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Thread: Low water temp?

  1. #1
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
    Posts
    11

    Low water temp?

    I just bought a very low mile, all original SC. Spent the last three days driving it from Omaha to California.

    The one thing I've noticed is the water temp never gets much above the low mark.

    I searched the site, and all the temp related post seem to deal with the opposite problem of over heating.

    This shows the typical level at speed. The interior heater is barely warm with the lever all the way to the right.
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    This show the level crawling along between 3-6mph do to an accident.
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    It actually moved up a bit more than this, but still well under the middle mark.

    I'm going to have a friend test the radiator temp with a laser thermometer to see at what temp the thermostat opens up.
    This is a totally stock pristine engine bay, I'd rather not open anything up if it's just the sensor, or some other problem.

  2. #2
    Join Date
    Jan 2010
    Location
    Bossier City, LA
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    2,156
    There is a TSB (TSB 95-13-2 if you have a way to look it up) on the one wire sending unit for the gauge failing, causing it to read low.

    Before I worried about ANYTHING else, especially if it's "pristine", I'd swap that sending unit out and see what happens.

    RwP

  3. #3
    Join Date
    Dec 2007
    Location
    Salem, OR
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    6,340
    Mine did that when I got it - I removed the press on connector at the temp sender on the thermostat housing, cleaned off the corrosion on it and the stem, then crimped the connector down a bit more so it would fit tighter and re-installed. After that the reading was much more reliable on the gauge.

    But if that doesn't do it, you may have a thermostat that is stuck open, especially if the heater isn't putting out.

    And finally, air trapped in the system can make the temp sender act up and also affect the heater output. The air bleed standoff at the thermostat housing is there for a reason.
    Last edited by KMT; 03-21-2016 at 07:55 PM.

  4. #4
    Join Date
    Feb 2016
    Location
    Saskatoon sk Canada
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    15
    Odd I got the same problem, but tons of heat

  5. #5
    Join Date
    May 2012
    Location
    Southern Indiana
    Posts
    86
    I had same issue after a tranny install...I could tell it was hotter than gauge was letting on. Gauge never moved past the N. Changed both coolant sensor and that fixed the issue.
    Pearl White 95 SC-stock for now
    White 93 SC-Currently on the DL

  6. #6
    Join Date
    Feb 2014
    Posts
    840
    It's probably a thermostat that's stuck open.....my Mustang had a stuck open thermostat just a couple of weeks back, and the temp gauge was always reading low. There's a possibility that it's the coolant temp sensor too, as others have mentioned. Either way, it's a cheap and easy fix.

  7. #7
    Join Date
    Feb 2004
    Location
    IA
    Posts
    4,252
    Where in Omaha did you buy it from?
    Honor, Grace and Dignity......Remember these

  8. #8
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
    Posts
    11
    Quote Originally Posted by BirdofPrey97 View Post
    Where in Omaha did you buy it from?
    I got it from C & S Motorsports. Lots of low mileage cars. Paul was very helpful. I wanted new tires put on to the stock rims instead of the aftermarket rims that were on the car to begin with. He took care of that. The stereo stopped working, he asked if I wanted an aftermarket unit. I sent him a model number, he dealt with the stereo shop. They had some issues. The first adapter showed that the amp was also bad. So they used an amp bypass adapter. Works great other than no sub-woofer. Now I'll have to figure that one out.

    By the way pics of the car are in the garage area. I just posted them yesterday.
    Last edited by daveh; 03-21-2016 at 04:41 PM.

  9. #9
    Join Date
    Jan 2008
    Location
    windsorlocks,ct
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    169
    i remember my 93 sc had the same problem, i got it with low miles (33000) i replaced the temp sender and that didnt solve it, so i got a aftermarket mechanical temp. guage and called it a day, by the way i remember seeing this car in autabuy magazine it had 11000 miles on it !!!! i didnt really care for the aftermarket wheels on it though, good call putting the stock rims back on, really nice supercoupe

  10. #10
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
    Posts
    11
    Quote Originally Posted by tmz93sc View Post
    i remember my 93 sc had the same problem, i got it with low miles (33000) i replaced the temp sender and that didnt solve it, so i got a aftermarket mechanical temp. guage and called it a day, by the way i remember seeing this car in autabuy magazine it had 11000 miles on it !!!! i didnt really care for the aftermarket wheels on it though, good call putting the stock rims back on, really nice supercoupe
    The previous owner had the original wheels as part of the car. I have the aftermarket BBS look-a-like wheels in the trunk. The other thing I had Paul do was get someone to remove the supercharged emblems the previous owner had installed on the just ahead of the front wheels.
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    I got to schedule a time I can get my Edsel collector friend to look at some of these issues. I'd like to get the mechanical things squared away before I try getting it smog'd so I can get a California license.

  11. #11
    Join Date
    Feb 2014
    Posts
    840
    Welcome to the forum! Sounds like you'd got a good SC. Is it your first, or have you owned an SC before?

  12. #12
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
    Posts
    11
    Quote Originally Posted by 1FSTBRD View Post
    Welcome to the forum! Sounds like you'd got a good SC. Is it your first, or have you owned an SC before?
    No this isn't my first SC, in '92 I bought a two year old '90 SC 5-sp, white with blue leather, fully optioned except for moonroof More head room for me. It had 21k on it when I bought it. I'd paid just a little less than I bought this '89 for. I loved the 5-sp. The state of Bay Area traffic now makes a stick not fun, and my knees can't handle pushing in the clutch 1000 times in traffic.

    Sadly it met it's demise in '99 at an intersection with a stuck light. I had green, the other three directions red. Unknown to me they were all taking turns running the red light. As I approached @ 30-35mph, an elderly lady in a mile long Caddy made a left in front of me. I had time to put the brake on the floor, look up at the light and say "But I have a green light". Bam! I hit her in the passenger door and pushed her across the intersection into a car waiting to make a right turn.

  13. #13
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
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    11
    I thought it would be a good idea to follow up on this thread now that the thermostat has been replaced. Hopefully this will help others that may want to know what they are getting into before they start.

    I took the car to my friend Dave, and Edsel collector who works on lots of old cars for other collectors. In exchange for a lot of computer help I’ve given him he performed the work.

    Parts: (Assuming you want everything stock)
    Gasket = Fel-Pro 35459
    Theomostat = Motorcraft RT-1152 This is a 197 degree thermostat, which is the stock temp.
    Temp Sender = Motorcraft SW-2328
    Antifreeze = Prestone undiluted, 2 gallons + I had a partial gallon of 50/50 mix
    Distilled water = 6 or more gallons for multiple flushes.
    Flush = Prestone Flush + Cleaner
    Gasket sealer = Permatex

    One note on this pic, the two gaskets in the back are the Victor Reinz C26888, that I got from O’Reilly Auto Parts. They have an adhesive on one side.
    When I mentioned what I’d picked up to Dave, he said those are bad, they never seal correctly he’s had nothing but problems with them. His suggestion was the blue Fel-Pro gasket, which I got at AutoZone.
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    Diagnosing:
    The first thing we did was from a cold start he used a laser thermometer to measure the heat on thermostat housing/sending unit, and also on the boss that the sending unit to the computer is attached to. You can feel from the radiator hose when the thermostat starts to open. In my case it was opening way early, ~140-150 degrees

    It was also obvious that the coolant hadn’t been changed in the car in a long time if ever. It really should be flushed and replace at least every 4 years.

    Flushing the system:
    We spent the rest of the day flushing the system since it was too difficult to get the drain plugs out of the block. After flushing the system twice with tap water, we picked up 6 gallons of distilled water and did two more flushes with that. Then on the next fill, we added the Prestone flush & cleaner. I then took the car home and to work the next day before dropping it off to Dave again.

    I should note that each time we added new fluid we brought the system up to temp so that the thermostat was open. Also, you should have the heater on full inside the car so your flushing that also.

    Obviously this would have been simpler if we could have drained the block & heater core.

    Replacing the Thermostat:
    You have to remove the bypass hose in order to get to the bolts.
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    This is what the port on the intake looks like after disassembly.
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    Here is the new and the old thermostat. The arrows are pointing to where both say 197. Also notice that the old one doesn’t have the little bleeder button. Dave had to do a mod to get the new thermostat to fit because of the button.
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    This shows the intake port cleaned up.
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    Last edited by daveh; 04-02-2016 at 12:50 AM.

  14. #14
    Join Date
    Mar 2016
    Location
    Santa Rosa, CA
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    And this shows the thermostat housing cleaned up. Notice the flats on the top and bottom. These are so when you turn the thermostat, which isn’t round, that it lodges itself in there.
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    This shows the gasket & new thermostat in place. There is sealer on both sides of the gasket. Note that you have to completely surround the thermostat and the bypass hole, but not the bolt holes.
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    Dave’s process is to wait until the sealer has air dried until it’s tacky then place it on the housing. Then apply it to the other side and wait until that is tacky to assemble onto the intake manifold. Then he waits some more to snug it up. After that. He waits 24 hours before putting any fluid into the system.

    The first fluid test is with distilled water and the car brought up to heat. He measures once again with the laser thermometer to see when the thermostat is opening. In my case much better, and getting much more heat from the heater inside the car.

    After draining that water, he put in about a gallon and one quart of the undiluted anti-freeze. Which should yield about a 50/50 mix with the water that’s left in the block & heater core. Then you can fill the overflow up to the cold level with a 50/50 mix.

    Now after all of that, the gauge isn’t really reading any higher than is was, so we will be replacing the temp sender. I’ll update after that’s installed.

    Side note & question.
    As a side note, after getting the car back last night, I took it to DMV today, got the registration going, had to go get a smog test. Strangely the first testing place I took it to wouldn’t even touch the car, he said he’d had too many problems with them in the past. The second place had no issues at all, the car passed. I went back to DMV and got my registration and plates. So it now California legal.

    I do have one question. The front license plate holder didn’t have the correct screws for the license, I see it only held on by two press in studs near the top, there are no other attachments to the bumper, and by feeling under it I could tell that it has the proper embossed SC. How can I remove that holder without damaging the bumper? And does anyone make some plugs I could put in the holes to temporarily fill them just in case I’m forced to put the license back on the front.
    Last edited by daveh; 04-02-2016 at 12:52 AM.

  15. #15
    Join Date
    Mar 2017
    Location
    Sweden
    Posts
    9
    Great post, thanks!

    How did the temp sensor swap go?

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