Coolant weeping from head after gasket replacement

Stevehose

Stevehose

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Well I've put the head on, torqued it gradually up 3 times, put coolant in it and voila - small drops under the exhaust manifold bolts at the gasket :-x

Is there anything I can try like retorquing or heat cycling/retorquing to set the gasket or am I @%*^$* and have to disassemble again???

Engine has not been started yet since gasket replacement. Head and timing chain cover were planed. No gasket sealer used.

Exhausted and disappointed to say the least.
 
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Could the coolant be leaking from the hose that attaches to the rear of the head and then traveling along the head to drip at the manifolds?
 
Sven said:
Could the coolant be leaking from the hose that attaches to the rear of the head and then traveling along the head to drip at the manifolds?
Click to expand...

....hmmmm, it would have been a nice possibility, but i do not think so, the reason is that the engine lays with a small angle rearwards, and that means that any leakage in the rear part of the engine will go rearwards and not front wards

but that is theory, who knows if capilarity or other phenomena is working there,

it is a great idea Sven, Steve check everything before opeining that engine again, that rear tube

it is very strange that without coolant pressure after placing a head gasket and tightening the bolts you may have any leakage, there is virtually no pressure there, not even static pressure, there is almost no heigh of coolant in that position

i feel very sad for you after all your efforts, but yes do not start that engine !

could it be a crack ? did you have your head pressure checked ?

indeed a picture of the place in which the drops appeared will help

keep your faith, do not desperate
 
Thanks guys, last night I retorqued as per the head gasket instructions which is different than the BMW manual. Seemed to stop the dripping but this evening I will see if anything has dripped overnight on the paper under the car.

Don, I fastitiously cleaned the bore holes several times per your previous posts, they were dry and clean and I lightly oiled the threads on the bolts before installing.

Sven, I checked that hose connection and it is dry - new gasket sealed with Hylomar and new hose on tight.

DQ, the head was fine, it was an exhaust valve that needed replacing, otherwise checked out fine.

From what I could see under the car there was a drop under each manifold bolt, with the tilt of the engine it could be coming from the front and moving rearward. I had the car jacked up on one side so when I did that it slowed/stopped the drip volume from the tilt so it's back level and I will see later if the gasket retorquing has changed anything. I had drained the oil with the intention of changing it pre-start but have not refilled it, there is no coolant coming out of there.

This evening I will try and get a better read on exact location and report back. Also will check if it's leaking elsewhere and finding it's way underneath.

Thanks for the input.
 
It seems unlikely that torquing the head should affect this. The first tightening sequence should have been plenty to seal this from coolant flow on a cold non running engine.

Could the head gasket have a defect or been damaged during install? Wrong gasket? Something pinched in it?

Is everything dry along the front of the engine? Any leaks coming from the thermostat housing connection to the head? and then traveling around the front of the engine along the head gasket?

Long shot - do the lower exhaust manifold studs penetrate into the water channels of the head?

Cracked the head somehow?

You could pull off the exhaust manifolds to see if that would help trace the leak. For example, if the coolant is coming through the gasket then it will not drip from the exhaust studs, since the coolant would need to travel upwards to reach the base of the studs. With the manifolds on the bottom flanges are close enough that they could pick up coolant coming out of the gasket area (I think).
 
The head was skimmed. Did the machinist check the finish to confirm it met those standards? In other words an aluminum head requires a very fine finish. This normaly is a bigger issue on a boosted engine using cometic or solid type gaskets. I can't tell by your picture.

I know studs penetrate the head in oil areas. Perhaps Don knows more regarding water jackets. Pull the exhasut manifolds and determine where the leak is manifesting itself. Measure the rate of coolant loss, tape measure as I assume you have the brass tank and not the plastic. ( piece of tape)

Before you do anything regarding spinning that puppy, pull the dipstick and check for moisture. Pull the plugs. Make sure nothing's in the cylinders.
 
I checked under the car while out for lunch and it is dry - not a drop...

maybe the retorquing or when I tightened every other coolant related fitting I could find did something. No coolant in crank case. Will check cylinders tonight and if all is well will fire it up.

Jerry, the head has very fine circular grooves in it instead of a polished mirror finish, I read that this is so it can "bite" into the gasket?

I put some loctite on all stud threads intake and exhaust, I know one or two can pass oil on the exhaust side and wanted no chance of vacuum leaks on the intake side.

Thanks for the input, more to follow.
 
That is a "key hole "water jacket head-
Did you match your head gasket to it?
We're there dimples left in the head ?
What was your final torque?
What was the condition of your dowels?
 
sfdon said:
That is a "key hole "water jacket head-
Did you match your head gasket to it?

Yes I laid the new one on top of the original and verified they matched

We're there dimples left in the head ?

No dimples - just the fine resurface swirls

What was your final torque?

I don't have it in front of me but I think it was initial 60Nm followed by 80 degree angle (I did 40Nm before this for good measure). Then it's supposed to go another 25 degrees or so after first warm up - comments on this - should I use your 100Nm number I've seen? I'm not crazy on the angle idea, I'd rather know they are all the exact same torque reading.

What was the condition of your dowels?

I replaced them with new ones but could have used the old ones.
Click to expand...

Gracias senor
 
My comment on the head surface finish is based on knowing there is a specification for how smooth it needs to be by the manufacturer or BMW. There is a meter that measures the surface irregularities after skimming. I'm so used to Sunnen and a diamond cutter, I don't give it much thought except when there's a problem. It used to be hard to find them but now it surely shouldn't be an issue to skim an aluminum head.

But if ain't broke no mo....

Just one last nervous nelly item... angle torque. The theory was when this procedure started was that it increased the uniformity of the torque. BMW reportedly found that a torque wrench method only was sometimes as much as 10% between bolts readings. With the angle, it lowered the uniformity to 3% or less. If you believe what the propaganda says. A meter is cheap ( I've seen em in the auto parts store), but it can be done with a piece of paper and protractor with a mark on the socket. Don- don't look.:roll:

I'd suggest you do so and sleep good knowing you did all you could.

Now, if that @%@*** thing leaks... find somebody to read the surface finish. Or pack that puppy up and ship it to me and I will here in Houston.

Sorry to hear you're having so much trouble. But you surely learned a lot and perhaps inspired someone else. Way to go in my book.
 
I also read that the reason BMW switched to angle torque was to save dealership time from having to bring the car back in...so yes possible propoganda there.

I will do whatever you guys think is the better technique/final torque number!

I have learned more than I bargained for, and missed some supreme couping weather as well! It's not particularly difficult to R/R the head (lots of time though) but couldn't have done it without the support here. It's the farmed out work that I am concerned about. I'd rather be able to drive over to Houston in the car to say hi rather than have it arrive in a box!

But damn it looks all nice under the hood now (well, as much as a 40 year old engine compartment with bronzed paint can). All the blasted alum parts are sweet, and just brought my heat shields to be blasted cause they look like crap now!


61porsche said:
Just one last nervous nelly item... angle torque. The theory was when this procedure started was that it increased the uniformity of the torque. BMW reportedly found that a torque wrench method only was sometimes as much as 10% between bolts readings. With the angle, it lowered the uniformity to 3% or less. If you believe what the propaganda says. A meter is cheap ( I've seen em in the auto parts store), but it can be done with a piece of paper and protractor with a mark on the socket. Don- don't look.:roll:

I'd suggest you do so and sleep good knowing you did all you could.

Now, if that @%@*** thing leaks... find somebody to read the surface finish. Or pack that puppy up and ship it to me and I will here in Houston.

Sorry to hear you're having so much trouble. But you surely learned a lot and perhaps inspired someone else. Way to go in my book.
Click to expand...
 
Steve, i feel your pain having recently done a head and being less than comfortable that all was well after but I drove her 1300 miles in a weekend recently.

Could the coolant have come out of the block when you put the head down on it? Or could it have come from a hose the other side before tightening?

I like others find it hard to believe that with no pressure at all it could be escaping between the gasket and either head or block.

I used the angle torque method and it felt awful as some kept turning fairly easy while others felt like they would crack the head. It seems they are ok although i was losing a bit of coolant i think this was air working its way out. Everyone tells me that if the head was cracked the header tank would have a lot more pressure and she would run rougher.

Id use the angle method to finally torque up using the gasket maker's instructions and then fire her up. Then have a beer if it is or isn't successful.
 
I had a number of them last night while tracing my steps in my head and sorting through the logic of how coolant could drip! I will heed your advice and reload more beer for tonight's event. Or may need something stronger pending the outcome!

30csl said:
Id use the angle method to finally torque up using the gasket maker's instructions and then fire her up. Then have a beer if it is or isn't successful.
Click to expand...
 
One last item- what direction is the arrow on your oiler bar?
 
Forward is correct!
I can't say how much I hate angle torques- it's a bizarre deal when 1 bolt gets 70 lbs and the other 90 lbs.
I would re torque to 100 Nm.

I got a tough question for you- did set TDC for your crank and head?
Does the engine rotate when done gently by hand?
Feel free to send me pm if you want my ph. Number
 
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