Normal Operating Tempurature GS 455

[dbaker9323]

Hello all. I have a 71 Riv GS 455.  It runs well but I am wondering about the operating temperature.  It has aftermarket gauges, including a temp. gauge.   On a 90 degree day, driving down the Interstate for, say, 15 minutes, at a speed of 70 with the AC on, the gauge registers 220.  When stopping in traffic it rises to nearly 230.  Is this normal or too high?  The overflow tank registers full.  The radiator was replaced by a previous owner in 2007 (only about 2000 miles ago and the car has been exercised regularly since then).  All thoughts are welcome!  Thanks.

[sixxer]

I don't have your particular engine.... but plenty of times I've seen aftermarket gauges installed in positions on the engine that do read operating temps but aren't in the best spot for providing accurate temps. I have an LS motor in my 64 Chevy C10, my gauge on the dash will read 210 idling in traffic, up from its normal 195ish. When I plug in my laptop,

the ECU shows the truck hasn't even broken 200 yet. The problem is I installed the sending unit on the passenger side rear coolant port, which is conveniently 1/2" away from my header. For a while I could not figure out why my fans weren't coming out on. Now I know my gauges just reads high because it's picking up heat from the exhaust. That being said, I've checked several old Chevy 350s that I didn't trust the gauges with a really cheap no-contact thermometer from Harbor Freight. Everyone of them was off a little bit. If you aren't boiling coolant and your fan clutch is newer and working, I'd test your gauge!

 

http://m.harborfreight.com/hand-tools/thermometers/non-contact-infrared-thermometer-with-laser-targeting-69465.html

Edited June 3, 2016 by sixxer
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[EmTee]

If you're running 50/50 anti-freeze and water with a 15 psi radiator cap the boiling point of the coolant should be about 270 degrees F.  So, in theory you are not at risk of boiling the coolant at 230 degrees F and furthermore, since the radiator has not boiled at 230 degrees it seems as though the system is maintaining at least some pressure.  If you believe the car is running abnormally hot I would check the following: (1) check the condition of the lower radiator hose; if it feels spongy or is missing the internal spring it may collapse at speed due to suction from the water pump.  (2) Check that all fan shrouding and front air-dam/spoilers are in place and undamaged.  (3) Check the condition and adjustment of the belt(s) - especially the water pump belt(s).  If glazed, replace; if the pulley can be turned by hand (engine OFF) then tighten.  (4) Replace the thermostat.  This is a long-shot, but it's possible that an old thermostat may be weak and not opening fully.  I believe your car would use a 195 degree thermostat.  (5) Inspect your fan clutch.  Look for signs of oil leakage or bearing slop.

 

Lastly, the hand-held IR thermometer that sixxer recommends is a good idea.  I have one and you won't believe the things you'll use it for once you have it (caliper dragging - shoot each wheel hub and compare temps...).  Anyway, if your radiator is working properly you should see at least a 20 degree drop between the inlet and outlet temperatures.

[dbaker9323]

Sixxer and EM TEE - I appreciate the good advice.  I will get an IR thermometer and check I that way!!

[JZRIV]

Your engine temperature doesn't seem concerning in that environment as long as you are not overflowing excess coolant into the overflow jug. Start with basics. Make sure your fan clutch is functioning normally. On a hot day you should hear it roar (fully engaged) when starting out after idling in traffic. If you can't hear any difference in the sound of air its moving it might need replaced.

Make sure your timing is set properly and the vacuum advance module is working. Don't be afraid to advance the initial timing setpoint slightly as long as you don't get pinging/detonation during acceleration. Retarded timing makes the engine run hotter.

[RivNut]

The rich/lean mixture of your carb will have a tendency to make your engine run hot as well.  Take your thermostat out and put it in a pan of water on the stove.  Stick a candy thermometer in the pan and bring the water to a boil.  See if the thermostat opens when it's supposed to.  Lots of things, as mentioned above, go into keeping an engine running at a "normal" temperature.  

 

Does your car have exhaust manifold gaskets on it?  Strange question? No.  Buick did not use exhaust manifold gaskets.  They let some of the engine temperature dissipate via the exhaust.  Blocking the exhaust from the heads with gaskets traps the heat in the head.