Please Help me and My 318is overheating and very low idle

[Serge]

I have made too many posts and I apologise from now on I will stick to only this one, firstly I have replaced head gasket, all gaskets, seals, etc.. I put her all back together and I am overheating, I compression tested the engine and she is very healthy sitting at 180psi on all 4 cylinders.

I have tried 2 different thermostats, 2 water pumps, I have bled the system so much that there is barely any coolant left in the system as the water has overcome it. The engine seems to warm up very quickly from cold say approx 4 mins? I have bled the system accordingly including draining rad and block many times

Here is a list of all the items I have replaced

1. All vacuum and rubber fuel hoses
2. All gaskets intake, exhaust, head gasket, timing case profile gasket, valve cover gasket you name it I replaced it.
3. All coolant and radiator hoses
4. Oxygen sensor
5. Throttle Position Sensor
6. Spark plugs
7. Ignition Leads
6. All pulleys
7. All belts
8. Fuel/ Oil/ Air filter
9. Coolant Temperature Sensor (still have issue will get to that)
10. Coolant temperature sending senso (to cluster)
11. Knock sensors x2

The head was machined and pressure tested without any dramas.

Only three concerns are

1. The overheating
2. Very low bumpy idle at approximately 400- 600rpm (nearly stalls
3. Peake Research tool throwing up coolant temp sensor fault

The car is a 1993 318is M42 4Spd Auto.

All the parts are genuine BMW purchased from Pelican parts (cost me an arm and a leg)

There are no other fault codes apart from the coolant temp sensor error, which I figure must be a short or ground within the engine harness, I will get onto that.

What symptoms would arise from coolant temp sensor? bad idle?

She seems to have a slight miss, I will replace the coil pack and new fan clutch and report back...

Any help from anybody would be very highly appreciated as I'm running out of clues, patience and money. Serge

[DesktopDave]

That coolant temp sensor might be causing an idle issue, but I don't think it'd make for 400 rpm.  If that fails it'd probably lead to idle trouble before the car is warmed up.  Sounds like your ICV...clean & test that to see if it's stuck.

My car also heats up pretty quickly, 4 minutes sounds in the ballpark.

What are your overheating symptoms?  Does it just run too high, like into the red?  You checked your fan clutch & aux fan, right?

My car has the same overheating issues due to the aux fan not coming on.  I haven't figured it out yet, might be the little switch on the pass. side radiator.  I likely need a new thermostat & pump too.

[Serge]

Dave, thanks for the reply, I tested my clutch fan and it still seems to be on par, I noticed my aux fan is not coming on either, checked all the fuses etc..

Also my left bottom hose remains cold even when she overheats, is that normal?

Is this where my problem lies? the aux fan?

[Deftones]

if one of the hoses to the radiator is cold and the engine is hot your thermostat isn't open!

[romeomike]

Dave, thanks for the reply, I tested my clutch fan and it still seems to be on par, I noticed my aux fan is not coming on either, checked all the fuses etc..

Also my left bottom hose remains cold even when she overheats, is that normal?

Is this where my problem lies? the aux fan?

You should be able to achieve sufficient cooling with the water pump and engine fan alone. You can turn on your aux fan by running the AC.

In your coolant bleeding, I hope you're opening up the heater core to remove any air that might be trapped in it.

In normal operation the top radiator hose becomes hot when the thermostat opens. Hot coolant flows through that hose into the top of the radiator, exchanges heat with the outside, and cooler coolant comes back to the block through the lower radiator hose. So far in the parts replacement department, the radiator hasn't been mentioned yet, nor the idle control valve (part number 13 41 1 435 995).

You can test your thermostat in a pot of hot water and a suitable meat thermometer to ensure it's opening up at the proper temperature.

If you're going to pull the thermostat another time, please take a picture of how it's currently installed and pass on how you removed the thermostat housing as BlackBMWs might like to know how you got yours off (his is stuck on as I write this).

[chrisindy13]

Your radiator is blocked.  Replace it or have it professionaly opened stripped and cleaned.