Overheating 101

"I believe there is a test to see whether or not the antifreeze is still in good shape? What is that test?"

Why bother?

The green stuff , and distilled water in your engine has a service life of about 3 years.

The pink stuff costs way more but still has an in engine life too.

Thanks. I think I am turning things into rocket science when they don't need to be. I thought I remember reading somewhere in the 15,000 posts I have reviewed since buying the boat that you test or do something. However, seems much like my truck and no need to get all fancy. Will just flush and change antifreeze. The PO was kind enough to put virtually all new hoses, elbows, and exchangers on before cruising so most things I stare at in the engine room are only 3-4 years old. However, I don't think he did anything after beyond oil and trans changes.

Two good pieces of advice have popped up, thanks Smitty and FF. One, remove your engine heat exchangers to clean and inspect them. If one has after coolers do the same. Second, just change the coolant on a several year or hourly basis as it likely says in your book. Pulling the HXers and doing the coolant change go hand in hand.

What is the advantage of pulling them off the engine vs. inspection/cleaning in place? I know they can be pressure tested which makes sense. Is that what you mean by "inspected". What else can be viewed when they are off the engine totally?

One more question to help beat HE flushing into the ground... when using the recirculating method with Barnacle Buster, Muriatic Acid, etc. does the power of the bilge pump make any difference? Larger pump, more GPH pushes more water, faster and harder through the system vs. a small GPH model?

It might, but its not like you're scouring the building with moving water - its the chemical dissolving the buildup. I think the main benefit of using a pump is to keep moving "fresh" chemical and moving out the debris that has been dissolved. I used the cheapest Rule pump you can buy and in an hour a fairly neglected HE was spotless inside.

I found the before and after pictures.

Ken

Thanks. Did that cleaning have any noticeable effect on your engine temp? I was hoping the Rule 360 would work as (I believe) my HE's are 3/4" connections as is the Rule. Simple with no messing around with adapters or anything. Also read a post where a guy was having issues the the pump he had being able to push the water high enough. I don't think that is an issue in my case as its about the same level....

firstbase said:

Thanks. Did that cleaning have any noticeable effect on your engine temp? I was hoping the Rule 360 would work as (I believe) my HE's are 3/4" connections as is the Rule. Simple with no messing around with adapters or anything. Also read a post where a guy was having issues the the pump he had being able to push the water high enough. I don't think that is an issue in my case as its about the same level....

Click to expand...

Yes it had a huge effect. Before the cleaning my temps would continue to rise as I pushed above 1800 rpms. Afterwards, from 1800 to WOT there is only about a 5deg rise total.

I thought mine were 3/4 also but I measured one and it is 1". For something like this if you use cheap vinyl hose you can probably just crank on a hose clamp at the pump. The whole thing will be submerged in a bucket so even if it leaks a bit who cares?

Ken

Per engine builders protocol, just recently had Yard bucket soak my CuNi HXers in dilute muriatic for two hours. The HXers come off real easy. No pump needed, complete cleaning and much faster. Also a good time to clean stabilizer heat exchanger.

Both raw water and coolant passages looked new afterwards. Surprisingly, the coolant side was sufficiently crudded up that the bucket soak was warranted. The coolant test strips checked OK, but new coolant used anyway.

Thanks guys. Haven't really looked at how they come off on my engines. I know they seem to be "right there" and easy to get to. Would be nice to soak them all at once and get it over with and then back on. Will look at it. Hopefully when I open the bigger HE up I find it crudded up. That would most likely solve my overheat at WOT without anything else being wrong. Maybe.

firstbase said:

Thanks guys. Haven't really looked at how they come off on my engines. I know they seem to be "right there" and easy to get to. Would be nice to soak them all at once and get it over with and then back on. Will look at it. Hopefully when I open the bigger HE up I find it crudded up. That would most likely solve my overheat at WOT without anything else being wrong. Maybe.

Click to expand...

Yes but don't forget the engine oil HE (which is the first in line after the raw water pump) could have a bunch of debris in the front of it which could also by itself be preventing proper flow. That's also really easy to fix.

Ken

One main thing...don't loose sleep over this. Enjoy your boat, do what you have to do when you have the time. Keep your usual rpms and attack one component at a time. You'll get it sorted eventually. It's a cooling system after all.

A couple of things to keep in mind;
You will need to cut the HE zinc to no longer than 1 1/2" for it to fit.
The correct oil capacity including filter is either 13 1/2 or 14 1/2 qts depending on who you ask. I settled in 14 qts. Dipsticks may vary. 14 qts brings my dipstick oil level to the "I" in "min".

Thanks for the comments. Opening the heat exchanger is easy but can I open the oil cooler while it is still installed? How does it open up?

firstbase said:

Thanks for the comments. Opening the heat exchanger is easy but can I open the oil cooler while it is still installed? How does it open up?

Click to expand...

Do you mean engine oil or transmission oil? Many engine oil coolers use coolant rather than raw water. Transmission Hxers are normally quite easy to remove and bucket soak. Many prefer to scrap transmission HXers after a decade or less. They are cheap in comparison to a gear box rebuild.

firstbase said:

Thanks for the comments. Opening the heat exchanger is easy but can I open the oil cooler while it is still installed? How does it open up?

Click to expand...

The oil coolers on the SP135's don't really open. To look "inside" you take the hose off the end and look in. Its only the raw water circuit so you don't have to worry about oil, etc. As I said before, the one right after the raw water pump cools the engine oil and THAT is the one that will have bits of impeller and/or ocean debris. You really should look in there.

Ken

OK, finished the RW flush on both sides with a detour off to fix an elbow connection covered in another thread. Looked at HE (no tubes blocked but some gunk) and oil cooler (no pieces of anything). Took the boat out yesterday and both engines it ran at 180 degrees for a couple of hours no problem. Decided to test out WOT. The starboard engine went up to 190 degrees and stayed there. Although it took longer than the first time the port engine kept going and I backed off at 200 when the alarm sounded. Assuming an increase from 180 to 190 at WOT is within reason it had a positive effect on the starboard side but not on port. Again, new impellers, strainers clear visually, bottom just cleaned last week, and now system flushed. I guess I go back to square one and start with opening up strainer and then hose to pump. Make sure I am getting full flow of water. Maybe change port impeller again in case there is something funky there? This was the impeller that sat installed for a week or so before I opened up seacock and ran after replacement. Don't know why that would affect it though. Will also search old paperwork to see if water pumps were replaced at some point by the PO. Engines have 4,190 hours and if these are the original pumps maybe time to replace? I don't what "normal" hours before replacement are on these?

If you haven't been hauled for a while there may be something in your strainers. I found a dead fish in one of mine when I had a Lehman. Smelly.

Just a curiuous thought. its something I've come uppon a few times of 40 years working in a boatyard.

I've seen the thru hulls scoop type installed back wards causing a vacuum at high speeds and starving the pump.

I'd check the water flow at higher speed you could place plastic in the line to see if your pumping bubbles (cavitation) or a cheap totalizer $20-30 from amazon to do a measured time rpm static vs rpm moving etc.

Thanks. Excuse my ignorance but you mean a flow totalizer placed on the RW intake? Another simple thing I just thought of, too easy really, I am way overdue for a bottom painting. It is clean but growth is heavy and divers are complaining (and charging). Is it possible heavy growth is up in the intake tube where a diver can't get to it? Could that be blocking flow?

Its not just impellers on pumps. Cam wear, wear plate grooves add to the pleasure.

Yep just need a flow totalizer they come from garden hose size to 3" not expensiveput it after the pump. Run the engine for 10 mins at t/over then cruising rpm. Then check under load. It jus confirms flow better than looking over the stern and estimating. Look up the supposed pump output at the given rpm. Although as the rpm increases and the output is not a steady curve , you've got a blockage etc

The easier way of course is to take of the outlet hose stick it in a bucket , start the engine and look at the flow for a min or so. should be a good pressurized flow.

Some times folks unknowingly create their own problems.

Refilling a coolant tank with antifreez from the jug , instead of a mixture is one.

Antifreez only has 5/8 the heat transfer of pure water.

Eventually the engine may run hot .

It only takes 30% antifreez or so to give the corrosion protection we all desire.

As most antique engines have a 2 or 3 lb pressure cap , there is no heat protection from the antifreez high boil point..

15 -18 lbs like in a car needs the antifreez to operate over 210F.

Haven't touched my fresh water cooling system. Opened it up, looked in as the reserve container filled it to the top and then closed it up. It was a very nice, pretty blue. That's all I know about the shape of that part of my fresh water cooling system!

Could this possibly be a thermostat issue? I guess that's a stupid question..of course it COULD be...

Also, not sure on the starboard going from 180 to 190 and staying there. Is that within normal range/operation or should it just stay at 180?

Depending on the engine , most folks are pretty happy operating under 200F.

200F is arbitrary but it is below the temp where steam pockets will form in the circulating water .

Start with a haul-out. All of this could be due to growth.

Hmmm.... going to go back to this thread and tie it into another one I put up. Had the boat hauled, new paint, strainers removed and cleaned etc. All the normal stuff. Also rebuilt my old strainers, covered in another thread which addresses something I noticed after we went back in the water. As I run the engines the water in the strainers goes down to about 1/3 filled. No overheating just low raw water levle at 1800 RPM's or so. So...hmmm...I wonder if this is not a new issue but one that existed prior to the haul out and I just didn't notice it. I wonder if maybe my overheating at WOT is because my going full out increases the vacuum being created or the air leaking or whatever it is in the strainers to the point that the water continues to decrease which of course causes the overheat. Hmmm... this of course adds little to my discussion as I haven't checked it yet but I rarely (as in never) get to have an Ah HA! on this site so had to post something. I mean..it COULD be the cause right? So proud.

Sounds like the strainer and thru hull are to small for the strainer.

Not sure at this point. However, its a 30 year old boat with same Groco strainers and same Ford Lehman 135's. I am unaware of any past issues and am good friends with the previous owner of 5 years prior. Did the loop twice, Bahamas, nothing from him on it. Of course he gave me a curious look when I told him I tested them out at WOT. "Why would you do that?". Just not sure. I would be more inclined to suspect the RW pumps but...both engines at the same time? Now looking for some lame excuse to break away and go take the boat out and check my theory.

Sorry...didn't read the whole thread and don't know if this has been asked yet: has the intake grill/grate against the outside of the hull for the raw water thru hull been partially blocked by being painted over with bottom paint?