Minnesota Classic Glastron Forum
General Category => General Discussion => Topic started by: cv-19 on December 03, 2017, 08:36:40 PM
-
Took the boat out yesterday and developed a heating problem thats strange .CV-19 JET BOAT.
It runs 140-150 degrees normaly but on my return trip noticed 220 and thought I lost the belt.
Belt was on so I checked exhaust manifolds and hoses for temp. and they were normal to the touch .
NO weeds in the jet pump intake so I checked to see if it would get on plane . As soon as I took off
the temp gauge dropped like a rock to 100 for only10-15 seconds then right back up to 220 all within
30 seconds.Thought t-stat so I removed it ,still have the same problem. Took off supply water hose flushed
it out with garden hose and also flushed out to motor with good flow,still same problem.This motor has a water pump
but I wouldn't think a problem there would cause the huge temp. swing. Pump is not lose or leaking .Tomorrow will check it out more. Looking for
thoughts and imput. Never seen this problem before.
-
Just checked the oil and it looks a little cloudy may have a little water in it. Problem maybe head gasket or cracked head . Wouldn't think it would run that hot being lake water cooled?
-
We'll certainly could be a head gasket for water in the the oil.
As for the overheating I would maybe suspect a gauge of temp sensor.
I also had a similar problem one time chased it for quite awhile ended up that the risors on the exhaust manifolds were plugged up, removal and a soaking in mutation acid cured the problem.
-
Its that hot I can hear water boiling when I turn it off.
-
Ok thought you said they were normal to the touch.
-
That's what odd the manifolds are not hot. Tested it again today, has to have a bad gasket or head leakage. Bypassed the oil cooler just to see if it was the problem. Used a temp. gun and its 105 + - 2 degrees on both manifolds risers. The intake manifold
is 195 on one side by the temp. sensor and the other side is about 100. Got to be exhaust getting in causing problem.
-
water pump shot ? thats the only thing moving water through the motor with the take up system ?
-
That' was on my check list GIL but the water in the oil and it now has a miss in it makes me think head or gasket leaking.
Water can get into the oil pan from the water pump, had that happen before . Going to pressure test it tomorrow.I am an AC tech
and plan to use Freon to pressure test the motor. 15-20 PSI then remove spark plugs and use electronic leak detector to check .I think this will
will let me know.
-
Also strange is that the tstat housing is 100 degrees and 2 in. away is the temp sender that is in the intake manifold and its 195 and the hand touch proves the temps are correct.
-
Did you boil the t stat check it is working correctly?
-
Yes its a 140 and opens full at 150 .Took it out for now and it makes no difference.
-
100 degrees at one point, and 190 2-3" away can only be two things, obstruction or no water flow. Another remote possibility is the temp sensor is bad. Only time I've heard water boiling in an exhaust was when the impeller got destroyed, but that was an I/O. Not a jet guru, but the block has to receive water from some pressure source.
-
Temp sensor good and its accurate. Tested it.
-
Water supply is from the jet pump .
-
Failed the pressure test. #1 cylinder is the problem all other cylinders OK. That's very close to the temp sending unit
and I think thats why it was only hot in that area.
-
Time for a new motor! The water pump impeller split and came apart and off the shaft blocking water flow
that was the cause of the big temp swings. The greater water flow from the jet pump when RPM increased
supplied more water to the hot motor and cracked the block. Heads are good had them checked.Head gaskets
both looked good and sealed well.
-
Sorry to hear the temps caused the block crack. At least the heads are good, hopefully find a decent short block to replace yours.
-
Bummer !
New short block or rebuild used one ?
-
I have another 455 that was in the boat before years ago . Its been taken apart and my plan is to rebuild it .
-
Found 3 in. crack in # 3 cylinder wall.
-
Ouch, can it be sleeved as an option, should the rest check out ok?
-
Did it freeze ?
LOL ... sorry no funny ...
-
I thought about having it sleeved, but since it was over heated I don't trust the other cylinders
even if they check good now. I have another block that I am going to use
-
Probably a wise decision, metal undergoes a lot of change when quenched. Hopefully have everything back together when the water is soft again.
-
The White along the crack is how long it is. Water pump impeller blocked water flow to that side of block