Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 10-01-2008, 18:08   #1
Registered User

Join Date: Mar 2004
Boat: Pearson 323 Vision Quest
Posts: 40
Heat exchanger pressure cap size ?

Hi Everyone,

I have a 1977 Volvo MD11-C 23 HP Diesel. I think it may need a new pressure cap, I'm loosing coolant. The existing cap has engraved on it
7 lbs, this sounds low to me so can anyone give me some feedback before I buy a new one ????

Thanks again - Bob
__________________

__________________
bob_deb is offline   Reply With Quote
Old 10-01-2008, 18:40   #2
Now on the Dark Side: Stink Potter.
 
CSY Man's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Location: Ft. Lauderdale
Boat: 2001 Albin 28TE.
Posts: 3,399
Images: 115
Don't know about Volvos, but the Perkins has a 7 lbs cap..Not on the heat-exchanger, but on the reservoir tank.
__________________

__________________
Life is sexually transmitted
www.odincharters.com
www.susanhanssen.com
CSY Man is offline   Reply With Quote
Old 10-01-2008, 19:53   #3
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
7 to 10 pounds is average for most cooling systems. What it does is raise the boiling point of the coolant to around 250 F.

Without a pressure cap and recovery tank it allows the coolant to vaporize and dissipate.
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 17-10-2008, 19:13   #4
Registered User
 
svcattales's Avatar

Join Date: Apr 2005
Location: Apollo Beach, Fl
Boat: Privilege 37
Posts: 533
Images: 10
Question Volvo Pressure Cap

Quote:
Originally Posted by delmarrey View Post
7 to 10 pounds is average for most cooling systems. What it does is raise the boiling point of the coolant to around 250 F.

Without a pressure cap and recovery tank it allows the coolant to vaporize and dissipate.
I have a Volvo 3cylinder diesel (MD2030B) and I need a new pressure cap. The existing cap has "09" stamped on one of the ears. Can I assume that means 9 lbs and not some metric unit of pressure?

Also, I found caps in the auto parts store that fit, but their pressure ratings are 16, 18 & 20lbs. I wonder why autos would use higher pressures than marine diesels? Mostly because I can get them for 4 bucks and no shipping.
__________________
Greg, SV Cat Tales
svcattales is offline   Reply With Quote
Old 17-10-2008, 19:25   #5
Registered User

Join Date: Jun 2005
Posts: 1,901
Quote:
Originally Posted by svcattales View Post
I have a Volvo 3cylinder diesel (MD2030B) and I need a new pressure cap. The existing cap has "09" stamped on one of the ears. Can I assume that means 9 lbs and not some metric unit of pressure?

Also, I found caps in the auto parts store that fit, but their pressure ratings are 16, 18 & 20lbs. I wonder why autos would use higher pressures than marine diesels? Mostly because I can get them for 4 bucks and no shipping.
probably 0.9 Bar
__________________
never monday is offline   Reply With Quote
Old 17-10-2008, 19:51   #6
Registered User
 
svcattales's Avatar

Join Date: Apr 2005
Location: Apollo Beach, Fl
Boat: Privilege 37
Posts: 533
Images: 10
Quote:
Originally Posted by never monday View Post
probably 0.9 Bar
Thanks. Converting to PSI, that should be a little over 13. Would the auto parts store 16psi cap work or could I do damage to heat exchanger? (I don't have an expansion tank. Cap fits on top of heat exchanger)
__________________
Greg, SV Cat Tales
svcattales is offline   Reply With Quote
Old 17-10-2008, 21:16   #7
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
Shipping a pressure cap by USPS should cost much more than a buck and a half
__________________
Chief Engineer is offline   Reply With Quote
Old 18-10-2008, 06:20   #8
Registered User

Join Date: Jun 2005
Posts: 1,901
Quote:
Originally Posted by svcattales View Post
Thanks. Converting to PSI, that should be a little over 13. Would the auto parts store 16psi cap work or could I do damage to heat exchanger? (I don't have an expansion tank. Cap fits on top of heat exchanger)
you should either have a tube from the rad cap neck going to an overflow tank or the bilge. I wouldn't run a 16# cap.
__________________
never monday is offline   Reply With Quote
Old 18-10-2008, 07:47   #9
Registered User
 
svcattales's Avatar

Join Date: Apr 2005
Location: Apollo Beach, Fl
Boat: Privilege 37
Posts: 533
Images: 10
Quote:
Originally Posted by never monday View Post
you should either have a tube from the rad cap neck going to an overflow tank or the bilge. I wouldn't run a 16# cap.
Thanks for the advice.
__________________
Greg, SV Cat Tales
svcattales is offline   Reply With Quote
Old 18-10-2008, 09:22   #10
Marine Service Provider
 
AnchorageGuy's Avatar

Join Date: Mar 2003
Location: Wherever the boat is!
Boat: Marine Trader 34DC
Posts: 4,618
Quote:
Originally Posted by bob_deb View Post
Hi Everyone,

I have a 1977 Volvo MD11-C 23 HP Diesel. I think it may need a new pressure cap, I'm loosing coolant. The existing cap has engraved on it
7 lbs, this sounds low to me so can anyone give me some feedback before I buy a new one ????

Thanks again - Bob
Bob, My first question would be, are you sure you are loosing coolant from the pressure cap? If you can physically see it then OK, otherwise look at all possibilities also.
__________________
Chesapeake Bay, ICW Hampton Roads To Key West, The Gulf Coast, The Bahamas

The Trawler Beach House
Voyages Of Sea Trek
AnchorageGuy is offline   Reply With Quote
Old 18-10-2008, 22:53   #11
Eternal Member
 
Chief Engineer's Avatar

Join Date: Aug 2006
Location: North of Baltimore
Boat: Ericson 27 & 18' Herrmann Catboat
Posts: 3,798
What is the fluid level when engine is cold?

A lot of people fill their heat exchangers to the top.

If you don't have an overflow, expansion will cause it to drain out.

When the engine cools....you will have air there.
__________________

__________________
Chief Engineer is offline   Reply With Quote
Reply

Tags
heat exchanger

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Heat Exchanger Conversion clausont Engines and Propulsion Systems 15 21-02-2008 18:57
Caulking the inside cap rail MV Construction, Maintenance & Refit 7 14-09-2007 00:07
Yanmar heat exchanger R&B Engines and Propulsion Systems 10 21-02-2007 12:05
Heat Exchanger Anode chuckiebits Engines and Propulsion Systems 3 19-07-2006 14:51
cleaning heat exchanger AnotherSailorman Engines and Propulsion Systems 10 24-05-2005 19:30



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:29.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.