Head gasket replacement (m30)

[scoobysmak]

I have a 1992 535i with the M30 engine and standard transmission. I live in south Florida and around the end of Dec we had some cooler weather and I was driving home and stopped for gas. I started the car and got about a mile down the road and my temp gauge started for the red zone. It never made it all the way before I shut the car off but was the first thing that happened. I waited about 30 min and then finished my trip home (less than a mile). The next day I checked the coolant level and it was fine. I started the car and the temp gauge never stopped at the "normal" position. I took out the thermostat and replaced it. This seemed to fix my problem so I drove the car for 2 weeks with no problems and then my radiator hose from the water pump to the thermostat housing decided to bust open. Needless to say the car got hot again but not overheated. This time I had to get towed home, funny nobody sells these hoses on a Sat night. Now I go and buy a replacement hose and also the hose from the lower radiator to the thermostat. Well as luck would have it the lower radiator hose was out of stock but was able to replace the one I needed that day. Well then strike 3 happened, the lower radiator hose cracked open, a day before the new hose came in. I replaced this one the next day and everything I thought would be back to normal but as things go two days later I found water in the oil. I took out the spark plugs and it seems number 6 cylinder blew the head gasket. I then purchased a head gasket set and took my Bentley manual off the shelf. I took the head off and got it tested, they found it slightly warped and milled it and the timing chain cover. They also replaced the exhaust valve guides. I put everything back together and have a few problems. One, I have a huge oil leak between the front timing chain cover and the block (I lost 1/4 quart of oil in 14 miles, it seems that it dumps most of it when I shut off the motor, it even manages to squirt on the lower radiator hose). This should be obvious to fix but figured I would ask to see if there were any tricks that I should have done the first time. Second, the car idles rough and I am missing power above 2500 rpm. This second problem worries me more, I admit that I need a professional to adjust my valves, I tried for 2 hours to get them right but they still let me know that they need a better tuning. I asked and someone told me that I may have placed the cam in the wrong position causing both problems but I put the cam lined up with the head like the instructions said (along with having the lower end at TDC for cylinder number 1). The check engine light comes on erratically also, I got the code checked and it looks as if water and my O2 sensor did not get along with each other. Not sure if this could cause a problem or not but the check engine light does not say on. The only other hint of a problem is when looking for the oil leak I had the car in my garage and when I started it. It runs really rich, I could smell gas in the air like I spilled it all over the floor. I know this is part of the 02 sensor and just being cold but just giving as much information as possible to get my car back on the road.

[duckloads]

I might be wrong but,

Could your oil leak be coming from the timing chain tensioner bolt? There is oil pressure on the tensioner. That Might cause such a rapid oil loss. I can't imagine why it would dump oil at sutdown.

The last time I adjusted my valves, I turned the engine until each cam lobe's heal was on the follower. It required a bit more turning of the engine, but setting each cyl at TDC didn't put each heal 180 deg from the follower. It might not matter, but it made me feal better about it anyway.

What code did you actually get?

Good luck. Someone who really knows will come along soon.

[Kalevera]

You probably already know this...but perhaps the sequence of bolts used when reinstalling the timing chain cover was mixed up? All of those are different sized bolts and have to be installed in the exact same spot, IIRC.

The first thing to do regarding the oil leak is to determine exactly where it's coming from on the sucka :).

I've never had the occasion to change my O2 sensor, but I recall reading that one of the things that it definitely doesn't like is sniffing a lot of burnt coolant. Perhaps just change it? The other thing I was thinking re: check engine light is that something simple might have a loose connection (or not be connected at all) a la ICV or MAF. Of course, losing oil pressure can't be helping anything very much.

best, whit

[George M]

Would say most of your issues are in how you put it back together...but you likely know that. It really is all in the details. If your valves are loud, could very well be a slack timing chain as you very well may not have pumped the tensioner up properly...very common. Also many do get their cam set wrong when they put it back together...you have to get all the slack out of the driver side of the chain opposite the tensioner or very easy to be a tooth off. The tensioner piston plug has to be loose as you pump the tensioner or you can't purge all the air in the system. The little oil reservoir has to be full as well. After pulling the valve cover...double check for good oil distribution...make sure you put the oil distribution bar back on properly...> should point forward for proper hole alignment under the bar to each rocker. As to the oil leak...if you didn't remove your lower timing chain cover, then its likely how you attached the upper cover. Did you use a high temp gasket dressing? A common leak path from the upper timing chain cover is the long carriage bolt for the CPS...needs to be siliconed. Completely degrease the cover and double check the leak path. Personally if you are losing copious amounts of oil out front, I would remove the cover and start over. While apart, double check the cam and timing chain tension.
Don't get discouraged...your answers are in front of you and you will figure it out...the big six is wonderfully simple and robust.
George

[scoobysmak]

Thanks I am going to look at it again, pumping up the tensioner could be an issue. I got the head service and they put it back together but I did not look over there work (it is a very trusted shop in the area, not an excuse but I do not believe they would have messed up). The lower timing chain cover never came off so it has to be the upper cover. I am sure the bolts are correct, I put them on a cardboard cutout and they went in the exact same hole they came from. Something else I was told is that this motor runs with an internal vacuum on it. They told me to remove the dipstick at idle and it should start to run rough if you have a oil leak due to the nature this engine runs. I admit it doesn't idle that well to begin with but it gets worse if you remove the dipstick so it seems as if I do have a vacuum just dumps oil out when I turn it off. I appreciate everyone’s help, back to the garage.

[George M]

Take it back if they put the head on. They likely won't be able to fix it if they didn't do it right the first time. You would be better served to take a stab based upon what I wrote above. If you have any questions about precisely setting up the cam...exactly sure that is...be sure to post....the cam gets set to cylinder bore centerline...not to the ground. So the 7 o'clock cam sprocket reference hole is 7 o'clock to the cylinder bore centerline...not to the ground. The sprocket bolt holts are perpendicular to the cylinder block deck...not the ground. The engine is laid over 30 degrees. The chain has to be taut on the driver side when you place the sprocket back in place with the chain on so the tensioner can take all the slack out of the chain on the passenger side when you pump it up properly. Set all your valves to .012-.013 cold. Go around twice. A single valve out of adjustment will cause the big six to not run right.
Good Luck,
George

[scoobysmak]

Well I took the distributor off and was planning on taking the upper timing chain cover off but found something interesting. For some unknown reason (probablyl my stupidity) the bolt holding the rotor assymbaly was not tight (of course this screws into the cam). I severly injured the cap and rotor and there was oil all inside so I might have found the oil leak but want to make sure there are no other leaks. I replaced the gasket where the cam comes through on the timing chain cover so that shouldn't leak after I put everything back together "properly". The main question I have is priming the timing chain tensioner. I see in the manual they say to pour oil down inside the timing chain cover but is there a better way? I haven't checked to see if the cam is lined up but I am sure that I based the position from the pictures in the manual that it is correct (unless it moved because of the tensioner not being set right. Thanks for all the help

[George M]

at this point, IMHO, its a no brainer. I would pull the upper cover off and make sure the cam is timed correctly. For the cam rotor countersunk allen cap screw, you want to apply loctite 242 and make sure you don't over torque it. Those that have sometimes hold on to a nice broken off piece of camshaft. There is a reservoir/pocket on the most passenger side rear quadrant as you peer into the opening made my the upper timing chain cover at the front of the engine as you remove the valve cover. This reservoir automatically fills with oil when the engine is running by run off from the valve train pumped up from the bottom end through the oil distribution bar. You need to manually keep that reservoir filled when the engine is off and you are pumping the tensioner guide. Oil (and air) should wick past the threads on the tensioner plug which should be loose as you pump up the tensioner. Use a long neck trans funnel if you have one to keep the reservoir full of oil so you don't introduce any air. Any oil spill over simply falls into your pan sump...no big deal.
HTH,
George

[scoobysmak]

Well I finally got time to work on my car again. I took the upper timing chain cover off and took a few pics to see what everyone else thought too. I do belive it jumped one tooth but figure I would ask. The pics were taken with the crank at TDC and I do not have the tensioner back in. Any comments would be appreciated, thanks for your help. *Edited*- I had to add my pics one at a time.

[genphreak]

Be absoultely clear, the engine runs on a slant- not straight up and down.

From what I can tell the Bentley manual relates all things in the valve-train to the horizontal of the block itself- this is at around 30 odd degrees to everything else on the car, so when they say note the gear's bolt positions at N-E-S-W, its point of reference is the cylinder head/block surface, not the car/road/you.

One thing u must do... is make sure those 2 pesky dowels are where they should be in your upper timing cover, if not, the cover may not be on square and true to the engine... perhaps causing oil loss may then occur from where the gaskets butt, or from the seal around the rotor cap as it won't be centred right. The Bentley manual does not mention these dowels at all, although it does tell you where to put the different length bolts in the upper TC cover :).

It's very easy to loose em when u drop the cover and head into the shop for machining!

PS- I used Hylomar to seal my timing covers, worked a treat on the new gaskets. No leaks, zip.

oh, before the valve cover goes back on, make that timing chain piston is primed... but u know that I am sure.

Best of luck, am sure you'll be ok. The issues come down to torquing the head right. If you have a leak, just replace the head gasket and use NEW head bolts. I doubt you would have warped it, but watching the air bleed very carefully- check a few times to get it all out and be prepared to change hoses and clean the connections with a wire brush so they will seal well again. A leaks that introduces air into the head overnight may cause overheating the next morning. Should make for religious bleed (ie engine off, filling with coolant) in the morning a few days after you see no bubbles whatsoever come through the bleeder and you are happy its is all bedded in.

Torque them as per the manual. Mine worked out fine...

Oh, and your O2 sensor is probaly dead from the coolant vapor in your exhaust. If coolant is in the oil the engine must be shut down and the oil changed, its just that leaks make this damn near impossible.

If its any consolation, my head gasket needed to go at 17, and it went naturally without abuse... they are long engines, can only thinkg that heating up and cooling down all the time creates a lot of localised longitudinal stresses in the gasket... let us all know how u end up.

:) GP

[scoobysmak]

I am having to the pics one at a time.

[scoobysmak]

The last pic.

[Martin in Bellevue]

It looks advanced a bit, compared with the 2nd picture, of the lower timing mark lining up.

[Jeff N.]

ditto.


It looks advanced a bit, compared with the 2nd picture, of the lower timing mark lining up.

[632 Regal]

I agree with 1 tooth advanced, can you take a straight on pic of the cam sproket with the head behind it? Hard to guess at such an angle. Might even be 2 teeth off.

[scoobysmak]

I tried that, my camera wont focus being 2 inches away from the cam, need wide angle lens maybe. Otherwise I need to remove the radiator to take the pic at that angle. Thanks for the help. (Not sure if anyone saw the first pic, let me know if you don't see a total of three pics)

[632 Regal]

all pics are there, definetly 1 tooth

[Hector]

who used to own an immaculate m30. Don't know if George already mentioned this as I have not read all the post but a reason that you had oil inside the distributor cover could also be due to the oil seal not mating probably inside the valve cover hole. Check this just in case.

[genphreak]

Nice pics! Are the sprocket cogs badly worn? You need to look at them from underneath as the chain wraps around the top- so I can't tell. You should check for any broken teeth that would be a tell-tale. The stock sprocket has over 2mm of flat surface between each tooth.

A straight on pic taken from on top of the radiator would be much better for us to see... before you go moving things areound too much. Are the cam lobes at TDC on cylinder 1?

The sproket teeth were worn on mine, although the chain hadn't jumped... changing the lower sprocket requires removal of the sump, which requires jacking the engine up... :p if you end up doing that you need to replace your timing chain ($25) oil pump chain (?) and pump/perhaps some other little parts...

[scoobysmak]

This is so you can see the cam position.

[scoobysmak]

I took a pic of the teeth from the bottom side, there are none missing but the pic did not come out well due to the fact I had to have the camera so close. I don't think the sprocket is damaged, I think it jumped due to the tensioner not being properly set. If there is anything else someone might look at please let me know. Thanks

[632 Regal]

i doubt it jumped, more likely assembled 1 tooth off.

[genphreak]

I took a pic of the teeth from the bottom side, there are none missing but the pic did not come out well due to the fact I had to have the camera so close. I don't think the sprocket is damaged, I think it jumped due to the tensioner not being properly set. If there is anything else someone might look at please let me know. Thanks
Assuming the damper is set to TDC, the Cam looks slightly off, but you are better to judge the lobes being straight down in relation to the block than we are, as we can't tell if the camera is dead above the block or not (am imagining it was tho).

To judge your viewing position is not easy either, you have to make sure you have absolutely no parallax error, doing it one eyed probably won't work either :D

If the chain has moved a bit the cam lobes will not be pointing down **symetrically** around the perpendicular centreline coming up from the head, where they are in the 'rocking' position (perfectly closed, not one way or the other).

Re the cam teeth,
It is hard to tell from the focus of the cam sprocket photo but it looks like your teeth are not sharp :) -they appear to have some flat material between them.

Time to move the chain back a tooth perhpaps? If the lobes don't look dead on and the cam sprocket is not at 7 o'clock then perhaps another...

It's easier to tell by the sprocket though! Was hoping to see a pic shot dead-on to the cam sproket with the camera as much as possible horizontal to the radiator support, perhaps also one with the camera tipped a little so it is parallel with the block/head surfaces. Advice would be easier to give then! AM sure you can get it set right though- what the Bentley says about the cam sprocket bolt positions is right... let us know how it goes!
:)

[scoobysmak]

Well I finished putting it back together and so far so good, amazing when you adjust the valves with the right cam setting that they are much quiter now. I haven't driven the car pretty much since the middle of Jan so the battery was totally dead. After dealing with that issue, I started it and it ran much better than the last time I had it on the road. My belts were a bit noisy but think this was some coolant that ran out when I pulled the thermostat housing off. It seems have a strange idle, kinda puffs out the tail pipe (not smoke just normal exhaust, this also may be my imagination due to the fact I have been ridding a motorcycle for the past 3 months too). My check engine light comes on only at idle. This I am almost positive is my O2 sensor, think I saw something on here about checking engine codes but haven't found it. The only other thing that is a bit off is the power (seems like I got about 95%, this also may be off due to the fact I have been on a bike) and my gas milage (this is only by reading the gas indicator on the dash so after I run a complete tank of fuel I will have a better idea). It all maybe connected with the O2 sensor but if there are some ideas out there or something that I might want to look at while finishing this project let me know.

[Kalevera]

Do a stomp test for the DME codes: insert key and turn to ON while hitting the gas pedal 5 times in rapid succession. The light will come on for a second or two (solid), then start blinking. There are 4 numeral codes. Normal is 1 - 4 - 4 - 4 (it's pretty self explanatory when you see it). I forget what the O2 one is... Might as well replace the sensor anyway -- burnt coolant kills those suckas.

best, whit

[genphreak]

Do a stomp test for the DME codes: Might as well replace the sensor anyway -- burnt coolant kills those suckas.
best, whit
Great news, glad ur back on the road... (if only sort of). I second Whit's recommendation entirely.

Remember too, everything chain reacts- what I am thinking about here is your Cat. With the O2 sensor returning wrong readings to the ECU, your ECU is running the fuel injection incorrectly or it may even be running on limp mode (or whatever its called in BMW 'spreck'). This means low power/high consumption and lots of exhaust ;)... which is tough on your cat. This mode is designed to flash your warning lights and keep your car running just enough to get you out of your troubles and back to the dealer no matter what is wrong electronically.

Importantly, cats only last so long; they get killed by polutants such as ethylene glycol (in coolant) as well as other crap from the combustion process- especially if an engine is running badly. If yours has not been changed **do not stress it** by driving your car (unless you have a spare cat ready - they are very expensive and the oem replacements are nowhere near as good). Once you've checked your codes, changed the 02 sensor you've then just got to make sure everything is running in sync again. Do not drive the car until you do...

ie
Set the valves again if you are still not sure about how good you got them. Reset the ECU. Then run the car a bit and use an Oxy sensor in the exhaust to measure the CO (set it to 0.8-0.9 using the 'bypass air adjustment' bolt) on the AFM, this will ensure your car passes smog tests from now on... and will keep your new oxy sensor and not so new cat working in happy unison.. Then the job is well and truly done. How are the injectors btw? They are the only other thing I'd want to be sure are right before doing all this, they are critical in this process too and will upset your smog readings during the AFM setting process, problably prevent you getting the right setting altogether.

I think you'll be amazed by the reclaimed performance once all this is done, adn with any luck your cat will see another 40k miles at least ;)

NB. I had to change my cat a while ago, it went as at 150k the cam had worn on two lobes due to incorrect oiling (std banjo bolt problem). Correct valve adjustment was no longer possible on cyls 3 and 4... over about 30k miles I reckon this condition killed the cat as the engine was unable to run proerprly... a new cat and 02 sensor (jic) later things improved, however it required the new cam to get the engine performing again.

BTW; If your ECU error codes say anything about temp sensor failings, heed its advice, I've seen them go before. All these sensors have what I can best only describe as 'a big emotional effect' on how the ECU controls the engine... The ECU should not be returning codes at all in normal operation, no check engine lights, zip.

:) GP

[scoobysmak]

The results were 1-2-2-2, not sure what that is but still thinking O2 sensor. *Edited* After reading the bently manual, the fault code is: Oxygen sensor lean/rich control stop. The corrective action is to: Check for intake air leaks or reasons for rich mixture. I looked over the intake and everything was tight, wondering if just a faulty sensor or if I should examine something else.

[genphreak]

Coolant spilling from the breather alwys makes the water pump bearing/belts horribly noisy (for a few minutes)... mine did it for longer and I realised that I had a slow leak from the upper radiator hose where it connects to the water pump... a little tightening, a tad more air bleeding from the breather and presto. SYstem nice and sealed, working purrfectly. Of course changing the belts is always a nice thing to do, keeps things queit and gives you a nice feeling of invincibility... esp half way accross the desert... ;) GP

[Kalevera]

I think that means your sensor is "fuXored", and given the recent events, I wouldn't doubt it either :) Alternatively, if you have no record of the sensor being changed (...within the past two years or so??), it's a good idea to change it anyway. Yeah, I know - another $100 with BMA...

[scoobysmak]

Well I decieded to take another look at the coolant issue, humm well I have a leak from the upper radiator hose go figure (I replaced the other two, this one was a bit more and seemed in good condition but rather be safe than sorry so it will get a new one). I plan to replace the O2 sensor and the CAT but was looking and the price of a new CAT I could almost get a perfomance exhaust done. What would be the downside to getting a perfomance exhaust kit (or maybe have one built) VS having the stock componets back in the car. I might have a reason for the lower HP too (well lower than what I remember anyway, there really wasn't too much difference I would say barely noticable), I realized when testing the car after I put it back together that my fan clutch was not engaging all the way (it would spin but was not providing the airflow nessesary to cool the engine). I replaced this part so now my fan is cooling like it should but drawing some power from the motor. Last but not least, where do most of you get the wrench to remove the fan from the water pump. I looked at Sears, Autozone, Discount Auto, NAPA, and a few heavy duty tool stores in my area with no luck. The only thing I know to do is locate the local Snap-On tool truck and then I have to pay for this in advance (he doesn't stock a 32mm thin end wrench) and I then relocate him a week later to get it. At this moment with the tools I have is to remove 2 of the water pump pulley bolts and then I can get a wrench to remove the fan. I know that the Snap-On tool is an option but wondering what everyone else has done.

[grave77]

by the way ... the fan clutch was ur original problem I think ... it heated up ur engine and blew up up the head gasket. then there was pressure in the water system the blew up the hoses one after one. most of the cars I saw that has head problems was due to this fan clutch and that's one major disadvantage.
for the time being ... disconnect the O2 sensor and see how it runs ... if u see any improvement then that's all u need to replace. the CAT is essential in ur area, but for me I hate the idea of having this blocking the engine exhaust so I chopped it 3 years ago ... I got more power and a little bit more noise when I step on it. congradulations for a good DIY job.

[Anthony (M5 in Calgary)]

Bike shops carry thin metric wrenches for low $$s. I picked up a 32/36mm open ended one for about $12C.
Cheers,
Anthont

[genphreak]

Leave the fan be. it draws a very small amount of power and the car has hundreds of horses of it; one horse could pull enough on a cog to run a hundred fans at once...

Re the cat- if you end up changing it stick with stock as both BMW and Merc really excel on exhaust systems. Not many aftermarket 'exhaust engineers' make anything that will perform as well even tho most are billed to you as 'performance'... stock cats and engine pipes are nice by anyone's standards (better than anything I've seen aftermarket), I bought stainless rear mufflers and pipes (nice) but would go completely stock if I had my time again. Unless you change the injectors, cam intake etc the std exhaust is more than sufficient. My local dealer told me (and they might be right) that my new exhaust had a 'Free Flow' muffler and this would affect the economy of the car, something I am still wrestling with.... :) GP

[Jon K]

I'll chime in.

If you need new cats, don't bother with OEM. They last long but you pay $1,000 installed usually. Forget that. Magnaflow hi-flow catalysts, $80 ea. Can't go wrong. I have M5 exhaust on my car with hi-flow catalysts, its really nice. I pass emissions too!

[Kalevera]

I got my 32mm wrench from Park Tool. It's a bicycle headset wrench and it cost me ~$3 (?). If you check their site, you might still be able to buy one...but IIRC, they were discontinuing them. Alternatively, if you have a grinder or a Plasma Cutter, you could make a tool to pull the fan clutch out of a piece of thin barstock (I know Bidoli's done it...sure others have, as well).

Agree with Jon on the exhaust - just get a magnaflow and an aftermarket resonator/box. Less expense, sounds fine.

best, whit