Westerbeke 4.5 spewed its coolant!!!

[Jimmy Buoy]

Anyone know what happened? Started the genny for the first time this year. Started fine, water flowing out of the exhaust, handling loads well, but of the two antifreeze lines going to the heat exchanger one is getting hot while the other is stone cold along with the exchanger itself...:huh:

I leave it to continue to heat up... then... pffft-pfft-pffttt!!! it spewed its red coolant all over the engine bay (up to 6' away). Of course, I shut it down and investigated.

Looks like it came out of the fill pressure cap on the top of the unit. The coolant reserve bottle level had not changed at that point, but while looking at the unit I heard gurgling type noises and could see the bottle level drop. The genny was sucking more coolant in apparently. I ended up refilling the bottle at that point. No additional red coolant was observed leaking at all - just the initial spew!

Any ideas??? I had taken the exchanger off during the winter to clean and repaint so I know that it is not plugged. Here's a couple of photos that may help.

 

[PlayDate]

I would check the thermostat and the pressure cap. A couple of weird things in your note. The pressure cap should have released pressure to the overflow tank not "spewing coolant" and the engine should have shut down on its own if it got that hot.

How many hours are on the unit?

-John

 

[Jimmy Buoy]

John,

Unit only has 248 hrs on it and it ran fine last year (just bought the boat last Aug).

I agree with what you have said, but I'm thinking that the motor did not overheat (there is no temp gauge) in the 5-10 min it was running. The motor itself really didn't seem to be that hot. Maybe the cap is not functioning properly? As I understand it, there are 2 seals in the cap. One for sealing the coolant in the genny - the other to stop coolant from flowing into the overflow bottle until there's enough pressure to push this seal upwards. Once the pressure is reduced, the spring pushes it back down, sealing the overflow once again - from what I've read.:huh:

Going to take a closer look at the cap today!

It seems to work just fine drawing more coolant from the overflow bottle when needed. As I said it almost drained a FULL BOTTLE after I shut the unit down to refill the genny. (and it didn't seem to be leaking out from anywhere after this):smt100

 

[fc3]

Bad pressure cap or the cap was incorrectly installed.

 

[Jimmy Buoy]

Went to remove/inspect the pressure cap today. It will turn counter-clockwise about 1/4 turn but it will not come out - seems stuck. I don't want to force it too much and damage the generator. The top part of the cap does rattle around showing that it's loose, but the bottom part of the cap seems jammed somehow. :smt013

I've only had the cap off once to fill it a month ago with new coolant. It is possible that when reinstalled it was not seated properly, but it appeared to fit in, down a bit, then rotated 1/4 turn clockwise to the stop point. Looked OK, but it's in a difficult spot to get a good look at it. :huh:

Suggestions on how to remove a stuck cap?? I'll try calling a rad shop tomorrow and ask them if they've ever had a rad cap jamm like this one!:thumbsup:

 

[osd9]

turn counter clock-wise till it losens, then push down and continue to turn counter-clockwise till it comes off.

 

[Skuza]

Is it possible the radiator cap was not installed correctly? When you remove most modern caps you turn it a 1/4 turn or so to vent it and then you push down on the cap and turn another 1/4 or so to actually remove it. Maybe the cap was half off but the seal was stuck enough to allow the system to build a little pressure then it popped spewing the coolant everywhere but not actually blowing off the cap. The purpose of the two stages in removal is to vent the system before the cap is actually loose and avoids pressure blowing the cap off in your face. Try pushing down on your cap and continueing to unscrew it. If that removes it then that was probably the problem. Still might be a good idea to replace the cap just to be sure. Coolant is MESSY!!!

 

[PlayDate]

Westerbeke's operate the same way. Two stop system. Turn counter clockwise 1/4 turn to vent. Push cap down and turn counter clockwise 1/4 to remove.

-John

 

[Jimmy Buoy]

Thanks for the advice guys. What Skuza says makes sense about what may have caused the "spewing". I'll try pressing down as both of you have suggested. No idea why this was not an issue when I removed it during the winter...:smt017

I will post what happens.:grin:

 

[Jimmy Buoy]

Well, guess what? I pressed down and the cap simply twisted another 1/4 turn counter clockwise and easily came out. I closely inspected the seals and one way coolant return valve and all looks fine.:smt038

Next time, I'll be following Westerbeke's directions which would have meant waiting till the boat was launched, starting the genny, and slowly filling while running, then installing the cap and watching the overflow level. Instead, I filled it as best I could while in winter storage without the genny running.:smt101

Ran it for more than half an hour today, just fine and dandy!:thumbsup:

Thanks for saving me from trying to pry off the cap, which in turn probably saved me some serious coin!:grin:

As a thank you, I've made the donation to become a CSR Silver Sponsor!!:smt038:smt038:smt038 - no how do I get that neat Silver Sponsor Logo on my posts??

 

[Jimmy Buoy]

:thumbsup:There it is!