1999 996 Milkshake Syndrome

[Rich69]

Hello 966 fans !
I have a 1999 996 with milkshake syndrome
It appears to have a blown hose (water?)near to the right side cylinder head
Looks like a heater sized hose ? Car was driven until over heated by former owner.
Many questions that I have...I am assuming that the head gasket(s) are blown or
that I have cracked head(s) ? Engine runs pretty good when dead cold then starts to smoke after about 1 minute but runs smooth does not shake ? There is some steam and oil smoke from the exhaust but does not seem to foul any of the plugs ??
I don't want to pull the heads to find out it was something else...
Can I pull the heads without removing the engine ?
Can I partially disassemble the engine in the car (remove exhaust and intake)
then remove it with out removing the transmission (6 speed) ??
Any tests or tricks that I should know about before dis-assembley ?

[JFP in PA]

These engine's never blow head gaskets, so you most likely have a cracked head.

As far as removing the heads with the engine in the car, yes, it can be done but is a real bear to do. It is vastly easier if you are going to pull both heads to simply drop the engine out first. It will also actually take less time if you pull the engine.

As for pulling the engine and trans as a unit then separating them, yes, you can do it that way, but I personally prefer pulling the trans first and then the engine. It is nearly impossible to just pull the engine and leave the trans as there is no room to do this.

[Rich69]

Great thanks for the tips...
First I will pull the plugs and see what they look like.
Once I pull the cams out I will pressurize the cooling system
and look for leaking cracks in the head(s)
I realize that 19 PSI may not be enough pressure to reveal a crack in a cold head
But it may be worth a try I think ?? I don't want to pull both sides if only one head is cracked...

[bell]

Im leaning more towards a cracked cylinder......if you have a bore scope you may be able to visually inspect the cylinder walls.....have seen this numerous times....

[Rich69]

If the cylinder(s) walls are cracked Wouldn;t there be clouds of oil smoke from the exhaust and rough running ?
Noy sure how these heads crack ? is it from the cooling jacket into the oil thru the cracked head or must it also involve the combustion chanber ?
How can the oil and water be so mixed and still not foul the plug(s) ???
thanks

[ltusler]

I pull the engine and trans as a unit. Search for step by step instructions they are around. Its really not too hard. Leave the exhaust on too. Once out separate the trans, then mount the engine on a stand. Then pull the exhaust, separate at the headers, if the bolts (some have pressed in studs, don't break those) are too rusty just snap them and then start on the block.

[JFP in PA]

Originally Posted by Rich69

If the cylinder(s) walls are cracked Wouldn;t there be clouds of oil smoke from the exhaust and rough running ?
Noy sure how these heads crack ? is it from the cooling jacket into the oil thru the cracked head or must it also involve the combustion chanber ?
How can the oil and water be so mixed and still not foul the plug(s) ???
thanks

No. We have seen cars with cracked heads that never smoked or ran rough.

As far as the intermix, it all depends upon where the crack is, in the right spot you get coolant in the oil with no change in the plug coloration.

[JFP in PA]

Originally Posted by Rich69

Great thanks for the tips...
First I will pull the plugs and see what they look like.
Once I pull the cams out I will pressurize the cooling system
and look for leaking cracks in the head(s)
I realize that 19 PSI may not be enough pressure to reveal a crack in a cold head
But it may be worth a try I think ?? I don't want to pull both sides if only one head is cracked...

If you are going to pull the engine and remove one head, it makes no sense to not remove the other and check it as well. You really don't want to be doing this twice.

[Rich69]

thanks !
I am considering buying a hydraulic lift table from Harbor Freight
As I am working on the ground
Anybody know the weight of the engine and trans ??
I can get a 500 lb. lift table for only 149.
Possibly I could pull the trans. first and then the engine
to reduce the weight limit requirements...?
I can get a 1000 lb. table it but costs twice as much and weighs twice as much too...
anybody done this ??

[JFP in PA]

The engine is 440 to 485 lbs., depending upon how it is equipped. The trans is another couple hundred pounds.

[Rich69]

thanks for that info. !
So the 500lb. lift table should work...Harbor Freight here I come
OK here is a theoretical question for you 996 engine experts out there...
The engine overheated due to a loss of coolant from a blown (water) hose next to the right side upper valve cover... assuming that this correct which head was more likely to overheat first or worse when the water pump started pumping air?
Only an expert would know the answer to this...your thoughts ?

[JFP in PA]

Originally Posted by Rich69

thanks for that info. !
So the 500lb. lift table should work...Harbor Freight here I come
OK here is a theoretical question for you 996 engine experts out there...
The engine overheated due to a loss of coolant from a blown (water) hose next to the right side upper valve cover... assuming that this correct which head was more likely to overheat first or worse when the water pump started pumping air?
Only an expert would know the answer to this...your thoughts ?

Coolant flow diagram:



Because air is induced into the system, and it tends to rise and trap in the highest points of the system, the most common cracking point is adjacent to the valve seats and plug wells where the cooling jacket passages are smallest and the air becomes trapped:



Once air is in the system, and particularly if an overheat occurs, you have a pretty equal chance that either, or both heads are cracked. I'd pull them both.

[Rich69]

Good answer I believe you thanks !