72 350 and TH350 troubleshooting?

[kna4977]

New to me 72 350 temperature gauge goes higher than my comfort level. Pretty much sits on the very last line of normal or on H. Check temps at thermostat housing and various other places and it’s in the 190s to low 200s running. Turn off and it goes up to around 210-220 range. Any ideas it’s anxiety inducing to have a gauge that seems to keep going up. Should I swap the thermostat for a 160 or 180 or ?

Transmission seems to take too long like a couple of seconds to go into reverse. Anything I can do outside of an overhaul to help this? Seems to shift fine otherwise and goes into forward gears normally.

[Wrenchbender Ret]

Try using a 180 therm. Replace the temp. sending unit while you have it drained. It sounds like the gauge is off some.
Change the fluid & filter. If it is really raunchy drain it again after you run awhile. It has a drain plug on the pan.

George

[RustyPile]

I agree with others, but something about the gauge that you're not understanding.. When the ignition switch is turned off, all power is removed from the gauge. What the gauge does then is of no consequences and is not an indication of coolant temperature.. The needle is simply seeking a "comfortable place" to rest...

[kna4977]

Originally Posted by RustyPile

I agree with others, but something about the gauge that you're not understanding.. When the ignition switch is turned off, all power is removed from the gauge. What the gauge does then is of no consequences and is not an indication of coolant temperature.. The needle is simply seeking a "comfortable place" to rest...

I understand the gauge. It stops at its last reading until the switch is turned on again. When I say off and list the temps I’m seeing those are from my infrared thermometer with the engine off not the gauge in the vehicle.

[RustyPile]

Originally Posted by kna4977

I understand the gauge. It stops at its last reading until the switch is turned on again. When I say off and list the temps I’m seeing those are from my infrared thermometer with the engine off not the gauge in the vehicle.

When you said, "it’s anxiety inducing to have a gauge that seems to keep going up.", I assumed you were referring to the temp gauge.

After the engine is shut off, the coolant continues to draw heat from the metal, but since it is not being circulated back to the radiator, its temperature has to rise.. It shouldn't reach boiling point, but it will rise.

You're dealing with a gauge that's over 50 years old.. It's quite possible it's lost some of its accuracy.. 190 - 200 degrees would put the gauge in the upper range of "normal".. As long as the temperature is within that "normal" range, I don't see a problem..

BTW, the spec'd thermostat is 180*.. A 160* thermostat won't give you much heat from the heater in the winter time.

[kna4977]

Any ideas on slow reverse engagement?

[Dead Parrot]

Keep in mind that the t-stat starts to open at the listed temp. Running temps will be ~5-20 degrees higher. Most SBCs came with a 195 t-stat.
Either get used to gauge quirks or try replacing and get stuck with the 'match the sender to the gauge game.' Lots of threads on that particular game. Changing the t-stat temp on an engine with proper operating temps isn't a good idea.

Might not hurt to clean all of the gauge connections but that requires digging into the gauge cluster. 50+ year old connections can get dirty.

Transmission - Being a bit slow to shift into reverse could be as simple as low fluid level or a filter that needs changing.

[AcampoDave]

Isn't there someplace on the dash to discretely put a modern temp guage? I use this one https://www.autometer.com/2-water-te...B&gclsrc=aw.ds it's got an electric sender so no big hole in the firewall.

[GASoline71]

What condition is your radiator in?

Gary

[kna4977]

Originally Posted by GASoline71

What condition is your radiator in?

Gary

It's a new 4 core. I believe there was just air in the system. Temps seem normal I just don't like where the factory gauge is at. May try a new one.

[AussieinNC]

Originally Posted by kna4977

Any ideas on slow reverse engagement?

TH350 slow into reverse is usually a sign of hardened Low/Reverse clutch seals, especially if the slowness lessens after the trans has warmed up.

The correct way to fix the issue is to pull the trans and rebuild it with new seals and clutches.

I have seen folk change the oil and filter and add a trans seal softener like Lucas etc and it sometimes helps, but the results are usually short lived, especially in cold climates.

[kna4977]

Originally Posted by AussieinNC

TH350 slow into reverse is usually a sign of hardened Low/Reverse clutch seals, especially if the slowness lessens after the trans has warmed up.

The correct way to fix the issue is to pull the trans and rebuild it with new seals and clutches.

I have seen folk change the oil and filter and add a trans seal softener like Lucas etc and it sometimes helps, but the results are usually short lived, especially in cold climates.

Doesn't seem to change cold or warm. I did try some Lucas and it has made a noticeable difference.