Idiling and overheating problems with my 318i-Please Help

flighty · 07-08-2005, 01:29 AM

Hi all, need some help!!
I have some problems with my 92 318i, Ill just get into the two most important ones here!! I am a novice so perhaps excuse my ignorance.

1. The engine revs up and down when idiling, especially bad when cold but it could just as easily happen after a three hour drive. Also, when i come to a junction and need to take my foot of the acelerator, the engine can sometimes just cut out. Again usually worse when cold
Any ideas?

2. When sitting in traffic, the engine overheats quite severly!! I have had this checked out and told all is fine.. Personnaly i feel the pump is gone or there is a blockage, the top hose feels like it has nothing in it and is hot after a journey. I have tried bleeding the system, and have got air out (Could be steam eeekk..), The only method i have of curing this is to turn on the heater and take the heat into the cabin, not so comfortable on a hot day... There is no problem when crusing along.
Any ideas?

Id appreciate any sort of feedback at all, and preferably some advice on what to do (Im Broke), im not a mechanic but pretty handy and will give anything a try and would very much like to solve these myself if possible.

Cheers.

BMWCowboy · 07-08-2005, 05:22 PM

First one could be ur idle valve-->or maybe cam or crank sensor.....any fault codes>>>Ck eng light?????.....second one sounds like maybe a bad fan clutch.....if its been overheating ~severly-->thats NOT good!!
U may have a leaking head gasket...do U have to add water??...U have
to bleed it till ALL the air is gone & its straight coolant

flighty · 07-12-2005, 12:55 AM

Where do i find fault codes? If they are on the instrument panel than no, i have no fault codes appearing....
As for the overheating, i dont have to put in water/coolant. I drained the system and put in new coolant as i thought that may be the problem but it has not solved it. The level has not dropped since and i have tried to bleed the system since and only water has come out.
I have no other signs of a gasket gone such as white smoke or cloudy oil...
Do you recommend coolant only as opposed to a mix of water and coolant?
I know this isnt much help but thanks for the reply.
Raymond

blkongry · 07-12-2005, 02:49 PM

Isn't the '92 model included in that nasty plastic water pump impeller problem? If you impeller is gone, then you aren't cycling your water, and it'll just over heat, especially at a stand still (since the water pump is engine RPM driven, and idle will cycle the least amout of water around... especially with a bad impeller).

I agree with Cowboy on looking at that idle valve. You could also have a vacuum leak somewhere causing an unstable idle. Check all your air intake pathways and around your manifold to make sure nothing has popped loose. Usually if you have a vacuum leak, higher engine RPMs will over ride any affect this has, but it shows up predominantly at idle... and when you get out of a long open run, the surge can be enough to cause your engine to die.

As far as the water pump, I'd pull the output hose from the radiator while the car is off, have someone start the engine and see if a gush of water comes out... if not, then you probably have a bad impeller. Only run the engine for a second or two... just enough to check flow. You'll have to refill and rebleed your system, but if your impeller is bad, you'd have to tear everything apart anyway. I think the water pump isn't too bad of a replacement job. Also, while you have the hoses off, you can flow water through the radiator and see how clear the pathways are.

flighty · 07-13-2005, 03:33 AM

Thanks guys, this is really usefull information. I tried to clean out the ICV last night, but was afraid to go too rough on it... I just removed some soot with a dry cloth.
I read an article advising cleaning it with an alcohol based cleaner and after spraying in some lubricant such as wd40, would you say this is a good method?
I also noticed the tubing coming from the air filter to the valve was cracked slightly on the part covering the nipple on the ICV, would this have a detrimental effect on the workings of it?
I will try disconnecting the hosing on the pump and see how that goes. You say to disconnect coming from the radiator, would it be a bad idea to disconnect after the pump and see if it pumps out steady for a second or two?
As for vacuum leaks... Not too sure which hoses to check but ill give em all the once over

Thanks,

Raymond

blkongry · 07-13-2005, 08:17 AM

Yeah, I'd think that crack in the tubing on the ICV could very well be your idling problem... that's a vacuum leak (if you are getting leaking).

As far as disconnecting one of your cooling hoses, it doesn't matter if it is from the radiator or from the pump... which ever is the easiest would be the best, just make sure it is on the discharge side of the pump so you can tell what's going on. If you disconnect from the radiator, that gives you some extra hose length, and you can fill it up with a little additional water to ensure the impeller is submerged before you start the engine. Either way you should be able to tell if the impeller is toast or not.

Good luck and let us know what you find.

flighty · 07-19-2005, 05:49 AM

Thanks again for the help, im away on holidays for the next two weeks and will get stuck back into the car then, will let ya know how it turns out.

Cheers

Wayne 962 · Wayne 962's Garage

I agree. The hunting problem is typically caused by a vacuum leak from one of the hoses. It causes the car to run rich, which then has a tendency to cause the idle to "hunt" up and down.

Here's my article on reading fault codes too, which you should do:

http://www.pelicanparts.com/bmw/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm

As for the overheating, I would make sure that the system is full bleed out - these cars can be difficult to fully bleed. Here's my article on that:

http://www.pelicanparts.com/bmw/techarticles/E36-Coolant_Flush/E36-Coolant-Flush.htm

-Wayne

flighty · 08-08-2005, 06:19 AM

Hi Guys,
Getting stuck back into my car here after two weeks of R&R... Just an aditional query on the fault of the irregular idle, during my research i have found that this could also be attributed to a faulty O2 sensor? I believe this can also lead to high fuel consumption and poor emission standards, i have spotted a good deal on a new one for an e36 but it is for an M52 engine, mine is the M42 i believe (mine is 16 valve)? Would this unit be compatible with my car?
I have no idea when/if it was ever replaced and i just thought while i am working on the car it it may not be a bad thing to replace and not a very complicated job...
Cheers,
Raymond

Jeron · Jeron's Garage

I would compare the O2 part numbers for each engine on Pelican or Realoem.com