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Engine Temp Seems Low?


55 Fargo

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Hey all, ran my engine tonight, outside ambient temp is 30, I now have an OEM used gauge, test using an infared thermometer to be about 7 degrees low at 160, so 160 is closer to 153.

So tonight I start the engine, back car out of garage, go for a short drive down road about 1 mile, then leat engine run another 15 minutes.

The highest the temp of the engine got to 135 on gaguge and temp of coolantin top of rad.

Now is the 160 t/stat the reason for this, or am I possibly looking a t/stat stuck open. I also have a 1/8 hole drilled in the lip of the t/stat, it is a modern type, used in the internal by-pass coolong system.

I am thinking she is running on the cool side, and it seems more evident with the stock gauge I now have, and my readings in the top of the rad with the laser thermometer. The old gauge which was a cheap Equiss gauge, that read about 10 degrees high.

I guess I should wait till warmer weather, and when I am able to go for a real 20 mile ride, to see what's up.

When Greybeard Dave says it takes a long time to heat these engines up, he was right. If I were driving this car for winter , I would need to cover the rad with cardboard, and get a 180 degree t/stat, this engine would run real cold at 0 farenheit...........Fred

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Fred I have to block the grill out in my 94 dakota for winter driving :) We just need warmer weather. I do think about jumping the dak from a 185 to the next higher thermostat which is I think a 210

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The infrared scanner tells you the temp of the surface it is pointed at. If you pointed it at the head and got 150 something, chances are the temp of the coolant near the sensor is close to the 160 degrees the stat is rated at. If you aren't going to be doig a lot of driving in near freezing temps. I wouldn't worry about it. I would rather it runs a bit too cool in cold temps than to hot in warm weather.

My father ran a piece of old carpet in front of all his mopar radiators till well int the 70's.

but he sat infront of the radiator witht he thermostat for the furnace set at 74.

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Thanx Greg and Ed, the infared temp gun, verified very simnilar temps in the top of the rad and what was registering on the gauge, pointing at the rear of the head gave a higher reading, but the coolant temp is what I am concerned with.

The new/used OEM gauge is most likely reading about 10 degrees to low...

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Siting here with the morning coffee, and thinking about this thread of mine.

I think the gauge I installed, which is a used OEM gauge is reading 10 degrees low.

Now I am going to keep an eye on it, when the warmer weather driving commences.

I am wondering, is it possible to plumb another gauge somehow, that way I can always havea verification eading if need be. I also have my hand held laser temp gun too..........

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When I was trying to figure out my gauge, I just carried a candy thermometer with me. I would just pull off to the side of the road (leaving the engine running), take off the non-pressurized radiator cap, and stick the thermometer in the top of the radiator. Virtually instant correlation.

Marty

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When I was trying to figure out my gauge, I just carried a candy thermometer with me. I would just pull off to the side of the road (leaving the engine running), take off the non-pressurized radiator cap, and stick the thermometer in the top of the radiator. Virtually instant correlation.

Marty

Hey Marty, been doing the same thing, I now have the handheld laser temp gun.

The gauge is reading about 10 degrees low, so will check things out once back on the raod ina bout a month.

Last night it toiok a long time to warm uo to about 135 to 140 degrees, witha 160 t/stat, and the outside ambient temp was around 28 to 30. But this is idling, and you reall need to be driving to get these old girls warmed up.

I was thinking my 160 t/stat was sticking open, but I also have a 1/8 hole drilled into the t/stat to allow air to rise out when re-filling the system, so maybe all is okay......Fred

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Hi all, just went outsdie started car and backed her out of the garage.

Ambient temp outside 32.

Within minutes of starting engine, top rad hose and rad started to feel warm, which leads me to believe, the 160 degree t/stat is stuck open, or the small 1/8 or 3/16 hole I drilled through the t/stat lip, is allowing instant circulation of the coolant through to the rad.

Ran the engine about 20 minutes or so, temp gauge in car around 130, the top of rad around 125, the head varied from rear at 130 to 120 along the head.

The intake manifold was 170, the exhaust manifold about 375. the oil pan about 95, the oil filter housing about 90. The top rad hose about 125.

I do have a 180 t/stat in the shop, not sure if I should swap to this or go get another 160 or 170. I know what Greybeard Dave say's on this, but I figure in Summer, once the t/stat opens at 160, it won't make much difference, becaue on hot days she runs about 180 on the highway anyway.

Just some of my observations on this, not sure is is of any use to the forum or not......

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Just pulled 160 t/stat, it was closed, but I drilled this big hole in the lip(about 3/16), no wonder, this wil certainly allow the coolant to flow.

I did button her back up again, and decided not to use the 180 stat I have, as it seems to stick it's mount, I figured it would not work right.

I will monitor the temps in warm driving weather this summer, and take it from there.......Fred

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Do you have a o-ring installed on top of the t-stat? If not that could be allowing coolant to flow past.

No, as I do not need one, my t/stat is a internal bypass modern type, so no O ring for the bigger external by-pass type.......

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Anytime I drilled a hole inn a t/stat, no matter how small ,it always took a lot longer to warm up . I Wouldn't drill it unless i really had to. And i'm also running a 180 in mine.

Mark

Hi Mark, I figure the same, will replace this soon...Fred

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