M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: n2motorsports on February 16, 2008, 05:50:03 PM
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hi everyone, hope someone can chime in before i just throw parts at this thing.
at idle my temp reaches the high temp mark and only cools down if i rev it or the car is moving.
i suspected the thermostat so i swapped in a new one. after filling up with coolant, i let the car idle and the temps eventually shot up high again. i felt the hoses and the one from the expansion tank side was hot and the other side was cool. is my water pump bad? or did i get a bad thermostat? the fan is running the whole time. also, the heater inside blows cool, though it's on the heat setting and there is a hint of antifreeze smell to it.
Oh, and no leaks from the water pump nor is it making a weird noise.
anyone else have this issue?
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i would check the fan, even if it turns, it might be dead. you should be able to feel resistance when turning it by hand. if it stops before completing a full turn you're good.
also bleed try to bleed your system
remove the entluftung screw on top of the radiator, let all the air come out by adding coolant continuoulsy. when there are no more bubbles, screw the entluftung back in and start the car... repeat if needed.. i'm sure you can find a better DIY then what i just said
if you had a bad thermostat i believe you the car would overheat all the time not only on idle. then again, that means your pump works, maybe not strong enough though
if the car is in good shape and you want to protect the engine for a while, i'd suggest you change the pump and fan. if the M42 overheats you can be sure to have lot more headaches as it has a aluminum head prone to warp with excessive heat.
hope this helps
good luck
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i've bleed it 3 times, and took it on a spin, about 25 miles on the highway. the car's temp needle is pegged on the high side and the heater blows cold air! once thing i did notice is there isn't much resistance when i turn the hvac knob to the hot side. could my heater be clogged?
btw, the fan does spin, with very little resistance. should i stick a rolled up piece of paper to see if it stops? is that the test?
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the heater could be clogged but i dont think that would make you engine run hot.
check the temperature knob and links under the dashboard. maybe you have something disconnected.
you could use a rolled newspaper and stick it in there, i dont think that test says much about your fan condition since it depends on how much the journalists in your town have to say! :p
if the fan seems to spin freely when you push it, chances are its fried
does the temperature get stable at a certain degree?
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yes. it's stablizes about 1mm from the red notch.
i read another thread and someone says if the engine is hot and the air is cold, then it could be some temp control valve...i wonder if that's the same thing as this? #16?
http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=64_0514&hg=64&fg=15
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maybe this? its a thermostat as well?
http://www.realoem.com/bmw/showparts.do?model=AJ93&mospid=47318&btnr=64_0135&hg=64&fg=99
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yes. it's stablizes about 1mm from the red notch.
i would check the thermostat first. see at what temperature it opens in boiling water
but dont know much about the temperature control
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Leaky heater core or heater valve can let air in the system and cause an overheat, but in my experience it will overheat whether driving or at idle.
What about that recall heater valve thingy against the firewall? If that siezes shut and doesn't flow coolant back to the head, it would seem that it could likely cause what you're seeing, no?
I would be careful in your troubleshooting. These heads apparently do not take well to hot conditions for too long.
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okay, im lost, but i need to fix one issue at a time. right now, there is no heat, it will blow hot air intitally then eventually become cold. this leads me to believe that the heater valve is closed and won't allow hot coolant to flow thru the core.
what's the best way to test this?
I know that the heater valve is controlled electronically, so if i remove it, i suppose i can put some power to it and see if it opens?
is there a way to test it while it's on the car? maybe stick a water hose into the inlet to see if it come out of the outlet?
what's this heater valve recall someone mentioned earlier, i couldn't find more info on it.
thnaks.
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what if you bypass it? hot air would go through the heater and you'd know its not blocked or leaking and that the valve is your problem.
i agree that you have 2 seperate problems and that you should take care of them as different issues but honestly i think the engine overheating is way more important for now than the no-heater... whatever temperature it is outside (i ran my car with no heat at -19 Celsius to go on a date with a girl and she's still turned on)
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I've been bleeding daily since Saturday and then magically, on Monday, the heater starts blowing hot air and the needle is solid at the notch right before the midway point.
However, now I'll randomly see a dime size pool of coolant over night and I've had to on 2-3 occassion, refill the expansion tank, it was near empty 2x. Today, I just topped it off to the indicator mark for "cold," it was about 2 inches below that mark. Other than the dime size coolant, I am not seeing where else I can be losing coolant. No damp areas in the cabin, no coolant lose behind tranny or under intake manifold. No smoke, no water in oil or vice versa. Is the system just finally purged out all the excess air? I did find it weird that when draining the coolant, I got nearly a gallon of old coolant, doesn't our cars have about 3 gallons?
Typically I measure what goes out, so I know what to put back in, since flushing, I've put in well over double the amount of coolant taken out.
Sorry for the long post, hopefully, it'll end up helping someone else out.
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I know my e36 holds almost two gallons. I know you have bleed the system, but how are you doing it?
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fill it up, turn car on with heater on and let it idle and keep adding coolant. then i'd rev it up a bit and add more coolant while letting air purge from the bleeder screw. then i'd go for a drive, and let it cool down a bit then repeat the process.
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Interresting post...but not fixed my problem:
I have changed :
-Fan clutch
-Thermostat
-Hose
-Radiator
I do :
-Bleeded the system
-Checked coolant
I push on the gaz. Sometimes, at 60 mph, my engine is overheating. Sometimes, when im at 100 mph, there's no problems!
Others times, when im running smootly in the street at 20 mph, my engine is overheating.
The heater core is fully working : When the engine is hot, IT like sahara in my car.
Timing chain cover gasket have been replaced after failing. My engine is about 335 000 Km (209 miles).
Someones have an idea?
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Also...There 2 thermostat for this engine : 92 and 88 degree. It can make a difference?
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Did you end up fixing this? I have a similar issue. Sometimes when Im sitting in traffic like today (60-65 ambient), I can make the temp gauge move from 2 mm RIGHT of the Middle, to directly in the middle.
Essentially I can change the temp gauge reading by changing the hvac control from blue to red and turning the fan to 1-4 speeds.
The 88C thermostat should put the normal operating temperature evenly in the middle correct?
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This afternoon Ive changed my water pump...flushed 3 time my system with special product....
So, new fan clutch, new water pump, clean system, new hose and still overheat ....This week I will put an original bmw 88 degree I got from the bmw official dealer....
If after that it will not work, I will check at all the f*cking stupid dumb bmw sensor all around the engine and in the car.....
And if my engine is still overheat after that.....ILL BURN IT!!!!!!!!!!!!!!
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As usual, im replying to all my messages to help people all around the internet with m42 engine trouble...
I got a question right now about my overheating prob:
This afternoon, when I was opening the drain plug, I noticed that the fan in the front of the engine was not alive....So, I dont think its normal...And Im not sure about this, but on january, when Ive repair my profile gasket, Ive removed the AC compressor.......AND...its since this moment my engine is overheating....
Someone have an idea?
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Go buy one of those laser temp gauges and check your coolant hoses and engines temp? Maybe your gauge or temp sensor is fried
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maybe your gauge is just reading wrong - replace the coolant temp sensor. Actually replace both as there are two. One for the gauge and one for the fuel injection system.
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This is the part of the discussion where Im very poor. Ive looked all around the engine and I only find the sensor at upper right side of the radiator....(me and sensor = 2)
If someone can tell me where is the possible faulty sensor and the name of it for know what to replace...
Also, I dont think my gauge is wrong because my engine is very hot when touching it after running a moment.
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Is anything blocking the ventilation to the radiator?
Are the hoses routed correctly?
Are you sure the gauge sender is ok? The sender wire could be touching a ground somewhere and sending an "overheat" signal to the gauge.
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Ok, both the temperature sensors are on the right hand side of the cylinder head just under the intake manifold. There are two sensors, one for the temp gauge and the other is for fuel injection and engine management. Check out realoem.com for a specific part no. and diagram for your vehicle. I would replace both. They are not expensive but can be a bit of pain to get to.
The other sensor you are talking about on the left hand side of the radiator (opposite side to the expansion tank) is the auxillary fan thermoswitch. I would also replace this.
Also before replacing anything, did you pressure test the cooling system?
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I have cleaned my system with prestone superflush 2 time, and cleaned 2 time with water. My water pump is working fine and my system have a good circulation.
This is what I dont understand........If circulation is okay, why my engine is overheating? If I change the sensor, what will change? What's sensor is controling?
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It's very weird. When im on idle, the temp is okay......What the f*ck is happening here....I will check with laser temp gun
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The two sensors on the cylinder head control the following: one gives the temp gauge signal and the other one gives the coolant temp signal to the engine ecu.
The third sensor which is located on the side of the radiator controls the electrical fan behind the front bumper.
This is a strange one because the viscous fan will cause overheating at idle and in stop- start traffic. The electrical fan will cause overheating at just over operating temp because it is not cutting in too help out for additional cooling. Check the aux switch on the radiator and replace it, see if that fixes the problem.
The radiator, hoses and water pump will usually cause overheating problems because they are leaking or damaged. If you've replaced these and bled the system properly there should not be a problem.
Have you installed the correct thermostat? If so is it in the correct way?
Also I would check your cooling system using a pressure tester. Leave it connected overnight and see if the system holds pressure.
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Thank for the reply, this will be helpfull. I will replace the thermostat tomorrow if I have time.
Do you have an idea where I can buy these sensor? On BMAPARTS i only find "Water Temperature Sensor/Fuel Injection" and the O2 sensor. the "Water Temperature Sensor/Fuel Injection" is the one I need?
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What year is your 318is?
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I would replace thermostat first, then the water temp sensor/fuel injection second, then if after replacing these if it is still overheating, replace the auxillary temp switch on the side of the radiator.
I can find some part no's for you if you give me the month and year your 318is was made?
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I will check for the month in 2 hours
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My car is a 318i 4DRS 1991 built in april 1991. (Last month of the E30 built!)
It have 212 000 miles!
I will change the thermostat this week-end. But im pretty sure its about sensor or the fan who not working in the front of the car (AC FAN) because somedays, the car is okay, it not overheat at all!
Others day, at same temp of the previous day, the temp needle is crazy and it told me my car is overheat.....
ITS WEIRD!
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Ok, I have got some part numbers for your vehicle from Pelican Parts.
The temp sensor for the temperature gauge -12-62-1-710-512-M323
The fuel injection coolant temp sensor (the main one) - 13-62-1-709-966-M323
And the auxillary fan thermoswitch - 61-31-1-378-073-M85
Good luck with the thermostat, hopefully that solves the problem although, I think it is one of the sensors mentioned above. Keep us informed.
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The thread is bookmarked.
I will change the thermostat probably this sunday. If it not solve my probs, i will change the 2 sensor and the switch. Thanks for the help, its very appreciated:o
I think the sensor will help me because my temp needle become crazy when im rolling. The gauge told me that my car is cold, and one second later the needle moving from left to right a couple of time and finaly it told me that my car is hot...but...I stop the car, waiting 1-2 minute, restarting it and, miracle, the temp is back to the middle...
So, now, I know what part I need, this will be very helpful, but I have to find where the 2 sensor:D
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The 2 sensors are on the cylinder head under the intake manifold.
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The 2 sensors are on the cylinder head under the intake manifold.
Are they easy to change or I need to lift up the intake?.....:eek: You probably know that this intake is pretty hard to replug with all wire and hose...
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Check out this picture: http://www.esatclear.ie/~bpurcell/inletcylhead.jpg
You can see the two sensors right below the inlet manifold ports for cylinder 1 & 2.
So I would say you will have to take off the manifold. Have a look if there is any room, cause I have a E36 318is M42. They have different manifolds.
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Hi!
With my M42 (in fact, you have a M44) the sensor is easy to take off. I have to remove one vaccum and other little thing and that it. Im happy to know that.....
So, the left sensor is the ECU sensor and the right one is the temp sensor (For everyone want to know)
When my problems will be fixed, I will reply describing all my story..(If i solve it....)...
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I have a M42 as well but E36. It's a 93 model. The M44 took over in 1996. Did you end up changing the thermostat?
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I have checked with a laser temp gun. I dont know what is the normal operating temperature for this engine, but this morning when the gauge told me that my engine was overheating the temp gun told me 75 Celcius (167 fahreinheit).
The gauge become crazy and im just hitting the needle over the lense and she return to normal position.
So, I think its the sensor. Im ordering new one tomorrow! (If its just sensor, I will be really happy!)
PS: I got the original BMW 88C thermostat from dealer but i dont want to replace the actually 92C one until I will have gasket for it. I will order at the same time of sensor.
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Ok cool, keep us posted
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Hi all!
Guess what, sensor have been replaced and the temperature is okay! (The temperature was great at the start, but now the gaude indicate the right temp).
So, this overheating problem is fixed! I will do some more other test for see if everything is alright but THIS problem is fixed.
Just dont forget if you replace this sensor, you have to remove the air filter and all the stuff around, a couple of wire and vacuum and you have to release the cooling system pressure if the engine is not cold. (Do not forget to not let open the radiator when unplug the sensor, if not, you will have a lot of cooling to replace, a driveway and all around the engine to clean)
Once the sensor is replaced, turn on the ignition switch and test if your needle is not crazy or something else. (If yes, your new sensor is bad...)
After that, do not forget that you have changed 300$ of part before thinking to a 6$ sensor.........Keep smile! :)
Thanks for your precious help nicknikolovski, you're very cool!
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Hey pifane, good to see your car has been fixed. Well done. And as far as the help - no worries.
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Ok, I have got some part numbers for your vehicle from Pelican Parts.
The temp sensor for the temperature gauge -12-62-1-710-512-M323
The fuel injection coolant temp sensor (the main one) - 13-62-1-709-966-M323
And the auxillary fan thermoswitch - 61-31-1-378-073-M85
Good luck with the thermostat, hopefully that solves the problem although, I think it is one of the sensors mentioned above. Keep us informed.
Would those same P/N's apply to my 1991 318i manufactured 09-04-1990?
Thanks
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Yes the part numbers are the same. And the auxillary fan switch is for cars with A/C which RealOEM indicates it does.