1998 528I Oil Filter Housing Gasket & “Freeze Plugs” Repair (E39)
DIY: 1998 528I Oil Filter Housing Gasket & "Freeze Plugs" 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
* 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 let's move on to fixing the Oil Filter Housing Leak itself.
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 1mm 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!
Cool! Yet another great writeup.
What's the purpose of the freeze plugs; as you asked in the other thread, why have a hole that's plugged….and never, ever opened?
^I was thinking the same as well lol.
Thanks CN, After about 4 hours of working on my OFH gasket installation and also replacing the freeze plug seals, supposedly I didnt insert the seal properly and it started leaking again. ill give another go at it tmw. Thx for the DIY :thumbup:
This is the E34 setup:
The E39 uses stake-punched in "Welch" Plug type with no O-ring at all.
But anyway, for E34, you need to press the O-ring in really tight, then the plug, then the Ring. Make sure you use the correct O-ring. People who used slightly off O-ring develop leaks again! Search E34 forum!
Well I ordered the O-rings on Pelicanparts and they looks slightly bigger than the older ones. I think it may have gotten cocked when I popped the cap back in because it was leaking pretty bad. And the e34 setup is identical to the e36 setup?
So far my "Freeze Plugs" are bone dry using the M7 bolt and washer, so it looks like this is permanent repair.
Another member emailed me: he mentioned that he tried to remove the "Freeze Plugs" to thread an NPT plug, but in the process of removing the "Freeze Plugs", the Housing hole is damaged, so he could not make new threads. He ended buying a brand new O. F. Housing.
So for those who want to remove the "Freeze Plugs" to tap new threads, I know it has been done before, but beware!
Well executed! :)
- 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.
- For most Tap and Die sets: the 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 the washer is in with RTV Gasket Material, use Toothpick to measure depth of the hole up to the washer. If you decide to use longer bolt such as 12 mm long then use 1-2 more washers. 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.
Well--I have started into the fix of my oil gasket leak and have removed the alt so to get to the oil f housing
when removing the alt I cracked the pully on the power steering pump--Didn't know that all of our pullys are plastic--imagine that--anyway I have a 2 hour drive to make now for another pully wheel--did get the oil filter housing off and have cleaned everything up so as to have a good start on her when I get back---the gasket on my housing was as hard as a dang rock--reminded me of the valve cover gasket--the gasket just broke into little pieces when trying to remove it---can see where this could be a job every 100k mile or so---if the car lasts that long---on the freeze plugs on the oil filter housing--mine are different from any seen so far--there is an allen wrench hole that you can use and allen wrench on and remove them--there are no leaks around them what so ever--so I'm leaving them alone--the was considerable amount of oil coming from around the oil housing though--hope that helps
Well, for those who, like me, are wondering why they left this hole in the engine, I looked it up on wikipedia. Apparently they're not technically freeze plugs. Freeze plugs are in the cooling system to help avoid cracking of the block if your antifreeze balance is incorrect and the fluid freezes. They need to be there in order to cast the part, and on properly designed engines are, in fact, threaded and blocked with a pipe plug.
So far my repair is bone dry.:thumbup:
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 during the next few checks after the drives, you may see a few drops here and there, and just wipe it with a rag. After 3-4 checks, you will see it is bone dry.
Below is info directly from Mann-Hummel HQ on how the "Freeze Plugs" were installed at factory by Friction Force and Loctite.
So the fit is very tight to withstand the oil pressure which can be as high as 60-80 psi.
So using the M7 bolt attached to the Freeze Plug is a very secured technique.
VOR DER MONTAGE LOCTITE-GERECHT GEWASCHEN
Wash the parts
BIS AUF ANSCHLAG EINGEPRESST – GESICHERT UND GEDICHTET MIT LOCTITE 620
Plug force fitted to block, secured and sealed with Loctite 620
AN 6 BIS 8 STELLEN VERSTEMMT
Calked at 6 to 8 points
MINDESTEINPRESSKRAFT: 1500 N
Minimum Fitting Force: 1500 Newton
MINDESTAUSPRESSKRAFT: 3000 N
Minimum Press out force: 3000 Newton
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!
Did you ever get a pretty rotten odor every time you started up your car? I have the oil leaking around the oil pan, and I also have a really funky odor every time engine is cranked in the mornings. It is not an oil smell, it's more like a foul odor, rotten egg, kind'a smell, that goes away in a few minutes after the engine's morning crank.
Great write up.
So why not use RTV alone instead of the roofing caulk?
Did you say NOT to use any RTV around the actual housing? I'm sure in a perfect world that might work but the fact is that the gasket failed..... so it needs some help imho.... same as the thermostat housing gasket which fails as well and is of the same type and design...CANNOT see how it would hurt to seal both sides of the gasket itself and the outer edge of the housing.....
#2. 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 in Blue, you may be OK. If you do so, then read the RTV package instruction, apply the seal as shwon in BLUE, then let it sit alone for 1-2h until it feels like rubber, then install the Housing back in the engine.
You may want to post a F/U info in this thread whether your technique works or not:
My 2 cents: Nothing lasts forever, most car mfg rubber gaskets fail around 80-100K miles anyway. If the OEM gasket lasts 80K miles, then it is fine, if I keep the car another 80K, then I will redo the gasket then.
I ended up putting a bead similar in location to your blue line but also one below and on top of the gasket itself.... just enough to cover it when squished. Then I tightened it down until I could see the RTV and stopped, waited 2-3 hours and then torqued it down. Worked wonderfully even thought he housing is aluminum and supposed to leak easily.
I'll take some pics here in a couple weekends and let you know how it goes..... maybe post them in both threads...
Thanks for the feedback.
Funny enough...I'm going to have to redo this as I still have a leak...I must have hosed some thing...so there will be a part 2 for me. :)
You can also change the housing with one from an M54 engine, the plugs are screwed in on these, all fittings are the same and as a bonus the M54 housing comes with an oil temp sender as standard
Did this job on my '99 e39. The write up was great. FYI- my model did not have the "freeze plugs", but here was a stock, star point screw already in place. I guess BMW must have addressed this leak spot after '99?
I'm about 2500 miles later. Not a drop of leaking.
Thoughts on the Job
Hey CN, your post on the oil filter housing repair was excellent. I hadn't seen that in all the time I have looked for info on repairing the oil pan gasket, but yesterday, it popped up and you were definitly correct. I had been thinking there is no way I'm going to repair the oil pan gasket, and to just let it leak, but when you run the car clean it all up and inspect the engine, all you see is seepage around the oil pan gasket. I previously went to town on the oil pan gasket with a bunch of commercial gasket maker, and thought... this ought to do the trick, but I was wrong (about the main source of leakage apparently) I do think that would work fairly well, as the oil pan is usually under vacuum, you can simply caulk around the whole thing and get a pretty good seal. It would be a bitch to pull the pan and do a proper replacement, but it works. I have 2 comments about your diy. 1) the bolts on the ps reservoir are 13 mm, not 14. 2) On repairing the 'freeze plugs' I definitly think tapping is the best way to go, but I'm not sure if you came to the same conclusion but I would use a gasket maker, not caulk. Caulk is not rated for high temps, and I'm certain roofing caulk would break down after some time. I like loctite instant gasket. It is thicker and silicon based, as opposed to the small clearance gasket makers. I have a later M52, and have the tapped holes. They had not leaked at all. 3) I noticed some 'etching' on the mating surfaces of the gasket, but didn't do anything about them. I was hoping that they would seal well with the new gasket, which was so much softer. 4) as far as diagnostics, the important thing to note is that if you lift the car, clean everything really well, and and wait, you will not see any dripping if it is the oil filter housing. If you then turn your car on, and run it in neutral at about 2000 rpm for about a minute, you will instantly see dripping around the upper side of the pan where that gasket sits. I hadn't ever run the engine while I was down there, which is why I mistook the location of the leak. 5) I have already pulled my clutch nut, but I found a trick that worked really well the first time. This time, it was not nearly so tight, so it came off easily, but I made a tool the first time that saved my tail. It was a foot long bar, about an 1/8 by 5/8 cross, with a 1/2" hole drilled in 1 end right next to the side wall. practically touching it. you can use this to slip the hole onto one of the nuts on the wp pulley and apply leverage on the next nut. I could send you a diagram if this makes no sense, which it might. Then you can apply torque to the clutch with another wrench without having the belt rotate. The first time I did it, I wasn't able to turn the clutch hard enough without having the belt slip. This time it was not a problem. Anyway, great writeup. I'll buy you a beer of your choice, hell two even, if your ever in college station. It really looked like it came from the oil pan housing. After pulling all of that off, there is no wonder why it leaked with all of the stuff bolted on there. There is the Alternator, Oil pump, belt tensioner, and oil filter cap that all apply tremendous amounts of torque to the housing. But I guess it did pretty well considering all that. Have you had any problems with the display on your radio. I have had some of my lcd panels go out and I'm wondering if there is any point in trying to fix that. Well, it was a pleasure working with your instructions yesterday, it got me through the job. I had already pulled out the tensioner, so I had done some of that easy enough, this was just a couple more things. Thanks
More thoughts on using gasket maker on the gasket.
I would not use roofing caulk, its not designed for high temps (engine high). Loctite instant gasket is approved up to 400dF, so I would use it if you feel the need to use something. We use it on our test rig, and that stuff never comes off, so my thoughts are to use no caulk on the gasket, as the original lasted well into the 100k mark for me. That way the next time it will come off really easy. If you use something like that, you will have to use a wire brush or scraper to get it really clean which makes it more likely to scar your mating surface. The old one came out without any troubles, and I reckon I could do the job again in about 2 hours. My 2 cents, feel the difference between the gasket you pulled and the 1 your putting in, they are not even the same material anymore. The new gasket should do the trick fine. If you need to use something else, I would go with an industrial gasket maker designed for oil and the temps were subjecting them to. That will hold well enough.
Glad you found this DIY useful.
I think Loctite instant gasket is an excellent choice too.
FYI, Roofing Caulk can handle the scorching sun on your house roof, so it can handle engine heat. The typical engine block temp is about 100C or so (give or take).
The roofing caulk I have had now for 8 months are rock solid, bone dry. Plus the roofing caulk is locked in place in the black RTV gasket maker.
I can tell you that this DIY helped me alot: it works, it is a simple fix and 8 months later, the car is bone-dry = priceless (I hate oil stain on driveway!).
Thanks all for your comments and tips. I had multiple issues that, in the end, I decided to tackle all at once. CCV went after starting my car after getting gas - filled the service station with oily gas. Some guy said something like "oh o-that don't look good. Proly blew your engine.".
I drove the car about 1/2 mile back to my work and ended up renting a uHaul car carrier for $60 to get it 27 miles home. Some say it'd be ok to drive the car but honestly I wouldn't be able to live with myself if something happened due to my laziness, so I pulled it home with my Ford Expedition.
After pulling the error codes (7) and reading these forums, I narrowed my problem down to the CCV. Come to find out, the culprit was actually one of the hoses attached to the CCV that had blew a hole. It created quite an oily mess. (HINT - clean everything real good while you have things apart. Makes for easy diagnosis in the future). I came home from the dealer with about $200 in parts (new CCV, 5 hoses) to add to my already growing pile of parts that had accumulated on my bench (belts, oil filter gasket).
Took me probably 6 hours of slow methodical progress just to get the CCV done. It's a 4 wrench job and it's tight in there but doable by shade tree mechanics. I never took my intake manifold off and opted to work around/under it. HINT - label all the electrical connections as you are taking them off. Take the tags off when you're reconnecting. I used masking tape and a sharpie. As I began to put it all back together I decided now was the time to do the oil filter housing gasket and belts as well. So off with the power steering reservoir, alternator and other misc parts to get at the oil filter housing. HINT I used the sharpie again to write numbers on the head of each bolt and wrote the number on the housing next to the hole since there are 8 or 10 bolts. Now for the controversial item - After spending 3 evenings working on this, I decided I didn't want to do this job again on this car so I bought the high temp copper RTV (sensor safe) and laid a bead just outside of the gasket as shown in other posts. I was ok with a very VERY thin bead not touching the gasket as I'd like both to work without the other.
About 2 hours to put everything back together (intake hoses, air box, MAF, Oil Filter housing, Alternator, Fan and shroud), now I get to sit and wait. The RTV takes 24 hours before it's completely dry so tomorrow afternoon will be my test start. fingers crossed. It'll be nice not leaving little half dollar sized oil spots on the ground everywhere I go.
Thanks again to everyone for their comments. People like us wouldn't be able to do them without great forums like these.
I can tell that you are a very meticulous person by nature LOL....:)
I think you will be fine. Before re-installing the oil housing, hold it up and look sideway to be sure the copper RTV is a bit shorter than the OEM seal. This way the RTV does not interfere with the OEM seal.
I think you will be glad to have a dry car.
Before doing this job, I had 4-5 drops of oil on my driveway.
After this DIY, I have nada, zip, zero oil on the driveway and I love it!!!
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