Community Forums

CountryB · 12-22-2018, 08:18 AM

My '05 Patriot with the plastic coolant surge tank has a 7 psi radiator cap. It looks like a standard "Stant" or equivalent automotive radiator cap (the name on it is Motorad), but it doesn't seem to fit well.
It is real hard to get on/off and it looks like it is not seating properly.
It looks like the tabs are not deep enough to fit around the extra thick plastic of the tank (unlike a thin copper radiator neck would be).

I see on the website where the replacement surge tank is sold, that they also sell a cap for it. https://shop.findmyrvparts.com/surge...3-p/190014.htm

They want $25 for the cap. https://shop.findmyrvparts.com/searc...190056&Submit= I'm wondering if this is a special cap for thick flange tanks (or if they are just marking up the price 100% for a regular automotive radiator cap.

Googling the 190056 part number does not turn up anything at Motorad or elsewhere (it is probably the vendors part number)

EDIT: i should also ask "is a 7 lb cap the correct one?". The one on the site to linked above looks to be a 16 lb cap.

Captjake1 · 12-22-2018, 08:57 AM

Motorad is s brand name for one of the parts chains. I can't remember which one, possibly O'Reilly.
Anyway,mine came with a 7psi cap when I bought it. I don't believe it was factory. The manual calls for a 16psi. I recently replaced it with a 13 that was for the aquahit (was at a shop getting work done and they happened to have that one).
I've noticed no difference with either, but the higher psi might hold coolant longer at higher temps. Mine is also hard to get off, but in my case I think it is where my tank is located.
Cold out now, but I will see if I can find a place on it today for you.
You might take a look at your AH cap and see if there is a number too. Or take that one to Napa to match up (did that a few years ago too) and found one that worked as a 7psi.

CountryB · 12-22-2018, 10:45 AM

Thanks for your reply. I was told on the Beaver forum that the 16 lb cap is the OEM Monaco/Beaver cap, but many replace it with a 7 lb as the plastic surge tank ages to reduce the chance that the higher pressure will crack the old plastic.

so I took a pair of needle-nose pliers and very slightly bent the tabs on the cap "open" more. It didn't take much. Now the cap comes off and goes on much easier.

Captjake1 · 12-22-2018, 10:45 AM

No number I can see on it. It is a Stant cap I used though, 13psi.

8.3Oilbuner · 12-22-2018, 12:56 PM

Good morning CountryB & Captjake1; I just got finished reading your posts. On my 01 Windsor, I have the replacement nylon expansion tank with the Ford low coolant sensor in the side of the tank. The previous owner replaced the tank as it cracked and took out the alternator as antifreeze poured over it. Whoever he had do the replacement on the tank did a bad job in drilling out the holes for the brass elbows and low coolant sensor. Sorry, too much info. Since I was having a hard time getting the sensor threads to seal, I replaced the pressure cap with a 7# instead of the 10# that was on the tank. Motorad comes from Auto Zone as I put one on my Jeep Wrangler. They are manufactured in India. On the coach I used a Stant cap and it fit just fine. To remove the cap I have found that you need to push down in the center of the cap to compress the spring some to get over the larger plastic lip that CountryB mentioned in his post. I know you guys have Cat engines. I found in the Cummins engine manual that comes with the coach that a minimum of 7# was needed for the cooling system. Monaco from the factory installed the 10# cap. I found no difference in cooling with the 7# cap installed.

windsorbill · 12-22-2018, 03:44 PM

Mike,

Originally my coach came with 16#. It was really hard to take off. I replaced it with a 7# from auto zone and that one was on there for years with zero issues. Just a couple months ago, I was concerned about the plastic tank splitting so I replaced it with the aluminum job that Source Engineering has. It was a easy swap out and it came with a new 7# Motorad.

Scooter363y · 12-23-2018, 05:29 PM

I replaced mine with a 9 psi cap from Orielys I didn't want to stress the old press tank and it was fairly inexpensive

Scooter

Scooter363y · 12-23-2018, 05:36 PM

Sorry, in answer to your question it is a standard cap. But be careful there are two different styles. I got a longer one first, the sealing rubber washer was a greater distance than the original one. The one that fit mine was the shorter one. So heads up on that dimension

Scooter