M5/S38 Gurus Come

[ILoveMPower]

Been driving the father's M lately trying to get it all primed up, still had a few questions after searching for a couple hours

Some of these are probably common sense, but as far as I'm concerned this vehicle is of a whole different calibre than my car, and I'm not taking any chances

- Slight belt squeal when I give it quick blips of the throttle at low rpms, belt seems in good condition, gave it some belt dressing, squeal reduced but not gone... is there a tensioner?

- Groan while turning wheel shortly after starting, seems to be power steering, possible belt-related?

- Clutch pedal (actual pedal itself) seems to be notchy, as if its sticking slightly, does something need replacing or should I start spritzing around down there with WD?

- After CODE is entered for stereo, none of the speakers make any sound. If you turn the volume up high, you can hear an extremely high-frequency whine, as you do from most speakers, but no sign of the music... possibly amplifier problems? Where is the amp located in the M?

- Random check engine lights (i've encountered 2 in probably 5-6 hours of driving time, both lasted about 3-4 seconds)

- Washer fluid low warning, fluid is topped off, just a bad sensor?

- Last but not least looking for a link to an engine bay cleaning method, I'm just worried with the 148k miles on this fine piece of machinery that I'll get some water where it doesn't want to be

Thanks so much to any comments, advice, or input you have.

- Jeremy

Btw the car is a 91 with 148k

[filip00]

well, i'm no m5 expert, but for the clutch - one of the clutch cylinders are broken. there are two of them, one on the pedal, and one on the transmission. when they break down, the pedal usually sticks, or feels spongy.

[MTechnik540i]

- Groan while turning wheel shortly after starting, seems to be power steering, possible belt-related?


Might want to change the filter in the PS reservoir. This along with some new fluid, might be the issue. It just sounds like PS pump groaning.

I'd also try to avoid low speed lock-to-lock while dead cold, if possible.

[ILoveMPower]

Yes I put some fresh fluid in there power steering and SLS are good to go

[Paul in NZ]

CODE for the stereo?The amp will be behind the lhs cover in the boot(trunk)
CODE is an immobiliser function on the OBC

[Ross]

Was the radio out of the car, is that it is asking for the code? Is the antenna connected?

[ILoveMPower]

Was the radio out of the car, is that it is asking for the code? Is the antenna connected?

The radio currently displays code, because the interior lights were left on and caused the battery to go dead.

But before this all happened, we entered the code and the radio APPEARED to be working, but nothing came out of the speakers

Haven't entered the CODE again just because I was waiting to do a bit of research to figure out if the amp was indeed the problem

[Brandon J]

The belt squeal happens more often than not. It still has the V-belt and either tighten the belt or it may need to be canged. There are 3 belts and no auto tensioner like the newer serpentine belt system. You have to look which one is squealing and then tighten it down.

Get the check engine codes via the stomp test. Those random lights are usually the O2 sensor going bad or some other related aspect. The spark plugs need to be changed every 8-12k miles with the exact Bosch plug specified. The O2 sensor does go bad faster than other e34s. The high revving does contribute to these 2 items wearing out quicker.

The '91 clutch pressure plates are known to be stiff. Many M5 owners update to the '93 style which still puts same amount of pressure onto the clutch disc, but with less pedal effort. This may be the solution you are looking for if your hydraulic parts are okay.

Sometimes with the radio an antenna gets unplugged over time or if someone removed the radio/amp. I would first just check all connections at the amp and at the rear of the head unit.

[The Bigfella]

Yes I put some fresh fluid in there power steering and SLS are good to go

I sure hope it was the correct Pentosin.....

Re the belts - I have heard of incorrect tensioning destroying an engine.

Washer fluid issue may be a bit of corrosion in the plug - try removing and re-installing the sensor plug. This should give you a bit of a clue about under-bonnet cleaning.