# Horrible screech, some white smoke



## ams740il (Jun 27, 2004)

We just bought a '94 740iL private sale with 100+ miles two days ago. Yesterday, it started making a horrible high pitched screech/squeel, periodic bursts of white smoke out of exhaust, close to stalling on start. The noise lets off a bit when increased acceleration but always returns. 

First thought was the belt, but so far the consensus seems to disagree. Can anyone PLEASE help give us a heads up on this problem??? Did we buy a LEMON????? :dunno:


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## Bruce (Dec 24, 2001)

the 4L V8 has a known engine block issue. I would never buy one without first doing a compression and leakdown test. They had a 6 yr 100k mile warranty on them- but obviously that has well passed.

You need to go get a compression and leakdown test done ASAP. You car might need a new block.


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## ams740il (Jun 27, 2004)

*Did that*



Bruce said:


> the 4L V8 has a known engine block issue. I would never buy one without first doing a compression and leakdown test. They had a 6 yr 100k mile warranty on them- but obviously that has well passed.
> 
> You need to go get a compression and leakdown test done ASAP. You car might need a new block.


The block was replaced already, have the receipts...I believe in 2000 with a 97 short block...


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## TerryY (Jul 20, 2003)

AC on or off? (The AC clutch and belt tensioner)

Does the car shake at idle--especially with the AC on and stopped with your foot on the brake? (vacuum leak - might have sound effects)


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## ams740il (Jun 27, 2004)

AC on for the most part and it does shake at idle. Weve only had it for a couple of days and really havent even driven it that much to have a consistent history. So far weve heard everything from belts, vacuum leak, head gasket (which we have pretty much ruled out), tensioner pulleys...you name it.


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## TerryY (Jul 20, 2003)

The shake at idle is quite probably intake manifold gaskets. No one seems to ever change the one under the throttle body on the front of the intake manifold.

Check the Oil (710) cap for a vacuum leak. The crankcase is part of the vacuum system too. A vacuum leak can make screetching sounds.

Just as a general thing, check to see if you have Pentosin in the hydraulic system rather than red ATF. Pentosin 11 is not red or brown. The hydraulic/power steering pump can make strange noises with ATF.


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## ams740il (Jun 27, 2004)

Thanks so much! The car is at the stealer now for diagnoses. As for the repairs, how complicated would it be for a diy-er to do? Would either of these fixes be related to the white smoke? We are considering that bad gas could be the culprit for that (used 89)...thoughts on that?


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## TerryY (Jul 20, 2003)

BMW uses a Hydraulic oil in what appears to be the power steering unit on the 7s. On the IL this is also the fluid for the suspension.

On the drivers side is a black canister with a hand knob on top. On the top of the canister, the proper fluid to use is stamped in. Earlier E32 7s used Pentosin 7.1 and the later ones use Pentosin 11.

Pentosin is very expensive but not as expensive as as the pump!!! Hydraulic oils like Pentosin pretty much share only the slippery feeling of oil characteristic with Automatic Transmission Fluid. ATF eats pumps and seems to speed leaking of the suspension accumulators in the self leveling suspension on the IL.


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## ams740il (Jun 27, 2004)

As for the repairs, how complicated would it be for a diy-er to do? Would either of these fixes be related to the white smoke? We are considering that bad gas could be the culprit for that (used 89)...thoughts on that?


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## TerryY (Jul 20, 2003)

The 4 liter v8 seems to collect oil in the bottom of the intake manifold. A surge in idle can pick that up sometimes. The hot catalysts usually seem to keep them from smoking. A converter not yet up to tem can pass puffs. 

Also bear in mind that the exaust system will "Steam" for quite a while until the 100 pounds of metal in the exaust all warms up.

Off to Work I go!! Let us know what the dealer says.


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## ams740il (Jun 27, 2004)

Thanks for all of your help! Will be sure to post problem when I know it!


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## ams740il (Jun 27, 2004)

*Diagnoses...*

The problem turned out to be something called the breather...less than $1000 to fix...couldve been worse!


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## TerryY (Jul 20, 2003)

If it has not had a leakdown test performed recently insist on doing that first. If it fails, call back here. Sorry to say that Gaskets and valve probably won't fix it then.

When they do the work, make sure they change all of the gaskets including the throttle body one.

Beware that some of the techs can change the PCV aka breather or "cover with non return valve" without pulling the fuel injection rails or intake manifold. You are paying for him to remove all of this stuff and to replace the gaskets under the intake manifold. Insist on the gasket changes. Loudly if you have to!


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