Cooling issue = Blown head gasket |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Posted: August-07-2016 at 11:32pm |
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Hey Gents, so I've been chasing a cooling issue since I bought my boat back in May (1989 SN 2001 351). When I had it on the lake back in June (last time out) it ran 170-180 with a few inconsistent spikes over 180ish, but never got over 190- and the risers were getting really warm which made me suspect a flow issue. I went through all of the tests at home in the driveway and couldn't figure it out.
I finally gave in a few weeks ago and took it the local inboard dealer. They tested all of the usual cooling suspects (tstat - yes a 143, strainer, connections, rwp, etc). No problems there...So after all of that they decided to do a fluid sniffer/smog test and it showed exhaust gas in the cooling system. They told me it's most likely a blown head gasket causing it to run hot. Good thing is there is no water in the oil and compression is 125+ on all 8 cylinders. So with all of that I'm just looking for a little feedback from the CCFAN "motor experts". The more I've researched the issue themore it makes sense- I just haven't seen it a lot on this forum. Is there anything I need to look out for or make sure the shop does when doing the repair work? I have an estimate from them to remove and check manifolds, remove, pressure test and resurface heads, install new gaskets and reassemble. And they said they would send the heads to a cylinder shop for the pressure testing and resurfacing. |
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1989 Ski Nautique 2001
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Is this the correct head gaskek kit?
Fel-pro gasket kit And I'm also planning on cleaning my manifolds and risers while they are off. Any suggestions on what to use to get the rust scale out? |
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1989 Ski Nautique 2001
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desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
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My engine has always run in the 160 - 190 range. Have you done a compression test?
edit: Just reread your post and saw that you have. I'm not an expert but shouldn't the compression check catch a bad head gasket. Was the check done when the engine was warm? |
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Silver15
Senior Member Joined: March-24-2010 Location: Orlando Fl Status: Offline Points: 398 |
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It seems to me there are other items to consider before tearing your engine down. Others will chime in with those possibilities. Personally, I would want to run engine while using a laser temp reader to quantify your findings. There's a chance that your indicator is incorrect and that your "warm" manifolds are totally normal.
Having said that, if you do end up pulling the heads, I agree it would be wise to have them tested and surfaced. If your budget permits, it may be a good time to upgrade to GT40p heads. I'm 99% sure they would bolt right up and the performance benefits would be appreciable. |
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2000 Air/Sport
1978 T16 |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3337 |
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Yeah I'm having a hard time seeing anything wrong here either.
Nor do I agree with the mechanism. Isn't your water temp almost 90 to start with ? I'd just go ski. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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I'm pretty sure its running hot. The manifolds and risers feel "hot" to the touch, not just warm. I've had multiple conversations with Vince at SkiDim and he said with a 143 tstat you should run 160 no matter the water temp. Spoke to him again this morning and he said the blown head gasket does make sense as to why it's running hot.
Here is what the shop says: |
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1989 Ski Nautique 2001
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Lakeview
Senior Member Joined: January-06-2004 Location: Branchville NJ Status: Offline Points: 247 |
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Check your impeller- if your flow is not good check the circulating pump
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Lakeview
1992 Barefoot Nautique 1967 Barracuda SS 1967 Chris Craft Cavalier |
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Smithfamily
Platinum Member Joined: December-26-2007 Location: Orlando, Fl Status: Offline Points: 1602 |
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+1 My 92 will run in the range of 170-185 +/-. Curious how they checked for "exhaust gasses in the cooling system"? As the raw water cooling flows out the exhaust? No water in oil is good. If the impellor is working, I, too would run it. Maybe plan on a rebuild come winter? In 2010 I pulled my engine myself and had it professionally rebuilt. Cost was $1800. Then I wound up doing the retro fit distributer, $500. She runs sweet. Good luck!! How many hours on it? Smith Family |
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Js
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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From speaking to the mechanic and doing some research myself the way I understand it is that the combustion gases aren't being kept in the cylinder and are blowing into the water jacket. I don't have water in the cylinders or oil at this point because of the location of the leak and because it's probably small...and it only happens when there is high pressure in the cylinder. Compression testing won't show it because it isn't high enough pressure for the leak to occur, but exploding combustion gas is enough to make it leak. Does this make sense?
FYI...The RWP and impeller are fine. |
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1989 Ski Nautique 2001
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10774 |
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I gotta agree with GottaSki This leak? is so small that you're not getting water into a cylinder or the oil but it can heat up a healthy flowrate of water thru the manifolds just don't pass the BS test. Can't see how they can measure the combustion products in the cooling system in a boat with an open cooling system that mixes exhaust and water anyways.. KenO |
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desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
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Easier to read this way:
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3620 |
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If your oil is clean and the compression is as stated, even in all 8 cylinders your head gasket is fine. In a boat your cooling system is overkill with constant access to cold cooling water your manifolds should never run hot and neither should your engine.
I did blow a head gasket in my 78, overheat while skiing when the RWP impeller failed. Any overheat can crush the head gaskets and then when it cools off they will fail soon after. With a blown head gasket my engine ran great for the summer. It never ran hot even with hot exhaust being blown into the cooling system from the one bad cylinder. I fixed it much later. A few times I had to pull the plug to dry the spark plug to keep it running on all 8. That cylinder was down on compression and had water in it from the head gasket failure. I suspect you have a flow issue that needs quick attention. Maybe a previous owner had an impeller fail. Sometimes the blades on the impeller will tear off and lodge upstream in your cooling system. This happens frequently with old impellers. You need to clean out the old rubber chunks that are blocking the cooling passages if that happened. Pull the hoses and inspect at the manifolds and at the thermostat. I think others have posted ways to check your intake by putting the raw water intake hose from the bottom of the boat in a 5 gallon bucket to see how much the engine is pulling as it runs. With mine the boat needs my home garden hose to be turned on to about half open to keep up at idle. 5/8 hose with city water pressure, 40 lbs estimated pressure, good flow. If any of your intake hoses have an air leak your engine will suck air rather than water. It is good to make sure all connections on the intake side are tight. Follow from the boat bottom intake all the way to the raw water pump connection. Does your boat have an intake water filter? Most do. It needs to be clean and it has to seal also to hold vacuum for your water intake to work. Several items to think about but you have an issue that needs to be fixed before you have a failure. |
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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You most likely have an air leak on the suction side of the raw water pump. It's time to replace all your hoses from hull pick up to the thermostat housing. I would first run a continuous piece from pick up to trans cooler eliminating the strainer (cut the hose and add back in later). "Bubbles in the strainer" is not normal. Many times in clear water you can't even tell there is liquid flowing through it. You might also have a cracked or loose strainer bowl, they get tight and very difficult to seal. Any exhaust gas that gets into the water jacket is going to quickly be cooled right back down. |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Thanks. So you think the mechanic is blowing smoke about the head gasket? He says it still ran hot running a hose directly to the RWP in a bucket. I guess I'm perplexed because they detected the exhaust gas in the cooling system with the fluid leak test. Wouldn't this be definitive of a gasket leak? I'm planning on doing some diagnostics myself this weekend. |
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1989 Ski Nautique 2001
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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Pulling off the manifolds and inspecting them and all hoses isn't a bad idea. You're dealing with a lot of unknowns on this new to you boat.
Were you the one who had the boat overheat on the test run? Getting the engine to idle at normal temperature should be easy. Zach's brother has a salt '89 that only warms up on hard long runs. |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Yes, it did overheat on the test run, but held steady at 170 after we got the RWP installed correctly.
Come down to Wichita and help me figure this damn thing out and I'll buy you a steak dinner LOL! |
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1989 Ski Nautique 2001
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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If you got it to run 170 then you should be able to repeat that.. Get your hands on a known good RWP. Plenty of Fords around here, someone must have one to loan out. I'm still skeptical of your strainer and hoses.
"Tried bucket run straight to raw water pump, still hot." ^wonder what "hot" meant to them |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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He said 175 is as cool as it ran for him.
Every time I've run it in the driveway it seems to be sucking good and getting plenty of water coming out of the exhaust. I would like to try a known good pump and see what happens...Anybody have one they would loan me? |
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1989 Ski Nautique 2001
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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1989 Ski Nautique 2001
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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clearly you're new to inboards
this doesn't mean much |
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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MY buddy said it's not hot - till you smell the engine paint burning
Double check all the hose clamps with a socket not just a screw driver, and ski. |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Not necessarily "new" to inboards. I've owned an inboard before, but haven't had to deal with a cooling issue like this. I realize you can still have good flow and be sucking air somewhere. Im just incredibly baffled because I have an inboard mechanic telling me I have a blown head gasket and all of you good folks telling me I don't. |
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1989 Ski Nautique 2001
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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Well you might, as could many of us, but I certainly don't have an evidence of that yet.
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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So you're not buying the fluid/combustion leak test? |
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1989 Ski Nautique 2001
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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I would like to know how they proved that it is a head gasket,i.e. What is their test procedure? I know how it's done on a car can't figure out how it's done on a boats system.
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13512 |
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I don't know anything about it but on a cool engine you could capture the recirculating coolant in the block and provide hose water to the manifolds. Also disconnect the RWP belt. It would take some plumbing but it's possible.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Online Points: 10774 |
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I figure that if you believed the shop and had a lot of faith in their diagnosis you wouldn't have been asking for the second opinion here. Ask the shop what this fluid test is.
Run the boat on the water so the engine is loaded, with the thermostat removed as a temporary test and see what you get for temperatures. Not all thermostats are created equal Not all new ones work right either t stat thread Look at the link above, you've looked at it before since you have a post in it. What kind/ style of thermostat do you have now. I've put in brand new thermostats before, just so I could replace it again with one that actually worked when the first new one did basically what you're seeing. Did the no t stat test to figure this out. |
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bb12
Senior Member Joined: March-24-2009 Location: Kansas, USA Status: Offline Points: 355 |
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Yes, I did ask him how he did it, but I can't explain it. He said one guy had to get up on a ladder with a long hose. Sounds like they had to get creative with how they rigged it. They used a tool like this |
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1989 Ski Nautique 2001
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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this is where I feel that the BS comes in.... since the exhaust gasses are present in the cooling system by design, I don't know how the mechanic was able to determine that the head gasket was leaking by doing a chemical test. in an automotive style application (much like Gary was saying) the coolant and the combustion gasses are not meant to intermingle. Therefore, if there are exhaust gasses in the radiator, you have a head gasket leak. It seems to me that with a wet exhaust on a boat, the water before the engine would be free of exhaust gas, as it comes from the lake or the hose or the bucket. On the exit side though, exhaust gasses would be present anywhere after the 90°collector at the top of the exhaust manifold. if Exhaust gasses were present before that, it could be just that the Exhaust manifold is leaking, or could be a head gasket leak, but I don't think you could realistically determine the source, or realistically connect the chemical collecting device.
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3620 |
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Check for blockages in the cooling system. Old impeller parts are a common blockage.
These would be upstream of the Raw Water Pump on the engine side. |
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