4fuelishpleasure

I think that I have a partial blockage on the starboard side of the block. The water is taking the path of least resistance and traveling through the bypass on my crossover. If I block off the bypass and remove the thermostat, everything runs cool. I flushed the block the best I could with a garden hose and the hot side of the block is definatley flowing less water. What could have caused this blockage? Sand? Rust? I haven't had an impeller failure and the oil cooler wasn't plugged. I do operate on a fairly shallow sandy lake and every once and a while the prop kisses the bottom. Where would the sand build up in the block if that was the problem?

Audiofn

What is your motor set up (size, hp)? I have heard that crossovers can cause stuff like that. I would assume that you have some kind of flow issue but maybe not a blockage because you said you can get it to run cool.

CIG3

Which way are you flushing the block? The best way is from the bottom up. Pull the block drain and cross over and flush upward floating any sand rust out.

Also check to make sure that the hose from the bypass is not kinked or colapsed.

Fixxxer22

Oh yeah, Welcome to OSO!

Rookie

iTrader: (4)

Did you just add the crossover and now having this problem or did it run good before with the crossover. When I added crossovers to my engine the head over #7 and #8 cylinder would get extremely hot and I started sticking exhaust valves and then hitting pistons. I had to drill out the back cooling ports of my intakes to get adequate flow through the cylinder heads for cooling.

ezstriper

just had a pair of small blocks apart and the coolant passages were full almost up to the heads, took lots of work and a pressure washer to get them cleaned out and would be impossible with the heads on, so ???

4fuelishpleasure

Everything was working fine before I installed the crossover. I think the water pump was circulating enough water to mask the problem. I have gotten into sand in recent years and had to use a hanger on the drain plug to get the water out of the block before winter. When flushing, I removed the crossover, the thermostat and the block plugs and flushed in every possible direction. I understand that the sand can really pack itself into nooks and crannies. I wonder if I should pop out the block plugs, maybe then I can get the coat hanger into different areas and have better access to flush? I'm not possitive that sand is the issue but the one side of the block is definately not flowing as much volume as the other. and it's a GenV,454mag, moderate cam, Gil exhaust, dry pipes, low hours (200) but older motor (18yrs)

Audiofn

You almost always need to put a coat hanger in to get the block to drain. So that is no suprise. Why did you put the crossover on? From what you are saying you have for power I would go back to a stock water pump.

4fuelishpleasure

I know that I could get rid of the crossover and re-install the water pump. Fortunatley I'm not losing precious time on the water. I am currently running with the bypass blocked and the thermostat out. I still would like to find out what is causing the problem. Water temps can be cold early and late season here in Minnesota, it would be nice to run a thermostat.

Rookie

iTrader: (4)

Even with a clean block on a fresh rebuild my crossover caused me problems. If I had to do it all over again I would have left the circulation pumps on. I now have the back ports on the intake drilled out and 3 holes in my thermostat to proprogate flow. With the bypass blocked off. I maintain ~130F water when idling. I have H2O pressure gauges.