ongoing overheating problems

[ss3964spd]

How, exactly?

Originally Posted by pascavone

Half open valves, will fill your intake gallery.

Rick, if the plugs look fine - all the same tan to slightly darker brown color, I'd rule out water in the cylinders. As I think Mike mentioned a gallon or two in the crankcase did not come from water getting past the piston rings.

From your description of water coming out of the back of the engine, that much water in the crankcase suggests to me that perhaps the intake manifold gasket(s) failed. The cylinder heads each have two water passages; 1 at the far front of the head and another at the far rear. The intake manifold covers and blocks off the one at the rear which forces all the water coming up from the block and into the heads to be pumped to the front of the heads. If that gasket(s) fails at those cylinder head to intake manifold water passage points water will definitely either come out visibly, go into the block invisibly, or both.

Dan

[pascavone]

since I changed my oil myself, after only idling my engine for 10 min, I can tell you you can fill up the engine to the top of the dip stick tube.

i used the pump and dip stick tube, but the pump would not pull the water, so I pulled the plug and it all landed in the bilge.

Note: since my boat is a fresh water cooled, it was easier to pin point the raw water, since the fresh closed look was in good shape.

[biggerseagar]

Pas .....please tell me you don't use those junky-***** fram oil filter....say it ain't so!

Roger

[mmwjr]

What Dan said has merit regarding it possibly being the intake. This would explain how a large amount of water can get into the oil and yet the engine still run OK.

The water jacket is at least an inch way from the nearest intake runner so water would probably not get into it.

Rick have you used a mirror to see whaere the water is leaking at? If it's the intake then it should be leaking between the intake and head.

[pascavone]

no that FRAM oil filter was my boat mechanic who was a Rinker dealer..... I changed it along with the water in the oil.

[mrxitmt]

I'm hoping you all are right I will pull the intake today.The shabby way the engine was put together I'm thinking that is the case ....Every bolt i have removed seems to be only a little more than hand tight .I know there are torque specs for the exhaust manifolds ..it took only one hand on a small ratchet handle to break them.I'm going to call Jasper today to see if I can find out who installed the motor!And by the way although the impeller in the OD looked ok there is much more pressure in the incomming water than before I replaced it , which may have caused the gasket to blow out. Wish me luck!

Rick

[mmwjr]

From what I have read the torque for the intake is done in 3 steps, 22lbs, 44lbs and then 66lbs.

Good luck

[ss3964spd]

Inch pounds, Mike?

Cuz 66 Ft/P is approaching cylinder head bolt torque.....

[mmwjr]

No that is foot lbs.

Head bolts are > 100 foot lbs.

[ss3964spd]

Huh. I can only relate to the BBC in my '66 Chevy as far as bolt torque goes. I'm almost positive that the intake manifold bolts get torqued to something like 25 or 30 Ft/P and the head bolts to 75 or 80.

I think I missed what engine the OP has. Nevertheless, the correct bolt torque is listed somewhere.

[mmwjr]

Ok my previous info is wrong, google doesn't always provide correct info.

Looking in my merc manual for 5.7L intake torque is 35 ft. lbs and yep cylinder head torque is 65 ft. lbs.

Sorry for the confussion

[mrxitmt]

OK so the more i dig the worse it gets..I decided to pull the heads after I found water in 2 cylinders and a compression check showed 160 150 120 The gaskets looked bad ..(Because the temp guage showed 160 the whole time the block was burning up ) then I saw what may be a crack in the cylinder wall (could be just an imperfection). Any way I,m not going to take any chances.My brother (a mechanical engineer) is going to get this dye and developer that will show any cracks . When I am absolutely sure the block is good I will start assembly. I just don,t want to have to do this twice .I am replacing everything that has to do with the cooling system.So far I havent lost my mind ..Yet

Rick

[mmwjr]

Rick can you post some picture of the potential crack? Also some pictures of the exhaust showing the interface between the manifold and elbow.

May be a scratch and not a crack. A crack would result in very low compression and would be the result of a dropped valve or broken piston. Blocks tpically crack from freezing but this is usually water jacket to the ouside of the block. The cylinder wall is rather thick and requires a catastrophic event to damage it.

[ss3964spd]

The 160 and 150 readings are fine, the 120 could easily be the result of a bad head gasket, which would also explain the water. Which cylinders dod you do the compression check on and which had water in them?

Agree with Mike, cylinder walls don't normally crack for no reason; a hard freeze can crack them or something hard gets into the cylinder.

The low compression reading can also be explained by a bad valve (intake or exhaust valve not sealing completely), and water in cylinders can also be cause by a cracked head. Be sure to have the heads completely inspected.

[mmwjr]

Dan is correct about having the heads checked. Burning water raises the exhaust temp and will melt te valve or valve seat which results in lower compression.

[mrxitmt]

Everything seems to check out ok so I am reassembling the motor.So far the heads are back on. Progress slow but sure

[mmwjr]

Cool, keep us posted and we always love pictures of the progress.