Thermometer radiator cap

G

greg crosby

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Mar 11, 2011
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I saw a post a while back suggesting a Mr. Gasket thermometer radiator cap as a good way to keep an eye on a 470's temp. I have an 88 3.7 470 and would like to find out which cap to order? The one thats on is a 14lb. and looks like a standard cap. Mr Gasket site does not support marine applications.

Anyone using one?
 
matt167

matt167

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Sep 27, 2012
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Re: Thermometer radiator cap

I don't think there is a marine rated radiator cap. Seems as tho my dads 488 just had an A/C Delco cap on the heat exchanger... MR.Gasket stuff is iffy at best, and the thermometer cap won't tell you what you want as the coolant temp will be altered by the raw water cooling the heat exchanger.. Best bet is a known good mechanical gauge ( verify with pot in heating water, use a candy thermometer to verify the temp ) in a cooling passage, and just mount the gauge pod where you want it under the engine cover.
 
Don S

Don S

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Re: Thermometer radiator cap

The book calls for a 14 lb cap. Just get one from you local auto parts store, you don't need a gauge on it, just something else to fail. Or was you planning on opening your engine hatch to watch it when running?

Spend some money or borrow an IR temp gun. Then take the engine temp on the engine right next to the gauge sender and see how it compares to your dash gauge.
 
GA_Boater

GA_Boater

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Re: Thermometer radiator cap

The silly question. Why? If you have the dog house on and you're running the boat around the lake, how will having a gauge in the radiator cap that you can't see help you? Don't you have a temp gauge on the dash? :confused:
 
G

greg crosby

Seaman Apprentice
Joined
Mar 11, 2011
Messages
38
Re: Thermometer radiator cap

an ounce of prevention---------- Dash gauge 1988, every now and then check it against direct thermo in cap. Do you run your boat with ears on and doghouse off when you check or tune engine? Never knew there was such a thing as a silly question.
 
Eric 3.7LX Alpha 1

Eric 3.7LX Alpha 1

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Mar 27, 2010
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3,008
Re: Thermometer radiator cap

I have one... and it's the 2nd one. First one did fail, started to leak slowly, just keep the original in the boat's tool box. I use it while working on the boat and to confirm the dash gauge. They have always read the same temp together.

I also have a inline fuel pressure gauge using a 3/8" flair tee with a gauge port in the center of it. Installed between the fuel pump and carb using all metal fuel line. If something is wrong, I can tell in a second if it's fuel pressure related.

Why have one in a car when you sit behind the wheel? same reason I guess ;)
 
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