Symptoms leaking head gasket or cracked cylinder head

[shogun]

Sometimes a leaking head gasket or a cracked cylinder allows a concentrated mixture of ethylene glycol coolant to leak into the crankcase.

An internal leak can result in coolant entering the crankcase.
The result is varnish-like oil that can plug oil rings and ruin valve guide seals. This sticky substance can actually seize the crankshaft (called thermoplastic seizure). The problem will happen again if the source of the leak is not found and repaired. Then, the engine and cooling system must be flushed. The condition will be very evident when a valve cover is removed.


A blown head gasket caused the oil to take on this appearance.
When a leak occurs between an oil and water passageway, pressurized oil (approximately 30 psi) will force its way into the cooling sytem (approximately 15 psi). The engine will overheat and pour a messy oil and water mixture from the radiator overflow.

A leaking head gasket or a crack in a cylinder head or bore can result in an internal leak.


When there is an internal leak, coolant will flow into the cylinder when the engine is off and during the intake stroke. During combustion, exhaust gas migrates into the cooling system.
When there is an internal coolant leak, the coolant level often drops. Leakage from the outside of the engine is not evident. When there is an internal leak, coolant will flow into the cylinder during the intake stroke and when the engine is off. During combustion, exhaust gas is forced into the cooling system and can appear as bubbles in the radiator.


Exhaust gas leaking into the cooling system can result in bubbles in the radiator.
There are several tests that can be done to confirm an internal leak.

•Look for bubbles in the radiator when the engine is warm and under a load. Rapidly accelerating the engine is usually enough of a load to produce the bubbles. Internal leakage can be spotted by installing a pressure tester on the radiator filler neck of a warmed-up engine.

A pressure tester installed on a radiator filler neck.
•A leaking head gasket will not always show up on a pressure test. ablock check tester or an infrared exhaust analyzer can also be used to check to see if there is exhaust gas in the coolant.
Cracks tend to leak more when the engine is cold. After warm-up, the crack closes. The radiator cap will blow off when the pressure from the combustion leak exceeds radiator cap pressure. To see if combustion pressure is indicated, put the radiator overflow hose into a container of water while the engine runs.


Air leaking into the system results in air bubbles coming out of the overflow tube.
If bubbles are evident, combustion pressure is getting in. Bubbles could also be present because the cooling system is drawing in air. To eliminate this possibility shut off the engine, loosen the drive belt to the coolant pump, and repeat the test. If the bubbles disappear, air was getting into the pump. When there is air in the system, corrosion occurs at about three times the normal rate. Air can leak into the cooling system through a leak in the lower radiator hose. The lower hose is the suction hose, where coolant is drawn into the pump. Air can leak in even though water may not leak out. To test a cooling system for air leakage, tape the filler neck of the radiator closed. Put a hose from the radiator overflow pipe into a jar of water. With the engine running, look for bubbles in the jar.

Sometimes an internal leak can result in one or more cylinders filling up with coolant after the engine is shut off. This happens because the radiator cap continues to exert pressure on the coolant, even though the engine is off. If the engine stops with a piston down in the cylinder while both of its valves are closed, the engine will be hydrolocked and the crankshaft will not be able to turn. If the spark plugs are removed, the engine will be able to crank. Water will pour out of the offending plug hole.

After disassembling the cylinder, inspect the head gasket. Look for evidence of coolant or oil leakage. If the gasket was sealing properly, there will be a well-defined line of thin carbon around the combustion chamber on both the head and the block. Carbon deposits on the metal rings of the gasket or a poorly defined combustion seal indicate possible compression leakage.

Coolant leaking from a bad head gasket or cracked cylinder head can also contaminate an oxygen sensor. Coolant leaves a white flaky deposit that sometimes has the sweet smell of ethylene glycol.


Here with pics, courtesy of Autozone Repair Info
http://www.autozone.com/autozone/rep...btitle=inspect

and here
http://www.arrowheadradiator.com/hea..._leak_test.htm
Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)



One method is to use a block tester, also known as a combustion leak tester, to determine if you have exhaust gases in your cooling system. A combustion test kit can be found at your local NAPA, auto parts store. The part number is 700-1006. The price for this part is less than $50.00. Exhaust gases in your cooling system can suggest a head gasket leak, a cracked block, or a warped head, etc. A leaking head gasket can create excessive heat and pressures exceeding the ability of the radiator’s cooling capacity, and should be repaired immediately to avoid additional costly repairs. Head gasket leaks are generally secondary to another problem, such as a clogged or leaking radiator. Make sure you identify and repair or replace the original problem or the vehicle may overheat and cause the head gasket to fail again.

To do the test, add the blue detector fluid to the (block-tester) plastic container according to the directions, and place it onto the radiator filler neck. The squeeze bulb is placed on top of the reservoir and squeezed repeatedly (Some block testers, have a tube that connects to a vacuum line instead of a squeeze bulb). Squeezing the bulb will draw air from the radiator through the test fluid. Block tester fluid is normally blue. Exhaust gases in the cooling system will change the color of the fluid to yellow, indicating a combustion leak. If the fluid remains blue, exhaust gases were not present during the test. The vehicle should be started and at operating temperature before performing the test. Vehicles with head gasket leaks may overheat, and purge hot water and steam out of the radiator. Perform this test, at your own risk, and do not do the test, unless you are experienced and are wearing clothing and equipment to protect you from burns, or injury.

Sometimes, engines with a head gasket leak show steam, water or white smoke exiting the exhaust pipe. Other symptoms include coolant in the oil, or oil in the radiator coolant.

headgasket failure
http://www.arrowheadradiator.com/hea...et_failure.htm
and on youtube shown
[ame]http://www.youtube.com/watch?v=CrA4DOHTFJk[/ame]

http://www.blockchek.com/


BTW: I am interested to buy one of these Combustion Leak Tester Kit With Tester & Fluid, also called block tester kit, or Combustion Leak Detector Tester

does anyone have a used one which he does not need anymore?
Or best place to buy?
I am not in urgent need, just to have it in my tool box

[mcnickolas]

Based on my experience when a head gasket / cylinder head gasket starts leaking, the engine motor smokes a lot and most of the time it over heats. If there's no symptoms like this. It’s possible that cylinder head/cylinder head gasket is not the problem. Other parts do… it maybe an internal hose or a clamp has a leak.

[shogun]

2 weeks ago I had noticed a blown head gasket on my wife's 2001 Nissan Micra K11, it leaked a bit of engine oil to the outside of the engine. Further noted that when the car was parked a long time, it smoked more than usual and when I hit the gas pedal it accelerated slowly in the beginning, so probably also the cylinders had coolant leak into the cylinders.
Removed the cylinder head, 1 head bolt completely cracked, 6cm with thread from total 16 cm stuck inside the engine block deep, no chance to get the bolt out with a simple bolt extractor. Another bolt was also cracked.
New bolts, head gaskets and maybe the cylinder head checking and machining would be more than the car was worth, so it was decided to give it to the parts disassembler. Replacement is a Nissan Micra K12 e-4WD from 2004 with a 1.4 Ltr engine with 98 HP and only 31kkm.
Interesting 4 wheel electric drive system from Hitachi : Development of Simple Driver-friendly Electric 4WD System
The problem with mechanical 4WD systems is that they require a bulky propeller shaft and transfer case to supply power to the rear wheels which reduces cabin space and luggage room in the vehicle, and the increased mass and added friction in the drivetrain
results in significantly lower fuel mileage compared to 2WD vehicles. To gain the benefits of 4WD without these drawbacks, Hitachi developed an electric 4WD system using an electric motor and an alternator (a synchronous generator). main power source via the junction box for the DC motor that drives the rear wheels. The 4WD control unit controls power generation of the water-cooled alternator and motor shunt wiring control based on the driving conditions.
http://www.hitachi.com/rev/pdf/2004/r2004_04_102_3.pdf

Outstanding start-off acceleration and driving stability on snowy and icy road surfaces
http://www.nissan-global.com/EN/DOCU..._tech_e4wd.pdf

Is this a hybrid? Yeah. Think of it as a mild series or serial hybrid, which is a kind of hybrid that uses a generator instead of a battery to power the electric motors. Wait a minute, you might say: aren't four wheel drives less efficient than two wheel drive cars? Yes but e-4WD is very light and compact because it's electric.

http://www.autoblog.com/2008/02/02/h...ee-e-4wd-work/

[mitch23]

As much as I love my e32, love wrenching on it, I also understand the only v12 gets a bad wrap as unreliable cause of the maintainence, but in all reality I am starting to believe that actually they might be at least a little right, everyone with a 750il seems to have done/planing/are in the process of a head gasket job, is it just my bad timing coming into the world of the m70 or is this no coincidence and a serious problem area on our cars.

[shogun]

M70 is no problem with that in general, quite rare with head gasket probs, the M30 has much more probs there. In our wrenching group with >10 M70 and Alpina B12 we never had to replace any headgasket in more than 15 years we are working together now. But let's face it, the youngest E32 is now >20 years old and there is a need to repair/service/care certain items, then they will last even longer.
I have the feeling cars produced now will not last that long as our E32. Interesting article on this on FORBES: cars-that-can-last-for-250000-miles http://www.forbes.com/sites/jimgorze...-250000-miles/
Today’s cars are built to last as long as 250,000 miles or more with simple routine care,” says ASE-certified Master Automobile Technician and Chicago Tribune auto-service columnist Bob Weber.....

[Lucihale]

Shogun, thanks a ton for this! I have an e36 M3 with an s52 that is really hard to start in the morning, but ONLY in the morning. I'm gonna try that block testing liquid since I've been trying to diagnose the possibility of a small internal coolant leak.

[shogun]

Maybe your fuel pump check valve is bad, allowing the fuel under pressure between pump and engine to run back into the fuel tank. The check valve is inside the fuel pump. https://www.bimmerforums.com/forum/s...k-valve-repair

[pgib8]

a tricky one is if there is a small leak that lets cylinder pressure into the coolant system. no white smoke, no weird oil, no typical symptoms until you take that multi-hour trip on the highway and the low-coolant light comes on.
more info and some tips here: http://forum.e46fanatics.com/showpos...2&postcount=22

[Fatandre]

I have a small question.
This summer I had my car after taking it for a hard drive in 35Celsius and when I stopped and turned it off the temp started rising like crazy. I put on the ventilation on max and hot and it rose to lets say the middle between the middle and the redline on the temp gauge. Should I worry something happened. It has not happened again since then.

[shogun]

35 degree C is nothing special for my M70 in summer and when all is working correct, the temp needle stays at 12 o clock and does not move at all. I had a similar problem abt 5 years ago, did the same as you did = switching on the heater to full and that helped to keep the temp between middle and redline.
Turned out the problem was with the aux fan, contact problems at the spades of the relays = aux fan did not work on high. On another 750 we also found the aux fan not working, there it was a contact problem on the plug of the wire loom which goes into the aux fan behind the front grill. In both cases contact enhancer did fix it.
If the temperature rises while engine is running in traffic jam or in front of red lights only, in most cases the flwg should be inspected
- visco fan
-aux fan, both speeds, suspects: relays, contact problems, temp feeler on radiator, also on older aux fans the magnets inside the motor tend to get loose and block the fan motor http://kharon.suomiforum.com/www/bmw...594_magnet.jpg
or in worst case the fuse does not blow of the aux fan as the A is just over the limit, and all wires melt between aux fan and fuse box including the fuse holder, happened to a wrenching buddy on his E32 750.
The aux fan has to work always hard and is subject to wear, so better replace the aux fan before it is too late.

As the BMW cluster temp gauge works on a so-called tableau (actually the temp shown is not exactly the real temperature), temp must rise or go down much before the needle moves. Inside the cluster chip there are 5 temperatures programmed (called temperature gauge support values), 2 are in the middle, only when the temp exceeds these set support values/temperatures, the needle moves, that means for example (depending on the programmed temp) shown 85 degree C at the middles means 85 plus/minus 10 degrees = between 75 and 95 degree C., explained here on page 6 http://www.e38.org/e32/BMW_pdfs/INST_info.pdf