Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Cooling System

Reply
 
Thread Tools Display Modes
  #1   IP: 24.224.237.154
Old 07-22-2020, 09:13 AM
Dave Corning Dave Corning is offline
Member
 
Join Date: Dec 2019
Posts: 2
Thanks: 1
Thanked 0 Times in 0 Posts
FWC overheating even when raw water exiting

Hi all!
Taking over my old man's sailboat and A4 engine maintenance is new to me. I've been spending hours reviewing and reading forum posts, this web site is the bomb.
We have a late model A4 with FWC. Years ago the raw water strainer was removed and never replaced. Engine hasn't seen a lot of use over the last 5 years or so, maybe 20 hours combined.
Engine began overheating during a sailing trip up the eastern shore (NS, Canada). Steam from the engine compartment as the coolant boiled over (we don't have a overflow/recovery bottle, it just dumps to bilge). A healthy amount of raw water still ejecting with the exhaust but we still double checked the sea water intake valve, raw water impeller, and hosing up to heat exchanger. Due to lack of strainer we then found and removed a healthy clump of seaweed salad in the raw water access port on the heat exchanger, but this didn't resolve the issue.
I believe the issue lies somewhere with the cooling system. The coolant ran dry but I believe this was due to boiling over but could a coolant leak be possible?

Here are the things that come to mind but I need help to figure out if I'm on point, missing anything, and what order of operations make sense:
- Blockage in the seawater tubes of the heat exchanger? We poked around with a narrow screwdriver but didn't find much.
- Thermostat blockage or failure?
- Coolant pump blockage or failure? (Is there some way to visualize whether coolant is flowing through the lines?)
- Manifold blockage? (Am I even correct that the manifold is the rectangular box right next to the block where coolant flows from the tstat housing to the manifold then to the heat exchanger?)
- could a downstream blockage in the exhaust cause the overheating conditions as described? Again, getting healthy amount of sea water exiting out the back

As far as order of operations, I'm thinking to first remove and asses tstat and clamp bypass line to gauge whether full coolant flow through engine solves problem.
Then, open up coolant pump to see if any blockage in impeller.
Then, check manifold output for blockage.
Then, somehow blow out heat exchanger?

What am I missing...
Any and all advice welcome.

Regards,
Dave C.
Attached Images
   
Reply With Quote
  #2   IP: 165.225.38.121
Old 07-22-2020, 11:35 AM
Surcouf's Avatar
Surcouf Surcouf is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2018
Posts: 361
Thanks: 328
Thanked 163 Times in 123 Posts
I will let the tough guys answer.
But regarding how to check if coolant is flowing through the lines, the easiest way is to disconnect the flex hoses staring at pump discharge, then making your way further down the system, start the engine, dump the coolant in a bucket so that you can check flow. If needed you may have to feed the pumps with a line + funnel. That will allow you to identify any plugged exchanger or line / broken impeller etc...
__________________
Surcouf
A nostalgic PO - Previously "Almost There" - Catalina 27 (1979)
Reply With Quote
The Following User Says Thank You to Surcouf For This Useful Post:
TimBSmith (07-17-2022)
  #3   IP: 38.27.109.137
Old 07-22-2020, 12:29 PM
Administrator's Avatar
Administrator Administrator is offline
MMI Webmaster
 
Join Date: Oct 2004
Location: Chestertown, MD (Langford Creek)
Posts: 2,198
Thanks: 1,335
Thanked 365 Times in 182 Posts
Are any of the vets among us familiar with the concept of bracketing (although maybe there aren't enough breakpoints to make the idea worthwhile)?

Bill

Last edited by Administrator; 07-22-2020 at 01:51 PM.
Reply With Quote
  #4   IP: 100.36.65.17
Old 07-22-2020, 01:13 PM
edwardc's Avatar
edwardc edwardc is offline
Afourian MVP
 
Join Date: Aug 2009
Location: Laurel, MD
Posts: 2,509
Thanks: 153
Thanked 595 Times in 388 Posts
Quote:
Originally Posted by Dave Corning View Post
... Due to lack of strainer we then found and removed a healthy clump of seaweed salad in the raw water access port on the heat exchanger, ...

...Blockage in the seawater tubes of the heat exchanger? We poked around with a narrow screwdriver but didn't find much. ...
Given the stringy nature of that seeweed, I suspect that your tubes are clogged with it. A screwdriver isn't enough. You will need to remove the access plate at the other end of the HX and rod-out each and every tube using a long stiff wire. I found that a straightened wire coathanger works well.
__________________
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4

Reply With Quote
The Following User Says Thank You to edwardc For This Useful Post:
Ando (07-22-2020)
  #5   IP: 207.32.169.48
Old 07-22-2020, 02:27 PM
capnward's Avatar
capnward capnward is offline
Afourian MVP
 
Join Date: Aug 2012
Location: Deer Harbor WA
Posts: 335
Thanks: 41
Thanked 147 Times in 107 Posts
I was going to ask "What is bracketing?", but I think edwardc just gave us a good example. I've been wondering how you guys do that.
Anyway Dave, since removing the seaweed salad from the HX intake did not resolve the issue, and you seem to have good flow out the back, it is also possible you have a FWC problem, not raw water, and need a new impeller in your Oberdorfer. Clean out your HX, but I would check your fresh water impeller first. The FWC problem may have been caused by the raw water obstruction, if your fresh water boiled over because of restricted raw water flow, and you didn't replenish it, then your impeller broke from running dry. That will be easy to discover. The impeller could still get brittle after years of sitting still. Have you been turning the grease cup before running it? Maybe there is a blockage where the coolant exits the manifold. That blockage may be parts of the broken impeller. If you blow into the hose from the pump to the water intake plate, and your eyes bulge out from too much resistance, that's another way of knowing if you have a blockage, either in the t-stat or, more likely, the manifold exit.
A coolant leak is very possible, even likely. It may be that it boiled over because your coolant ran dry and damaged the impeller. Boiling over will still leave enough water at the impeller for it to work after a coolant refill, if the impeller is not damaged. That happened to me a few days ago. My raw water pump seized up with belt screeching because I neglected to fix the leaking seals, and the bearings got shot. It still turns with effort, hopefully the shaft isn't shot as well, but it probably is. So after removing the belt, I limped home by running on the fresh water alone, watching the temperature and turning it off after a minute or two, as it approached boiling point. After waiting a while I removed the hot HX cap with a hot pad, and then some coolant water boiled out. I filled it with fresh water and ran for a few minutes more. Luckily I wasn't far from the marina, so I only repeated that process twice. The new pump is on its way, $307 later. I also ordered parts to fix the old one, so I will have a working spare. Monitor both your water pumps for leaks regularly. Always check coolant level in the HX before starting.
PS: After looking at the photo of the Oberdorfer pump, I noticed wire hose clamps, and extensive rust under the pump. I would use these kind of hose clamps:
https://moyermarine.com/product/stai...-58-hose-ohsp_
It may be those wire clamps been leaking, and the engine running for years with a low coolant level, wearing out the impeller quicker. Or the clamps may be perfectly tight.

Last edited by capnward; 07-22-2020 at 03:04 PM. Reason: wire clamps noticed
Reply With Quote
The Following User Says Thank You to capnward For This Useful Post:
TimBSmith (07-17-2022)
  #6   IP: 38.27.109.137
Old 07-22-2020, 03:25 PM
Administrator's Avatar
Administrator Administrator is offline
MMI Webmaster
 
Join Date: Oct 2004
Location: Chestertown, MD (Langford Creek)
Posts: 2,198
Thanks: 1,335
Thanked 365 Times in 182 Posts
Bracketing as defined by the DoD.

Bill
Attached Images
 
Reply With Quote
  #7   IP: 170.199.140.153
Old 07-25-2020, 07:08 AM
Dave Corning Dave Corning is offline
Member
 
Join Date: Dec 2019
Posts: 2
Thanks: 1
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by capnward View Post
Clean out your HX, but I would check your fresh water impeller first. The FWC problem may have been caused by the raw water obstruction, if your fresh water boiled over because of restricted raw water flow, and you didn't replenish it, then your impeller broke from running dry. That will be easy to discover. The impeller could still get brittle after years of sitting still. Have you been turning the grease cup before running it? Maybe there is a blockage where the coolant exits the manifold. That blockage may be parts of the broken impeller. If you blow into the hose from the pump to the water intake plate, and your eyes bulge out from too much resistance, that's another way of knowing if you have a blockage, either in the t-stat or, more likely, the manifold exit.
A coolant leak is very possible, even likely. It may be that it boiled over because your coolant ran dry and damaged the impeller. Boiling over will still leave enough water at the impeller for it to work after a coolant refill, if the impeller is not damaged.
...
Monitor both your water pumps for leaks regularly. Always check coolant level in the HX before starting.
PS: After looking at the photo of the Oberdorfer pump, I noticed wire hose clamps, and extensive rust under the pump. I would use these kind of hose clamps:
https://moyermarine.com/product/stai...-58-hose-ohsp_
It may be those wire clamps been leaking, and the engine running for years with a low coolant level, wearing out the impeller quicker. Or the clamps may be perfectly tight.
Thanks for the insights!
Well ... the coolant pump impeller was missing 6 of 6 pieces! Before we disconnected the pump we ran for a few minutes and didn't find any noticable coolant leaks.
Sadly, only 5 of 6 bits were retrieved. Struggled to remove the hose directly following the pump, but we only took the access plate off the pump,I suppose we have to remove the pump from the flange just to access to the hose?

Replaced coolant with water and the temps were running much much better but did start to climb over 160 toward 180 after about 15 mind, could that be tied to using water vs coolant?
How critical is finding that impeller bit...?
We'll check the manifold exit next, and replacing hosing and clamps by next spring.
Also, the grease cup is getting filled asap and worked in to our operating procedures.

Any more suggestions are welcome!
Thanks,
DC
Reply With Quote
  #8   IP: 24.152.132.140
Old 07-25-2020, 09:46 AM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,619
Thanks: 198
Thanked 2,208 Times in 1,425 Posts
Finding the sixth impeller bit is important, perhaps even critical. Hang in there. Further having seen the amount of seaweed you're pumping through, consider adding a raw water strainer ahead of the heat exchanger.
Attached Images
 
__________________
Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
Reply With Quote
  #9   IP: 100.36.65.17
Old 07-25-2020, 02:52 PM
edwardc's Avatar
edwardc edwardc is offline
Afourian MVP
 
Join Date: Aug 2009
Location: Laurel, MD
Posts: 2,509
Thanks: 153
Thanked 595 Times in 388 Posts
Those impeller bits tend to lodge in elbow fittings, as they are usually the most resrticted part of the flow.

Start with the first elbow downstream of the pump, and work your way downstream until you find it.
__________________
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4

Reply With Quote
Reply

Thread Tools
Display Modes

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Overheating engine detectives needed! NatySailor Cooling System 23 06-20-2016 08:36 AM
Low water flow dcsavitzky Cooling System 5 06-28-2013 08:47 PM
Overheating problems jdaly986 Cooling System 1 01-16-2008 10:32 AM
Another ethanol question Bob N Fuel System 7 01-07-2007 06:22 PM
Much much water in Atomic 4 seators Cooling System 3 08-10-2006 03:31 PM


All times are GMT -4. The time now is 04:17 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2024 Moyer Marine Inc.

All Rights Reserved