Engine coolant reservoir / overflow tank location, relocation. 2000 Mkll.

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Catalina Flyer
Joined: 1/14/21
Posts: 4
Engine coolant reservoir / overflow tank location, relocation. 2000 Mkll.

Has anyone relocated the engine coolant reservoir / overflow tank from the cockpit locker (2000 Mkll) to a location below the radiator cap height?  Is there a good reason it is located where it is?  The frustration with this stock location is, if you open the radiator cap the coolant flows from the reservoir down and and out the open cap on the engine.

Absolutely's picture
Joined: 4/21/21
Posts: 16

I have a few thoughts to contribute to this topic. 

First, I really like how easy it is to check the coolant level of the reservoir in the current location. Because it's easy, I check it a lot.  Frankly, I wish the sea water strainer and fuel filter were in there, too.

Second, I truly don't see a need to remove the engine cap very often at all. If the coolant needs to be topped-off for some reason, one can do that through the reservoir easily. The only reason I can think to remove the cap is when flushing/replacing the coolant. If I'm doing that, I have drained the entire system anyway and there is no coolant to leak out from the reservoir tank when I remove the cap. 

Third, if for some reason you really did
need to remove the engine cap with coolant in the reservoir, how about clamping the rubber hose off so coolant doesn't flow?  Or removing the hose from the cap area and plugging it with a golf tee or the like?

Just food for thought, but I vote for leaving it stock. 

Dale and Nikki

1998 C36 mkII SR hailing from Poulsbo, WA
1989 C25 TR/WK

alfricke's picture
Joined: 4/14/09
Posts: 81

Agree entirely with Dale and Nikki...much easier to use the reservoir to check coolant levels leaving it where it is. The only caveat is this. Once, on Jubilee, some crud stopped up the tube right as it enters by the radiator cap. I found this out when I cracked the cap open and no coolant flowed out. Easy fix. If it ain't broke, don't fix it,!!

Al Fricke
S/V Jubilee San Francisco Bay
Catalina 36' MkII  #1867
Universal 35-B

pkeyser's picture
Joined: 5/18/13
Posts: 594

Good points.
Additionally, if the reservoir is located below the radiator, there could be a slow drainage out of the engine. I'm sure the factory placed it high as possible to avoid this when the boat is on a heel.

Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B

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