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Engine temp 351, part II

Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=1910
Printed Date: May-13-2024 at 6:48pm


Topic: Engine temp 351, part II
Posted By: Guests
Subject: Engine temp 351, part II
Date Posted: June-22-2005 at 10:22am
How about this for odd. My temp cycles probably 15 degrees in normal operation. After pulling a skier, say, it goes up to 175 or so momentarily. Then goes right back down. Almost like the Tstat is slow to react. The RW pump only has about 200 hours on it and the impeller is changed every year, so I have narrowed it down to a slow Tstat, if there is such a thing. So last year I order a 160 stat from SkiDim and replace it, right side up and everything, and it goes right past 160 and into the 190 range. So I limp back to the dock and swap it out with the old one and all is good. I figure it is a dud. So I order a new one this year, change it out, and guess what? SAME THING, the temp flies right past 160. Put the old one back in at the dock and all is well again. What could this possibly be? 2 bad Tstats in a row? I am positive it is the exact right part, stamped 160 and looks exactly the same as the old one.



Replies:
Posted By: 79nautique
Date Posted: June-22-2005 at 12:14pm
I would look at a restriction in the tranny cooler or clean your sea strainer. If you don't have a sea strainer get one before you suck something into the water intake and it completely clogs the tranny cooler. I would say that your old Tstat is open slightly all of the time and will get worse the older it gets.

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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique


Posted By: Guests
Date Posted: June-22-2005 at 4:22pm
79- I have a sea strainer and it is not clogged. I like the idea of the old tstat open slightly but it looked closed when I took it out. Putting the new stat in vs the old was like black and white. New = overheat immediately, Old = immediately goes down to 160. I'm completely stumped. Water delivery passages are clear as far as I know but I will check and recheck.


Posted By: David F
Date Posted: June-22-2005 at 5:12pm
190 degrees is not exactly overheating. Maybe your sending unit/gauge is inaccurate and you have been too cool with the old t-stat.

Put the new t-stat in a pot of water and measure the temperature at which it starts to open. Compare to your old t-state. This will tell you what is actually going on with the engine and/or gauge/sending unit.


Posted By: Guests
Date Posted: June-25-2005 at 3:44pm
I just did a test where I had both the old and new tstats in a sauce pan in a steamer basket side by side, in water, with a stem thermometer. Sure enough , the old one opened right at 160 and the new one did not even crack until 180 or so. What are the chances?


Posted By: Guests
Date Posted: June-26-2005 at 5:08pm
Ok, I bought a 3rd Tstat. Put it in a pot on the stove, and according to the stem thermometer, it opened at 180. So, 3 tstats all opening exactly 20 degrees after the old one. My new theory is my gauge is 20 degrees off and so is the stem thermometer. The old Tstat must be a 140.


Posted By: JEFF KOSTIS
Date Posted: June-26-2005 at 6:24pm
It is possible they have a bad batch. Ive seen it where it goes through manufacturing wrong and a bunch are messed up(possibly marked and packaged wrong). Ive tried your exact method on our 74 mustang 17 and both opened exactly within a few degress. Try another manufacturer if possible.

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MUSTANG COUNTRY
http://www.correctcraftfan.com/diaries/details.asp?ID=1074 - 1974 Mustang 17
http://www.correctcraftfan.com/diaries/details.asp?ID=1093 - 1976 Mustang 17



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