Thermostat Temperature

[Alleycat]

The owners manual for my 1976 J20 360 2B recommends a 195 degree thermostat. My old school mechanic buddy said he thought that 195 was pretty hot and that the likely reason for the 195 degree rcommendation back then was to help the engine meet emissions (I removed all the emissions junk from my engine). He recommends going much colder down to 160 - saying that colder is almost always better. I have read that running colder can be harder on internal engine parts but with an engine thats 50 years old gets driven 2000 miles a year max - that's not a concern. Any thoughts?

Also seems like Failsafe brand has some haters. Any other easily attainable brand anyone would recommend?

[Stuka]

160 is fine for a race vehicle or the like that needs all the cooling it can, and gets its oil changed after each race.

However, in something being driven on the street, a 160 stat is asking for trouble. Two things that come immediately to mind is that 160 degrees is not hot enough to evaporate water out of the oil. This will cause condensation to build up and start to turn your oil into milk in areas of the engine that run cooler (Valve covers, intake manifold, etc). I actually learned this the hard way when I was younger thinking it was as your friend said, colder is better. Switching back to a 195 got rid of the moisture issue. These days, a google search will show the same.

Also, current modern oils are formulated to operate best at temps over 195. So you sacrifice lubrication unless you are running an oil formulated for a race application, which gets pricy.

Modern engines that have very tight tolerances, running them too cold can cause excessive wear as the engineers take thermal expansion of engine components into account. Maybe not an issue on an older, higher mileage engine.

If your cooling system is working properly, it should be able to cool with a 195 stat. If you really want it to run cooler, personally I would not go below 180.

[tgreese]

Interesting ... the TSM does not show the 2V available with the 360 in a model 46 (the J20) - only the 4V.

JMO - removing the smog equipment seems wrong headed to me. The air guard system (air pump) can be a headache but the rest of it is at least benign and in some cases beneficial. Not much smog equipment on a '76 J20 by modern standards. Indeed, if you have the factory 2V and disabled/removed the EGR, you're now running too lean. This seems way more likely to be bad for the engine than the factory operating temperature.

Air guard, EGR, fuel return, TAC. No vapor recovery, no cat. Check the TSM, page 4A-43. Minimal stuff - I'd say you're much better off with factory emissions gear and factory operating temperature. Removing all the "junk" won't make much difference and could be harmful in the long run. IMO removing smog stuff is more of a service competence/aesthetic issue for most owners (especially when you have so little "junk"), and removal degrades the engine performance and raises new service issues.

A hotter operating temperature is more efficient, just due to the thermodynamics. Modern multivis detergent oils handle the higher operating temperatures very well, so that's not a concern. You should be changing your oil annually anyway, regardless of mileage. To me, changing to a lower temperature is kinda like, you could, but why bother?

California or elsewhere? It matters to the emissions systems. With a 160 thermostat, you'll have no cabin heat, if you care about that.

[Alleycat]

Thanks for the replies. I'm going 195. Tgreese, the pump was already removed when I bought the truck and the charcoal canister, if even ever there, was gone. The metal lines coming off the manifolds had been cut and cripmed closed so I drilled them out of manifold and tapped and filled them with pipe fittings. To clarify my, engine is a 2 barrel 360. Thanks !

[tgreese]

According to the TSM, a '76 J20 has no vapor recovery from the factory, ie no charcoal canister. Even my '77 49-states 258 J10 has no vapor recovery. Not necessarily present on these over-6000-lbs GVWR vehicles in this era.

Yeah, the air guard system is a real pain on older vehicle like this - they don't survive. No tears shed for its demise. I would leave it off too if I lived in a locale that did not check for smog equipment (some locales do check, even on a '76, and there you'd be required to have it).

No doubt you have what you say you have, a 2V 360. Assuming it's the original motor. The TSM claims they don't exist in a J20. Occasional errors appear in these factory books, but not nearly with the same frequency as in the Haynes or Chiltons parts-store manuals.

TSM.png

[seventynine]

FWIW…I agree with Tim and Stuka. I have a 360 I just pulled out of my rock crawler CJ-7 that is going in my ‘77 Chief. I had a 160 thermostat in it while in the CJ as it spent most of its time going very slow in the summer heat. It made sense to me in that application. But I’m definitely swapping in a 195 for the Chief which will be a driver.

[Srdayflyer]

i had a rough time sorting out high temp issues last summer, what i do know is this, the manual call for an old school testing procedure to trouble shoot a bad stat, however no one does that we just buy a new one again however this always overlooked procedure explains the operating cycle of the cooling system, a 195 stat begins to open at that temp to .003 thousands and is fully open at 218, and water circulates full flow at that temp thru the radiator so air flow thru the radiator has to be high flow, so if you have a lower temp stat the same dynamics apply just at a lower temp, the whole nature of the stat is to restrict flow to allow the coolant and radiator to allow heat transfer at a sustainable rate , high flow less heat transfer, highr temp, restricted flow slower rate higher heat transfer, also rusted and scaled cooling passages also interferes with cooling transfer, hope this helps

[letank]

Always a good idea to test a thermostat, too many poor quality control shortcuts. Do the same when buying alternators or starters at your local parts place.

As for the EGR it is very beneficial as it reduces the combustion temperature.

https://forums.4wdmechanix.com/topic/12 ... peratures/

or the short version

(exhaust gas re-circulation) is a system designed to lower the upper cylinder temperatures in an internal combustion engine. Above 2500 degrees F, the engine's combustion process produces nitrogen oxide (NOx). So, the intent of EGR is to lower combustion temperatures and cool the upper cylinders. In a gasoline engine without EGR, temperatures can soar above 4800 degrees F, enough heat to melt many metals