Brought home the new? 65 Valiant this weekend and everything worked fine with the exception of the wandering temperature gauge. I've read every post on the guages and in most situations see that the fuel and temp gauges usually experience problems as a pair. Not so in this case. I friend suggested checking the grounds, particularly at the engine to body point. Any other suggestions? As an aside, the guage doesn't seem to fluctuate, or so I've not noticed, with rpms.

Could you describe the behavior of the guage in a little more detail? A little wandering may be normal.

A little wandering can be normal like Reed said your car could 'warm up' and after quite a bit of driving reach a peak in temp on the gauge, then the thermostat opens up, allowing some flow through the radiator causing the temp to dip slightly, then it might rise again depending on driving habits, weather, etc...

Make sure to check your fluid regularly, since your car didn't come stock with an over flow bottle, if your car 'purges', you'll loose some fluid to the pavement/driveway. Also check the color of your fluid, brown = rust = needs to be flushed....


-D.idiot

Backflush the radiator and change your thermostat and hoses and I think your gauge indication will be steady.

My wifes new 63 4dr 170 dart did the same thing and I changed the sending unit----problem solved.
HyperValiant

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1960 Hyper-Pac Valiant(rolling test-bed)
1963 Valiant V2OO(Son's summer project,- he just turned 15 )
1972 Valiant 4dr(Daughter Kelly's repair in progress)
1974 Valiant (v8) daughter Kelly's work in progress

Reed: Per your suggestion: Bought the car about 30 miles from home. The gauge was say 1/4 way away from the C side. After some "city" driving of about 2 miles, it moved near the top of the H side of the gauge. Got on the freeway headed home, engine running smoothly, etc., and noticed the gauge moved to first position above and after a couple of miles back up towards H. This continued all the way home. I have an overflow tank on the radiator, and the contents didn't change from the first time I saw the car in the previous owner's driveway. I am leaning towards thinking it might be an electrical problem.

I agree. For peace of mind I would drop in a new $2 190 degree thermostat and a $5 temp sending unit and see what happens from there.

I would agree on the flush and also a new sender...

I have a '64 Valiant and was having cooling issues (mostly a clogged radiator).

I still find the dash gauge very "reactive", or "Sensitive"...if I put the headlights on, I can watch the needle move from the "m" to the "p" of the word "Temperature"...usually, the faster I drive, the hotter is runs...

I am thinking of adding a good mechanical temp gauge, just to get an idea of what's really going on...


Try the simple fixes first.

Good Luck!

De Soto Frank

Bought a new temp sensor and thermostat this am. Car is outside and don't feel like installing them due to rain. I took off the radiator cap and noticed some "stuff" floating ont he surface of the water. Took my wife's best turkey baster (sp?) and drew out some fluid. It wasn't a really healthy green or orange so I would surmise that the whole engine could use a good flushing. How is that done? After that I will install the new parts and see if I corrected the problem. Man, these cars are easier to work on than my race cars.

As Desoto Frank pointed out, with the climbing temp as speed increases, classic sign of a clogged radiator. May need to pull that one and send it to the rad shop for a GOOD cleaning. A wandering temp gauge, on a newer
wrong wheel drive car, is usually a sign of a head gasket that is either blown or about to be.

If the radiator is indeed clogged, you might want to pull your heater core and get that boiled out as well. I have had sevewral cars that overheated due to a clogged heater core.

You could try one of those Prestone "Flush & Fill" kits that include a "Tee" that installs in a heater hose; the kit usually comes with a bottle of flushing solution (which ain't what they used to be, now that we're all enviromentally concious...).

Follow the directions...once your radiator is cleaned and drained, look down through the filler, at the tops of the tubes: if there's whitish crusty crud accumulated in the tubes, that's "scale" and your rad probably needs a trip to the radiator man; but try a test drive first, and see if anything improved.

My local radiator shop got rid of his "hot tank" a number of years ago; he said the increased use of "plastic" radiators and stricter envrionmental & insurance controls made it more trouble than it was worth...


Good Luck,

Frank

Thanks to all who have responded so far! Did a more in-depth analysis of the problem today and came up with a couple of noteworthy items. First I found the inside of the cap that plugs into the temperature sensor on the intake was crudded up some. Instead of a bright brass finish, it was greasy and black. Cleaned all that out and brightened up things. The sending unit itself appears to be new, but in light of the crud mentioned above (a sign that there might have been a leak), I went ahead and installed the new sensor I had. Next, I drew enough fluid from the radiator to expose the top of the core and I think I found my problem...most, if not all the holes I could see where about closed off with white, flaky junk. Next, seeing that there was a bit of fluid in the overflow (aftermarket) canister, I siphoned a bit of that off too, and it was pure mud! The top of the fluid there was about 3 inches below the cool level indicator line. So...pulled the radiator and off to the shop it went. Keep in mind, the prior owner had installed an aftermarket air conditioner, and it also seems he found a radiator that would fit and help him keep temps down with the added burden of air. Its a two-core and, according to my shop manager, didn't come on a 65 Valiant. After dropping off the radiator, went ahead and pulled out the old thermostat (195 deg). It looked o.k., but will be replaced tomorrow. Didn't have the wherewithall to flush the engine, so while the thermostat was out, I hooked up the garden hose and let it run until clear water only came out the lower radiator house from the block. One item has me confused though..the prior owner installed a 7 lb Stant radiator cap (the one you can lift up the plastic tang to relieve pressure with). If my memory serves me correctly, I should be running a 15 lb. Thoughts on this would be appreciated. After everything is put back together tomorrow night, hopefully, I will let you know how it all works.

I second the heater core flushing as well.

Also, some blocks came with a coolant drain plug. If your standing at the passenger side of the car, looking towards the driver side, look down and to the left of the oil filter. It is a square plug. It is probably baked on well after all these years, but try removing it. This leads to the coolant passage in the block, and should be flowing freely when you have the garden hose in the engine.

You can do the same thing with the freeze plugs. Use a coat hanger or other implement of choice to scrape around in there if you see any crud.

Put a 15 lb rad cap on it, especially if there is A/C.