Aftermarket heat exchanger question

[deblen]

Congrats on solving your problem.I agree with you-your new manifold has a rad.cap on it,so that suggests it is the exp. tank also.Oh well...
Some 2003T stuff popped up on ebay UK FYI,including a complete rebuilt 2003T.

Volvo Penta 2003T Heat Exchanger, Cooler Part No: 858129 | eBay

[MarkSF]

Let's get our terms right.

What the OP added is an atmospheric coolant catch tank, not an expansion tank.

Also in this application, the term header tank is preferred for the tank with a pressure cap on it, as it should be operated with as little air in it as possible.

[Cheechako]

maybe you need a higher pressure cap?

[MarkSF]

Originally Posted by Cheechako

maybe you need a higher pressure cap?

No he doesn't, it's working as designed.

You might need a higher pressure cap if you are getting some localised boiling which usually shows up as excessive amounts of air in the system.

[a64pilot]

I can't explain why on your heat ex / tank issue,
But I can almost absolutely assure you that your expansion tank will work, just don't be surprised if the level of the coolant drops initially, what happens is the cap will burp out some air occasionally, but on cooling suck back in coolant. Tank volume will change a little with engine temp too.

[deblen]

Originally Posted by MarkSF

Let's get our terms right.

What the OP added is an atmospheric coolant catch tank, not an expansion tank.

Also in this application, the term header tank is preferred for the tank with a pressure cap on it, as it should be operated with as little air in it as possible.

OK-that terminology makes sense.Atmospheric Coolant Catch Tank!
So-when coolant in engine/header tank expands,it lifts pressure cap & flows into ACC tank. When engine/header tank cools down,coolant is drawn back from ACC tank,thru a "bypass port" in pressure cap/neck?,& no air comes in contact with coolant. That about right?

[Cheechako]

Originally Posted by MarkSF

No he doesn't, it's working as designed.

You might need a higher pressure cap if you are getting some localised boiling which usually shows up as excessive amounts of air in the system.

If it's an aftermarket tank... how do we know he has the right pressure cap?
Fwiw, my Perkins had no overflow catch tank, and never burped out coolant.. Not sure why that is...

[Rustic Charm]

Thanks guys, sorry for the delay in responding but for some reason CF were not sending me the usual email notifications that I had other replies.

This is 'all' very helpful.

If the 'header tank' that came with the Luxford is meant to operate with as little air as possible, therefore filled up, then I was meant to add the extra tank as others recommended.

But am I right in my logic that I should have just purchased a heat exchanger without the header tank and then fed that from the original volvo tank?

This seems to be working now. I'll go for and extended sail over the weekend and really test it out over some hours, but I'm pretty sure this has fixed the problem. But I'm still ignorant of why the heat exchanger has it's own header tank if I then have to add this second 'overflow' or 'expansion' tank.