Coolant Resevoir Keeps Filling Up.

[bigpursuit]

I own a 2000 Pursuit 7.4 Crusaders.* Last year I had a problem with the fresh water cooling system.* The Coolant resevoir was constantly overflowing.* This would only happen when the boat was moving under a load, not at the dock.* I would go out 10 or 12 miles and notice the smell of the anti freeze.* The boat temperature would rise slightly but never overheat.* I also began to notice the resevoir was bubbling.* Mechanics checked everything out(heat exchanger, exhaust elbow, impellers).* I finally asked for a compression check and it was concluded there was a potential head gasket problem.* Over the winter the head gaskets were replaced.

Put in the water couple weeks ago and went for a test run.* Things seemed ok but I hadn't gone very far.* Couple days later went out fishing, drove out to spot, trolled on that motor, total of 4 hours on engine.* When I got back in I noticed the resevoir had overflowed again.* Not much but considering the coolant level in the resevoir was below the add level when I started it had pushed alot of fluid out of the engine.* I left the boat alone to cool down (overnight) and came back to notice none of the fluid had been sucked back into the engine.* I drained fluid out of the resevoir and refilled the fluid in the engine.* I ran the boat @ idle until it warmed up let it cool and filled the engine again.* I haven't had it out since do to family and the holiday but i am really worried the replacement of the head gaskets didn't work.*

Is it possible there is just air in the system.* How do you tell that all air is purged from the fresh water system?* Any help would be greatly appreciated.

[diver_dave]

It would be good to know if you are getting raw (salt?) water in the coolant. A special test strip would reveal that. In any case, I would warm the engine and test for coolant leaks with a radiator type pressure tester.

[bigpursuit]

It would be good to know if you are getting raw (salt?) water in the coolant. A special test strip would reveal that. In any case, I would warm the engine and test for coolant leaks with a radiator type pressure tester.

I have tested the coolant it looks fine. Performed a pressure test last year before the head gaskets were replaced. By the way I am on Lake Michigan - no salt.

[diver_dave]

Is the heat exchanger higher than the thermostat housing? If not, you should purge air by bleeding at the highest point in the system. Are you using a 7psi cap in good shape?

[bigpursuit]

The thermostat is in a copper tube just outside the heat exchanger. It is in the line which flows coolant into the heat exchanger. There is a plug on top of the heat exchanger itself. The radiator cap is on top of the engine. The cap is 7psi. I switched caps from the other engine to make sure it is ok.

[diver_dave]

Quite a bit of work has occurred since the last pressure test. I would do a warm engine pressure test. It is unlikely this will not detect a leak into the system.

[makomark]

He's got the newer GEN X closed cooling system - the HX will be lower than the fill riser which received the pressure cap. Concur with the need to redo the pressure test. Any feedback from the head gasket job?

These systems pretty much self purge after a couple hot-cold cycles. Raw water entering via a HX leak is unlikely due to the pressure differences; I've only seen coolant leave via a leak there, never raw water enter the closed side.

another option is to find a low range (say 30 PSI) pressure gauge and an adapter, and install it in one of the threaded bungs in the fill riser to see exactly what the pressure is in the closed side. Coolant going into the degas (overflow) bottle means the cap isn't sealing or the pressure on the closed side is getting too high and expelling it. a leaking cap will also prevent the coolant from being drawn back in when the engine cools.

A good pressure tester kit will have the adapter to check the cap too. caps are cheap so just replacing it may be worth the trip to get them.

[diver_dave]

Also, I just thought of this problem. A small defect in the brass sealing surface of the HE fill neck could keep the coolant from returning back to the HE. Inspect carefully the brass ring shaped sealing surface after pressure cap removal.

[bigpursuit]

Thanks for the suggestions guys I will try a few things will check back thank you.

[RicardoMarine]

Also, I just thought of this problem. A small defect in the brass sealing surface of the HE fill neck could keep the coolant from returning back to the HE. Inspect carefully the brass ring shaped sealing surface after pressure cap removal.

Bingo!
This must be capable of creating the necessary siphon that will draw coolant back from the reservoir.

The pressure cap must also be the style that is specific to a recovery system (valve and two sealing surfaces).
If not, it won't siphon the coolant from the recovery reservoir no matter how good the neck the is.


With all working correctly, the only thing that your Closed Cooling System should undergo, would be coolant expansion from heat..... nothing else.
The expansion dumps the excess into the recovery reservoir.

If the coolant recovery system is working, at the end of the day, there should a zero sum gain.... meaning that as the engine cools down, any over-flowed coolant in the recovery reservoir will return to the H/E... and both levels should be the same as when you began.


.

[bigpursuit]

I had the marina do another compression test. They came up with the following result:1-160,2-150,3-150,4-150,5-140,6-150,7-150,8-160.
This doesn't look good to me! The numbers are very close to what they were before. Have I been ripped off?

[makomark]

They are serviceable numbers.

Think there were 3 or 4 recommendations to get the cheaper cooling system pressure test done....has that happened yet? Tested the cap? checked the filler port's opening to ensure no flaws in the sealing surfaces?

A compression test gives you some insight into the state of the combustion chamber...a leakdown test is a much better test.

You usually are better off spending the money on diagnostic tests vs. just throwing parts and labor at an issue.

[bigpursuit]

The compression test was just done because the marina replaced the head gaskets over the winter. The cap is the one from the other engine. Pressure test was done last year before the head gaskets were replaced.
Do the numbers make since for an engine which had the head gaskets replaced 2 month ago? Thank for the input!
( I agree with checking further On the other suggestions. I haven 't had a chance to perform them yet. The marina went ahead with the compression check to ensure the head gasket was done correctly)

[kimcrwbr1]

You can do a leakdown on the engine the compression test just tells you it it leaking a leakdown tells you where. Put each cylinder on TDC on the compression stroke apply 30-40 lbs air pressure to the cylinder and see if air is pushing into the water jacket it is head or head gasket. If you hear air in the carb it is intake valve air in the exhaust is exhaust valve or air in the block it is rings. One way to determine if it is the engine. Plus it gives you a idea of the overall health of the engine. Like killing two birds.

[bigpursuit]

You can do a leakdown on the engine the compression test just tells you it it leaking a leakdown tells you where. Put each cylinder on TDC on the compression stroke apply 30-40 lbs air pressure to the cylinder and see if air is pushing into the water jacket it is head or head gasket. If you hear air in the carb it is intake valve air in the exhaust is exhaust valve or air in the block it is rings. One way to determine if it is the engine. Plus it gives you a idea of the overall health of the engine. Like killing two birds.

Yeah but I did all that last fall! That's why they replaced the head gaskets.

[kimcrwbr1]

Last fall maybe it was not fixed correctly. Do a leakdown and if bubbles come out the engine coolant you will need to pull the heads again. Did you have the head/s magnafluxed for cracks.

[bigpursuit]

Last fall maybe it was not fixed correctly. Do a leakdown and if bubbles come out the engine coolant you will need to pull the heads again. Did you have the head/s magnafluxed for cracks.

I don't believe they checked for cracks. I do believe if there was a crack I would have bigger problems. The boat runs fine it just keeps getting air in the cooling system.

[bigpursuit]

So I checked the fill riser to ensure no abnormalities. The cap works fine on the other engine. Just took the boat for a ride. Noticed bubbles in the coolant reservoir as the engine decelerates. It bubbles a lot for a few seconds then stops. I recorded with my phone, check it out: http://www.youtube.com/watch?v=fKIR5...hannel&list=UL

[fastjeff]

Hot spot somewhere that's boiling the coolant, one caused by a blockage in a passage?

Jeff

[makomark]

Seriously, If they had the heads off and didn't disassemble them and get them magnafluxed, I'd look for a new mechanic. Not saying that is the issue, it's just penny wise and pound (your dollars) foolish.

When was the last time the raw water pump was serviced? If you have an IR temp gun, shots of all four exhaust elbows and the HX's would be another good thing to do. If the cooling water flow is marginal, it will show after a five to ten minute run on plane, right when the throttles are backed off like in your video...just food for thought

[bigpursuit]

Seriously, If they had the heads off and didn't disassemble them and get them magnafluxed, I'd look for a new mechanic. Not saying that is the issue, it's just penny wise and pound (your dollars) foolish.

When was the last time the raw water pump was serviced? If you have an IR temp gun, shots of all four exhaust elbows and the HX's would be another good thing to do. If the cooling water flow is marginal, it will show after a five to ten minute run on plane, right when the throttles are backed off like in your video...just food for thought

I fully agree with you I need a new mechanic. Any suggestion on finding one? I am unhappy with both the boat
manufacturer and crusader both are useless.
If the block is cracked does that mean a new engine?

Also the raw water side had been completely checked out and is fine. It really looks like head gasket or crack in the block.

[kimcrwbr1]

Dont rit it apart if it passes a proper leakdown it probably isnt in the engine. After thinking about it it could be the dip tube going into the expansion reservor when the coolant heats up it expands and the reservor catches it but when the engine cools it pulls coolant back into the engine. it could be just a leaky fitting sucking air instead of coolant. To test it try and siphon the reservor dry, if it dont siphon the resorvor or fitting is defective. I had the same problem with my ford ranger and the plastic tank had a crack on top of the built in suction tube and a chumk of something in the bottom of the tank. My theory is the piece of crap would clog the tube and when the engine cooled it created vacuum pressure similar to what youe engine is doing when you let off on the gas. Another of my theories why you get the bubbles is when the engine is at high rpms it causees the water pump side hose to collapse slightly from negative pressure when you let off the gas the hose expands back to normal and puts the systen in a neg pressure trying to pull coolant back into the engine. I am voting for the reservor/fitting being defective.

[bigpursuit]

For those who haven't seen it this is a video of the coolant resevoir in my boat. It starts to bubble as the engine decelerates. http://www.youtube.com/watch?v=fKIR5...hannel&list=UL
My question is if it is a cracked block does that mean a new engine?

[diver_dave]

Did you say you had already tested for combustion gases in the coolant? If not; here is one option:
http://www.amazon.com/UVIEW-560000-C.../dp/B000NPDL76
I haven't used that particular type, however.

Combustion gas vs "boiling coolant" will drive completely different fixes.

[makomark]

good mechanics are local treasures...ask around the local dock. Worst case is you will learn who to Avoid.

The heads are more likely to crak than the block. cracked block usualyy equals replacement block.

Don't throw the towel in on Crusader. they aren't perfect but make a very decent product for the money.

Keep up and do some more diagnostics. Do enough and the answer will become apparent. Most poster here started in the "same boat" you are in...a little collaboration goes a long way and may even save you a small fortune.

[bigpursuit]

good mechanics are local treasures...ask around the local dock. Worst case is you will learn who to Avoid.

The heads are more likely to crak than the block. cracked block usualyy equals replacement block.

Don't throw the towel in on Crusader. they aren't perfect but make a very decent product for the money.

Keep up and do some more diagnostics. Do enough and the answer will become apparent. Most poster here started in the "same boat" you are in...a little collaboration goes a long way and may even save you a small fortune.

Thanks everyone I appreciate the time you've taken to help!

[bigpursuit]

I tested the air in the resevoir with one of those test kits that test for combustion gas. It proved to be negative. While the engine was running @ 3400 rpm I went below with an IR Heat gun and checked every part of both engine I could get a read on. everything on both engines was around 160 except the port side exhaust manifold on the engine with the problem. That manifold read 240! After all this messing with the heads and gaskets it appears the bubbles were boiling fluid and not combustion gas. The engine never overheated because the blockage kept the hot liquid from getting to the rest of the engine.

I believe problem solved! I am going to replace manifolds on both sides.

[diver_dave]

I tested the air in the resevoir with one of those test kits that test for combustion gas. It proved to be negative. While the engine was running @ 3400 rpm I went below with an IR Heat gun and checked every part of both engine I could get a read on. everything on both engines was around 160 except the port side exhaust manifold on the engine with the problem. That manifold read 240! After all this messing with the heads and gaskets it appears the bubbles were boiling fluid and not combustion gas. The engine never overheated because the blockage kept the hot liquid from getting to the rest of the engine.

I believe problem solved! I am going to replace manifolds on both sides.

First, check those 1" hoses and barb fittings. Hoses can delaminate internally. Manifold passages are pretty big, and it's rather rare to see a coolant filled manifold plug like this. Actually, disconnect the two hoses and try to shoot a water hose jet thru it all.

[bigpursuit]

First, check those 1" hoses and barb fittings. Hoses can delaminate internally. Manifold passages are pretty big, and it's rather rare to see a coolant filled manifold plug like this. Actually, disconnect the two hoses and try to shoot a water hose jet thru it all.

I disconnected hoses from the engine so they were only connected to the manifold. I then ran water through the whole thing in both directions. It gets through. Possible part blockage inside somewhere I assume?

[diver_dave]

I disconnected hoses from the engine so they were only connected to the manifold. I then ran water through the whole thing in both directions. It gets through. Possible part blockage inside somewhere I assume?

I'd remove both 1 1/4" hoses and boresite thru them to insure there is no loose rubber internally. The manifolds are exactly in parallel, so the output from the thermostat housing splits and cools each manifold with about half of the coolant flow. Of course, the hot end ends up at the HE. There should not be much resistance to flow.

One more thing. You did not measure very low on the manifold right? That's too close to the single wall exhaust passage.

One more/more thing. Make sure the thermostat is open before you debug on the manifolds. A closed thermostat, during warmup, will heat quite hot the manifold coolant. Then, as the stat opens, they will cool off quite a bit.