The Stovebolt Site Forums The Shop Area Engine Shop 235 thermostat

Did a science experiment this morning... started my 54 3100 with a 57 235 at 9 degrees. Started just fine... hauled a load of wood to the house but the temp never got past 100. Need a thermostat. Should I get a 180 degree standard flow, high flow or a bypass thermostat?
Recommendations?
Jethro.

A conventional 180 will work fine. Its a good idea to drill a tiny hole in it to allow the air out.

George

I recently bought a new thermostat for my '28 Canopy Express (same thermo as in a '53 Chevy) and it already had a small hole off to the side, but also had a tiny, brass valve going through it to prevent flow through the hole when the engine is running.

Dean

Operating the engine at such low temperatures without a thermostat causes much extra cylinder wear, pollutes the oil, and wastes gas.

Don't panic, Panic... It failed, I'm going to replace it. I jsimply asked for a recommendation, not a dissertation on the consequences of too low operating temperatures, of which I am well aware.. Thanks anyway. Jethro.

Nothing in your orignal post suggests that you're aware of the consequences.
I'll be careful not to help in future.

I'm not ungrateful... but I have seen too many posts morph into discussions that don't answer the original posted question. Sorry if I offended you. The 'stat in the truck finally failed after 35 years. At least it didn't stick closed.

I went to NAPA for a 180 thermostat and was given a "SafetyStat." Didn't open the box. Got it home and found it is the type that once heated past a certain temperature will remain open and must be replaced. There is no specification as to what temperature "overheat" is but it seems to me that on my truck pulling a grade in summer when, not if, the temperature goes over 212 the safetystat may fail open. I'm going to return it for a plain one if they have it.

I have a 160 in my 261 powered '51 one-ton. It has not been above freezing for well over a month here. On a recent short trip (15 mi.) with the temperature about 10F, the temperature gauge says about 140 and the heater is anemic even with cardboard covering about 2/3 of the radiator. I hope the new 180 will cure that but it's too cold to change it. Supposed to warm in a few days.

Is your 160 degree t-stat stuck open?

I'm in Florida and I run a 160 degree thermostat. When it's 85 or 90 degrees and I get stopped in traffic idling I like that extra 20 degree cushion. It don't take long for it to climb to 190 if I'm sitting still idling. Otherwise it runs at 160.

When the thermostat opens (160 or 180) has nothing at all to do with causation of overheating.
In cold weather, with a 160 degree thermostat, you will likely suffer from cold feet on a short trip. If it is extremely cold out, your feet will be cold for the entire trip. Condensation in the oil will not be boiled off either. That is bad news.
A 160 degree thermostat opens at 160 degrees. It does not regulate the maximum temperature whatsoever after that point. The radiator/fan/coolant/water pump/waterjacket condition/timing/air-fuel mixture dictates the coolant temperature above the opening temperature of the thermostat.

My point was, in my truck the temp. climbs when idling and sitting still. I would rather have it start climbing at 160 than 180 degrees. I've never driven it in weather under 40 degrees. We just had 6 nights in a row in the mid 20s, that's extremely cold for us!

What is the pressure rating on your radiator cap?

My 216 uses a 4lb cap and I use a coolant reservoir like a modern car. This works perfectly , filling up the reservoir when hot and returning to the cold level after shutdown.

The gauge on the dash stays at 180 at all times. It did creep up to 185 or 190 during the hottest part of the summer.

Absolutely no overheating problems whatsoever.

Mine is 0 pressure, The over flow tube is on the brass piece below the NOS factory cap. Mine is a COE,I don't know if that makes a difference, I check the coolant level in the rad. tank with a paint stir stick since I can't get my head above the fill to see.

A clean radiator the proper size for the engine will keep an engine at or near the opening point of the thermostat. If your engine heats up at idle, you need a cleaner, and/or bigger radiator or more airflow across it. Thy a big rig fan with more blades.
Jerry

Does it have a shroud?
A fan with larger diameter and more blades, turning more slowly (pulley sizes) moves more air with less power than stock.

I'm fine with it. I have a 1962 235 with a 1946 COE radiator that I tipped upside down and shook chunks of rust out of and flushed it out with a garden hose 15 years ago when I put it together. It has never been over 190 in a extended idle or 160 moving down the road.

Every 216 and 235 I have ever run has had a 180 thermostat and the temperature gauge has always been dead on at between the 8 and the 0 of the 180 mark. I always figured that the designers wanted the engine to reach 180 as soon as possible and that the entire cooling system was designed to maintain a temperature of 180, and that the fact that the thermostat opens at 180 and closes when it is below 180 was a coincidence with the fact that the engineered preferred temperature is also 180.

For clarification, are you suggesting that, once a 160 thermostat opens at 160, the coolant won't go above 160?

I think you're right. Mine never gets beyond this point. I thought the gauge might have been faulty but infrared thermometer readings confirm its accuracy.

I'm now on a road trip with the 1-ton and camper. The weather finally warmed up to 20F so I swapped the 160 t'stat for a 180. NAPA didn't have a non-safetystat so that's what I used. When I got to a warmer area along the Columbia R. I pulled the cardboard from in front of the radiator and now the temp sits right on 180. No drifting down toward 140 on the down hills like with the Robert Shaw 160; and the heater works much better. Temp has been in the 30s today and when pulling even a slight grade the temperature gauge headed toward 212 with the cardboard "winterfront" on. Two weeks ago when it was near zero, even turning the heater on pulled the temperature gauge down, hence the cardboard. Climbing "Cabbage Hill" near Pendelton OR, which is miles and miles of 7% grade, gauge never moved from 180. Ambient temperature was mid 30s. Snowed like mad through the Blue Mountains this evening. Supposed to be better tomorrow.

Sounds like everything is working as it should. Do you use a zero pressure radiator cap or a low pressure 4-6lb cap?

Post pics of your rig.

I use a 7lb. cap. The truck no longer has the original heater nor the Harrison ribbon-cellular radiator but a fin & tube core.