From digest.v7.n257 Thu Sep 11 04:50:01 1997
From: Olav Berthold <berthold at mail.ifw.uni-hannover.de>
Date: Thu, 11 Sep 1997 11:11:20 +-200
Subject: <E28> 535i oil leaks - SUMMARY (and LONG, sorry)

Fellow enthusiast,

first let me say thank you for the huge amount of answers I received to = this question about possible oil leaks of the E28 535i.=20

Thanks to Erick Baumeister, Jonathan Selig, Mario L. Langsten, Reed = Hunt, Andrej Gaspari, Daniel L. Turner, Tom Jarlock, Karl L. Preisach, = Larry Franks, Curtis Kiser and Steve D'Gerolamo. I hope that you all = don't feel insulted if I am not going to thank you individually !

I will try to summarize this information to make it available to the = public. I didn't do any verification and for at least one possible = leaking area, we have a problem of "How is that d..... thing called ?"

"GENERAL STRATEGY TO DETECT LEAKS"
"To troubleshoot more closely, use a high-pressure carwash to clean the = engine compartment, engine, and what parts of the tranny and chassis you = can reach from above and below the car, let it 'drip dry', drive it hard = and park it over spread newspapers, noting location and color of drips. = NOTE: When using a high pressure spray (if you do) avoid full pressure = on any of the switch units: oil pressure switch, p/s light switches, = WOT switch, etc. The 2000 psi can push it's way in and kill 'em! (Ask = me how I know . . . )."

Possible leaks of the Engine:
"EASY FIX"

1. Oil filter housing to block
2. Valve cover gasket: "Check cover for flatness."

"Same seepage as the head gasket, made worse if the cam cover has been = off for valve adjustment (or whatever) and the gasket reused. Easy to = replace."=20

3) Oil pressure sender
"Located at the top rear left side of the cylinder head."

"In the rear of the cylinder head. Leaks and the oil ends up coming down = the back of the engine. Easy fix - get a new one."

"Check opposite the spark plug nearest the fire wall. I mean opposite = side of the head. There is a sensor that remotely resembles a spark = plug that is your oil pressure sensor switch. It leaks frequently. $6.00 = to replace. Check there first. You will notice oil that looks like it = is coming from the union of the
tranny and motor. Don't fret. Oh yea, the sensor is covered by a = rubber boot. Feel the boot, shine a light in there, you will see the = oil."

"One place you might check that is a very common source of an oil leak = is the oil pressure switch. It is located towards the rear of the engine = under the throttle linkage bracket. If you pull the boot off and it is = oily, this is the culprit. Very easy and inexpensive repair."

"NOT SO EASY TO FIX"
4) Front and rear crankshaft seals

5) Timing cover seals

6) Oil pan and oil pan gasket:=20
"Cracks and weeps on older/high milage vehicle. Replacement requires = lifting engine of it's mount to drop the pan enough to r&r gasket. Using = a good gasket sealant that tolerate petroleum based liquids is = advisable. If you do this gasket replacement it also becomes a good = opportunity to change drive belts (alt., ps, ac) as you have to slack = off on these for the pan removal. Approx 4 hours labor."

"This is one of those $7 parts and $200 labor deals. Basically, the = engine has to be lifted slightly to remove the pan - probably work for = the shop."

"Oil pan replacement is a dificult do-it-yourself job, and often = tightening the bolts will reduce the leak. On the E28 chassis, one has = to drop the subframe from the engine to gain clearance to remove the oil = pan.This requires supporting the engine as the engine mounts on the = subframe.

If the oil pan has been hit, which is common, check around the level = sender, as often a tiny crack will develop here, and no sealant = conventionally applied will work. One contributor has fractured a pan on = his lowered car, and has repaired it by washing the entire damaged area = with acetone, and then using a kneadable 2 part epoxy, which worked well = until he completed his vacation."=20

"One 86 535 leaked oil when the current owner first got it and much to = his surprise the oil pan bolts/nuts were not very tight. He tightened = them all and that stopped the leak."

7) Distributor plate gasket (?):
"Rear of cylinder head there is a rear plate gasket (believed to be = referred to as the distributor plate gasket). Approx. 2 hours labor"

7a) Rocker shaft end seal cover plate (or something like that...) (?):=20 "Plate held on by 6 bolts on the back of the cylinder head. Real PITA to = get
at, unless you have very small and limber hands. Both the gasket and the fat rubber-filled washer on one of the bolts leak."

"Look on the rear of the engine head just below the valve cover. The = plate on the rear of the head has about 4 to 6 bolts on it to secure it = to the head. That gasket (or profile) can leak alittle so I use a rag = and wipe it every 2 months. As you can see by the frequency of this = cleanup that it's not bad enough to cause drips on the garage floor."

7b) Rear inspection cover gasket
"Don't forget the bolt seal that goes with this."

8) Head gasket:
"These seep a good bit. Not much to do but replace it. Probably not = worth it for a little oil."

"OTHERS"
8) Power steering pump:
"It will leak slowly around the shaft, and they sometimes fail, and = sometimes
last forever."=20

9) "Back of the engine near the transmission" "This was a fairly easy location for the dealer to access and the gasket = was not too bad either."=20

10) Fuel line to cold start valve
"The other place to look for drips is from the fuel line that goes to = the cold start valve. It becomes dry rotten and will leak."=20

"TRANSMISSION"
"Getrag 5-speed - I have no experience with the 4 speed autos.

1. Shifter shaft seal - abnoxious to do, but worth it.
2. Rear main seal - easy, once the exhaust and driveline are out.
3. Transmission case half seals - both of mine weep, very slowly.
4. Clutch slave cylinder - seepage from bottom of bell housing.

   Color not always 'clear', but always smells like brake fluid!

5. Spring detent cover on top of tranny mentioned in earlier posts.
6. Tranny vent clogged, on top, mentioned in earlier posts."

"Transmission leaks are generally the output flange seal and selector = shaft seal (rear pump seals are common on A/T cars). And of course, = most differential flanges leak/weep slightly at the output flanges."

I hope that this information is of some use for E28 big six owners.

Olav Berthold
(Hannover, Germany)