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roberni

coolant leak and dense white smoke

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roberni

Hello,

I've bought a Wakesetter VLX 2008 in Juli this year. The impeller, the riser and manifold on both sides was brand new. Unfortunately it followed unwanted problems with the purchase.

The motor has a coolant leak. It emits dense white smoke which smells kinda sweet and it consumes coolant.

The first thing I did was to replace the manifold-riser gaskets on both side. I also replaced the manifold-motor block gaskets on both sides which I now realize in retrospect that was unnecessary. Anyway, none of this did help.

Then a mechanic helped me further on with the troubleshooting. He discovered a crack in the port cylinder heads. So we replaced this with a brand new one. The cylinder head gaskets on both sides was replaced and also the intake gasket. The motor was then started on land and it did no longer emit the dense white smoke. But after driving it for about 30 minutes on the water the familiar white dense smoke was back. So still a leakage.

The boat back on land the mechanic pressure tested the heat exchanger but found no leakage. He also pressuretested the riser-manifold gasket and the manifold-motor block gasket on both side but found no leaks here either. Then he examined the starboard cylinder heads and after a while discovered at least one crack in this one too. So this got replaced with a brand new one and the gasket was replaced ones again. Started on land the motor did not emit the dense white smoke but ones again after about 30 minutes driving on the water the dense white smoke appeared. Still a leakage...

Now, does this mean that the last leak source is in the engine block? Or have we forgot something in our troobleshooting?
I would really appreciate some good tips. Most of the short wakeboard season has been ruined because of this. Thanks in advance!

Best regards from Norway :)

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Jimmypooh

Sounds like the engine could have overheated and warped. You might need to get it re-decked. I'm no mechanic but I'm sure others will chime in.

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zone 5

There has to be a root cause of why both heads were cracked. You stated that you at first only found one head cracked, but replaced both head gaskets. Are you saying that at that point, only the one head was cracked? Were the head gaskets blown? Where were the cracks in the heads?

SB chevy heads don't usually just crack. freezing of course could cause it. I suppose if you detonated the motor bad enough and blew a gasket you could cause it too, but I've seen that in only very high horsepower BB engines, not stock SB ones that are computer controlled to retard timing and not allow this to happen. I'm not sure if your engine has iron or aluminum heads. If they are iron, they have to really overheat, and probably do it multiple times to cause a warp. Aluminum heads will warp sooner. Usually this blows the gasket first. but if it was bad enough I suppose the deck could also warp.

If the mechanic pressure tested the heat exchanger by itself, then you do not know what the condition of the block itself is, Based on what you said has been replaced, and "assuming" that it was all done correctly, that only leaves the block as the source of the leak.

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roberni

There has to be a root cause of why both heads were cracked. You stated that you at first only found one head cracked, but replaced both head gaskets. Are you saying that at that point, only the one head was cracked? Were the head gaskets blown? Where were the cracks in the heads?

SB chevy heads don't usually just crack. freezing of course could cause it. I suppose if you detonated the motor bad enough and blew a gasket you could cause it too, but I've seen that in only very high horsepower BB engines, not stock SB ones that are computer controlled to retard timing and not allow this to happen. I'm not sure if your engine has iron or aluminum heads. If they are iron, they have to really overheat, and probably do it multiple times to cause a warp. Aluminum heads will warp sooner. Usually this blows the gasket first. but if it was bad enough I suppose the deck could also warp.

If the mechanic pressure tested the heat exchanger by itself, then you do not know what the condition of the block itself is, Based on what you said has been replaced, and "assuming" that it was all done correctly, that only leaves the block as the source of the leak.

Thanks for reply.

The first crack we found was on the head on port side. This crack was between a coolant channel and a cylinder. It found itself at the very top so we saw it by looking straight down on the cylinder. When we found this crack we unfortunately did not check the other head that well. That is, visually we could not find anything wrong with it. We replaced both head gaskets to make sure that they where not part of the problem. The mechanic said that the port side head gasket showed signs of a leakage between two cylinders.

When this repair proved to be adequate the mechanic examined the starboard head closer. He dismantled it and then I think he filled all the exhaust channels around the cylinders with some kind of alcoholic liquid. The level of this liquid started to fall on at least two of these channels which indirectly showed cracks in the material.

Unfortunately I'm not sure if the heads are iron or aluminium. At least I know they are called Vortec.

It's more likely that the cracks has appeared due to overheat and not cold. I've bought a MerCruiser Scan Tool kit ( http://www.rinda.com/marine/mtspec.htm ) and by connecting it to the motor computer it tells me that the motor has

become overheated a total of eight times. Now, based on this I'm wondering if it is possible that symptoms of cracks first can appear after the last case of overheating?

Edited by roberni

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Falko

Do a compression and leak down test on the cylinders. You may have a cracked cylinder wall as well. Sounds like this engine was either extremely overheated or frozen (which is odd for a closed system unless they never checked anit-freeze levels.)

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zone 5

as stated above by Falco, a-leak down and/or compression test is where you need to go now. overheated 8 times. is definitely not a good thing. and where the heads cracked is unique most cracks and I usually see are on the valve seat area. As ess stated, with closed cooled you usually don't get cracked heads or blocks but until I knew you had this many over heats it was just one of the more common ways for this many cracks.

Sent from my droid in the boonies

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