Another Head Gasket update

[Andrew]

Hey guys

Well, I got my engine back together after dropping in a new head and started her up. The good news is that the car starts and runs fairly quietly (maybe another valve adjustment is needed but it is at least 10x quieter than before!)

The bad news is that I am getting a lot of steam and smoke from the engine compartment. Both coolant and oil are dripping from the back of the car (most likely along the head gasket.) All the hoses and such are not leaking and there is no steam or water eminating out the tail pipe. So far I DO NOT see coolant and oil mixing inside the engine...

Should I go back under the head cover and retorque the head bolts? I am thinking that maybe the cheapo torque wrench that I bought on eBay is not calibrated right. I will go out and by a new Craftsman one or something. I have NOT torqued the bolts another 35 degrees yet as I have been too scared to run the engine for 25 minutes. (Could this be the problem?)

The other issue is that I might havea big air pocket in the cooling system as the coolant needle never made it out of the blue area...

Thanks in advance for any advice!
Andrew
'90 535i

[genphreak]

Hipefully I have good news- I never got a significant tailpipe drip (I did get some) but I got steam before mine were torqued. Bad news perhaps though; if you have already filled your cooling system with coolant the etheylene-glycol steam will have killed your O2 sensor- in some cases the headgasket leaks coolant into a combustion chamber in which case the o2 sensor would be gone prior to this anyway. Where was you gasket leaking? Mine was slightly cracked only between teh water jacket and the outside of the engine back on Cylinder 6- causing a leak when the cooling system was under significant heat stress.

Once you got the extra 35 degrees (assuming you got new bolts- this is very important- if not I'd be tempted to get new ones immediately ($2.20each) and perhaps replace each of them one by one- perhaps Winfred or one of the other more experienced crew will be able to give better advice here before doing this (just in case it could warp the head now its 'almost' in place) and then torque each bolt the extra 35 degrees.

Once she is torqued properly you should check your valve clearances, check all is ok and after a few days operation do a full drain of the cooloing system and fill with a pre-mix of at least 300ml BMW coolant to every litre of distilled water.

Perhaps all will be ok with a final torque-up? I sure hope it is... :) GP

[632 Regal]

first things first, did you torque the bolts by the angle method, did you make sure the bolt hole bosses were completley clean (if not you could have hydrolocked the block and cracked it) theer are no torque values for our cars, just the angle method. Did you use new bolts, if you did use the angle method you MUST retorque them the final value after warmed, make sure you bleed it good while warming and have no fear.

Good luck!

[winfred]

it may be residual blowing out the exhaust, it shouldn't be leaking even if not torqued to the final stage, air pocket is a big possibility

[winfred]

m30 bolts are the only ones that you can get away with reusing, everything else is crap

[Kalevera]

True.

[Andrew]

Wow thanks for all the quick replies!

I DID use brand new bolts and I spent about 3 hours cleaning out the oil and junk from inside the bolt holes. They were dry and clean when I was finished. I was able to thread the bolts with my fingers before torqueing them down.

The Bentley manual says to torque the bolts 43 ft lbs, wait 20 minutes, then torque up to 57 ft-lbs (from memory.) It then says to run the engine for 25 minutes and then torque 35 DEGREES. I did the second stage 1.5 days ago and have NOT done the last step yet...perhaps thats the problem???

Sorry for the confusion about the leak. The leaks are coming from the back of the HEAD (not the tailpipe.) In fact, there is no steam or fluid coming out the exhaust at all. (I probably should have phrazed that sentence better in the original post.)

Tomorrow I guess I will let the engine idle and bleed the trapped air (which I also suspect) and add 35 degrees to the torque unless you guys dont agree with the manual.

I promise that once I get this straightened out I will post some notes on my experiences with the refurbished head and the head gasket replacement process in general.

Last but not least, I will let you know what happens with these leaks!

Andrew

[winfred]

if it's dumping out the back it's possible that the gasket got dammaged by dropping the head on it, i know people that have seen it happen. if it's just oil perhaps somethings a miss with the little plate on the back of the head if you took it off, theres a seal ring that goes around one of the 10mm bolts that holds in oil

[Andrew]

Thanks Winfred. I paid special attention to those gaskets, plates, and washers on the back of the head. They are all new from the dealer. I think the leak is coming from BELOW the plate and is all along the rear of the gasket. I suppose I could have damaged the gasket when dropping the head but I was pretty careful. It only took me a week to replace the head gasket and transfer the parts to the new head... I suppose another week of my time and $100 for another gasket will be the worst case scenerio at this point.

I think the leak may have slowed down when I ran it the second time... I will give it yet another try while bleeding the system tomorrow. And of course, there are still 35 degrees of torque needed.

Andrew

[Craig in Davis]

suspicion would be the coolant hose on the back of the head is leaking either because the hose is bad, clamp not tightened or hose not properly seated onto fitting.

I believe you bought a new head. I would like to think they put the cover plate o-ring on properly but who knows. One of the bolts, I believe it is the one towards the passenger side on the top should have a thick washer/o-ring on it to prevent oil leaks. Did you verify it isn't dripping down from the valve cover? You used a new valve cover gasket right?

Craig


if it's dumping out the back it's possible that the gasket got dammaged by dropping the head on it, i know people that have seen it happen. if it's just oil perhaps somethings a miss with the little plate on the back of the head if you took it off, theres a seal ring that goes around one of the 10mm bolts that holds in oil

[Andrew]

Hi Craig

I did buy a new head and I put the seals and o-rings on myself. (For future reference, the head arrived in good shape but was missing critical studs and seals.) The covers were bolted down snugly.

Unfortunately the hoses in the back of the car are new and the clamps are secure. The leak is soley on the passenger side of the car. It is possible that the oil is coming from the valve cover... something to look at closer in the morning.

This is so frustrating! I hope that I do not have to re-do the head gasket!

BTW the valve cover gasket is new as well.



suspicion would be the coolant hose on the back of the head is leaking either because the hose is bad, clamp not tightened or hose not properly seated onto fitting.

I believe you bought a new head. I would like to think they put the cover plate o-ring on properly but who knows. One of the bolts, I believe it is the one towards the passenger side on the top should have a thick washer/o-ring on it to prevent oil leaks. Did you verify it isn't dripping down from the valve cover? You used a new valve cover gasket right?

Craig

[Craig in Davis]

They have been known to leak quite generous amounts of oil but it usually drips down the drivers side and off the bottom of the engine.

Is it possible the coolant is coming from the overflow tank? Maybe it got hit and has a small crack in it that is dripping onto the engine making it look like the headgasket it leaking? Is it definately from the head area or is it possible it is the block drain leaking down the passenger side of the block?

Unless the head came to you warped, the block wasn't clean and smooth, or you dropped the head on the gasket I believe the leaks are from something other than the headgasket. I have replaced several m30 headgaskets and not had leaks even when the head is sat on the gasket and removed 2 or 3 times before finally being torqued down properly. Maybe I've been lucky or you unlucky but personally I would keep looking elsewhere for the leaks.

Craig



Hi Craig

I did buy a new head and I put the seals and o-rings on myself. (For future reference, the head arrived in good shape but was missing critical studs and seals.) The covers were bolted down snugly.

Unfortunately the hoses in the back of the car are new and the clamps are secure. The leak is soley on the passenger side of the car. It is possible that the oil is coming from the valve cover... something to look at closer in the morning.

This is so frustrating! I hope that I do not have to re-do the head gasket!

BTW the valve cover gasket is new as well.

[genphreak]

Good to see the board helping a battler out so well. On ya everyone... Yes, that o-ring is a crtitical one- it details it in the Bently, dead easy to get it in the wrong hole and tighten it up too much. The oil pressure switch is ok and not cracked/leaking? Its weird to go losing oil at the back, I don't remember an oil gallery passing through the gasket near the back face of cyl 6... only that little plate arrangement on the head itself... but I could be wrong... :) GP

[Andrew]

I can't wait to get home and start looking at my car again!

I suppose it is possible that the coolant came from the expansion tank when I was filling it (as the overflow does drop down where I am seeeing moisture.)

Maybe the oil came from the head when I removed it? I thought I cleaned the transmission area and block well with a rag but I maybe I missed it.

As mentioned by all of you, I think I need to let the engine run and pray that all this burning stuff is residual mess...

Andrew

[Martin in Bellevue]

Didja check the 3 bolt cover on the back of the head? The 1 longer bolt that bottoms into an oil galley needs an o ring gasket; I think it is the bolt around 5 o'clock. Access is limited, if the leak is here. Isolate the leak before running the motor, & complete the torque proceedure.

Somewhere on mye28 archives, is listed a torque proceedure for 70's era m30's as 40, 60, & 80 lb-ft sequence. This isn't as precise as using the correct torque angle proceedure with new bolts.