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Recommended Posts

Posted

Hi all

This is a follow up post from my last one ( A picture is worth a thousand words)

Well had my 996 checked out by PCI & also by a very respected indy.

PCI said that the mixing problem could be, due to an Oil Cooler problem,

it might need a new Oil Cooler unit? & the indy say's that it is for sure a "Cylinder Head Problem"

That it does not need a new Oil Cooler unit because it looks very NEW?

So of I go back to the dealer where I got the car (whit my reports) & he's not happy & said...

There was a new Oil Cooler unit put into the car, (Me,so it's not that) & that if there is no smoke & if the engine is not

over heating that it's NOT a Cylinder Head Problem, that the fluids just needs to be bleed from the engine,

that it's condensation in the system????

So I need some Porsche Forum HELP & ADVICE, what do you guys all think?

Does the engine always have to be, over heating & have blue smoke, to say it has a Cylinder Head Problem, (which my 996 does NOT have)

or is Oil & Coolant mix enough to suggest that's its the the beginning of a Cylinder Head Problem????

Thanks

Posted

You should have a leak down test completed. That should confirm if you have a cylinder head problem or not. You should also get your oil tested to determine for sure if you have coolant mix with it or just water from condensation.

In your earlier post you said your coolant light started flashing. That’s what happened to my car and I ended up having to replace the engine. I never found out for sure what was wrong with my engine but the most like problem was a cylinder head.

Keep us posted and good luck.

Posted (edited)

The first thing I would do is flush both the oil system and coolant system. It will then be easy to see if you have any intermixing problems or it was just leftover from your oil cooler problem. Fast and cheap.

Edited by 1999Porsche911
Posted

My engine never did smoke at all. I'm guessing from the blinking coolant light, that your coolant level was very low, due to consumption by the engine. I had that same issue, and required a replacement. Just like Lee above, I don't know exactly what was wrong due to the fact you can't open the engine without losing your core return.

Good luck.

Posted

Thanks guys for your reply's

Jee what is a Leak down test?

Flushing out both the oil system and coolant system, (to see if you have any intermixing problems)

seems tempting but I think it has already been done, I will anyway mention it...

God I just can imagine how you guys felt when you here that you need a new engine, I've been told but just don't

want to believe it, & am trying all other options first.

I don't know about in the US but in Ireland a new 911 engine cost about €24,000 (inl, fit) that's around $35,000

Thanks I still have the warranty, this is maybe why the dealer is not answering the phone...

Posted

A leak down or "cylinder leakage" test is similar to a compression test in that it tells you how well your engine’s cylinders are sealing. But instead of measuring pressure, it measures pressure loss.

A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine’s firing order.

A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.

An engine in great condition should generally show only 5 to 10% leakage. An engine that’s still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

The neat thing about a leakage test (as opposed to a compression test) is that it’s faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.

If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.

If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire).

Posted
A leak down or "cylinder leakage" test is similar to a compression test in that it tells you how well your engine’s cylinders are sealing. But instead of measuring pressure, it measures pressure loss.

A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine’s firing order.

A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.

An engine in great condition should generally show only 5 to 10% leakage. An engine that’s still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.

The neat thing about a leakage test (as opposed to a compression test) is that it’s faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.

A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.

A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.

If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.

If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire).

Lee:

Thanks for the excellent summary. Very informative, very educational, and very succinctly stated.

Regards, Maurice.

Posted

Yeah cheers, thanks, Lee

I've just copy/paste your explanation for a print out,

(will sort out the royalties with you, an other day :) )

I think it will come in very handy when I go to the garage.

watch this space, will keep you's all posted guys A.S.A.P

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