Pirrex

I got the engine back into the car now half a year later, and I was not in for a happy surprise. Yesterday i got the engine put into the car, and i figured it couldn't hurt starting it and running for like 30 seconds without coolant. Today i put the coolant in, and immediately noticed it didn't run perfect, pretty much like i was running on only three, and had white smoke coming out. I still thought it just might have been "normal". I soon stopped the engine, as i had a leak too. A while later i tried starting it again, but only got a small BAM, and it didn't start anymore. This i'm pretty sure means coolant in the cylinders.

Can you really blow a headgasket by running it for half a minute without coolant? What would be the smartest move right now, to put a little pressure in the coolant system, and see if air really comes out of one spark plug hole. Any input is welcome, if not anything else, bash me.

Paulyy

it's not recommended to run with out coolant but it for 30 seconds it wouldn't do much harm at all.

White smoke is never normal.

if i where you, i'd be pulling that head off and inspecting the damage. i can't think if anywhere else you would get a bang noise from other then under the cam cover or cylinder contact with the valves. possibly something smacking against the crank shaft but doubt it.

F18Rep

I don't think its the no water thing, but if you've ever held on to an exhaust manifold to locate a miss, you'll find the ones that are hitting get too hot to touch in about 3 seconds. Which is how I justified a IR sense gun.... my sympathies hombre.

PS...I'm pulling a 944 engine now and having deja vu, all over again. Its funny how the mind blocks out remembering the little pains and leaves that it-was-fun impression...;] Bruce

Pirrex

It wasn't really a bang noise, more of a POOFF, when it was supposed to start. I guess i'll start ripping it apart tomorrow, and i can't even explain how i'm hoping i won't have to lift the engine out again.

Tom M'Guinn

Before tearing it apart, check the basics. No coolant for 30 seconds is a non-no, even on cold start up, but no need to punish yourself tearing it down until you look into a bit more. Some things are easier to check with the motor still togetther. I'd start by pressure testing the coolant system to see where the external leak is coming from. If it gets under the timing belt covers, the belt acts like a little conveyor belt to the cap and rotor -- which kills ignition from the wetness. Also, since it went POOFF then didn't start, I'd check to make sure your timing belt alignment marks are all lined up still. Backfires and sputtering can be the result of the cam being out of time. If that's ok, then pull the distributor cap and see if it's wet in there and confirm that the rotor is still screwed on tight. If that's ok, then check the firing order of your plugs, and make sure all you fuel injector plugs are on their injectors nice and tight. If all that checks out, run a compression check. White smoke on start up could be as simple as condensation in pipes that have been sitting that long. Try starting with the plugs removed and see if you smell any coolant in the clyinders, and check the plugs for coolant when you pull them out. Double check all your vaccum hook-ups too. I once had an intake gasket that wasn't lined up right (only got a bolt through one of the holes) and it ran terrible on start up. Found that by pulling plug wires one at a time until I found the cylinder that wasn't firing.

Pirrex

I found the external leak, it was just the pipe just by the bleeder screw. I checked the cap and rotor, and all dry. Also didn't figure anything out from the spark plugs. Now when i tried again, it idled good, but didn't take any throttle, which can probably be explained, because i did break one vacuum line, so the DME and FPR didn't get any vacuum. But then again, five seconds after starting the engine, there was white smoke again. Got to start by getting a new banjo-bolt for the vacuum lines.

Edit: Oh yes, and the timing appears to be correct.

xsboost90

vac lines to the klr only work the gauge. THats it. Have you checked compression or looked at the plugs?

Pirrex

Haven't checked the compression yet, and will try pressurizing the system as soon as i get the equipment. I am however starting to think it might have been a false alarm, as i reconnected the afm, injectors, plugs etc, and checked all the vacuum lines, it runs great.

I do have a little smoke and a small amount of water coming out from the exhaust, but that might just be because i've had the exhaust outside for the winter. Also the black water coming out from the exhaust doesn't even taste a little like coolant.

lee101315

Speaking from experience:

Smoke is NORMAL starting up an engine after a rebuild. Anything from the lubrication used to install the pistons in the cylinders, to antifreeze falling into the exhaust system can cause that. It SHOULD clear up within a few minutes. If not, remove the spark plugs ( not the cylinder head ) and see which cylinder is smoking.

Running without antifreeze for 30 secs will do NO damage to an engine. Many newer mercedes have a clutch type of device that disengages the water pump for 3 minutes on a cold start to heat the engine up faster. Its not a smart idea to run an engine without antifreeze, but no harm will be done either

I suspect you damaged the harness while working on your engine. The wire insulation tends to become hard and inflexible, and moving it around will cause the insulation to fall off and short circuit ( especially the fuel injector harness )

I did have one 'genius' mechanic that worked with me who managed to damage the compression ring on the head gasket on a 944 before putting the head on the car, and that car burned antifreeze and smoke as soon as the engine started. Its not easy to do, but its possible. Pulling all four spark plugs if the smoking doesnt go away will tell you which cylinder is burning antifreeze.

Tom M'Guinn

Coolant is seriously poisonous to people and pets -- you shouldn't be tasting any fluids from the car, but especially coolant!

Pirrex

I had already gotten optimistic, that the car was fine, but no. Now i've pressure tested the system, and as i first was afraid, i have quite a lot of coolant coming out from plug hole #1. So i don't have much choise but to open it up.

Also problem getting to get the clutch working, even if it doesn't push out any bubbles when bleeding. How much is the slave piston supposed to move, when pressing the clutch pedal to the floor?

Pirrex

Well, the head is off, but no visual clue what's going on, so probably running without the coolant wasn't the reason for the leak. Don't know what else to do, but to try cleaning the block better, and install a new gasket. The head should be flat and good, as it was completely rebuilt.