1992 SN overheat - tried everything
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=4041
Printed Date: January-29-2025 at 4:15am
Topic: 1992 SN overheat - tried everything
Posted By: Chill99
Subject: 1992 SN overheat - tried everything
Date Posted: July-03-2006 at 11:06am
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I posted this on another forum, but not getting much response. I've tried everything I can find to get the temp down.
When I bought the boat a couple of months ago, it was running 160 degrees. Now it's at 180 at idle. Here's what I've done: 1. New impeller. 2. Did a flow test per instructions on skidim.com and it tests perfect. 3. New thermostat - 160 degree. 4. Went thru all hoses looking for old impeller parts. 5. Pulled all engine plugs looked for debris. 6. Check strainer for cracks and bad o-ring. Made sure it was on tight. 7. Tightened all hose connections. 8. Put in new temp sending unit. 9. Performed test listed on skidim.com to check that temp gauge is performing correctly (although it doesn't test the accuracy of the gauge). What is left to do? Could the new t-stat be defective? Could the temp gauge be defective? |
Replies:
Posted By: David F
Date Posted: July-03-2006 at 11:38am
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Yes.
Check t-state in pot of heated water with thermometer. Observe at what temperature it opens up. Check the electrical connections (especially) grounds between sending unit and temperature guage. ------------- |
Posted By: PLBC
Date Posted: July-03-2006 at 12:26pm
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I'll second checking the electrical connections and it wouldn't hurt to double the check the (new) impeller. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5164&sort=&pagenum=1" rel="nofollow - 99 |
Posted By: Tim D
Date Posted: July-03-2006 at 12:30pm
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If the impellor had blades to break off, there is a good chance you have some stuck in the block restricting water flow. When mine broke off I found three in the exhaust manifolds and one in the bypass fitting behind the thermostat. They can't pass down the veins in the exhaust manifolds. ------------- Tim D |
Posted By: Chill99
Date Posted: July-03-2006 at 1:10pm
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Excellent stuff.
I have rechecked the new impeller - twice now. Always looks ok - no fins missing. The pump test shows it's working well. I'll definitely check the electrical part. When I initially changed the t-stat, I did find about four large chunks of impeller. They must have been in there a long time. The impeller I replaced was intact. I've checked all hoses for more parts and found none. What's the best way to check exhaust manifolds for impeller parts? |
Posted By: GottaSki
Date Posted: July-03-2006 at 1:15pm
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I'm thinking upside-down t-stat. Is it possible, dimentionally? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: Tim D
Date Posted: July-03-2006 at 1:29pm
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Check the exhaust where the water enters at the front, which splits and goes inside each wall. ------------- Tim D |
Posted By: Chill99
Date Posted: July-03-2006 at 2:24pm
| I'm pretty sure I got that t-stat in correct. The pointed end goes up - correct? |
Posted By: Tim D
Date Posted: July-03-2006 at 2:26pm
Correct. This is from the top side.
 ------------- Tim D |
Posted By: ccskier16
Date Posted: July-03-2006 at 6:20pm
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Get a 142 degree t-stat. That will bring your temperature down. ------------- |
Posted By: 79nautique
Date Posted: July-04-2006 at 1:18am
nothing is wrong leave sh*t alone. It runs 180 now because you replace the 142 t-stat that was fine, with a 160 t-stat that you didn't need to change in the first place. Put since you have leave it a lone it's fine. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Chill99 wrote:Posted By: Chill99
Date Posted: July-04-2006 at 6:10pm
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79nautique:
The part I didn't bother to mention at the onset of this post was that this whole thing started because my temp was soaring up over 200. The old t-stat that came out was shot (and I had some old impeller parts in the t-stat housing from the previous owner). It was so old that I couldn't read the temp markings on it to know what it was. I put in a 160 because that is what skidim recommends, as well as many people on this forum and PN forum. So I agree, if it ain't broke don't fix it, but this was "broke". Chances are that everything is fine now, but it still makes no sense to me that I'm running a 160 t-stat and the gauge is showing 180? Until I know why, I'll always be a little suspicious that something else isn't quite right. ccskier16: Good idea to go to a 142, but that will just mask the problem and doesn't fix it (if there is one). Thanks for all the input from everyone. I have learned a lot from this forum and PN. I also learned a lot more about my boat and how the cooling system works. If anyone else has more ideas, please send them my way. |
Posted By: ccskier16
Date Posted: July-05-2006 at 9:30am
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Chill99
I am assuming you have a 351 with ProTech? My understanding is that these Fords ran with a 142. In the late 90's with the switches to EFI and GM then the t-stats/operating temperature required a 160 t-stat. I run a 142 degree in my 91. From my expreience it runs at 142 under power but at times does run 160 at idle. My guess is with the 142 you woun't be masking any problems. ------------- |
Posted By: TRBenj
Date Posted: July-05-2006 at 9:49am
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Chill99,
It was news to me, but I was told by the dealer that the 143 degree thermostat is what is recommended for our boats. I believe it should allow the motor to run ~160 degrees. Your 160 deg thermostat is whats causing you to run warm. I think 180 degrees is just fine for the motor if you dont want to bother changing it again. ------------- |
Posted By: dans
Date Posted: July-05-2006 at 3:50pm
| I had the same problem.I thought I checked all the hoses good by looking into them for impeller parts.Next time I removed all the hoses competely from both ends. I found so many old pieces from previous owner in the really long hose after the oil cooler before the impeller . They were hidding in the middle stuck.Now my boat never goes to 180.I have a 160 thermo & that's as hot as she gets , 160.My oil cooler also had some leaves in there. Dan |
Posted By: 1970 Mustang
Date Posted: July-05-2006 at 6:48pm
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It does sound like there is blockage, not a thermostat prob. No reason it should run that hot with a 160 thermostat.
Try taking off every hose in the cooling system and running water through them with a hose backwards, it may dislodge something which is positioned just right where it will not pass though. If this doesn't change anything I would pop out all of the freeze plugs and see what is in the cooling jackets around the bottom of the motor. Sand and rust can accumulate there and really screw with cooling issues, and maybe some of the pieces from the old water pump. |
Posted By: Chill99
Date Posted: July-05-2006 at 8:42pm
| Awesome replies and ideas. Thanks. I'll post how it turns out. |