white smoke out the tailpipe - 69 280 sl
 

our 280SL made a 'funny noise from the engine' and then my wife
noticed 'lots of white smoke' out the back of the car. groan.
Luckily she has learned from the first 'smoke' incident that 'smoke
is bad' and she pulled over quickly.

she indicates that the smoke was white to greenish white, no oil
color or smell to it. the radiator reservoir is empty, but no sign
of oil in there either. there is no water on the dipstick, nor any
signs of leaks around the engine block.

I am thinking that the issue is likely a head gasket, but am
wondering about my troubleshooting procedures.

My plan is to pull the plugs and examine, then compression test - by
hand cranking - each cylinder to see if there are any noticeable
issues. then what? is the head gasket on the 110 engine a big deal,
little deal, or something left to Dr. Mercedes at the classic car
hospital?

is there anything else that I should be looking for? I'm trying to
think of happy thoughts and little things it might be, but cannot
think of any other way that water gets out the tail pipe that does
not sound serious!!

thanks

tom

Headgasket is not a big deal on a '69 280SL, unless the car has or had A/C. The reason for it blowing might be a bigger deal.
The engine is an M130, not a 110.

Refill the radiator and leave the cap off. Let the engine warm up and see if water is burbling out of the radiator. That would be air bubbles (and an obvious leak).

You've pulled the plugs? I doubt that you'll find a smoking gun there (like green drops on them), but if too are super ugly and the rest have a delicate patina of grey ash, then you know which cylinders are in trouble.

Also, you won't necessarily find water on the dipstick, since oil floats on water. However keep looking for a chocolate milkish foam on the oil filler cap and the dipstick forming when the engine cools down. That would be bad.

Replacing a headgasket on the M130 is straight forward. Drain the engine fluids and unblot everything, send the head to a competent and experienced machinist withe the cam tower still attached and the valves in and then put everything back in the right place. Worse thing that happens is you do it wrong and have to take things apart again. You can't make it worse.

Having A/C adds a few bolts and means a bit more heavy lifting in a tight space.

-CTH

I went through this on my 71 250C that also has the M130 six.

First head was warped and already planed down to min thickness, so I couldn't use it.

Replaced the entire engine with another from a sedan, then a year later had the valve stem seals go. This head, while not already planed or warped, exhibited significant galvanic corrosion and water jacket plugging.

Chuck Taylor sent the head to Metric Motors for weld buildup and we were able to save it.

My experience on this engine to date is to expect additional problems once the head is off. Be prepared to see the anticipated cost at least double.

Jim

whimper
 

thanks guys...that is certainly not the best news of the day, but I thank you for chiming in.

now, for the diagnostics and troubleshooting....am I on the right track with what to look for [see above] or is the diagnosis solid enough to start pulling the head and look inside to see what the damage is?

and, if I need to pull the head, is Haynes Manual good enough for a guide or should I try to come up with a shop manual?

maybe someone here has already described the procedure in some detail?

thanks all...

tom

Why don't you just do a leak-down test.????????????

Another easy check is to pull the plugs and compare.

A cylinder that is seeing water will often have a very clean looking plug relative to a used one that is not seeing water.

Remember the trick about slowly pouring some water down the carb throat to clean carbon off the piston and valves?

Jim

"Funny noise at the front of the engine and then lots of white smoke" sounds more like a water pump seal to me. I suggest putting water in the radiator and looking for a leak. Could be that it's not a head gasket at all.

Agreed. "White smoke out the back of the car" doesn't necessarily mean "White smoke out the tailpipe". Could be a blown hose spraying onto hot exhaust as well.

if the head is warped often they can be straightened with heat and brace devices. My favorite machinist straightens them all the time. The mercedes engine really should not be planed straight because of the cam towers. Planing a warped head straight on the mating surface will result in cam towers out of line causing undue wear and stress on your cam.