Overheat on my 3.0l...

[NetDoc]

Yesterday, I was cruising just west of Garden Cove here in Key Largo heading to Cary's Ft reef for some diving. The boat was doing great thru the back channels from Pennekamp park, and we were just in open ocean doing about 25 mph @ 4,000 rpm with I hear a change in the timbre of the engine. I back down on the throttle, checked the oil pressure and then I saw that the temp light was pegged!

I throttled down and waited 15 or so minutes for the engine to cool. Checked the oil and see that there is no water in it. I put out the dive ladder and jumped in with a mask. Nothing was fouling the intake, the hose was on tight. I had my son put it in neutral and start the engine. It started right up with a puff of black oily smoke, which cleared right up. It idled sy s higher than normal temp for a few moments until I heard what sounded like steam coming out with the exhaust. I had my son shut it down and I noticed a bit of oil coming out of the exhaust. It wasn't going to be repaired out in the open so we called sea tow for a ride back to the park. The tow boat operator, Captain Mike, was as nice as can be and suggested that he thought the problem was the exhaust manifold. Mind you, I have seen rust develop around the head gasket and was not impressed with this "rebuilt" engine that seemed to have car parts on it rather than marine specific (like the water pump). My first impression is that I have a bad gasket or a cracked head. But I recognize that my expertise is with cars and I don't fully understand the exhaust manifold that somehow mixes water and exhaust without flooding the engine. I'm sure I'm about to find out.

I have parked the boat in the back yard and when it's light, I will be attaching the hose, checking the oil and starting the engine. What's my procedure for checking the issue, the core issue. Captain Mike suggested that while it might be a head gasket issue, the root of the problem is probably in the exhaust manifold. I hate changing parts on a hunch, though I have done that. How do I test the exhaust manifold for proper operation. I can do a leak down test on the head to see if the gasket has popped, but how do I check something that I don't fully understand? Your help is appreciated.

 

[Bondo]

Re: Overheat on my 3.0l...

Ayuh,.... Change the Impeller, 'n move on from there....

 

[fat fanny]

Re: Overheat on my 3.0l...

What Bondo said. After some reading up in the adults only stickie this info will give a little better understanding of the cooling system of your rig. Odds are the impellar is shot and or circulating pump on block but a compression test on all cylinders is another good test for bad head gasket after reaching that temp. Dont forget the little 5$ part thermostat. Good luck!!!

 

[NetDoc]

Re: Overheat on my 3.0l...

It's a fairly new impeller, but I'll take a look at it. BTW, I did not look at the motor yesterday at all. It was one of those be a couch potato days.

 

[NetDoc]

Re: Overheat on my 3.0l...

It's a fairly new impeller,

and it was TOAST. I installed a new one with lots of dish soap as lube. I then back filled it through the output pipe on top. I made sure the key was in when I put it together and carefully tightened down the screws. When I started it up, no water came out the exhaust. CRAP! I guess the key in the key way pushed out some how. I hope I didn't screw this one up. I have been too busy being sick and teaching scuba to give a whole lot more time to this. Other than the key, are there any other things I should look for???

 

[fishrdan]

Re: Overheat on my 3.0l...

It's a fairly new impeller, and it was TOAST. Other than the key, are there any other things I should look for???

How toasted, if piece were missing, they could be jammed up in the water passages, causing lack of water flow.

 

[Bondo]

Re: Overheat on my 3.0l...

Originally Posted by NetDoc
It's a fairly new impeller, and it was TOAST. Other than the key, are there any other things I should look for???

How toasted, if piece were missing, they could be jammed up in the water passages, causing lack of water flow.

Ayuh,... Probably oughta had back-flushed from the T-stat housing, Before the lower was put back on,....

 

[Don S]

Re: Overheat on my 3.0l...

He's got an old Volvo 200 drive on that Mercruiser engine guys. His raw water pump is belt driven. To loose the impeller like that to begin with and now won't pump also leads me to believe he might have air leaks in the drive causing no water to the pump.

Possibly a transom mounted water pickup, instead of trying to fix that old of a drive. Mercruiser uses one like this.



His engine and pump setup.

 

[NetDoc]

Re: Overheat on my 3.0l...

Bad Impeller!​

OK, I went back in and found that I could turn the pump easily by hand. Way too easily! When I pulled the back of the pump off, I found the key sitting on top of the impeller! So, I tried several times to get it back in, but the key was always popping out, so I pulled the entire pump and did it on my work bench. I put the pump back on and every thing was going great until I heard a God awful noise. I traced it to the raw water pump and stopped the engine.

​

I first noticed that pulley screws seemed to be loose. I had checked them for tightness yesterday, but there were pieces of the split washers in the bilge. As I pulled it apart, it was evident that that the center of the pulley was broken out. When it was apart, I found a plastic shim under the pulley, probably there to fix an alignment issue. You can see it just above the broken out center piece by the pulley. The pulley is 5 inches across with a 5/8" center. The bolts are 1 3/4" across the pulley. I haven't measured the depth yet, but where do I find a pulley?

​

Here is the pump out of the boat. It's made by Sherwood Brass and I didn't like the way it felt when I turned it in the vise. I took out the impeller and it feels just fine.

​

Back view of the water pump.

​

From the back side of the pulley. I guess I need to know the depth of the beast as well.

Can I replace this with an electric pump??? I hate the tensioning on this. It's obviously been rigged, and not well done at that.

 

[NetDoc]

Re: Overheat on my 3.0l...

Possibly a transom mounted water pickup, instead of trying to fix that old of a drive. Mercruiser uses one like this.

View attachment 142822

I like this with the screen. I think I sucked up some mud just before this happened.

 

[NetDoc]

Re: Overheat on my 3.0l...

I am thinking something like this: http://www.google.com/products/cata...=4HeYT4PWOsqX6QGco4m-Bg&sqi=2&ved=0CFcQ8wIwAg

 

[NetDoc]

Re: Overheat on my 3.0l...

BTW, I am trying to find a replacement pump and haven't found a direct replacement yet.

 

[Bondo]

Re: Overheat on my 3.0l...

I am thinking something like this: http://www.google.com/products/cata...=4HeYT4PWOsqX6QGco4m-Bg&sqi=2&ved=0CFcQ8wIwAg

Ayuh,.... I can't feature feedin' cooling water to the motor, with a bilge pump....

 

[mark1905]

Re: Overheat on my 3.0l...

View attachment 143023​

Can I replace this with an electric pump??? I hate the tensioning on this. It's obviously been rigged, and not well done at that.

:facepalm:

Wow. That's a first for me. The center of your pulley completely ripping out.. damn. How is your belt alignment? That thing must have been badly corroded to do something like that..

Check with marine surplus stores.. there are tons in FL.. or do the ebay thing. A quick search found many: http://www.ebay.com/sch/i.html?_nkw...cruiser+water+pump+pulley&_osacat=0&_from=R40

Get yourself a new water pump, new pulley, replace the belts, be done with it. This is not the norm..

What year motor? I can't imagine it being that difficult to find a replacement pump..??

 

[NetDoc]

Re: Overheat on my 3.0l...

Ayuh,.... I can't feature feedin' cooling water to the motor, with a bilge pump....

It pumps 30-80 gallons per minute depending on the back pressure. How many bilge pumps do that? Here are the factory specs: http://www.xylemflowcontrol.com/files/50840%2043000_0820.pdf

:facepalm:

Wow. That's a first for me. The center of your pulley completely ripping out.. damn. How is your belt alignment?

Belt alignment was fine and there was no excessive wear on the belt. When pulley alignment is critically off, the belt will take a bend that can be seen after it's off and/or you can see belt dust all over. Not so here. I think the culprit was the plastic spacer the old owner put under the pulley. It didn't sit flat against the flange and was able to flex/work harden until it broke.

When I had the pump on the vise, it felt very stiff and even felt like it had the first signs of bearing seizure. I see a slight wear pattern on the back of the shaft where it inserts into a bronze slip bearing, but after I pulled the impeller out, the shaft turns pretty freely. I do feel a tiny bit of a catch, and am worried that the bearings are toast and you can't feel it when there is no pressure on them.

Earlier, I had to replace the harmonic balance pulley (crankshaft). Actually, I had this one rebuilt. When I put the new one on, I found that the alternator pulley alignment was way off. I found that the alternator bracket had been ground to allow it to be repositioned further forward. Putting it back to it's original placement got the pulleys back in alignment. The raw water pump only works off of the water pump so it wasn't really affected by the misaligned crankshaft pulley.

I think I am going to disassemble the water pump today and see if I can't replace the bearings and seals. It looks pretty straight forward, but few things on this boat have turned out that way.

One last thing, I heard a strange hum develop when the engine approached 4K rpms. This was from the beginning and I reduced a lot of it by tightening the pivot bolt on the pump. The adjustment bracket looks home made, and the angle does not lend itself to stabilising the pump adequately (IMHO). Over tightening the pivot bolt really added some stability to the system, but I always had that vibration. I hate vibrations, so I always operated the boat under that rpm. Now I think it came from the pulley being improperly shimmed.

I hate it when people don't solve issues thereby creating more for others behind them. Do it right the first time and don't leave hidden time bombs to surprise subsequent owners. [/rant]

 

[Don S]

Re: Overheat on my 3.0l...

I have a feeling one of the problem is your engine. The 3.0L engines when cold jump around a lot on the rubber mounts. Problem is, with a tight belt, the pump doesn't jump around and the belts don't flex. so guess what's happening.

Volvo used to use a belt driven pump that was mounted to the engine. http://www.volvopentastore.com/Cool...on_id.304029034--store_id.366--view_id.787213
They now use a crankshaft mounted pump and the motor mounts are on the sides like V engines.
Perhaps you can find a pump and make a bracket similar to what Volvo had.

I sure wouldn't go with the electric pump either. You can't flow 30 gallons of water a minute through the engine, and that electric motor will not like the constant heavy load or long hours of use.

 

[NetDoc]

Re: Overheat on my 3.0l...

I have a feeling one of the problem is your engine. The 3.0L engines when cold jump around a lot on the rubber mounts. Problem is, with a tight belt, the pump doesn't jump around and the belts don't flex. so guess what's happening.

The pump is bracketed to the engine, not the boat, so it jumps when the engine jumps. Fortunately, this is one smooth running engine even on initial starts here in the Keys.

 

[NetDoc]

Re: Overheat on my 3.0l...

OK, the pump was easy to disassemble and I need one bearing and one seal to put it back together. I found the bearing easily as the part number was on the old bearing. 6204.RS is the number and a quick Google search shows it will only cost me about 2 or three bucks.

The seal is the problem. I found pieces of the old vanes in the seal area. It was pretty catastrophic, but here are some pics.



With the shaft out of the way, you can see the carnage.



What came out of the cavity.



This is what the spring rides on in the housing.



I have tried to recreate how it sat in the pump.



The actual seal that I need.

 

[NetDoc]

Re: Overheat on my 3.0l...

One final thing. The pulley may be salvageable. The broken center fits perfectly into the pulley and I think that I could weld her right back in with no distortion.

 

[Bondo]

Re: Overheat on my 3.0l...

One final thing. The pulley may be salvageable. The broken center fits perfectly into the pulley and I think that I could weld her right back in with no distortion.

View attachment 143179
I hate it when people don't solve issues thereby creating more for others behind them. Do it right the first time and don't leave hidden time bombs to surprise subsequent owners. [/rant]

Ayuh,.... Ironic,.... yer ignorin' yer own rant...

To be Honest,....
You've got a cobbed up piece of Poo, assembled with mis-fittin', broken parts,....

Now,... is the time to buy a raw water pump, 'n the bracketry to properly mount it to a 3.0l block....