Guinness
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 posted on 13/4/09 at 11:27 AM |
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Cooling system problem
Stuck a bottle of K-Seal in the Indy on Saturday, replaced the fuel hose, and went out on Sunday for the Big Breakfast.
Car ran fine all day, but it was obvious from the temp gauge I was having problems, so I kept it about 75% effort / pace all day.
It took an age to warm up in the morning, but I initally put that down to the very low ambient (2C). But then later in the day it was running very
hot.
I couldn't touch the water pipe from the thermostat to the rad, but the return was stone cold.
So I got home, let it cool down and drained the cooling system. Took the thermostat apart and tested it, works fine, opens in a mug of hot water.
Then I flushed the system with a hose from the thermostat down to the bottom hose through the rad, no obvious blockage or gunk coming out.
So I flushed the system from the hose, through the block and water pump back to the bottom hose. Again ran straight through, with no obvious
blockage, delay or gunk.
So I guess with a working thermostat, no blocked pipes, or waterways, it's a bust water pump. Removed the clutch slave to get to the water
pump. Replaced the water pump with a spare. Re-filled the system last night to check for leaks. There is no obvious damage to the pump, the
impeller is still attached to the shaft.
Will go out later and run it up to temp to see if that has fixed it.
However, the water pump is run off a drive shaft that comes off the end of the oil pump. I guess the oil pump was running yesterday, as I had decent
oil pressure all day, and there is no way it would do 250 miles with out oil.
I couldn't turn the drive shaft from the oil pump to the water pump at all, so it's either seized, or won't spin without the engine
turning.
So, assuming that the "new" pump doesn't fix it, I can either drop the sump and replace the oil pump (in an effort to free the stuck
drive shaft) or forget the water pump altogether, and plumb in an external 12v electric pump.
What do we think? Is my fault finding / diagnosis process correct so far?
Cheers
Mike
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nitram38
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| posted on 13/4/09 at 11:55 AM |
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Not sure what engine, but your oil pump shaft will be difficult to move as it is attached to the rest of the engine!
Briefly turn the starter over and see if the oil pump shaft moves.
An airlock is more likely the cause of your problem.
Have you got an expansion bottle in your system?
[Edited on 13/4/2009 by nitram38]
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John Bonnett
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| posted on 13/4/09 at 12:00 PM |
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quote; An airlock is more likely the cause of your problem.
I agree with Nitram. Even if the water pump was doing nothing I think you would still get circulation from thermo-syphon. Sometimes, air can be
difficult to remove but my advice would be to persevere along those lines certainly to start with.
[Edited on 13/4/09 by John Bonnett]
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nitram38
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| posted on 13/4/09 at 01:16 PM |
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If you haven't got an expansion bottle/tank, then fit one. It should be the highest point in your system.
The bottle should have two pipes. Probably a 16mm OD at the bottom and an 8mm OD at the top.
You should tee off your bottom rad hose (the one that returns to the pump) and plumb that into the 16mm pipe.
For the 8mm, tap off somewhere in the top hose to the rad or the top of the rad. You can also tee the 8mm into a cylinder head waterway or before the
thermostat.
The different sizes and pressure difference ensure that there is a constant flow into the bottle via the 8mm and back out via the 16mm hose.
Not only does this allow for the water to expand when hot, any air will collect in the airspace above the water level, especially when filling from
cold when the stat will be closed.
A closed stat is the most common cause of an airlock.
That is why you often see mechanics running the engines with the cap off (on none expansion systems) and topping up, but this can be dangerous, not
just from getting burned, but the cold water hitting your hot cylinder head and cracking it.
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Guinness
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| posted on 13/4/09 at 04:28 PM |
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Well something worked.
Just ran the engine up to temp. Thermostat opened, rad got hot. Bottom hose warmed up. Fan kicked in.
All seems well in Indy land.
Will let the water out in a while and refill with coolant.
Then test again.
Mike
(I have plumbed the car exactly as per the installation in the bike, but with a much bigger radiator)
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mr henderson
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| posted on 13/4/09 at 04:50 PM |
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One quick test for air in the system, which may have been the problem before, is to squeeze the hoses. As long as they are not too stiff you can
usually tell if there is water or air in them.
CBS do a good little kit for about £55 if you get filling/bleeding problems in the future
John
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