Coolant circulation issue - is the water pump working?

[jaybeegee]

Hi All,

In a seperate thread of many months back, I reported that my coolant water drain tap installed on a Beta Marine 20hp does not work as there is a blockage and I am not able to get past the elbow to unblock it! Pic here coolant | Flickr - Photo Sharing!

I have since given up on the blockage as I was recommended a good workaround to break the lowest hose connection to remove the coolant although I am aware that this will not remove most of the coolant - my guess around 30% - is this correct?




So last year I used a coolant with a very strong green colour base and recently drained it and topped up with a coolant which is semi transparent and had a light blue stain. Now I removed the heat exchanger, I found it full with more of the light blue type coolant but removing the pipe I got the strong green tint!

How is this even possible?! Could it be that the pump is not working and there is no circulation!?! I have now ordered a hand pump to be able to extract more of the fluid but how can I confirm that the pump is functioning?!

thanks, Jay

[dabnis]

You may have an air pocket somewhere. You might try running it with the coolant cap off. Some engines have a bleed screw, probably at the highest part of the block.

Paul T

[jaybeegee]

thanks for that - I did try running the engine without the cap for several minutes and unfortunately it is not an air bubble related problem!

[H2814D]

Are you absolutely sure you are warming the engine up to a point the thermostat is opening and allowing coolant to flow through the engine?

[chucklesR]

Remind us again why precisely you are draining your coolant on a frequent and regular basis?
Checking a water pump is simple, with the engine at operating temperature loosen a hose on the output side and look for squirting fluid. Bring a sponge to the test

[lancelot9898]

Is your engine overheating under load? If not...then it's working.

[dabnis]

Originally Posted by lancelot9898

Is your engine overheating under load? If not...then it's working.

If that is the case maybe some of your impeller blades are missing or severely worn?

Paul T

[jaybeegee]

thanks for your feedback which is appreciated!

first of all the background and to answer some of the questions ... I empty the coolant once a year typically around April which is the time I also do an annual service. I check the coolant before every outing and most times would need to top up 1/2 glass so around 5 cl to overflow it as I have small leak around the o-ring of the heat exchanger!

So last year I removed the coolant (dark green dye) via the pipe marked in the pic above and added Shell 50/50 blue coolant - this year I did the same only to find lots of green colour coolant which subsequently triggered the post!

The engine has only over heated once - it was after a semi longish journey (4 hours at around 2500-3000 revs) and I found it was low on coolant. I removed the heat exchanger because of the leak and also to make sure it is in good shape since I was aware of the blockage on the drain plus it had never been serviced in 7 years (500hours)

After reading the posts above I have now learnt that the engine must be hot for the thermostat to kick in before the coolant is circulated *blush* I didnt know that! So it could very well be why the green coolant has not really mixed with the blue one but does not really hold as last season I did many long trips plus the overheating experience!

So as a next step I am going to drain via this syphon pump that I have ordered which has acquarium type pipe which should help me get out most of the coolant and sort out the leak!

I am seriosuly considering installing a temp guage since all I have is an alarm. Would appreciate any tips on this now?!

thanks again.

[chucklesR]

A temp gauge requires a sensor - what you have now is a 'switch'
You ARE in luck because Beta Marine does offer one.
Beta Marine | Marine Diesel Propulsion Engines and Generating Sets
The sensor and a guage will likely set you back about a 150 bucks - and they are not hard at all to put in.

Coolant flush should only be needed about every five years. When I was in the Navy they did a study and found that the most common cause of failure on a lot of gear was the preventative maintenance (i.e. if it works, leave it alone).

I'd install a gauge (I am in the process of doing that on my new to me boat), fix the leak, fill the system and leave it be unless it overheats.

Also if you don't have one, get a book on diesel maintenance and troubleshooting (Calder's is best I think); or take a couple evenings and sign up for a class at your local community college, some have excellent programs.

Folks don't need to know much about cars these days, they can pull over and call a tow truck - hard to do that on a lee shore at 4am when the rode breaks.

[chef2sail]

I would suggest that you use a special marine antifreeze as opposed to regular shell antifreze of thats what you are using, which is not poisonous to the environement, animals and humans, especially since you already said you have a leak, which goes to your bildge and then gets pumped out. Although it is major diluted it isnt good to have the ethalyene glycol which is toxic put into the water. Also some of the antifreezes have rust inhibitors different from car antifreeze.

Polar Preferred Marine Anti Freeze / Coolant

SIERRA® Antifreeze/Coolant