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grafxman · 10-24-2012, 07:26 AM

I decided to flush the radiator on my 20 year Chevy P30 chassis Winnie. Fortunately I decided to remove the radiator cap first. It won't come off! I even applied some gentle persuasion via a large set of channel locks. Then I read the writing on the cap. It says closed system. It has an overflow bottle with a small tube going into it and I know that's where the coolant is added but I would like to drain the radiator and go through a flushing procedure. It is 20 years old after all and likely has never been done. I didn't check underneath but I wouldn't be surprised if the radiator doesn't have a drain valve. Any ideas/knowledge/experience? Is a flush even necessary?

336muffin · 10-24-2012, 07:37 AM

I would not use channelocks, these caps takes more downward pressure than a regular cap. Push down firmly and gently turn as usual. These caps are very common on many cars and trucks. It might be in a awkward location to access in your MH.

Triker56 · 10-24-2012, 07:42 AM

On the 83 P30 I had. You had to push down on the cap and then twist.
It did come off.

It developed a leak and I had to buy a new one.
Old one couldn't be fixed.

clyon51 · 10-24-2012, 07:45 AM

All I can tell you is radiator caps must be pushed down before they can be twisted off. This is a safety item to let pressure off before removal. If it will not turn off fully closed position, try tapping the top with a hammer. If loose, it should about a quarter turn, then push down while turning the rest of the way. Flushing is not a bad idea.

Davdeb1 · 10-24-2012, 08:14 AM

If this hasn't been flushed in 20 years, you are fortunate to have a working radiator. Flush by all means.

450Donn · 10-24-2012, 08:24 AM

Unless you have the proper method of capturing the used coolant it is wise to take it to a qualified radiator shop and pay the, to do it right. Besides I suspect you don't have a way to back flush the system. Meaning that you cannot get the old crud out of the system. Please do yourself and the environment a favor. Pay to have it done.

grafxman · 10-24-2012, 08:29 AM

Quote:

Originally Posted by 336muffin

I would not use channelocks, these caps takes more downward pressure than a regular cap. Push down firmly and gently turn as usual. These caps are very common on many cars and trucks. It might be in a awkward location to access in your MH.

It's pretty easy to get to and I did push down, quite hard in fact. It will only turn about ¼ turn. It has arrows on it with text instructing the user to make sure an arrow points towards the overflow tube.

monkey · 10-24-2012, 08:32 AM

IF you are thinking of using a "radiator flush treatment" instead of just water,, you might want to do some research.... A LOT of horror stories of using a "radiator flush" treatment in a bottle... Other than that, I agree, it's a Great idea to flush out the old coolant, with water... Just know to get the thermostat open , (to circulate inside the engine) you need to get the engine to operating temp. Best way (simple) IN MY OPINION is loosen or remove the cap as stated so it won't build pressure, make sure you can open the drain valve,,( but don't drain yet, mine is plastic on my 95 P32,, ) grrrr,, then start the engine,, after it is warmed up, (Be Careful), remove the LOOSE radiator cap,or remove the cap before starting the engine, you should see the coolant moving if the thermostat is open, then open the drain plug. Get ready with your water hose, and keep filling the radiator as it drains out till it looks fairly clean with engine running. Also turn on your heater full to circulate in the heater core!! Shut the drain plug, shut off the engine,, wait a few minutes so you are not exposing the warm engine to no coolant,, drain the exsisting water, and replace with the proper mixture of coolant/water,,, or get a premix coolant. Hope I didn't miss anything,,, tired here...
Monkey

monkey · 10-24-2012, 08:33 AM

Good point about "don't run the old stuff out on the ground !!" .... Very bad....

monkey · 10-24-2012, 08:35 AM

Quote:

Originally Posted by grafxman

It's pretty easy to get to and I did push down, quite hard in fact. It will only turn about ¼ turn. It has arrows on it with text instructing the user to make sure an arrow points towards the overflow tube.

Could be it is rusted enough under the cap where air might be, to make it hard to remove... If you can get the cap off with the arrows pointed like you said, a new cap is cheap insurance...

KSCRUDE · 10-24-2012, 09:15 AM

Quote:

Originally Posted by 450Donn

Unless you have the proper method of capturing the used coolant it is wise to take it to a qualified radiator shop and pay the, to do it right. Besides I suspect you don't have a way to back flush the system. Meaning that you cannot get the old crud out of the system. Please do yourself and the environment a favor. Pay to have it done.

our local radiator shop pours the old coolant right down the drain into the city sewer system. I asked the owner about this and he said the city approves of this kind of disposal. You would be really shocked if you knew what all goes down a city's sewer system. When I change the coolant on my diesel trucks, I drain it all out then flush with clean water. Then add a cup of tide laundry detergent and run for 30 minutes or sometimes all day on a job. Then drain and fresh water flush. Then fill with Cat brand premixed antifreeze. Use it in all brands of engines as it is made with distiller water and is good for about 5 years or 500,000 miles. I usually try to change them around every two years, then you never have to worry about the PH level or add conditioners. Antifreeze is cheap, new pistons and liners cost mega bucks.

TQ60 · 10-24-2012, 10:33 AM

Old school trick...

Get a can of two step, it has acid on one end and antacid on the other

Flush while running as described above, then add acid and go for a drive as you need it to flow well and everywhere.

5 to 10 miles should do it, full heat too.

Now running flush until clear, add antacid and repeat drive, flush etc

You keep engine running the whole time unless you cannot get to the drain.

When finished let fully cool, drain and fill with CORRECT antifreeze, many on market now need to be sure to get correct one, make them LOOK IT UP...

450Donn · 10-24-2012, 11:09 AM

Quote:

Originally Posted by KSCRUDE

our local radiator shop pours the old coolant right down the drain into the city sewer system. I asked the owner about this and he said the city approves of this kind of disposal. You would be really shocked if you knew what all goes down a city's sewer system.

Wonder how many animals have been killed by his practices? Antifreeze is one nasty killer of all sorts of animals. I guess in some of the more progressive states, they have already figured that out and banned the practice.

JimM68 · 10-24-2012, 11:43 AM

An '83? hmmm. you could be trying to open a real can of worms there. Sometimes it is better to let them sleeping dogs lie.

If nothing was leaking, the overflow tank always had the same amount of coolant in it and you never have to add, and it doesn't overheat...
I'd leave it be.

Any one of the above, yes, that cap has to come off. But be ready. you'll probably be replacing the radiator. All the rubber hoses for sure. Thermostat? you betcha. belts? yup.