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Still Running Hot!  Rating:  Rating
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 Posted: 09-19-2008 02:42 am
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dciaccio
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 I continue to have a cooling problem for my '73 JH  #12248.  I have put in a 3-row radiator, voltage stabilizer, new temp sensor unit, new radiator cap, changed the coolant, added 'water wetter' and it continues to run hotter and hotter. Even today, the temp outside was only 70 degrees and the engine temp ran up to the redline....hotter than its ever gotten.  I cannot find a correlation. Faster speeds/rpms seems to cool it down sometimes, other times heats it up more .  The temp gauge always reads slightly over mid-way but lately its increasing more. It will fluctuate between 3/4 of the way up and just under the redline.  It never used to get this high. It seems to have gotten progressively higher over this summer even in cooler weather. I by-passed the heater core thinking it might be corroded and blocking the coolant flow. No change.  The timing may be a little too far advance since I occasionally get 'run on' when turned off.
 
 Maybe the water pump starting to go?  Voltage regulator in alternator?  Or is simply the gauge bad?  Car seems to run OK even when its on the 'redline".  Also, the fuel gauge appears to be about a quarter tank high as well.
 
Any help out there would be appreciated!
 
Dave Ciaccio
Omaha, NE

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 Posted: 09-19-2008 03:23 am
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John Finch
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Dave, one way to verify the coolant temp compared to the gauge is to use an infared temp sensor on the back of of the thermostat housing. Mine runs about 170f max at long idle on a cool 70 degree day. My guage never gets past 3/4 even when running on a 90 degree day. Usually just to the right of center. You can find inexpensive IR's on ebay. Maybe Grainger or Northern Hydraulics or a Fleet Farm type store will have one locally.  Have you replaced the thermostat and if so with the 2 stage one? Best of luck.

John

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 Posted: 09-19-2008 12:05 pm
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Brett Gibson JH5 20497
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I would have said the voltage stabilzer seeing the gas gauge is running high as well, but you state you replaced that, next best thing other than as John mentions the thermostat, would be to check the water pump seeing you did every thing else, could be a bad impeller, or the impeller sliping on it's shaft, or even debris clogging the vanes in it.  Assuming the gauge is good.

Brett

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 Posted: 09-19-2008 04:36 pm
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Joel
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Lots of stuff in the archives.  I replaced my gauge with one that actually tell the temp instead of just letting me guess.

And my car ALWAYS ran hot until I put the front spoiler on.  I think it looks like crap and I smashed it a bunch of times until it fell apart.  But it made a HUGE difference in cooling.

Since I didn't like the spoiler - I made my own.  I took a 1/4 sheet of plywood, cut to fit, covered with epoxy and painted it black.  it sticks out jut 4" and works just as well as the monster spoiler.  I did hit a curb but it's easy (and cheap) to replace.


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 Posted: 09-19-2008 05:58 pm
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jgreen
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Judson make a slick looking one out of aluminum.  It only sticks out a few inches and is barely noticable. Once I paint it black, it will blend right in with the radiator. It really does the job of extra cooling well.

If you are going to replace gauges...... autometer makes ones which actually work extremely well and don't require the "voltage stabilizer" thing. They fit right in the pod. Of course, you have to be comfortable with losing the stock look.

oh Yeah.... the autometer gauges can actually be seen at night.





 


Last edited on 09-19-2008 06:02 pm by jgreen

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 Posted: 09-19-2008 06:17 pm
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Joel
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JP, I'd love to see a pic of the aluminum 'spoiler'.  that's a really good idea.  Since I crunched mine on a curb - I think aluminum is probably the way to go.  Damn good idea.


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 Posted: 09-19-2008 06:53 pm
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Bob McDonald
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Dave-I have had the same problem when I was playing with the ignition curves.

If you have run on then make sure your not running over 34 degrees @2500rpm

Mine was just about in the red on the temp/gauge while cruising at 50mph

After correcting the timing it then became normal middle on the gauge.

good luck.Bob

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 Posted: 09-19-2008 10:02 pm
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Judson Manning
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Dave,

As I (re)discovered with John Cronin's car recently the factory temp sender, voltage stabilizer, wiring and gauge are doing about as good as they can for being 30+ years old.  As John Finch suggests, it's a good idea to use something that is a bit more reliable.  In John Cronin's case I drilled and tapped for an aftermarket sensor and wired up a temporary gauge.  Really funny to watch the factory gauge swing all over the place as the Autometer ran solid at ~180^F.

The aluminum 'spoiler' is just a formed piece of sheetmetal bolted in place under the factory lower lip and utilizes the oil cooler hardware for mounting.  It extends down about 3-4 inches and does a great job of pushing up extra air.  The spoiler is extremely helpful since we replaced John's engine driven fan with a smaller electric version.

Maybe John can post some pics???

Judson

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 Posted: 09-19-2008 10:59 pm
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dciaccio
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guys, great food for thought.  I did replace the T-stat last driving season. Probably before I begin tearing into a water pump, I will pick up a IR temp sensor to check the actual engine temp as John suggests. IF it is indeed running hot, I will check the timing (easiest things first right?....as I never do).  IF it is STILL running hot, I will give you all the results and we can determine the next steps.  thanks.

Dave

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 Posted: 09-20-2008 12:45 am
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Joel
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Judson, I did the same thing with 1/4" plywood.  It's amazing the difference it made.

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 Posted: 09-20-2008 01:45 am
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jgreen
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I am out of town but I will see if I can post some pics when I get back. I will add a funny story about Judson.......

I was picking up my car in Atlanta in which the temperature is usually over 95 degrees in the summer. Where I live, the temperature rarely hits 95 all summer anyway, so I never had a cooling problem to speak of. Judson was test driving my car after installing his rebuilt engine in a rather "shady" section of town when all of a sudden, my temp gauge started swinging wildly to the right and pegged. It moved around a little but mostly stayed pegged to the right. After verifying my engine was fine and was never in any danger of overheating, Judson quickly installed an "autometer" temp gauge as he said " My heart could just not take the palpatations your stock temperature gauge creates"  Poor guy almost had a stroke and heart attack  at the same time. A smith gauge will do that too you early. Anyway, after the autometer gauge installed the temp was rock solid @ 180 degrees.  The electric fan Judson installed was also quite a big improvment over the engine driven fan at idle. I was stuck in a traffic jam outside Charlotte NC for 35 minutes, idling with the outside air temperature of 90 degrees. The gauge never went over 190. Normally, without the electric fan, I would have been  over 3/4 to the H on the smith gauge. Of course I am still running a 2 core radiator too. ( I know, I should change it but I do live up north ;) )

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 Posted: 09-20-2008 02:58 am
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dciaccio
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OK guys, I said try the simple things first. So tonight it occurred to me that in the morning when i start the car I get a squeal.  Ahha!  Loose belt. Went out to check and sure enough, you could take the fan blade and turn the entire belt around the alternator. tightened it up tonight will test tomorrow. now i did NOT replace the voltage stabilizer on this car, it was my MG.  So, I have one. did a quick look under the dash, could not easily see it. Where is this little guy located?

Dave

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 Posted: 09-20-2008 03:10 am
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dciaccio
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Nobody reply!!!  found it. got my fat head under there after looking at the wiring diagram and found it tucked up between the temp and fuel gauge.  wow, productive friday night! now only if it solves the problem for tomorrow's run.

thanks all.

will post you tomorrow on the saga....

dave

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 Posted: 10-08-2009 11:32 pm
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Circmand
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Been informed of something I did not know. I have been running hot for awhile. I took it to a radiator shop to test and happened to mention my gas gauge was reading high as well. Turns out there is a voltage stabilizer that keeps voltage constant. I ordered one from Delta. They are on back order but will post if this corrects once I receive it.

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 Posted: 10-09-2009 02:45 am
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rossjfox
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I used a voltage stabilizer from a Triumph Spitfire.  Looks and works identically.  Readily available from Moss Motors and I'm sure other Triumph parts houses.  I think it was about $14.

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 Posted: 10-09-2009 02:50 am
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JodyKerr
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Best prices on Spitfire bits is generally http://www.spitbits.com I buy all the parts for Mum's Spitfire from there.

Jody

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 Posted: 10-20-2009 12:42 am
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Circmand
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were you able to replace the voltage stabilizer without taking out the dash? How hard was it?

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 Posted: 10-20-2009 01:28 am
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rossjfox
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No need to remove the dash.  Just the gauge cluster.  2 screws - one in each upper corner of the cluster, then pull.  (How hard depends on how rusty the metal shaft is behind the gauge cluster.)

You'll see the voltage stabilizer at about the top center of the gauge cluster.  Then just remove and replace. 

Really quite easy.  To make it even easier, I think I removed the steering wheel, but I don't think this is absolutely necessary.

Ross

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