#26
IP: 98.171.165.120
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A possible explanation for this is when the bypass is blocked as the engine heats up and the thermostat opens water can't can't flow through the engine or bypass all goes to hell in a hand basket. I assumed Brian had water flow out the exhaust when the engine was cold, but the water flow out the exhaust stopped when when the engine heated up. Maybe not. If there is no water coming out the exhaust ever then there is for sure a blockage somewhere. Edits to a previous post: When you remove the sending unit do not use a open end wrench. You will only round the soft brass. I had good luck with a closed end wrench and a hammer. When you start the engine with the nipple in place clamp the bypass. This will divert all the water into the engine and hopefully through the engine. TRUE GRIT |
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BlueWhale (01-02-2016) |
#27
IP: 107.0.6.242
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BlueWhale (01-02-2016) |
#28
IP: 73.133.219.4
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No grinding sound or attempts to get unstuck. No mud in impeller. The rubber part separated from the inner ring. None of the fins came off. I replaced the Tstat with the same type (double action, three legs). No spacer or valve. Water flows out the exhaust until the temp rises above 180 - then only steam. |
#29
IP: 73.133.219.4
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#30
IP: 24.152.132.65
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Seems clear to me your block/head is clogged. When the temp is low, the double action thermostat allows water through the bypass directly to the manifold. As it warms the thermostat opens the block/head passage and restricts the bypass. Your water flow out the exhaust should lessen (not that it should but I expect yours does). When it reaches 180° the thermostat has fully closed the bypass and fully opened the block/head passage in favor of full block/head flow and since it's clogged there isn't any flow.
At least that's how I see it. If this is correct, I don't expect an acid flush will help at this stage of occlusion. I think you're looking at a manual mucking out and depending on your sailing area be prepared for stuff as hard as concrete. On my spare engine I went after it with a pneumatic needle scaler, like a mini jack hammer. And expect to remove the head for access to several small passages. Sorry.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 01-01-2016 at 10:49 PM. |
#31
IP: 107.0.6.150
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It isn't good news and I see that Neil concurs with the diagnosis. However, since you are facing a removal of the head anyway you have nothing to lose by following John's procedure regarding the temp sender. The outside possibility is that you might jar enough junk loose to give the acid a shot at clearing the rest of the blockage. You will need maximum available pressure so clamp the by pass and give it a shot. If you get cleared as far as the sender, do the acid and maybe breakup some junk further downstream. If this fails you will have to pull the head and do the cleaning mechanically. Actually, though, if you are laid up for the season this is a good excuse for a look-see under that cylinder head. Just sayin'.
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BlueWhale (01-02-2016) |
#32
IP: 76.7.180.104
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BlueWhale. Thanks for the additional info. That clears things up for me. I asked about a possible grounding because often mud and other crud can be pulled in thru the raw water intake as we gun the engine in an effort to get to deeper water. DAHIKT.
Dan S/V Marian Claire |
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BlueWhale (01-02-2016) |
#33
IP: 24.138.22.213
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I ran across a similar issue a few years back helping a friend with a Yanmar 2gm diesel. We let go the pump and blew compressed air back through the block and rust scale came out inlet where the pump line went on...that was the end of his issues. We figured scale would move and cause a blockage. I don't think the Yanmar has the metallurgic composition of the A4 and might rust prematurely.... Not sure at all if that would be a viable option or issue for the A4. At the time we did that we'd tried everything we could think of to clear it. It would be fine at idle and as soon as it worked it would heat up.
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Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
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BlueWhale (01-02-2016) |
#34
IP: 76.7.180.104
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Has the cap been checked as a possible point of blockage?
Reason I ask is the block and head have multiple openings and passage ways. All of them would have to be clogged for there to be zero flow out the exhaust after the T-stat closes the bypass. I was amazed at how blocked my passages were when I rebuilt my A-4. But even as bad as they were I never overheated. The cap or the T to the cap seems to be the one place that if blocked would shut down the whole flow. Just something to look if you haven't already. Dan S/V Marian Claire Last edited by Marian Claire; 01-02-2016 at 08:34 AM. |
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BlueWhale (01-02-2016) |
#35
IP: 98.171.165.120
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If you have trouble breaking the temp sending unit (or head nuts or exhaust flange bolts) try this:
Shoot the area up with PB blaster or your favorite goop for a few days.* Start the engine and run it until it is up to operating temp. Brian, in your case be careful not to overheat and ruin the engine or exhaust system. While the engine is running and hot lay a closed end wrench on it. A 6 sided box end wrench would be a good choice of tools. Tap on the wrench gently to firmly until the sending unit breaks loose. No pounding. You'll only break something pounding on it with a hammer. The engine heat + engine vibration + shock from pounding on the wrench will break the sending unit loose. Once the sending unit is broken loose turn the engine off and finish removing it. *I don't like the idea of using PB blaster on exhaust flange bolts on anything that gets real hot. It cooks off and what is left acts as a thread lock. TRUE GRIT Last edited by JOHN COOKSON; 01-02-2016 at 09:57 AM. |
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BlueWhale (01-02-2016) |
#36
IP: 71.59.125.65
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Another alt for back flushing.
Remove the T stat Seal off the inlet hose barn on the T stat fitting with a bolt and a short pc of hose Disconnect the hose going from the pump to the T fitting at the water jacket cover. Seal off the second hose connected to the T fitting that went to the T stat. In essence you have made it so that water can ONLY flow.through the block from the water jacket fitting to the out flow.of the t stat housing. Attach a garden hose to the out flow or discharge connection or the t stat housing. Put the hose from the t fitting at the water jacket cover in a bucket., you want to capture the crud that may come.out Now.be careful! A typical garden hose will produce 20 - 40 lbs of water pressure. Your engine CANNOT withstand that much pressure. Place a small ball valve fitting, available at any hardware store, into the garden hose connection just before the engine so you can quickly make flow adjustments. Turn the water on just a little. ( not.a.bad idea to play With the available.flow.prior to attaching to the engine so you have feel for about 1/4 available flow) If you can not push water through the block backwards, from t stat to t fitting at water.jacket cover, with 1/4 house pressure your not.going to do so with more pressure. Trying too much pressure and flow WILL trash the engine.( It might not but better to assume it will) If you get some.water flow, even just a little, let it run for a while, the longer the better. Then reverse the hoses and pump 1/4 possible line flow through the engine in the normal direction. Remember to capture the outflow of water out of the engine in both directions. It may tell you a lot by the type of crud it deposits in the bucket. Disclaimer. If the head ports.are.clogged all the flushing in the world.is not.going to open them up. The water is going.to take.the path of least resistance. However, if a passage is restricted, flushing MAY break loose some of the crud and open things up enough to make an acid flush usefull. Normally opening the water jacket cover will allow for a good cleaning with picks and shovels. (Awl , spoon anything you can greet in there to scrape it out)l have seen some of the pictures on this forum showing cruddy vs. Cleaned out water jackets?
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Bill 1974, Tartan 30, Unchained Melody www.CanvasWorks.US Last edited by BadaBing; 01-02-2016 at 11:30 AM. |
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BlueWhale (01-02-2016) |
#37
IP: 70.192.195.193
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Well, it seems that "All is Lost" and head removal is the next step. I tried the flush removing the heat sending unit to no avail. I'm located in Baltimore, MD and am still in the water. I don't have great access to the engine and am not looking forward to this task. Thanks for all the advice and walking me through the "easy" fixes.
Brian S/V Rekofa, The Blue Whale C&C 34, 1979 |
#38
IP: 70.192.195.193
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Brian |
#39
IP: 70.192.195.193
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Ok, now "All is Lost" 😔. The flush did not get out enuf gunk. Question, if I do the muriatic acid flush and it does not work, will the muriatic acid left in the engine remain there and cause damage? In other words given the blockage will the flush go through the system?
Brian |
#40
IP: 76.7.180.104
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You can always use vinegar with no fear of damage.
Dan S/V Marian Claire |
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Administrator (01-02-2016) |
#41
IP: 24.138.22.213
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...anyway, you have flow before it heats up so draw the muriatic acid in...shut down for a bit then fire it up and run 5 gallons of water through...the acid will dilute. Throw some food coloring in your muriatic acid if you need to know how much to draw in...lets say you use blue, at about 3/4 gallon drop from your suction bucket you should see it spit blue out the transom. Once you see that allow it to sit, have a beer or two, in peace and then start it up under normal conditions using fresh water from your bucket. One start up you will see dark brown and maybe a bit of black...normal...might even see some crud come out...normal. PS: I seem to remember a similar situation, perhaps it was on this forum. Water flow at low idle, and decrease water flow, temp increase with rpm increase. The T-stat removed, and exhaust manifold fitting was checked, later to be found out that a rust scale inside the manifold would work it's way up under the increased flow and block the exit....muriatic flush might help with that as well. Once water pressure built in the manifold it floated up the flake of rust and blocked the exit. If it's a crustacean in the block there causing the issue, I imagine it would be coming out the exhaust. The other thing to consider, I believe it was mentioned, is buildup up of deposits after operating at higher temps for long periods of time...stalactites, in a manner of speaking.
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Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. Last edited by Mo; 01-03-2016 at 06:42 AM. |
#42
IP: 98.171.165.120
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Please do a couple of things before you pull the head. REMOVE THE THERMOSTAT. Then put the housing back on, and attach a hose to the output barb and see if you get good water flow. Keep disconnecting cooling system hoses and starring the engine then reconnect the hose and move on down the cooling system in this manner to the back of the boat until you get no flow then you will have the clog localized. I know this idea flys in the face of a lot of theories presented so far but it would be a bummer to pull the head and still have the overheating problem after you reinstall it so be sure there is free flow in the the entire engine, manifold, exhaust system first. TRUE GRIT |
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Mo (01-03-2016) |
#43
IP: 24.138.22.213
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__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#44
IP: 70.106.195.215
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It's suppose to get cold over the next couple of days but I think I'll endure it and give it a try. Thanks. Brian |
#45
IP: 73.27.138.11
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I think you would have a valve on the by pass. You can adjust the temperature that way.
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#46
IP: 98.171.165.120
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Once again try removing the thermostat and clamping the bypass. TRUE GRIT |
#47
IP: 76.7.180.104
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Bluewhale. Yes things have been confusing but I also think you have got it.
I would do this test: 1.T-stat removed, 2. Bypass hose clamped shut 3. T-stat housing off. *** I would only use water for this test. No risk of splashing acid.This way you can actually see how much water, if any is going thru the block/head and the only way it can get to the "open housing" is thru the block. If you want to have the temp sensor removed that is fine and may be easier to see any flow depending on your access. It will not take long to tell and will probable make a mess so be ready to shut her down. You may even have some water coming thru the bypass if the clamp is not perfect so be ready for that. I do not think you will damage anything down stream during this brief test. The bottom line is we must have flow thru the block to cool the engine. Forget about everything else until flow thru the block is confirmed. Dan S/V Marian Claire Other questions/comments. I wonder if this test could be done with air? I believe BW does not have a valve in his bypass line because he has the double-action T-stat. Last edited by Marian Claire; 01-04-2016 at 02:59 AM. |
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BadaBing (01-05-2016) |
#48
IP: 70.106.195.215
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Thanks for the clarification. It was too cold to try it today. It should be in the 50s this weekend. I'll keep you posted.
Brian |
#49
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Where are you Brian? 7F here in Halifax today.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#50
IP: 24.138.22.213
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__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
01-05-2016, 01:54 PM |
Marian Claire |
This message has been deleted by Marian Claire.
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cooling system, cooling water stops, overheating, thermostat |
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