316i coolant and engine problems

[SAWYERBOY]

Hi everyone

My first BMW. I have bought a 96 bmw 316i (m43) which has two (maybe the same problem). The first problem. The coolant system seems to be presurising over the normal level. All hoses are hard. I have renewed fluid, the themostat, the plastic pipe on the back of the cylinder head, checked the water pump which was ok (metal impellor type) and back flushed the whole system and bleed correctly. The rad seems to be in an ok condition with no obstructions and has good flow. There is no white scum in the oil, no coolant loss, and compresion test reveiled nothing out of the ordinary. I don´t think head gasket has gone or is at fault.
The second problem, the car is next to impossible to start. The starter goes perfect, engine turns but ís hard to start. It seems to all most fire up but not quite. Once it does start the engine goes perfect. No smoke, no Power lose and no eratic idling, just drive. If i turn the engine off it the same story, very hard to start agian. I does not matter if the engine is cold or hot. I have checked to see if it is getting fuel, which it is. Renewed all spark plugs and changed the fuel and air filters. I have checked the spark plug leads, no problem there its getting a good spark. Can this be a cam or crank sensor problem? or maybe a knock sensor or air flow sensor? Grateful for any insight anybody has.

[witeshark]

The starting issue may well be a sensor problem. As to the coolant, are you sure the ratio of anti-freeze and water is correct? If there's enough water in the mix, it may expand and cause the pressurization you've been seeing. Oh, and

[marti5]

2nd problem camshaft sensor, more likely fuel pump / filter

1st problem water pump, but more likely thermostat

[Shadetree]

Not too sure about your first problem...The only two hoses that are generally soft are the two large (top & bottom of the radiator). All the smaller circulation hoses are always hard (at least mine are on the 325i). This is the first time I've seen anyone having pressurization probs on here...usually overheating issues.

For problem #2...
1. Check your battery terminals.
Make sure they're tight and not corroded.
2. Throw a volt meter on on the battery
You should have a reading of 12v (±0.2v)
3. Start your car and do the same on the alt
You should have a reading of 14v (±0.2v)
4. Check your air filter
Make sure it's clean.
*5. Do a compression test.
*6. Check your injector system.
*7. Check your ignition system.
*These are a bit lengthy to get into for this post but I'm sure with a little diligence and forum hunting you'll find a decent enough DIY

If you haven't had any luck fixing your problem by #7, I would take it in a BMW mechanic and have it looked at.

OH and...


P.S. The title was merely a clever ruse to make people read this thread

[SAWYERBOY]

Thanks for everyones ideas. Turns out the first problem was indeed a dodgy thermostat. Brand and faulty, hard to believe, cheap tat for ya. The new orignal part thermostat works a dream.

The second problem (starting) has left me gasping for air though! I took the car to bmw´s today for a full dianostic. Turns out its the DME not working correctly. Estimated repair bill a massive 950 pounds. Not such a cheap run about after all.
Does anyone know if you can change these DME modules yourself? The guy at BMW seemed to think that you could not replace it with second hand one? Only a new one will do! Not taking his word for it I have found a DME in the scrap for 100 pounds. Has anyone changed one with out the aid of NASA and is there anything i have to look out when buying one other than the dreaded water damage. Does it have to be programed to my keys or coded to something?

Grateful for any wisdom

[german-speed-demon]

shouldn't be too hard, biggest problem with stealerships is they charge you for new OEM parts, (about 400-ish, i would imagine) and then hit you with 70-100 dollars an hour for labor. buy a bentley manual and tackle it. if i can rebuild an m20 from a bentley, you can replace a DME.