67-327/350hp Temperature Sender

[Steve]

I have an aftermarket temperature sender and a 160 degree thermostat installed in my rebuilt 1967 matching numbers 327/350hp. My problem is that my temperature gage stays at about 130 degrees. I read an NCRS article that discussed inaccurate temperature gage readings (the typical problem appears to be readings that are to hot as compared to my situation) and ways to get an acurate reading through trial and error using various senders from a salvage yard.

Does anyone know where I can find a NOS or aftermarket correct sender? My research leads me to believe that the 160 degree thermostat is correct for this engine does anyone have a different idea?

Thanks

[Duke W.]

Re: 67-327/350hp Temperature Sender

Don't know where you might find a temp. sender, but the proper thermostat for your engine is 180 degrees. GM began using 180 degree thermostats when they switched from alcohol based to "permanent" (ethylene glycol) type antifreeze sometime in the fifties. Higher coolant temperatures improve engine efficiency by reducing cylinder wall friction and reducing heat rejection to the water jacket.

Duke

http://www.kelseytire.com

[Gary Schisler]

Re: 67-327/350hp Temperature Sender

Steve, in addition to Duke's good advice, this topic has been addressed to great length here. If my memory serves me correctly (this is always up for grabs) the gist of the discussion was that these temp sending units are notoriously unreliable and generally require "massaging" of one form or another to have a truly accurate system. I also THINK that the only one doing this sort of work is Fred Oliva, who reads this board. Some folks have spliced in resistors to make the temp gauge read higher, and maybe others have fixes for this error. My 66, for example had an overheating problem that was only solved when I put in a repro Harrison radiator (which I love, by the way). Now the gauge won't exceed the first hash mark. But that's ok because it no longer overheats. Gary

[Gary B.]

Re: 67-327/350hp Temperature Sender

Steve,

Fred Oliva is the man you want to talk to. He can be reached at (561) 998-2373 ext. 281. He can do magic with temperature senders.

Gary

[Jimmy G.]

Re: 67-327/350hp Temperature Sender

Call John Pirkle. He usually has a good supply of used original units that will work. 706-860-9047 before 10 pm EST

[Ed Jennings]

Re: 67-327/350hp Temperature Sender

Before I did anything else, I would determine what the water temperature really is. If you have access to an infrared thermometer (temp gun) they do a real good job. I like to get the reading at the thermostat housing base when I know the engine is hot enough for the water to be circulating. Once you know the actual temp you can worry about gauge calibration.

[Bill D.]

Re: 67-327/350hp Temperature Sender

Steve,

As Ed suggested, you need your true temp reading before going to Fred or John. One common error that is made, sealant tape on the threads. If there is any on there, the sender cannot ground properly to give an accurate reading. Good luck!

WB

[Steve]

Re: 67-327/350hp Temperature Sender

Duke

Thanks for the advice. Further research last nite confirmed that 180 degrees is the right thermostat.

Steve

[Steve]

Re: 67-327/350hp Temperature Sender

Thanks

[g.r.rogers]

Re: 67-327/350hp Temperature Sender

I had the same problem with a 70 LT1. I changed over to a 160 degree thermostat also. After being out of the country for several months I came home and fired up the car and noticed the temp gauge reading very low. Like I had a broken gauge or not getting the proper sending unit operation. Luckily I have access to thermometers that read 0-250+ with 6" stems. I started up the car with the radiator cap off stuck in my thermometer and found my thermostat was opening at the designed temp(feeling the intake to radiator hose) and my engine was operating properly at the temp I had chosen to reduce to. within a couple degrees. Please keep in mind my thermometers have stnl/stl. stems. Be careful now. Usually the last thing you changed is the problem. Mine wasn't a problem it was just the thermostat I put in (160 degree) wasn't designed to relate to the gauge.Good luck,GRR#33570.

[Terry M.]