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TwelveVolt · 12-08-2018, 06:01 AM

It looks like I can reach the coolant filter on the Cummins ISC block from above. I have always had this done at shops before and am wondering how much coolant spill to expect if the engine has not run for a few weeks. Will it be just what is in the can, or will it start siphoning out?

Thanks

mackwrench · 12-08-2018, 07:41 AM

There's a plastic 1/4 turn Valve you can turn to stop flow to filter/conditioner. It's made into filter head. Should be able to turn it by hand but, you may try a pair of pliers to turn it, but be careful, it'll snap if it's very hard to turn,
Hopefully your regular service tech was using it and it'll be fine.

However to answer your question, you will lose a small amount of coolant, plus what's in the filter.
Place a small drain pan under it, have the replacement filter handy and swap it out. Put a little out on the filter o-ring and tighten by hand.

mackwrench · 12-08-2018, 08:41 AM

......also change filter/conditioner before radiator cap is removed. That help slow coolant flow from filter head while old one is off.

Ray,IN · 12-08-2018, 05:39 PM

The type coolant you use will determine the filter to buy. I changed mine from underneath, didn't want to chance dripping anti-freeze on the bedroom carpeting, it washed off me.

rvtips · 10-29-2021, 10:23 PM

Quote:

Originally Posted by mackwrench

......also change filter/conditioner before radiator cap is removed. That help slow coolant flow from filter head while old one is off.

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I thought it was the opposite.I always take the coolant cap off.I would think if you left it on there may be some pressure in the system.

CountryB · 10-30-2021, 05:13 AM

Quote:

Originally Posted by rvtips

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I thought it was the opposite.I always take the coolant cap off.I would think if you left it on there may be some pressure in the system.

Your right, you don't want any pressure in the cooling system. Either let the coolant cool off completely (if its hot from driving) or remove the cap to relive any pressure then reinstall it. The idea is to leave the cap on so air can't enter the system while your changing the filter. When air can enter at the top, the coolant drains fast. With the cap on, the coolant drains slow (like glug, glug, glug). Same as when you drain the oil on your car/truck, if you leave the oil fill cap on the oil drains more slowly.

mackwrench · 10-30-2021, 07:18 AM

Quote:

Originally Posted by rvtips

===============================================

I thought it was the opposite.I always take the coolant cap off.I would think if you left it on there may be some pressure in the system.

With cold engine, (like overnight) you can remove the conditioner with cap on. There's no pressure in system.

mackwrench · 10-30-2021, 07:19 AM

Quote:

Originally Posted by CountryB

Your right, you don't want any pressure in the cooling system. Either let the coolant cool off completely (if its hot from driving) or remove the cap to relive any pressure then reinstall it. The idea is to leave the cap on so air can't enter the system while your changing the filter. When air can enter at the top, the coolant drains fast. With the cap on, the coolant drains slow (like glug, glug, glug). Same as when you drain the oil on your car/truck, if you leave the oil fill cap on the oil drains more slowly.

What he said!