Community Forums

avfordguy · 09-30-2022, 09:51 AM

This might be worth a try....Ford F650 w/cummins/allison uses a "de gass" tank which is similar to the monaco tanks that crack, has the same fittings just in different places, might be worth a look.

jdw1 · 10-01-2022, 03:54 AM

Quote:

Originally Posted by avfordguy

This might be worth a try....Ford F650 w/cummins/allison uses a "de gass" tank which is similar to the monaco tanks that crack, has the same fittings just in different places, might be worth a look.

What year of F650?

rvtips · 10-03-2022, 03:01 PM

Quote:

Originally Posted by kb7uxe

Hello from Dan..
Our 2008 Monaco 5.9L dressed as a 6.7, had the plastic coolant tank. and, I thought it broke, but it was just the bottom hose leaking. so, I know they are prone to failure and I decided to replace it. what I found was, the replacement tank is about $500 ouch !. But in searching I found that the Peterbilt 320 series uses a round steel tank with the same connections. and with minimal modification just about fits right in. I ordered mine from a wrecking yard, and it cam with brackets, cap, water level sensor. 1st I enlarged the access port. and removed the old tank. That required removing the entire air filter housing from the side panel driver side behind the tire. once the Air filter housing was removed, it came right out. the metal that the bottom of the original tank was mounted to I was able to drill 2 new holes to fit the new tank bracket. the upper bracket will mount to the original upper mounts. I added the 1.25 diameter x 1/2" pipe brass barb for the bottom. the upper mount needed to be lowered. I used flat bar in an X configuration to add rigidity. the water sensor even plugged right in and worked ! The 2 small upper mystery hose fitting has to be replaced with straight fittings.
Bottom line the Peterbilt 320 series tank does fit and works well for a lot less $..

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Well we made it home with no problems.
I have the old tank off and the new one ready to go BUT, the lower hose fittings are different,the old tank fitting is 34MM or 1.3 in/the new tank fitting is 25MM or 1.0 in. Not sure what to do .Also I don't see a low coolant sensor unless the black thing on top is it.
If that is the sensor,I don't know why it never came on?
Thanks Dan.

moisheh · 10-03-2022, 03:39 PM

The op can give you a correct answer but I think he changed that lower fitting to a larger size. It is in his parts list.

kb7uxe · 10-07-2022, 10:52 PM

Hello from Dan.
Been on the road. I'm camped at the south end of Ohop lake in Washington at the Atkins Rotary Factory.
RVTIPS please post a few images of your new tank so I can see what you have to go in. Your tank may be a little different, no worries, we can adjust..
Ture Value hardware is where I bought the larger brass fittings for the bottom of the tank, and straight barb fittings for the 2 top hoses. yes, my bottom fitting was about 3/4 "
I installed 1 1/4' same as plastic tank. easy..
show the tank so we can look it over.
It should have top opening with filler cap,
2 barbed fittings at near top of tank,
1 fitting on side for level sensor,
and fluid level indicator.. the 320 uses a sight tube.
I think the 340 used a simple glass bubble.
and of course the large fitting at the bottom that
goes to the bottom radiator hose.
Thanks
Dan.

jacwjames · 10-09-2022, 02:41 PM

The black rubber "thingy" on the top is the low coolant level probe. It is long and sticks ~2/3 down into the tank.
On my 2002 Moncao Windsor I had a probe like that. The way the low coolant alarm works is that it relies on the coolant as a grounding mechanism that goes through the probe. It then wired to a Kysor low coolant module, with it doesn't see the ground the light comes on.

When I replaced my tank with a similar one I used a Ford low coolant sensor that I mounted in the side of the tank. It works on the same principle, it uses the coolant as a ground circuit.

rvtips · 10-09-2022, 10:04 PM

Quote:

Originally Posted by jacwjames

The black rubber "thingy" on the top is the low coolant level probe. It is long and sticks ~2/3 down into the tank.
On my 2002 Moncao Windsor I had a probe like that. The way the low coolant alarm works is that it relies on the coolant as a grounding mechanism that goes through the probe. It then wired to a Kysor low coolant module, with it doesn't see the ground the light comes on.

When I replaced my tank with a similar one I used a Ford low coolant sensor that I mounted in the side of the tank. It works on the same principle, it uses the coolant as a ground circuit.

==========================================
How can this work,there are NO wires connected to it?

jacwjames · 10-10-2022, 07:24 PM

The old probes were notorious for getting corroded and sending a false signal. My guess is the previous owner took the wire and put it to ground to eliminate the low coolant warning light.

rvtips · 10-10-2022, 10:58 PM

Quote:

Originally Posted by jacwjames

The old probes were notorious for getting corroded and sending a false signal. My guess is the previous owner took the wire and put it to ground to eliminate the low coolant warning light.

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I bought it from the original owner when it was almost new,he did not make any changes to it.
The black thing on the top of the old tank looks like it never had any thing connected to it?

kb7uxe · 10-11-2022, 12:24 AM

I wonder if the wire fell out, and has been touching something meatal so light doesn't come on ..

rvtips · 10-11-2022, 02:53 PM

Quote:

Originally Posted by kb7uxe

I wonder if the wire fell out, and has been touching something meatal so light doesn't come on ..

===============================================
No I don't think so.I have it all apart and no sign on any wire,also the black thing on top looks like it has never had anything hooked to it.

rvtips · 10-17-2022, 02:26 PM

Quote:

Originally Posted by rvtips

=============================================
Well we made it home with no problems.
I have the old tank off and the new one ready to go BUT, the lower hose fittings are different,the old tank fitting is 34MM or 1.3 in/the new tank fitting is 25MM or 1.0 in. Not sure what to do .Also I don't see a low coolant sensor unless the black thing on top is it.
If that is the sensor,I don't know why it never came on?
Thanks Dan.

=============================================
I have the new surge tank installed and it is working good.The new tank has a 1" fitting on the bottom,I had to use an adapter to get my 1&1/4" hose to fit.
The tank that I used is Peterbilt 385 Radiator Overflow Bottle / Surge Tank.

moisheh · 10-19-2022, 12:20 PM

I have been looking for the 320 tank. So fat no one has stock. Tried some big truck salvage yards in the East and in Arizona. Nothing
Mine is not leaking but it is so yellowed ypu cannot see the level. I have to dip something in the tank

rvtips · 10-19-2022, 10:24 PM

Quote:

Originally Posted by moisheh

I have been looking for the 320 tank. So fat no one has stock. Tried some big truck salvage yards in the East and in Arizona. Nothing
Mine is not leaking but it is so yellowed ypu cannot see the level. I have to dip something in the tank

==============================================
Good luck,I spent 2-3 hours on the pc looking for the 320 tank,I could not wait any longer.That is why I went with this on.