DIY: 1998 528I Oil Filter Housing Gasket (Part I) & "Freeze Plugs" (Part II) Repair
- I have what seems to be an oil leak along the Oil Pan Gasket. To replace the Oil Pan Gasket, it is a massive job on the 6-cylinder engine!!! So I went to the BWM dealer and they say that they virtually never sell an Oil Pan Gasket!
But they fix quite a bit of Oil Filter Housing Gasket, actually they have a whole bunch of these gaskets in stock!
- I did a little more research and apparently the Oil Pan Gasket is made out of some very tough material with a steel re-enforcement and should last into 180-200K miles. So I figure out common things are common and rare things are rare!
- As it turns out, I have leak at both Oil Filter Housing Gasket and "Freeze Plugs". It is an easy DIY, roughly 3-4h job.
- To my pleasant surprise, I have no more oil leak after one week, so those who think you have a leak at Oil Pan Gasket, think again, it is likely the Oil Filter Housing Gasket and "Freeze Plugs" Leak!!!
* The issue of "Freeze Plugs" leak was discussed here:
Instead of removing the "Freeze Plugs" and tap threads for an "NPT Thread" Plug, I decided to use an M7 bolts + washer for repair, and it works great (see below).
* To check for a Freeze Plug Leak, use a mirror and flashlight:
* Info on drive belt layout and belt tensioner (32-mm thin wrench for Fan Clutch Nut <REVERSE Thread> and 5/16" Allen wrench for tensioner):
* Info on how to remove Air Filter Housing is part of my DIY for ICV, CCV etc.:
- Check realoem.com for your PN.
- Check your belt layout and make a diagram before taking it off.
- The PN for my 1998 528I Oil Filter Housing Gasket is 11421719855 ($5.00 at BMW dealer).
- Observe Torque Values (look it up) for different bolts.
M8 bolts = 22 Nm (Oil Filter Housing)
M10 bolts = 33 Nm
PART I: OIL FILTER HOUSING, ALTERNATOR REMOVAL
1. Disconnect Battery Positive Terminal in the trunk (10-mm wrench, be careful not to short with the ground bar!)
2. Remove Fan Clutch: 32-mm wrench. Note it is REVERSE thread!
During re-installation if you have difficult threading the Fan Clutch Nut back on the Water Pump bolt, you can use my "Poultry Cord" trick:
Use 5/16" Allen wrench for tensioner to remove belt.
3. Disconnect the DSC System Connector.
4. Remove the Air Filter Housing/Air Mass Meter as a Unit. Remove the 10-mm bolt and clamps and wiggle the whole thing out watching not to damage the Intake Rubber Elbow.
5. Remove the 13-mm Bolts the PS Reservoir and set it aside:
6. Alternator is mounted by two (2) 16-mm bolts. The UPPER Bolt holds the Pulley.
The positive cable connection is a 13-mm Nut.
- D/C connector
- D/C Cooling Air Intake
- Then Alternator comes out (It swivels on the LOWER bolt).
- During re-installation, use a smaller rod or screwdriver to help guide the Alternator back on the slot.
7. To remove the Oil Filter Housing:
- Disconnect VANOS Banjo-style Oil Line attachment to the VANOS using 19-mm wrench.
- Do NOT lose the 2 aluminum washers, I re-use these washers. Torque for this 19-mm Banjo Bolts: 32 Nm.
- Optional: Remove Tensioner (Yellow Arrows) using 13-mm sockets. You don't have to do this step as it can be left attached to the O.F. Housing.
- The O.F. Housing is held by a total of 8 bolts.
- The six (6) 13-mm bolts have different lengths: mark them #1-6 to avoid confusion. In the event that you forgot to mark them, no worry, I laid them out in order as shown.
- Remove two (2) 13-mm bolts (# 7-8) on top of the PS Pump:
8. Now the O.F. Housing comes out easily. Remove old gasket and clean the mating surfaces to make sure it is spotless for re-installation.
9. If you decide to de-grease this area, go slowly!!! Stuff a rag inside the Engine Housing to prevent dirt or water from coming in. Avoid garden hose or pressure washer for obvious reasons!!!
- Wipe it clean with a rag and Q-tips so no oil is left behind:
10. Have a look at the O.F. Housing:
- Note the Oil Pressure Sensor on the back side.
- Note the Engine Oil Anti-Drain Back Valve.
- When installing new gasket, I use a thin smear of grease to seal any imperfection (this is just my way, you don't have to do it).
- Check both the mating surfaces to be sure it is spotless before re-installation:
- The Gasket barely sticks out (maybe 0.2 mm), so avoid using additional gasket maker here because it can potentially affect the Factory Gasket sealing:
- Note all connectors and re-install them.
- Watch torque values.
- Wipe all oil leak in engine compartment and along oil pan gasket area so you can monitor these areas later.
- Re-connect Battery Positive Terminal.
- Start engine and check for any oil leaks at Housing or Banjo connection.
Congrats, you just spent $5.00 and saved some 4h of labor charge at dealer or indy!
- Now, moving on to fixing the "Freeze Plugs" Leak. Read on...
PART II: OIL FILTER HOUSING "FREEZE PLUGS" LEAK REPAIR
- After the following repair of "Freeze Plug" Leak, my car is bone dry, not a single drop of oil leak!
Parts List (All of these can be obtained at Ace Hardware Store) for about $12.00:
- Stainless Steel M7 x 10 mm bolts; qty = 2.
- Optional: M6 x 10 mm bolts; qty = 2 for "dry fit".
- Stainless Steel Washers O.D. = 1-1/4"; I.D. = 5/16" (5/16" = 8 mm to accept the 7 mm bolt).
- Red LocTite, small tube
- Permatex Black RTV Gasket Maker
- Roofing Black Asphalt Caulk
- The "Freeze Plugs" are actually not "Freeze Plugs" but basically Welch Plugs that are stake-punched in from factory to close off holes from casting. It should have been plugged with bolts and washer (later models use bolts and washers). But this design of "Freeze Plugs" is known to cause oil leak in different BMW models.
- A new O.F. Housing is $330!!!
- The leak from my "Freeze Plugs" is about 4-5 drops on the driveway every night. But there is more leak than that (oil blown off on the road and collecting under the oil sump).
1. The hole in the "Freeze Plugs" is made from Aluminum and has a diameter of 6 mm and the M7 bolt fits perfectly.
- Do a search on tap and die of bolts and nuts, but as a rule, the hole to be threaded is always a bit smaller than the new bolt. This is because the M7 bolt has a diameter of 7 mm measured at the tip of the pitches but the measurement at the valley of the pitches is about 6 mm.
- To tap new threads, you can use a tap and die set but if you don't have a tap/die set, no problems. Use the M7 bolt to tap it with 1/4" ratchet. Keep steady pressure and maintain perpendicular path. The bolt is Stainless Steel and the Plug is Aluminum, so the bolts makes new threads with no problem (this is what I did).
- Tap a few turns at a time while removing the metal fragments. The hole is about 5 mm deep.
- Clean the hole from any debris:
2. Now use the smaller M6 x 10 mm bolt to make sure it fits nicely. The idea is: the washer should be 1mm from the housing. This is because this space will be occupied by Permatex RTV Gasket Maker, which will cure into a rubber-like material:
3. Now fit the washer and the M7 x 10 mm bolt as a "dry run". When the bolt is completely in, you should see a 1 mm gap between the washer and the housing. Do NOT over-torque this M7 bolt, very easy to strip it!
- Now, remove the bolt and washer and proceed with the sealing job.
4. Apply Roofing Black Asphalt Caulk at the edges. This is where the oil leak happens. The Black Asphalt Caulk will seal it nicely and has a wide range of temp tolerance.
5. Now apply Permatex RTV Gasket Maker as shown, leaving the hole alone. Use Q-tips to clean the hole:
6. Place washer then rotate it a bit to spread the RTV sealant. The Permatex procedure calls for letting the sealant cure for about 2h before tightening the bolt. However I install the bolt right away, read on.....
7. The M7 x 10 mm bolt: apply a drop of LocTite on the thread and a very small drop of RTV sealant near the bolt's head. Again, use 1/4" ratchet and do NOT over-torque this M7 bolt, very easy to strip it!
8. When the bolt is fully seated, you should be able to rotate the washer because there is 1 mm gap filled with RTV sealant (but after 24h of cure, the RTV sealant will be rubberized and you should not be able to rotate the washer). Clean excess RTV Sealant. This is what it looks like prior to re-install:
9. The key thing: you can install everything back in the car but don't start the engine until 24h later to allow the RTV Sealant 24h to completely cure.
Congrats, you just fixed the most difficult problems of Oil Leak from "Freeze Plugs" faced by many BMW drivers for $12.00!
Last edited by cnn; 03-04-2010 at 12:07 PM.
Please review my thread: http://www.bimmerforums.com/forum/sh...o-Improve-Ride
So far so good, the O.F. Housing is bone dry.
So the repair seems to be permanent.
I will post Update regularly.
Cam, you are a genius.
Looking for a DIY? Parts? Check this out, it might be your ticket
Stable: e92is, e53 N62, e46M54B25, Tribby & e39 M54B30 R.I.P.
- I need to add this important addendum. If you deal with nuts and bolts and know the “science” behind it, stop reading. If you don’t, then you may want to Google how nuts and bolts work, and the bolt sizes (SAE vs Metric), Thread Pitch Spacing etc.
- For ex, if the bolt is M7 x 1.0, this means the diameter of the bolt is 7 mm and the distance between the threads is 1 mm.
To make it easy for you:
- If the hole is 6mm, then use M7 bolt (M7 = diameter of the bolt measured at the peaks of the threads)
- If you mess it up during the first time, then drill the hole to the next size which is 7 mm, then use M8 bolts. Be careful to put masking tape on the drill bit so you stop at 5 mm depth or so to prevent drilling right through.
- Most Tap and Die set: Tap has almost no effect during its first 3-4 mm. The very tip of the Tap is usually tapered a bit with almost no effect on making threads at all. So a Tap is basically useless here because the blind hole is very shallow (5 mm deep).
- Use some oil to help when making threads
- When making threads, make one (1) turn then back off to remove debris because you are threading with a bolt and not a tap.
- After washer is in with RTV Gasket Material, use Toothpick to measure depth of the hole up to the washer. Whatever you do, the bolt should go into the hole for about 4 mm or so.
- You should have about 1.0-1.5 mm of RTV Gasket Material between the Washer and Housing. And best is to apply the washer and gently squeeze it down until you have about 1.0-1.5 mm of RTV Gasket Material, then let it sit for about 2-3h, then tighten with the bolt.
- Again, use 1/4” ratchet and when the bolt stops, just tug it with 2 fingers and that is it. No need for force here.
Last edited by cnn; 11-30-2009 at 12:30 PM.
After the repair is done, there may be a a few drops of engine oil here and there on the oil pan gasket area, this is because during the re-installation of the O.F. Housing, some oil may be leaking from the O.F. Housing, so don't worry.
During the next few checks after different driving trips, you may see a few drops here and there, just wipe it with a rag. After 3-4 checks, you will see it is bone dry.
Last edited by cnn; 11-30-2009 at 12:31 PM.
Cam, Nice job! A friend of mine just had his housing replaced for something like $450. If he had seen this earlier, he could have saved the $400 or so.
Thanks for writing this up...
1999 540it - Schwartz II/Sand Beige, style 5 rims, Conti DWS 235/45 tires, Billy HD/Sports, Stoptech S/S BL, F1 Pinacle 35% tint, Zionsville Cooling kit
1998 318ti Cali Sport - Schwartz II/Schwartz Anthratz, staggered style 23
1997 318ti Sport - Schwartz II/Schwartz Anthratz, staggered style 68 ,
1995 318ti Active - Alpineweib III/Schwartz, squared style 32
1994 325i - Bostongrau/Tan, Billy Sports, H&R springs
1991 318ic - Schwarz/Anthratz Stoff, Bilstien HD, Z4 3.0 SS, Magnaflow, S/S Stress bar, x-brace, M20 FW, Elipsoid/HID, K&N
1995 318ti Sport Schwartz II/Schwartz Anthratz - Sold
1985 635CSI - Schwartz\Sand - Sold
1984 533i "Max" - Schwarz/Schwarz, - Sold
1984 318i - Champagne/Tan, Stock - Sold
My oil leak from the 2 "Freeze Plugs" (I called them "Freeze Plugs" for lack of better words...LOL) was nothing serious, just 4-5 drops on the driveway every night. But you know how it goes, it was annoying.
Now my driveway is bone-dry! I just crawled underneath and not a single drop of oil. I am very happy with this inexpensive fix ($12 for the M7 bolts, washer, asphalt caulk!).
Thanks so much for this guide.
Question - what did you use to clean the freeze plug area on the OFH before adding the roofing caulk and gasket maker? I imagine you want to make sure there are no remnants of oil to assure a good bond.
Thanks for the quick reply.
I hope to tackle this job this weekend. One more question. Did you give the roof caulk time to cure before proceeding to the gasket maker?
- Then apply RTV Gasket maker, read the package label, but in general, wait one hour for material to feel like rubber, then tighten the M7 bolt finger-tight. Do NOT over-torque the M7 bolt. It is easy to strip it.
If in doubt, get a piece of aluminum (old control arm or thrust arm), drill it with 6mm drill bit then use the M7 bolt to make new threads as "target practice".
- Read the M7 bolt section carefully, simply make new thread with the M7 bolt, no need for tap and die set; to make new threads: turn the bolt one turn then back it out to remove metal fragments, then do it again, one turn at a time.
- Leave the splashguard out for 2-3 weeks so you can easily monitor any leak (I doubt it).
PS: Don't forget to post a feedback 2-3 weeks after the repair so others can learn from it.
Last edited by cnn; 01-06-2010 at 05:12 PM.
I replaced my oil filter housing gasket, cleaned up all the oil around it, and now it's leaking again. The freeze plugs look dry to me. Maybe I didn't install the gasket correctly? Is it supposedly to go on dry (gasket to metal contact)?
I started a thread on "Oil Filter HOUSING: Additional Blue RTV Sealant?" here FYI. The concensus is no need for RTV. However, if you carefully apply a very thin bead as shown, you may be OK.
If you do so, you may want to post a F/U info in this thread whether your technique works or not:
Just did the oil Filter housing gasket...great write up!
e39 Touring SOLD.
Three (3) months and 2,000 miles Follow-up:
- The Engine Oil Sump is Bone Dry, not a single drop of oil!
- The morale of this lesson is: if you think you have a leak from the Oil Pan Gasket, think again!
Oil is likely leaking from the Oil Filter Housing Gasket and the 2 Freeze Plugs in the back of the Oil Filter Housing and not the Oil Pan Gasket!
In your addendum you say:
"And best is to apply the washer and gently squeeze it down until you have about 1.0-1.5 mm of RTV Gasket Material, then let it sit for about 2-3h, then tighten with the bolt."
Doesn't the red loctite harden during the 2-3 hour interval? (I profess ignorance about how loctite actually works.)
All Loctite does is to create sticky material so the bolt less likely to move.
1. Apply Caulk, RTV sealant, and loctite as shown.
2. Put the washer on and GENTLY tighten the bolt using only 1 finger.
Some RTV will be queezed out of the washer.
3. Stop and wait 1-2h for the RTV to cure.
4. Then give the bolt a slight twist (maybe from 12 o'clock to 1 o'clock turn).
- Another option is to apply Caulk and RTV, leaving the center hole untouched (clean it with a BBQ skewer or small screwdriver).
- Place the washer down so it is approx. 1mm gap btw the washer and the housing.
- 1-2h later, after the RTV has cured, apply Loctite and tighten the bolt down.
Last edited by cnn; 03-19-2010 at 03:20 PM.
Can't wait to do this..
Question, how much oil did leak out of the filter housing? I'm about to do this job, as the gasket is leaking slightly, along with the CCV. I'd just need to know if I should buy some oil beforehand, as I don't want to do this with the engine even lukewarm.
Last edited by MehMan; 08-20-2010 at 01:35 PM.
>Question, how much oil did leak out of the filter housing? I'm about to do this job, as the gasket is leaking slightly, along with the CCV. I'd just need to know if I should buy some oil beforehand, as I don't want to do this with the engine even lukewarm.
Wonderful writeup!! I just did this last week and I didn't buy any oil beforehand.
There's very little oil in the housing itself. When I was putting the housing back, there was a little oil coming over the gasket, so I cleaned out the oil from inside the housing so that the gasket was clear of oil.
Kudos to CNN for sharing the job with pics and details.
Sidenote: I was able to do this without taking out the clutch fan, which can be a bear to remove at times.
Well, I did this and the CCV, planned 8 hours to do it, took 7, so good job. Most of it was spent cleaning and rubbing down this.
One problem, I didn't torque the nuts down enough, I used the torque wrench, but didn't know the exact value and torqued it down at 26 Nm, while my manual says they should be torqued down to 40 Nm. Any need to worry and to it again?(no biggie though, now that I know how to do it, it should be done in a jiffy.