiator hoses are hot to the touch too, I open my bleeder screw close to half on the temp gauge and let it just bleed out.

[RCtheRed]

First the location of temp sensors. The sensor closest to the firewall should be the black plug, that sensor is for your dash temp gauge. The second, closest to the front of the car, is blue, that sensor is for the ECU.

Okay and now for the heater core. The bottom hose is your inlet to the heater core coming off the head providing the hot coolant, and the top is your return going down and around down back to your radiator. No matter if your heater core or heater valve work, both hoses should be hot when your car is running and coolant is circulating properly. If both are not hot then there is unfortunaly air in the system which probably means there's air trapped in your block or elsewhere stopping circulation and causing the temp problem.

I had the problem of my thermostat not opening up once I had everything reinstalled and I was trying to bleed the system. Somehow I did not have enough coolant to be able to have it all circulate even though coolant would pour out of the bleed screw hole on the radiator. I drove it around, and then raised the car again so the front of the car was about 4-6 inches off the ground. Filled up my reservoir till it came out of the bleed screw, messaged hoses, and then ran it. The thermostat finally opened up and both rad hoses heated up and then my heater core hoses warmed up and I had hot air and proper temperature. It stays around half mark now on my dash, at higher speeds it's less than half.

Good luck and don't give up! It's just a matter of repeating it till the system is filled with fluid throughout.

[salvuhdor]

Wow is it a pain! It kept almost reaching the red mark.... Finally I ran it with the bleed screw open and the radiator cap off - filled it as it was running through the coolant system and jacked up 6 inches

Finally it stood dead still at the mid mark for a while. Then I closed the bleed screw and ran fine for about 3 mins before it jumped just a tad above the mid mark and my father said to bleed it again tomorrow.

Edit: All hoses from radiator and heater valve and now hot and blows hot air, the temp gauge stays at mid mark for a while before just jumping a tad over to the hot side - some slight air still in the system I suppose.

THANKS YOU GUYS FOR EVERYTHING! hopefully this should be it for the coolant system

[salvuhdor]

I Just open the upper radiator hose and filled it from there.

Does not overheat!

Edit: please remember to check the direction of your thermostat. It goes a certain way for air to escape... yea...

This thread is closed! Once again thank you everyone!

[fresh_TD]

I just went through this on mine..I bleed and re bled and nothing..I pulled the cluster, the temp gauge ground nut was lose. I tightened it and bam..all good now

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